US20020070172A1 - Contact and adsorbent granules - Google Patents
Contact and adsorbent granules Download PDFInfo
- Publication number
- US20020070172A1 US20020070172A1 US09/962,935 US96293501A US2002070172A1 US 20020070172 A1 US20020070172 A1 US 20020070172A1 US 96293501 A US96293501 A US 96293501A US 2002070172 A1 US2002070172 A1 US 2002070172A1
- Authority
- US
- United States
- Prior art keywords
- water
- paste
- iron
- residue
- particle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000008187 granular material Substances 0.000 title description 46
- 239000003463 adsorbent Substances 0.000 title description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 70
- 238000000034 method Methods 0.000 claims abstract description 50
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 46
- CUPCBVUMRUSXIU-UHFFFAOYSA-N [Fe].OOO Chemical compound [Fe].OOO CUPCBVUMRUSXIU-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000010419 fine particle Substances 0.000 claims abstract description 39
- 230000008569 process Effects 0.000 claims abstract description 36
- 239000002245 particle Substances 0.000 claims abstract description 34
- 235000013980 iron oxide Nutrition 0.000 claims abstract description 31
- 238000001035 drying Methods 0.000 claims abstract description 21
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000001914 filtration Methods 0.000 claims abstract description 15
- 229910021519 iron(III) oxide-hydroxide Inorganic materials 0.000 claims abstract description 14
- 238000005406 washing Methods 0.000 claims abstract description 10
- 239000000470 constituent Substances 0.000 claims abstract description 9
- 239000007900 aqueous suspension Substances 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 37
- 239000000725 suspension Substances 0.000 claims description 33
- 239000012065 filter cake Substances 0.000 claims description 25
- 238000004519 manufacturing process Methods 0.000 claims description 23
- 238000005299 abrasion Methods 0.000 claims description 20
- 239000008188 pellet Substances 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 14
- 239000007788 liquid Substances 0.000 claims description 10
- 238000007493 shaping process Methods 0.000 claims description 10
- 229910001385 heavy metal Inorganic materials 0.000 claims description 8
- 239000001034 iron oxide pigment Substances 0.000 claims description 8
- 150000003839 salts Chemical class 0.000 claims description 6
- 229910052787 antimony Inorganic materials 0.000 claims description 5
- 239000012530 fluid Substances 0.000 claims description 5
- 238000000227 grinding Methods 0.000 claims description 5
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 4
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims description 4
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims description 4
- 229910052698 phosphorus Inorganic materials 0.000 claims description 4
- 239000011574 phosphorus Substances 0.000 claims description 4
- 229910052711 selenium Inorganic materials 0.000 claims description 4
- 239000011669 selenium Substances 0.000 claims description 4
- 229910052714 tellurium Inorganic materials 0.000 claims description 4
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 claims description 4
- 150000001495 arsenic compounds Chemical class 0.000 claims description 2
- 229910052790 beryllium Inorganic materials 0.000 claims description 2
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 claims description 2
- -1 cyano compound Chemical class 0.000 claims description 2
- 238000001704 evaporation Methods 0.000 claims description 2
- 230000008020 evaporation Effects 0.000 claims description 2
- 229940093920 gynecological arsenic compound Drugs 0.000 claims description 2
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 51
- 238000001179 sorption measurement Methods 0.000 description 40
- 239000000243 solution Substances 0.000 description 25
- 229910002588 FeOOH Inorganic materials 0.000 description 23
- 239000000047 product Substances 0.000 description 20
- 239000000049 pigment Substances 0.000 description 17
- 229910006540 α-FeOOH Inorganic materials 0.000 description 17
- HAYXDMNJJFVXCI-UHFFFAOYSA-N arsenic(5+) Chemical compound [As+5] HAYXDMNJJFVXCI-UHFFFAOYSA-N 0.000 description 16
- 235000014413 iron hydroxide Nutrition 0.000 description 16
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 16
- 239000011230 binding agent Substances 0.000 description 14
- 229910052785 arsenic Inorganic materials 0.000 description 13
- 239000000356 contaminant Substances 0.000 description 13
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical class [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 12
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 12
- 238000007254 oxidation reaction Methods 0.000 description 12
- 239000000126 substance Substances 0.000 description 12
- 238000001878 scanning electron micrograph Methods 0.000 description 11
- 239000011734 sodium Substances 0.000 description 11
- 229910003328 NaAsO2 Inorganic materials 0.000 description 10
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 10
- 239000002609 medium Substances 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 10
- PTLRDCMBXHILCL-UHFFFAOYSA-M sodium arsenite Chemical compound [Na+].[O-][As]=O PTLRDCMBXHILCL-UHFFFAOYSA-M 0.000 description 10
- 239000002253 acid Substances 0.000 description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 9
- 239000012071 phase Substances 0.000 description 9
- 238000001556 precipitation Methods 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 239000003651 drinking water Substances 0.000 description 8
- 235000020188 drinking water Nutrition 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 239000002105 nanoparticle Substances 0.000 description 7
- 238000000746 purification Methods 0.000 description 7
- 239000002351 wastewater Substances 0.000 description 7
- 239000007864 aqueous solution Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- 238000007792 addition Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000000706 filtrate Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000003607 modifier Substances 0.000 description 5
- 239000012266 salt solution Substances 0.000 description 5
- 239000002699 waste material Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000004411 aluminium Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 4
- 238000011109 contamination Methods 0.000 description 4
- 238000005469 granulation Methods 0.000 description 4
- 230000003179 granulation Effects 0.000 description 4
- 239000011164 primary particle Substances 0.000 description 4
- 239000002912 waste gas Substances 0.000 description 4
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical class [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 125000004093 cyano group Chemical class *C#N 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 3
- 238000011010 flushing procedure Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- FLTRNWIFKITPIO-UHFFFAOYSA-N iron;trihydrate Chemical compound O.O.O.[Fe] FLTRNWIFKITPIO-UHFFFAOYSA-N 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 150000002736 metal compounds Chemical class 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000012256 powdered iron Substances 0.000 description 3
- 238000012958 reprocessing Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 description 2
- 229910021577 Iron(II) chloride Inorganic materials 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical class [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 238000007605 air drying Methods 0.000 description 2
- YKYOUMDCQGMQQO-UHFFFAOYSA-L cadmium dichloride Chemical compound Cl[Cd]Cl YKYOUMDCQGMQQO-UHFFFAOYSA-L 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 238000004040 coloring Methods 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 238000005202 decontamination Methods 0.000 description 2
- 230000003588 decontaminative effect Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 229910052598 goethite Inorganic materials 0.000 description 2
- 239000003673 groundwater Substances 0.000 description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 2
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 2
- 229910000358 iron sulfate Inorganic materials 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 2
- HWSZZLVAJGOAAY-UHFFFAOYSA-L lead(II) chloride Chemical compound Cl[Pb]Cl HWSZZLVAJGOAAY-UHFFFAOYSA-L 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 230000035800 maturation Effects 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 244000005700 microbiome Species 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 235000021317 phosphate Nutrition 0.000 description 2
- 125000002467 phosphate group Chemical class [H]OP(=O)(O[H])O[*] 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Chemical class 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 208000024827 Alzheimer disease Diseases 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- 241000195493 Cryptophyta Species 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical class [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- FQIOHYRHRMILMJ-UHFFFAOYSA-N [Fe+3].OOO Chemical class [Fe+3].OOO FQIOHYRHRMILMJ-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- GHPGOEFPKIHBNM-UHFFFAOYSA-N antimony(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Sb+3].[Sb+3] GHPGOEFPKIHBNM-UHFFFAOYSA-N 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- LULLIKNODDLMDQ-UHFFFAOYSA-N arsenic(3+) Chemical compound [As+3] LULLIKNODDLMDQ-UHFFFAOYSA-N 0.000 description 1
- 238000001636 atomic emission spectroscopy Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- MMCOUVMKNAHQOY-UHFFFAOYSA-N carbonoperoxoic acid Chemical class OOC(O)=O MMCOUVMKNAHQOY-UHFFFAOYSA-N 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000000701 coagulant Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000004815 dispersion polymer Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002389 environmental scanning electron microscopy Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- MSNWSDPPULHLDL-UHFFFAOYSA-K ferric hydroxide Chemical compound [OH-].[OH-].[OH-].[Fe+3] MSNWSDPPULHLDL-UHFFFAOYSA-K 0.000 description 1
- RAQDACVRFCEPDA-UHFFFAOYSA-L ferrous carbonate Chemical class [Fe+2].[O-]C([O-])=O RAQDACVRFCEPDA-UHFFFAOYSA-L 0.000 description 1
- 230000009969 flowable effect Effects 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 229910052595 hematite Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009616 inductively coupled plasma Methods 0.000 description 1
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 239000001023 inorganic pigment Substances 0.000 description 1
- 235000010213 iron oxides and hydroxides Nutrition 0.000 description 1
- 239000004407 iron oxides and hydroxides Substances 0.000 description 1
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 1
- LDHBWEYLDHLIBQ-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide;hydrate Chemical compound O.[OH-].[O-2].[Fe+3] LDHBWEYLDHLIBQ-UHFFFAOYSA-M 0.000 description 1
- BMWMWYBEJWFCJI-UHFFFAOYSA-K iron(3+);trioxido(oxo)-$l^{5}-arsane Chemical compound [Fe+3].[O-][As]([O-])([O-])=O BMWMWYBEJWFCJI-UHFFFAOYSA-K 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 125000005341 metaphosphate group Chemical group 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000010841 municipal wastewater Substances 0.000 description 1
- 239000008239 natural water Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 235000011837 pasties Nutrition 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 239000012254 powdered material Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000012070 reactive reagent Substances 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 230000002110 toxicologic effect Effects 0.000 description 1
- 231100000027 toxicology Toxicity 0.000 description 1
- 239000001052 yellow pigment Substances 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910003145 α-Fe2O3 Inorganic materials 0.000 description 1
- 229910006297 γ-Fe2O3 Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
- B01J20/0225—Compounds of Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt
- B01J20/0229—Compounds of Fe
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
- B01J20/08—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04 comprising aluminium oxide or hydroxide; comprising bauxite
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
- B01J20/2803—Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
- B01J20/28057—Surface area, e.g. B.E.T specific surface area
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/3028—Granulating, agglomerating or aggregating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/0018—Mixed oxides or hydroxides
- C01G49/0036—Mixed oxides or hydroxides containing one alkaline earth metal, magnesium or lead
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/0018—Mixed oxides or hydroxides
- C01G49/0045—Mixed oxides or hydroxides containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/06—Ferric oxide (Fe2O3)
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/288—Treatment of water, waste water, or sewage by sorption using composite sorbents, e.g. coated, impregnated, multi-layered
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
- B01D2253/10—Inorganic adsorbents
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/50—Agglomerated particles
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/002—Construction details of the apparatus
- C02F2201/006—Cartridges
Definitions
- the present invention relates to particles, pellets or granules of fine-particle or nanoparticle iron oxides and/or iron oxyhydroxides having a large specific surface area (50 to 500 m 2 /g according to BET), and processes for their production.
- These pellets have high mechanical resistance and can be used as a contact, adsorbent, or catalyst for the catalysis of chemical reactions, for the treatment of fluid media like liquids and/or for gas, specifically the removal of impurities.
- Adsorbents/catalysts containing iron oxides and hydroxides can advantageously be used e.g. in the area of water purification or gas purification.
- this agent is used in horizontal- or vertical-flow filters or adsorber columns or added to the water to be treated in order to remove dissolved, suspended or emulsified organic or inorganic phosphorus, arsenic, antimony, sulfur, selenium, tellurium, beryllium, cyano and heavy metal compounds from, for example, drinking water, process water, industrial and municipal waste water, mineral, holy and medicinal water as well as garden pond and agricultural water. It can also be used in so-called reactive walls to separate the cited contaminants from ground water and seepage water aquifers from contaminated sites (waste disposal sites).
- the agent is used in adsorbers for binding undesirable components such as hydrogen sulfide, mercaptans and hydrogen cyanide, as well as other phosphorus, arsenic, antimony, sulfur, selenium, tellurium, cyano and heavy metal compounds in waste gases. Gases such as HF, HCl, H 2 S, SO x , NO x can also be adsorbed.
- DE-A 3 120 891 describes a process in which a filtration is performed using activated alumina with a grain size of 1 to 3 mm for the separation principally of phosphates from surface water.
- DE-A 3 800 873 describes an adsorbent based on porous materials such as e.g. hydrophobed chalk with a fine to medium grain size to remove contaminants from water.
- DE-A 3 703 169 discloses a process for the production of a granulated filter medium to treat natural water.
- the adsorbent is produced by granulating an aqueous suspension of kaolin with addition of powdered dolomite in a fluidised bed. The granules are then baked at 900 to 950° C.
- a process for the production and use of highly reactive reagents for waste gas and waste water purification is known from DE-A 40 34 417. Mixtures consisting of Ca(OH) 2 with additions of clays, stone dust, entrained dust and fly ashes, made porous and having a surface area of approx. 200 m 2 /g, are described here.
- the cited processes have the disadvantage that the component responsible in each case for the selective adsorption of constituents of the media to be cleaned, in other words the actual adsorbent, must be supplemented with large quantities of additives to enable it to be shaped into granules. This significantly reduces the binding capacity for the water contaminants to be removed. Moreover, subsequent reprocessing or reuse of the material is problematic since the binder substances first have to be separated out.
- DE-A 4 214 487 describes a process and a reactor for the removal of impurities from water.
- the medium flows horizontally through a funnel-shaped reactor, in which finely divided iron hydroxide in flocculent form is used as a sorption agent for water impurities.
- the disadvantage of this process lies in the use of the iron hydroxide in flocculent form, which means that because there is little difference in density between water and iron hydroxide, a reactor of this type can be operated at only very low flow rates and there is a risk of the sorption agent, which is possibly already loaded with contaminants, being discharged from the reactor along with the water.
- JP-A 55 132 633 describes granulated red mud, a by-product of aluminium production, as an adsorbent for arsenic. This consists of Fe 2 O 3 , Al 2 O 3 and SiO 2 . No mention is made of the stability of the granules or of the granulation process.
- a further disadvantage of this adsorbent is the lack of consistency in the composition of the product, its unreliable availability and the possible contamination of the drinking water with aluminium. Since aluminium is suspected of encouraging the development of Alzheimer's Disease, contamination with this substance in particular is to be avoided.
- DE-A 19 826 186 describes a process for the production of an adsorbent containing iron hydroxide.
- An aqueous polymer dispersion is incorporated into iron hydroxide in water-dispersible form. This mixture is then either dried until it reaches a solid state and the solid material then comminuted mechanically to the desired shape and/or size or the mixture is shaped, optionally after a preliminary drying stage, and a final drying stage then performed, during which a solid state is achieved.
- a material is obtained in which the iron hydroxide is firmly embedded in the polymer and which is said to display a high binding capacity for the contaminants conventionally contained in waste waters or waste gases.
- the disadvantage of this process lies in the use of organic binders, which further contaminate the water to be treated due to leaching and/or abrasion of organic substances. Furthermore, the stability of the adsorbent composite is not guaranteed in extended use. Bacteria and other microorganisms can also serve as a nutrient medium for an organic binder, presenting a risk that microorganisms may populate the contact and thereby contaminate the medium.
- DE-A 4 320 003 describes a process for the removal of dissolved arsenic from ground water with the aid of colloidal or granulated iron hydroxide. Where fine, suspended iron(III) hydroxide products are used, it is recommended here that the iron hydroxide suspension be placed in fixed-bed filters filled with granular material or other supports having a high external or internal porosity. This process likewise has the disadvantage that, relative to the adsorbent “substrate+iron hydroxide”, only low specific loading capacities are achievable. Furthermore, there is only a weak bond between substrate and iron hydroxide, which means that there is a risk of iron hydroxide or iron arsenate being discharged during subsequent treatment with arsenic-containing water.
- This publication also cites the use of granulated iron hydroxide as an adsorption material for a fixed-bed reactor.
- the granulated iron hydroxide is produced by freeze conditioning (freeze drying) of iron hydroxide obtained by neutralisation of acid iron(III) salt solutions at temperatures of below minus 5° C.
- This production process is extremely energy-intensive and leads to heavily salt-contaminated waste waters.
- this production process only very small granules with low mechanical resistance are obtained.
- this means that the size spectrum is significantly reduced by mechanical abrasion of the particles during operation, which in turn results in finely dispersed particles of contaminated or uncontaminated adsorption agent being discharged from the reactor.
- a further disadvantage of these granules lies in the fact that the adsorption capacity in respect of arsenic compounds is reduced considerably if the granules lose water, by being stored dry for extended periods for example.
- Adsorbent/binder systems obtained by removing a sufficiently large amount of water from a mixture of (a) a crosslinkable binder consisting of colloidal metal or non-metal oxides, (b) oxidic adsorbents such as metal oxides and (c) an acid such that components (a) and (b) crosslink to form an adsorbent/binder system, are known from U.S. Pat. No. 5,948,726. According to the disclosure, colloidal alumina or aluminium oxide is used as binder.
- compositions lie in the need to use acid in their production (column 9, line 4) and in the fact that they are not pure but heterogeneous substances, which is undesirable both for the production, regeneration, removal and permanent disposal of such adsorbents, e.g. on a waste disposal site.
- scope of disclosure of this publication is also intended to include adsorbents that are suitable for the adsorption of arsenic; specific examples are not provided, however. Aluminium oxide is known to be significantly inferior to iron oxides in regard to force of adsorption for arsenic.
- Continuous adsorbers which are commonly grouped together in parallel for operation, are preferably used for water treatment.
- such adsorbers are filled with activated carbon.
- the available adsorbers are then operated in parallel to prevent the flow rate from rising above the upper limit permitted by the particular arrangement.
- individual adsorbers are taken out of operation and can be serviced, for example, whereby the adsorption material is subjected to special loads, as described in greater detail below.
- the use of such materials in adsorbers, for example, particularly continuous models, for water purification is therefore of only limited interest.
- the abraded material renders the waste water from back-flushing extremely turbid. This is unacceptable for a number of reasons: firstly, adsorption material, which is heavily laden with impurities and therefore toxic after extended use, is lost.
- the stream of waste water is laden with abraded material, which can sediment, damaging piping systems and ultimately subjecting the waste treatment plant to undesirable physical and toxicological stresses, to name but a few reasons.
- the abrasion should be below 20% by weight, more preferably below 15% by weight, 10% by weight or most preferably below 5% by weight according to the method described in the examples of the present invention.
- An object of the present invention was therefore to provide a contact or an adsorbent/catalyst based on iron-oxygen compounds in pellet form, exhibiting high mechanical resistance in conjunction with a good binding capacity for contaminants contained in liquids and gases without the need to use organic binders or inorganic foreign binders to achieve adequate mechanical resistance, and plants operated with such media.
- This object is achieved by the contacts or adsorbents/catalysts according to the invention, their preparation, their use and the units filled therewith.
- the invention relates to a unit suitable for the through-flow of a fluid medium at least partially filled with particles agglomerated from fine-particle iron oxide and/or iron oxyhydroxide, wherein the fine-particle iron oxide and/or iron oxyhydroxide displays a particle size of up to 500 nm and a BET surface area of 50 to 500 m 2 /g.
- the invention also relates to a process for the production of particles from fine-particle iron oxide and/or iron oxyhydroxide comprising the steps of producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m 2 /g, and removing the water and dissolved constituents by either I) a) first removing only the water from the suspension, b) introducing the residue thus obtained in water, c) filtering the material obtained, d) washing the residue, and e) either e1) completely dehydrating the filter cake obtained as residue and comminuting the material thus obtained to the desired shape and/or size or e2) partially dehydrating the filtercake to obtain a paste, shaping the paste and subsequently additionally drying the paste until a pellet is obtained, or II) a) filtering the suspension, b) washing the residue, c) either c1) completely dehydrating the filter cake obtained as residue in the form of a solid to semisolid paste and then
- an aqueous suspension of fine-particle iron oxyhydroxides and/or iron oxides is first produced according to the prior art.
- the water and constituents dissolved within it can be removed from this in two different ways:
- the suspension is filtered and the residue washed until it is substantially free from salts.
- the filter cake obtained as residue is a solid to semisolid paste. This can then be completely or partially dehydrated, and the material thus obtained can then be comminuted to the desired shape and/or size.
- the paste or filter cake optionally after predrying to achieve a sufficiently solid state, can undergo shaping followed by (additional) drying until a pellet state is achieved.
- the subsequent application of the granules determines the preferred procedure to be followed for their production, which can be determined by the person skilled in the art in the particular field of application by means of simple preliminary orienting experiments. Both the directly dried filter cake and the dried shaped bodies can then be used as contact or adsorbent.
- the products obtained according to method 1 are less mechanically resistant, filtration can be performed more easily and quickly.
- the fine-particle pigments isolated in this way can moreover be incorporated very easily into paints and polymers, for example, because considerably less shear force is required than is needed to incorporate the fine-particle pigments obtained according to method 2.
- the fine-particle iron oxide and/or iron oxyhydroxide used has a particle size of up to 500 nm, preferably up to 100 nm, particularly preferably 4 to 50 nm, and a BET surface area of 50 to 500 m 2 /g, preferably 80 to 200 m 2 /g.
- the primary particle size was determined by measurement from scanning electron micrographs, e.g. at a magnification of 60000:1 (instrument: XL30 ESEM FEG, Philips). If the primary particles are needle-shaped, as in the ⁇ -FeOOH phase for example, the needle width can be given as a measurement for the particle size. Needle widths of up to 100 nm, but mainly between 4 and 50 nm, are observed in the case of nanoparticle ⁇ -FeOOH particles. ⁇ -FeOOH primary particles conventionally have a length:width ratio of 5:1 to 50:1, typically of 5:1 to 20:1. The length:width ratio of the needle shapes can be varied, however, by doping or by special reaction processes. If the primary particles are isometric, as in the ⁇ -Fe 2 O 3 , ⁇ -Fe 2 O 3 , Fe 3 O 4 phases for example, the particle diameters can quite easily also be below 20 nm.
- Products obtainable by methods 1) and 2) can then be comminuted further, for example by rough grinding or grinding. However, since the products reduce in size on first coming into contact with water, for example when a freshly charged adsorber unit is first filled with water, this will generally be unnecessary.
- Granulation of a semi-wet paste has proven effective as another method of producing granules.
- pellets or strands are formed from a semi-wet paste, e.g. using a simple perforated metal sheet, a roll press or an extruder, and either dried immediately or additionally shaped into a spherical or granular form by means of a spheroniser.
- the still wet spherules or granules can subsequently be dried to any moisture content whatsoever.
- a residual moisture content of ⁇ 50% is recommended to prevent the granules from agglomerating.
- a spherical shape of this type can be advantageous for use in fixed-bed adsorbers due to the improved packing in the adsorber vessel that is obtained in comparison with rough-ground granules or pellets in strand form.
- the filtration performance of the suspensions can generally be improved by the use of conventional filtration-improving measures, such as are described for example in Solid-Liquid Filtration and Separation Technology, A. Rushton, A. S. Ward, R. G. Holdich, 2nd edition 2000, Wiley-VCH, Weinheim, and in Handbuch der Industriellen Fest/Flüssig-Filtration, H. Gasper, D. ⁇ chsle, E. Pongratz, 2nd edition 2000, Wiley-VCH Weinheim. Coagulants can thus be added to the suspensions, for example.
- Iron carbonates can also be used in addition to or in place of the iron oxyhydroxides.
- the products according to the invention can undergo drying in air, and/or in vacuo, and/or in a drying oven and/or on belt dryers or by spray drying, preferably at temperatures from ⁇ 25 to 250° C., particularly preferably at 60 to 120° C.
- the products according to the invention preferably have a residual water content of less than 20 wt. %.
- pellets or granules obtained in this way have a high binding capacity for contaminants contained in water, liquids or gases and they additionally have an adequately high resistance to flowing media in terms of mechanical or hydraulic stressing.
- Transparent iron oxyhydroxide pigments for example, having an average particle size of less than 0.1 ⁇ m and specific surface areas of greater than 80 m 2 , are suitable for the use according to the invention of fine-particle iron oxyhydroxides.
- fine-particle iron oxide pigments preferably haematite, magnetite or maghemite, can also be used, however.
- the production of yellow fine-particle iron oxyhydroxide pigments (e.g. goethite) in the acid or alkaline pH range, known as acid or alkaline nuclei, is known.
- the production of other fine-particle iron oxide or iron oxyhydroxide pigments is also known.
- Such pigments can contain structures based on ⁇ , ⁇ , ⁇ , ⁇ , ⁇ ′, ⁇ phases and/or Fe(OH) 2 and mixed and intermediate phases thereof.
- Fine-particle yellow iron oxyhydroxides can be calcined to fine-particle red iron oxides.
- Fine-particle yellow iron oxyhydroxide pigments are generally synthesized by precipitating iron(II) hydroxides or carbonates from corresponding iron(II) salt solutions such as e.g. FeSO 4 , FeCl 2 in pure form or as pickling solutions in the acid or alkaline pH range, followed by oxidation to iron(III) oxyhydroxides (see inter alia G. Buxbaum, Industrial Inorganic Pigments, VCH Weinheim, 2nd edition, 1998, p. 231ff). Oxidation of the divalent to the trivalent iron is preferably performed with air, whereby intensive aeration is advantageous. Oxidation with H 2 O 2 also leads to fine-particle iron oxyhydroxides.
- iron(II) salt solutions such as e.g. FeSO 4 , FeCl 2 in pure form or as pickling solutions in the acid or alkaline pH range
- Oxidation of the divalent to the trivalent iron is preferably performed with air, whereby intensive aeration
- the temperature chosen for precipitation and oxidation should be as low as possible in order to obtain very fine-particle yellow pigments. It is preferably between 15° C. and 45° C.
- NaOH is preferably used as alkaline precipitant.
- Other precipitants such as KOH, Na 2 CO 3 , K 2 CO 3 , CaO, Ca(OH) 2 , CaCO 3 , NH 3 , NH 4 OH, MgO and/or MgCO 3 , can also be used, however.
- nanoparticle ⁇ , ⁇ , ⁇ , ⁇ phases and mixed phases of iron oxyhydroxides displaying a large specific surface area can be prepared, such that the nanoparticles agglomerate in the dry state and possess a high resistance to mechanical and fluid-mechanical abrasion in comminuted form.
- the precipitations e.g. of yellow ⁇ -FeOOH as described in patents U.S. Pat. No. 2,558,303 and U.S. Pat. No. 2,558,304, are performed in the alkaline pH range with alkali carbonates as precipitants, and modifiers such as SiO 2 , zinc, aluminium or magnesium salts, hydroxycarbonic acids, phosphates and metaphosphates are generally added. Products produced in this way are described in U.S. Pat. No. 2,558,302. Such nucleus modifiers do not interfere with the subsequent reprocessing, recycling or any other use of the adsorbents according to the invention. In the case of precipitation processes in an aqueous medium, it is known that precipitations in an alkaline environment lead to less solidly agglomerated powders than those in an acid environment.
- nucleus modifiers One of the advantages of nucleus modifiers, however, is that an adequate fine-particle character can be obtained even at elevated reaction temperatures.
- DE-A 4 235 945 reports on the production of fine-particle iron oxides using a precipitation method in the acid pH range and without modifiers.
- DE-A 4 434 669 describes a process by which highly transparent yellow, chemically pure iron oxide pigments can be produced by secondary treatment thereof with sodium hydroxide solution.
- DE-A 4 434 972 reports on highly transparent, yellow iron oxide pigments in the ⁇ -FeOOH modification having a specific surface area of over 100 m 2 /g and high temperature resistance.
- DE-A 4 434 973 describes highly transparent yellow iron oxide pigments, which are produced by means of the process steps of nuclear precipitation in the acid pH range, nuclear oxidation, nuclear maturation and pigment formulation.
- Red, transparent iron oxide pigments obtained by calcining from yellow, transparent iron oxide pigments are known from DE-A 4 434 668 and DE-A 4 235 946.
- Drying is conveniently performed at temperatures of up to 250° C.
- the material can also be vacuum or freeze dried.
- the particle size of the material can be freely selected but is preferably between 0.2 and 40 mm, particularly preferably between 0.2 and 20 mm. This can be achieved by shaping the semisolid, pasty filter cake mechanically, before drying, in a granulation or pelletising plant or in an extruder to form shaped bodies whose size is in the range between 0.2 and 20 mm, with subsequent drying in the air, on a belt dryer or in a drying oven, and/or by mechanical comminution to the desired particle size after drying.
- the products described, the process for their production and their use represent an improvement over the prior art.
- the granules according to the invention based on fine-particle iron oxyhydroxides and/or oxides can be subjected to much higher stresses and therefore display a much greater abrasion resistance to mechanical and hydraulic stressing. They can be used directly as such.
- adsorber plants for water purification for example, there is no need even for comminution or rough grinding of the crude dry substance initially obtained from filter cakes or extruders, since the coarse pellets break down independently on contact with water. This results in a random particle-size distribution, but no particles of such a size that they are discharged from the adsorber to any significant extent by the flowing medium.
- the suspensions of fine-particle iron oxyhydroxides or iron oxides can also be supplemented with conventional powdered iron oxyhydroxides or iron oxides.
- the quantities in each case are determined by the properties of these powdered iron oxyhydroxides or iron oxides and by the requirements of the product according to the invention in terms of its mechanical stability and abrasion resistance.
- powdered pigments will generally reduce the mechanical strength of the products according to the invention, filtration of the fine-particle suspensions is made easier.
- the person skilled in the art and practising in the particular field of application will be able to determine the optimum mixing ratio for the intended application by means of a few orienting experiments.
- nanoparticle nuclei are conveniently produced in an excess of sodium hydroxide solution.
- a quantity of Fe 2 (SO 4 ) 3 corresponding to the NaOH excess can also be added to the suspensions of the alkaline fine-particle nuclei. This measure considerably improves the filterability of the suspension.
- the initially amorphous Fe(OH) 3 produced matures over time, to the ⁇ -FeOOH phase, for example. This ensures that the sodium hydroxide solution used in excess to produce the alkaline nucleus is completely used up.
- the material thus obtained also displays large specific surface areas. Just like the iron oxyhydroxides described above, the material is extremely suitable for use in adsorbers since it possesses a high resistance to mechanical loading in addition to a high adsorption capacity.
- the granules according to the invention are particularly preferably used in the cleaning of liquids, especially for the removal of heavy metals.
- a preferred application in this industrial field is the decontamination of water, particularly of drinking water. Particular attention has recently been paid to the removal of arsenic from drinking water.
- the granules according to the invention are extremely suitable for this purpose, since levels that not only meet but actually fall below even the lowest limiting values set by the US authority the EPA can be achieved using the granules according to the invention.
- the granules can be used in conventional adsorber units, such as are already used with a charge of activated carbon, for example, to remove other types of contaminants.
- Batchwise operation in cisterns or similar containers for example, optionally fitted with agitators, is also possible.
- use in continuous plants such as continuous-flow adsorbers is preferred.
- adsorbents Since untreated water to be processed into drinking water conventionally also contains organic impurities such as algae and similar organisms, the surface of adsorbents, especially the outer surface of granular adsorbents, becomes coated during use with mostly slimy deposits, which impede or even prevent the inflow of water and hence the adsorption of constituents to be removed. For this reason adsorber units are periodically back-flushed with water, a process which is preferably performed at times of low water consumption (see above) on individual units that have been taken out of service. The adsorbent is whirled up and the associated mechanical stress to which the surface is subjected causes the undesirable coating to be removed and discharged against the direction of flow during active operation.
- the wash water is conventionally sent to a sewage treatment plant.
- the adsorbents according to the invention have proven to be particularly effective in this process, since their high strength enables them to be cleaned quickly without suffering any significant losses of adsorption material and without the back-flush water sent for waste treatment being rich in discharged adsorption material, which is possibly already highly contaminated with heavy metals.
- the material is comparatively easy to dispose of after use.
- the adsorbed arsenic can be removed by thermal or chemical means in special units, for example, resulting in an iron oxide pigment as a pure substance which can either be recycled for use in the same application or supplied for conventional pigment applications.
- the content of the adsorber can also be used without prior removal of the heavy metals, for example as a pigment for colouring durable construction materials such as concrete, since the heavy metals removed from the drinking water are permanently immobilised in this way and taken out of the hydrological cycle.
- the invention therefore also provides water treatment plants or waterworks in which units filled with the granules according to the invention are operated, and processes for the decontamination of water by means of such units, as well as such units themselves.
- the sample is baked for 1 h at 140° C. in a stream of dry nitrogen before measurement.
- the As, Sb, Cd, Cr, Hg or Pb contents of the contaminated iron oxyhydroxide or of the solutions are determined using mass spectrometry (ICP-MS) according to DIN 38406-29 (1999) or by optical emission spectroscopy (ICP-OES) according to EN-ISO 11885 (1998), with inductively coupled plasma as excitation agent in each case.
- ICP-MS mass spectrometry
- ICP-OES optical emission spectroscopy
- the mechanical and hydraulic abrasion resistance was assessed using the following method: 150 ml of demineralised water were added to 10 g of the granules to be tested, having particle sizes >0.1 mm, in a 500 ml Erlenmeyer flask, which was rotated on a LabShaker shaking machine (Kühner model from Braun) for a period of 30 minutes at 250 rpm. The >0.1 mm fraction was then isolated from the suspension using a screen, dried and weighed. The weight ratio between the amount weighed out and the amount weighed in determines the abrasion value in %.
- the yellow suspension thus obtained was filtered out through a filter press and the solid washed until the residual filtrate conductivity was 1 mS/cm.
- the filter cake was in the form of a spreadable and kneadable paste, which was dried on metal sheets in a circulating air drying oven at 75° C. until the residual moisture content was 3 wt. %.
- the dried material was then roughly ground to produce particle sizes of between 0.5 and 2 mm.
- the hard pellets thus obtained were then placed directly in an adsorber tank.
- the product consisted of 100% ⁇ -FeOOH with an extremely short-needled habit, whereby the needles were congregated to form solid macroscopic agglomerates.
- the needle widths were measured at between 15 and 35 nm, the needle lengths between 150 and 350 nm.
- the needles were extremely agglomerated.
- the BET specific surface area was 122 m 2 /g.
- the adsorption rate for NaAsO 2 with an original concentration of 2.3 mg (As 3+ )/l was 2.14 mg(As 3+ )/g(FeOOH).h
- Na 2 HAsO 4 with an original concentration of 2.7 mg (As 5+ )/l it was 2.29 mg(As 5+ )/g(FeOOH).h.
- the dark brown suspension was filtered out through a filter press and the solid washed until the residual filtrate conductivity was 1 mS/cm.
- the filter cake was dried at 70° C. in a circulating air drying oven to a residual moisture of 5%, and the very hard blackish brown dry product was roughly ground in a roller crusher to particle sizes of up to 2 mm. The fine fraction ⁇ 0.2 mm was separated out using a screen.
- An X-ray diffractogram showed that the product consisted of 100% ⁇ -FeOOH.
- the needle widths were measured at between 15 and 20 nm, the needle lengths between 50 and 80 nm.
- the particles were extremely agglomerated.
- the BET specific surface area was 202 m 2 /g.
- the granules thus obtained were placed directly in an adsorber tank with no further treatment.
- the granules displayed an excellent adsorption performance in respect of the contaminants contained in the flowing water and demonstrated a high abrasion resistance, particularly when the adsorber tank is being back-flushed causing the granules to be whirled up strongly.
- the abrasion value after 30 minutes was only 1%.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.4 mg (As 3+ )/l was 1.0 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.8 mg (As 5+ )/l it was 2.07 mg(As 3+ )/g(FeOOH).h.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.3 mg/l was 1.1 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.8 mg/l it was 1.7 mg(As 3+ )/g(FeOOH).h.
- An X-ray diffractogram showed that the product consisted of 100% ⁇ -FeOOH.
- the needle widths were measured at between 15 and 50 nm, the needle lengths between 100 and 200 nm.
- the needles were extremely agglomerated.
- the BET specific surface area was 132 m 2 l/g.
- the granules thus obtained were placed in an adsorber tank with no further treatment.
- the granules displayed an excellent adsorption performance in respect of the contaminants contained in the water and demonstrated a high abrasion resistance, particularly when the adsorber tank is being back-flushed causing the granules to be whirled up strongly.
- the abrasion value after 30 minutes was only 12 wt. %.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.4 mg (As 3+ )/l was 2.11 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.7 mg (As 5+ )/l it was 2.03 mg(As 5+ )/g(FeOOH).h.
- An X-ray diffractogram showed that the product consisted of 100% ⁇ -FeOOH.
- the needle widths were measured at between 15 and 35 nm, the needle lengths between 70 and 180 nm.
- the needles were extremely agglomerated.
- the BET specific surface area was 131 m 2 /g.
- the abrasion value after 30 minutes was only 7 wt. %.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.3 mg (As 3+ )/l was 1.7 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.7 mg (As 5+ )/l it was 1.2 mg(As 5+ )/g(FeOOH).h.
- the strands were dried on a belt dryer to a residual moisture of approx. 3%.
- An X-ray diffractogram showed that the product consisted of 100% ⁇ -FeOOH with very short needles.
- the needle widths were measured at between 30 and 50 nm.
- the needle lengths could not be clearly determined as the needles were too greatly agglomerated.
- the BET specific surface area was 145 m 2 /g.
- the abrasion value after 30 minutes was only 6%.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.5 mg (As 3+ )/l was 1.8 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.9 mg (As 5+ )/l it was 1.5 mg(As 5+ )/g(FeOOH).h.
- the material thus obtained had a BET specific surface area of 153 m 2 /g and consisted of 100% ⁇ -FeOOH.
- the needle widths were measured at between 15 and 35 nm, the needle lengths between 50 and 100 nm.
- the needles were extremely agglomerated.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.7 mg (As 3+ )/l was 1.7 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.8 mg (As 5+ )/l it was 1.4 mg(As 5+ )/g(FeOOH).h.
- the suspension was filtered on a filter press and washed until the residual filtrate conductivity was ⁇ 1000 ⁇ S/cm, the paste was pushed through a perforated metal plate and were dried on a belt dryer to a residual moisture of less than 20%.
- the dry pellets were roughly ground to obtain a particle size of less than 2 mm. The portion of the particles with less then 0.5 mm was removed.
- the material thus obtained had a BET specific surface area of 145 m 2 /g and consisted of 100% ⁇ -FeOOH.
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.7 mg (As 3+ )/l was 2.0 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.7 mg (As 5+ )/l it was 1.9 mg(As 5+ )/g(FeOOH).h, for KSb(OH) 6 (original concentration 3.0 mg (Sb 5+ )/l) the adsorption was 2.5 mg (Sb 5+ )/g (FeOOH).h, for Na 2 CrO 4 (original concentration 47 ⁇ g (Cr 6+ )/l) 42 ⁇ g (Cr 6+ )/g(FeOOH).h were adsorbed, for PbCl 2 (original concentration 0.94 mg (Pb 2+ )/l) 0.46 mg (Pb 2+ )/g
- Adsorption performance The adsorption rate for NaAsO 2 with an original concentration of 2.7 mg (As 3+ )/l was 1.1 mg(As 3+ )/g(FeOOH).h, for Na 2 HAsO 4 with an original concentration of 2.7 mg (As 5+ )/l it was 1.0 mg(As 5+ )/g(FeOOH).h.
Abstract
The present invention relates to a filtering unit at least partially filled with particles agglomerated from fine-particle iron oxide and/or iron oxyhydroxide by producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m2/g, and removing the water and dissolved constituents by a set of washing drying and filtering steps and processes of using the particles.
Description
- The present invention relates to particles, pellets or granules of fine-particle or nanoparticle iron oxides and/or iron oxyhydroxides having a large specific surface area (50 to 500 m2/g according to BET), and processes for their production. These pellets have high mechanical resistance and can be used as a contact, adsorbent, or catalyst for the catalysis of chemical reactions, for the treatment of fluid media like liquids and/or for gas, specifically the removal of impurities.
- Contact and adsorbent granules, including those based on iron oxides and/or iron oxyhydroxides, have already been described. They are predominantly used in continuous processes. They are conventionally found in tower or column-type units through which the medium to be treated flows, and the chemical or physical reaction or adsorption processes take place at the outer and inner surface of the granules. Powdered materials cannot be used for this purpose because they compact in the direction of flow of the medium, thereby increasing the flow resistance until the unit becomes blocked. If a unit is cleaned by back-flushing (see below), large amounts of the powder are discharged and lost or cause an unacceptable contamination of the waste water.
- The flowing media also exert forces on the granules, however, which can lead to abrasion and/or movement through to violent agitation of the granules. Consequently the granules collide, leading to undesirable abrasion. This results in loss of contact or adsorbent material and contamination of the medium to be treated.
- Adsorbents/catalysts containing iron oxides and hydroxides can advantageously be used e.g. in the area of water purification or gas purification. In water purification this agent is used in horizontal- or vertical-flow filters or adsorber columns or added to the water to be treated in order to remove dissolved, suspended or emulsified organic or inorganic phosphorus, arsenic, antimony, sulfur, selenium, tellurium, beryllium, cyano and heavy metal compounds from, for example, drinking water, process water, industrial and municipal waste water, mineral, holy and medicinal water as well as garden pond and agricultural water. It can also be used in so-called reactive walls to separate the cited contaminants from ground water and seepage water aquifers from contaminated sites (waste disposal sites).
- In gas purification the agent is used in adsorbers for binding undesirable components such as hydrogen sulfide, mercaptans and hydrogen cyanide, as well as other phosphorus, arsenic, antimony, sulfur, selenium, tellurium, cyano and heavy metal compounds in waste gases. Gases such as HF, HCl, H2S, SOx, NOx can also be adsorbed.
- The removal of phosphorus, arsenic, antimony, selenium, tellurium, cyano and heavy metal compounds from waste oils and other contaminated organic solvents is also possible.
- Contact and adsorbent granules based on iron oxides and/or iron oxyhydroxides are also used for the catalysis of chemical reactions in the gas phase or in the liquid phase.
- Various methods of removing trace constituents and contaminants from aqueous systems with the aid of adsorbents are also known.
- For example, DE-A 3 120 891 describes a process in which a filtration is performed using activated alumina with a grain size of 1 to 3 mm for the separation principally of phosphates from surface water.
- DE-A 3 800 873 describes an adsorbent based on porous materials such as e.g. hydrophobed chalk with a fine to medium grain size to remove contaminants from water.
- DE-A 3 703 169 discloses a process for the production of a granulated filter medium to treat natural water. The adsorbent is produced by granulating an aqueous suspension of kaolin with addition of powdered dolomite in a fluidised bed. The granules are then baked at 900 to 950° C.
- A process for the production and use of highly reactive reagents for waste gas and waste water purification is known from DE-A 40 34 417. Mixtures consisting of Ca(OH)2 with additions of clays, stone dust, entrained dust and fly ashes, made porous and having a surface area of approx. 200 m2/g, are described here.
- The cited processes have the disadvantage that the component responsible in each case for the selective adsorption of constituents of the media to be cleaned, in other words the actual adsorbent, must be supplemented with large quantities of additives to enable it to be shaped into granules. This significantly reduces the binding capacity for the water contaminants to be removed. Moreover, subsequent reprocessing or reuse of the material is problematic since the binder substances first have to be separated out.
- DE-A 4 214 487 describes a process and a reactor for the removal of impurities from water. The medium flows horizontally through a funnel-shaped reactor, in which finely divided iron hydroxide in flocculent form is used as a sorption agent for water impurities. The disadvantage of this process lies in the use of the iron hydroxide in flocculent form, which means that because there is little difference in density between water and iron hydroxide, a reactor of this type can be operated at only very low flow rates and there is a risk of the sorption agent, which is possibly already loaded with contaminants, being discharged from the reactor along with the water.
- JP-A 55 132 633 describes granulated red mud, a by-product of aluminium production, as an adsorbent for arsenic. This consists of Fe2O3, Al2O3 and SiO2. No mention is made of the stability of the granules or of the granulation process. A further disadvantage of this adsorbent is the lack of consistency in the composition of the product, its unreliable availability and the possible contamination of the drinking water with aluminium. Since aluminium is suspected of encouraging the development of Alzheimer's Disease, contamination with this substance in particular is to be avoided.
- DE-A 19 826 186 describes a process for the production of an adsorbent containing iron hydroxide. An aqueous polymer dispersion is incorporated into iron hydroxide in water-dispersible form. This mixture is then either dried until it reaches a solid state and the solid material then comminuted mechanically to the desired shape and/or size or the mixture is shaped, optionally after a preliminary drying stage, and a final drying stage then performed, during which a solid state is achieved. In this way a material is obtained in which the iron hydroxide is firmly embedded in the polymer and which is said to display a high binding capacity for the contaminants conventionally contained in waste waters or waste gases.
- The disadvantage of this process lies in the use of organic binders, which further contaminate the water to be treated due to leaching and/or abrasion of organic substances. Furthermore, the stability of the adsorbent composite is not guaranteed in extended use. Bacteria and other microorganisms can also serve as a nutrient medium for an organic binder, presenting a risk that microorganisms may populate the contact and thereby contaminate the medium.
- The presence of foreign auxiliary substances, which are required for the manufacture of the adsorbents, during reprocessing, recycling or reuse of used adsorbents is disadvantageous in principle because the reuse of pure substances is less problematic than is the case with mixed substances. For example, polymeric binders are disadvantageous when iron oxide-based adsorption materials are reused as pigments for concrete coloration because these binders inhibit dispersion of the pigment in liquid concrete.
- DE-A 4 320 003 describes a process for the removal of dissolved arsenic from ground water with the aid of colloidal or granulated iron hydroxide. Where fine, suspended iron(III) hydroxide products are used, it is recommended here that the iron hydroxide suspension be placed in fixed-bed filters filled with granular material or other supports having a high external or internal porosity. This process likewise has the disadvantage that, relative to the adsorbent “substrate+iron hydroxide”, only low specific loading capacities are achievable. Furthermore, there is only a weak bond between substrate and iron hydroxide, which means that there is a risk of iron hydroxide or iron arsenate being discharged during subsequent treatment with arsenic-containing water. This publication also cites the use of granulated iron hydroxide as an adsorption material for a fixed-bed reactor. The granulated iron hydroxide is produced by freeze conditioning (freeze drying) of iron hydroxide obtained by neutralisation of acid iron(III) salt solutions at temperatures of below minus 5° C. This production process is extremely energy-intensive and leads to heavily salt-contaminated waste waters. Moreover, as a result of this production process only very small granules with low mechanical resistance are obtained. When used in a fixed-bed reactor, this means that the size spectrum is significantly reduced by mechanical abrasion of the particles during operation, which in turn results in finely dispersed particles of contaminated or uncontaminated adsorption agent being discharged from the reactor. A further disadvantage of these granules lies in the fact that the adsorption capacity in respect of arsenic compounds is reduced considerably if the granules lose water, by being stored dry for extended periods for example.
- Adsorbent/binder systems obtained by removing a sufficiently large amount of water from a mixture of (a) a crosslinkable binder consisting of colloidal metal or non-metal oxides, (b) oxidic adsorbents such as metal oxides and (c) an acid such that components (a) and (b) crosslink to form an adsorbent/binder system, are known from U.S. Pat. No. 5,948,726. According to the disclosure, colloidal alumina or aluminium oxide is used as binder.
- The disadvantage of these compositions lies in the need to use acid in their production (column 9, line 4) and in the fact that they are not pure but heterogeneous substances, which is undesirable both for the production, regeneration, removal and permanent disposal of such adsorbents, e.g. on a waste disposal site. The scope of disclosure of this publication is also intended to include adsorbents that are suitable for the adsorption of arsenic; specific examples are not provided, however. Aluminium oxide is known to be significantly inferior to iron oxides in regard to force of adsorption for arsenic.
- Continuous adsorbers, which are commonly grouped together in parallel for operation, are preferably used for water treatment. To free drinking water from organic impurities, for example, such adsorbers are filled with activated carbon. At peak consumption times, the available adsorbers are then operated in parallel to prevent the flow rate from rising above the upper limit permitted by the particular arrangement. At times of lower water consumption, individual adsorbers are taken out of operation and can be serviced, for example, whereby the adsorption material is subjected to special loads, as described in greater detail below.
- The use of granules, which can be produced by compacting e.g. powdered iron oxide using high linear forces, has also already been considered. Such granules have already been described as a means of homogeneously colouring liquid concrete. The use of high linear forces for compacting is extremely expensive and energy-intensive, and the stability of the compacted materials is inadequate for extended use in adsorbers.
- The use of such materials in adsorbers, for example, particularly continuous models, for water purification is therefore of only limited interest. During maintenance or cleaning of adsorber plants by back-flushing in particular (see below), such granules lose large amounts of substance due to the associated agitation. The abraded material renders the waste water from back-flushing extremely turbid. This is unacceptable for a number of reasons: firstly, adsorption material, which is heavily laden with impurities and therefore toxic after extended use, is lost. Secondly, the stream of waste water is laden with abraded material, which can sediment, damaging piping systems and ultimately subjecting the waste treatment plant to undesirable physical and toxicological stresses, to name but a few reasons. Preferably the abrasion should be below 20% by weight, more preferably below 15% by weight, 10% by weight or most preferably below 5% by weight according to the method described in the examples of the present invention.
- An object of the present invention was therefore to provide a contact or an adsorbent/catalyst based on iron-oxygen compounds in pellet form, exhibiting high mechanical resistance in conjunction with a good binding capacity for contaminants contained in liquids and gases without the need to use organic binders or inorganic foreign binders to achieve adequate mechanical resistance, and plants operated with such media. This object is achieved by the contacts or adsorbents/catalysts according to the invention, their preparation, their use and the units filled therewith.
- The invention relates to a unit suitable for the through-flow of a fluid medium at least partially filled with particles agglomerated from fine-particle iron oxide and/or iron oxyhydroxide, wherein the fine-particle iron oxide and/or iron oxyhydroxide displays a particle size of up to 500 nm and a BET surface area of 50 to 500 m2/g.
- The invention also relates to a process for the production of particles from fine-particle iron oxide and/or iron oxyhydroxide comprising the steps of producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m2/g, and removing the water and dissolved constituents by either I) a) first removing only the water from the suspension, b) introducing the residue thus obtained in water, c) filtering the material obtained, d) washing the residue, and e) either e1) completely dehydrating the filter cake obtained as residue and comminuting the material thus obtained to the desired shape and/or size or e2) partially dehydrating the filtercake to obtain a paste, shaping the paste and subsequently additionally drying the paste until a pellet is obtained, or II) a) filtering the suspension, b) washing the residue, c) either c1) completely dehydrating the filter cake obtained as residue in the form of a solid to semisolid paste and then comminuting the material thus obtained to the desired shape and/or size or c2) partially dehydrating the filtercake to obtain a paste, shaping the paste, and subsequently additionally drying the paste until a pellet is obtained.
- To prepare the granules according to the invention, an aqueous suspension of fine-particle iron oxyhydroxides and/or iron oxides is first produced according to the prior art. The water and constituents dissolved within it can be removed from this in two different ways:
- Method 1:
- For applications in which lower demands are made of the mechanical strength of the granules/contacts, only the water is removed initially, e.g. by evaporation. A residue is obtained which in addition to the fine-particle iron oxide and/or hydroxide also contains the entire salt content. This residue is redispersed in water after being dried, for which purpose only relatively little shear force needs to be applied. This suspension is then filtered and the residue washed until it is substantially free from salts. The filter cake obtained as residue is a solid to semisolid paste which generally has a water content of between 10 and 90 wt. %.
- This can then be completely or partially dehydrated, and the material thus obtained can then be comminuted to the desired shape and/or size. Alternatively the paste or filter cake, optionally after predrying to achieve a sufficiently solid state, can undergo shaping followed by (additional) drying until a pellet state is achieved. The subsequent application of the granules determines the preferred procedure to be followed for their production, which can be determined by the person skilled in the art in the particular field of application by means of simple preliminary orienting experiments. Both the directly dried filter cake and the dried shaped bodies can then be used as contact or adsorbent.
- Method 2:
- For applications in which higher demands are made of the mechanical strength of the granules/contacts, the suspension is filtered and the residue washed until it is substantially free from salts. The filter cake obtained as residue is a solid to semisolid paste. This can then be completely or partially dehydrated, and the material thus obtained can then be comminuted to the desired shape and/or size. Alternatively the paste or filter cake, optionally after predrying to achieve a sufficiently solid state, can undergo shaping followed by (additional) drying until a pellet state is achieved. The subsequent application of the granules determines the preferred procedure to be followed for their production, which can be determined by the person skilled in the art in the particular field of application by means of simple preliminary orienting experiments. Both the directly dried filter cake and the dried shaped bodies can then be used as contact or adsorbent.
- Although the products obtained according to method 1 are less mechanically resistant, filtration can be performed more easily and quickly. The fine-particle pigments isolated in this way can moreover be incorporated very easily into paints and polymers, for example, because considerably less shear force is required than is needed to incorporate the fine-particle pigments obtained according to method 2.
- The fine-particle iron oxide and/or iron oxyhydroxide used has a particle size of up to 500 nm, preferably up to 100 nm, particularly preferably 4 to 50 nm, and a BET surface area of 50 to 500 m2/g, preferably 80 to 200 m2/g.
- The primary particle size was determined by measurement from scanning electron micrographs, e.g. at a magnification of 60000:1 (instrument: XL30 ESEM FEG, Philips). If the primary particles are needle-shaped, as in the α-FeOOH phase for example, the needle width can be given as a measurement for the particle size. Needle widths of up to 100 nm, but mainly between 4 and 50 nm, are observed in the case of nanoparticle α-FeOOH particles. α-FeOOH primary particles conventionally have a length:width ratio of 5:1 to 50:1, typically of 5:1 to 20:1. The length:width ratio of the needle shapes can be varied, however, by doping or by special reaction processes. If the primary particles are isometric, as in the α-Fe2O3, γ-Fe2O3, Fe3O4 phases for example, the particle diameters can quite easily also be below 20 nm.
- By mixing nanoparticle iron oxides or iron (oxy)hydroxides with pigments and/or Fe(OH)3, the presence of the cited pigment or nucleus particles in their known particle morphology, held or glued together by the nanoparticle nucleus particles or the amorphous Fe(OH)3 polymer, can be detected on the scanning electron micrographs.
- Products obtainable by methods 1) and 2) can then be comminuted further, for example by rough grinding or grinding. However, since the products reduce in size on first coming into contact with water, for example when a freshly charged adsorber unit is first filled with water, this will generally be unnecessary.
- Granulation of a semi-wet paste has proven effective as another method of producing granules. Here pellets or strands are formed from a semi-wet paste, e.g. using a simple perforated metal sheet, a roll press or an extruder, and either dried immediately or additionally shaped into a spherical or granular form by means of a spheroniser. The still wet spherules or granules can subsequently be dried to any moisture content whatsoever. A residual moisture content of <50% is recommended to prevent the granules from agglomerating. A spherical shape of this type can be advantageous for use in fixed-bed adsorbers due to the improved packing in the adsorber vessel that is obtained in comparison with rough-ground granules or pellets in strand form.
- The filtration performance of the suspensions can generally be improved by the use of conventional filtration-improving measures, such as are described for example in Solid-Liquid Filtration and Separation Technology, A. Rushton, A. S. Ward, R. G. Holdich, 2nd edition 2000, Wiley-VCH, Weinheim, and in Handbuch der Industriellen Fest/Flüssig-Filtration, H. Gasper, D. Öchsle, E. Pongratz, 2nd edition 2000, Wiley-VCH Weinheim. Coagulants can thus be added to the suspensions, for example.
- Iron carbonates can also be used in addition to or in place of the iron oxyhydroxides.
- The products according to the invention can undergo drying in air, and/or in vacuo, and/or in a drying oven and/or on belt dryers or by spray drying, preferably at temperatures from −25 to 250° C., particularly preferably at 60 to 120° C.
- The products according to the invention preferably have a residual water content of less than 20 wt. %.
- It was found that the pellets or granules obtained in this way have a high binding capacity for contaminants contained in water, liquids or gases and they additionally have an adequately high resistance to flowing media in terms of mechanical or hydraulic stressing.
- It is particularly surprising that during drying, fine-particle iron oxyhydroxides or iron oxides having large specific surface areas solidify into very hard agglomerates, which without the addition of binders have a high mechanical abrasion resistance and high hydraulic resistance to contact with flowing water, and which have a high binding capacity for the contaminants and trace constituents contained in the water.
- Transparent iron oxyhydroxide pigments, for example, having an average particle size of less than 0.1 μm and specific surface areas of greater than 80 m2, are suitable for the use according to the invention of fine-particle iron oxyhydroxides. Correspondingly fine-particle iron oxide pigments, preferably haematite, magnetite or maghemite, can also be used, however.
- The production of yellow fine-particle iron oxyhydroxide pigments (e.g. goethite) in the acid or alkaline pH range, known as acid or alkaline nuclei, is known. The production of other fine-particle iron oxide or iron oxyhydroxide pigments is also known. Such pigments can contain structures based on α, β, γ, δ, δ′, ε phases and/or Fe(OH)2 and mixed and intermediate phases thereof. Fine-particle yellow iron oxyhydroxides can be calcined to fine-particle red iron oxides.
- The production of transparent iron oxides and iron oxyhydroxides is known e.g. according to DE-A 2 603 050 from BIOS 1144, p. 29 to 33 or from FIAT 814, p. 1 to 26.
- Fine-particle yellow iron oxyhydroxide pigments are generally synthesized by precipitating iron(II) hydroxides or carbonates from corresponding iron(II) salt solutions such as e.g. FeSO4, FeCl2 in pure form or as pickling solutions in the acid or alkaline pH range, followed by oxidation to iron(III) oxyhydroxides (see inter alia G. Buxbaum, Industrial Inorganic Pigments, VCH Weinheim, 2nd edition, 1998, p. 231ff). Oxidation of the divalent to the trivalent iron is preferably performed with air, whereby intensive aeration is advantageous. Oxidation with H2O2 also leads to fine-particle iron oxyhydroxides. The temperature chosen for precipitation and oxidation should be as low as possible in order to obtain very fine-particle yellow pigments. It is preferably between 15° C. and 45° C. NaOH is preferably used as alkaline precipitant. Other precipitants, such as KOH, Na2CO3, K2CO3, CaO, Ca(OH)2, CaCO3, NH3, NH4OH, MgO and/or MgCO3, can also be used, however.
- By choosing suitable precipitation and oxidation conditions, nanoparticle α, β, γ, δ phases and mixed phases of iron oxyhydroxides displaying a large specific surface area can be prepared, such that the nanoparticles agglomerate in the dry state and possess a high resistance to mechanical and fluid-mechanical abrasion in comminuted form.
- Production of fine-particle iron oxyhydroxides by simultaneous rapid treatment of iron(II) salt solutions with NaOH and air has proven to be particularly beneficial in practice because this production method leads to particularly fine-particle iron (oxy)hydroxides and hence to a greater stability of the finished product in addition to a higher force of adsorption.
- To steer the precipitated pigments in the direction of the extremely fine-particle character that is required, the precipitations, e.g. of yellow α-FeOOH as described in patents U.S. Pat. No. 2,558,303 and U.S. Pat. No. 2,558,304, are performed in the alkaline pH range with alkali carbonates as precipitants, and modifiers such as SiO2, zinc, aluminium or magnesium salts, hydroxycarbonic acids, phosphates and metaphosphates are generally added. Products produced in this way are described in U.S. Pat. No. 2,558,302. Such nucleus modifiers do not interfere with the subsequent reprocessing, recycling or any other use of the adsorbents according to the invention. In the case of precipitation processes in an aqueous medium, it is known that precipitations in an alkaline environment lead to less solidly agglomerated powders than those in an acid environment.
- One of the advantages of nucleus modifiers, however, is that an adequate fine-particle character can be obtained even at elevated reaction temperatures.
- DE-A 4 235 945 reports on the production of fine-particle iron oxides using a precipitation method in the acid pH range and without modifiers.
- DE-A 4 434 669 describes a process by which highly transparent yellow, chemically pure iron oxide pigments can be produced by secondary treatment thereof with sodium hydroxide solution.
- DE-A 4 434 972 reports on highly transparent, yellow iron oxide pigments in the α-FeOOH modification having a specific surface area of over 100 m2/g and high temperature resistance.
- DE-A 4 434 973 describes highly transparent yellow iron oxide pigments, which are produced by means of the process steps of nuclear precipitation in the acid pH range, nuclear oxidation, nuclear maturation and pigment formulation.
- Red, transparent iron oxide pigments obtained by calcining from yellow, transparent iron oxide pigments are known from DE-A 4 434 668 and DE-A 4 235 946.
- By preparing diverse phases of iron oxyhydroxides in pure form or in any mixture from iron(II) salt solutions using the known precipitation and oxidation reactions, separating the resultant iron oxyhydroxides out of the suspension, optionally after a secondary treatment, by filtering the salt solution and washing them until they are largely free from salts, preferably down to a residual conductivity of <5 mS/cm, then drying the solid or semisolid filter cake just as it is or optionally after mechanical shaping until it achieves a solid state, a mechanically highly resistant material displaying a high binding capacity for the contaminants conventionally contained in waste waters or waste gases is obtained.
- Drying is conveniently performed at temperatures of up to 250° C. The material can also be vacuum or freeze dried. The particle size of the material can be freely selected but is preferably between 0.2 and 40 mm, particularly preferably between 0.2 and 20 mm. This can be achieved by shaping the semisolid, pasty filter cake mechanically, before drying, in a granulation or pelletising plant or in an extruder to form shaped bodies whose size is in the range between 0.2 and 20 mm, with subsequent drying in the air, on a belt dryer or in a drying oven, and/or by mechanical comminution to the desired particle size after drying.
- The products described, the process for their production and their use represent an improvement over the prior art. In contrast to those based on coarse-particle iron oxyhydroxides and/or oxides, the granules according to the invention based on fine-particle iron oxyhydroxides and/or oxides can be subjected to much higher stresses and therefore display a much greater abrasion resistance to mechanical and hydraulic stressing. They can be used directly as such. When used in adsorber plants for water purification, for example, there is no need even for comminution or rough grinding of the crude dry substance initially obtained from filter cakes or extruders, since the coarse pellets break down independently on contact with water. This results in a random particle-size distribution, but no particles of such a size that they are discharged from the adsorber to any significant extent by the flowing medium.
- There is absolutely no need for a separate granulation process, such as would be necessary when using conventional iron oxyhydroxides in the form of (flowable) powders, either with the aid of foreign binders or using extremely high linear forces during compacting.
- According to the invention, the suspensions of fine-particle iron oxyhydroxides or iron oxides can also be supplemented with conventional powdered iron oxyhydroxides or iron oxides. The quantities in each case are determined by the properties of these powdered iron oxyhydroxides or iron oxides and by the requirements of the product according to the invention in terms of its mechanical stability and abrasion resistance. Although the addition of powdered pigments will generally reduce the mechanical strength of the products according to the invention, filtration of the fine-particle suspensions is made easier. The person skilled in the art and practising in the particular field of application will be able to determine the optimum mixing ratio for the intended application by means of a few orienting experiments.
- The nanoparticle nuclei are conveniently produced in an excess of sodium hydroxide solution.
- A quantity of Fe2(SO4)3 corresponding to the NaOH excess can also be added to the suspensions of the alkaline fine-particle nuclei. This measure considerably improves the filterability of the suspension. The initially amorphous Fe(OH)3 produced matures over time, to the α-FeOOH phase, for example. This ensures that the sodium hydroxide solution used in excess to produce the alkaline nucleus is completely used up. The material thus obtained also displays large specific surface areas. Just like the iron oxyhydroxides described above, the material is extremely suitable for use in adsorbers since it possesses a high resistance to mechanical loading in addition to a high adsorption capacity.
- The granules according to the invention are particularly preferably used in the cleaning of liquids, especially for the removal of heavy metals. A preferred application in this industrial field is the decontamination of water, particularly of drinking water. Particular attention has recently been paid to the removal of arsenic from drinking water. The granules according to the invention are extremely suitable for this purpose, since levels that not only meet but actually fall below even the lowest limiting values set by the US authority the EPA can be achieved using the granules according to the invention.
- To this end the granules can be used in conventional adsorber units, such as are already used with a charge of activated carbon, for example, to remove other types of contaminants. Batchwise operation, in cisterns or similar containers for example, optionally fitted with agitators, is also possible. However, use in continuous plants such as continuous-flow adsorbers is preferred.
- Since untreated water to be processed into drinking water conventionally also contains organic impurities such as algae and similar organisms, the surface of adsorbents, especially the outer surface of granular adsorbents, becomes coated during use with mostly slimy deposits, which impede or even prevent the inflow of water and hence the adsorption of constituents to be removed. For this reason adsorber units are periodically back-flushed with water, a process which is preferably performed at times of low water consumption (see above) on individual units that have been taken out of service. The adsorbent is whirled up and the associated mechanical stress to which the surface is subjected causes the undesirable coating to be removed and discharged against the direction of flow during active operation. The wash water is conventionally sent to a sewage treatment plant. The adsorbents according to the invention have proven to be particularly effective in this process, since their high strength enables them to be cleaned quickly without suffering any significant losses of adsorption material and without the back-flush water sent for waste treatment being rich in discharged adsorption material, which is possibly already highly contaminated with heavy metals.
- Since the granules according to the invention are free from foreign binders, the material is comparatively easy to dispose of after use. For instance, the adsorbed arsenic can be removed by thermal or chemical means in special units, for example, resulting in an iron oxide pigment as a pure substance which can either be recycled for use in the same application or supplied for conventional pigment applications. Depending on the application and legal regulations, the content of the adsorber can also be used without prior removal of the heavy metals, for example as a pigment for colouring durable construction materials such as concrete, since the heavy metals removed from the drinking water are permanently immobilised in this way and taken out of the hydrological cycle.
- The invention therefore also provides water treatment plants or waterworks in which units filled with the granules according to the invention are operated, and processes for the decontamination of water by means of such units, as well as such units themselves.
- For many applications, particularly those in which a maximum mechanical strength is not required of the granules, the addition of powdered pigments during production of the granules according to the invention is a preferred embodiment.
- Thus, for example, up to 40 wt. % of commercial goethite (Bayferrox 920, Bayer A G, Leverkusen D E) can be added to a nucleus suspension according to example 2 of the present application if the granules obtained according to the invention are to be used for the removal of arsenic from drinking water in adsorbers with a through-flow of water.
- The BET specific surface area of the products according to the invention is determined by the carrier gas process (He:N2=90:10) using the single-point method, according to DIN 66131 (1993). The sample is baked for 1 h at 140° C. in a stream of dry nitrogen before measurement.
- In order to measure the adsorption of arsenic(III) and arsenic(V), 3 liters of an aqueous solution of NaAsO2 or Na2HAsO4, each with the specified concentration of approx. 2-3 mg/l arsenic, are treated with 3 g of the sample to be tested in a 5 liter PE flask for a specific period and the flask moved on rotating rollers. The adsorption rate of As ions on iron hydroxide over this specific period, e.g. one hour, is stated as mg(As3+/5+)/g(FeOOH).h, calculated from the balance of the As3+/5+ ions remaining in solution.
- The adsorption of Sb3+, Sb5+, Hg2+, Pb2+, Cr6+ or Cd2+ ions is measured in the same way, whereby the desired concentrations are established by dissolving appropriate amounts of Sb2O3, KSb(OH)6, PbCl2, NaCrO4 or CdCl2 in H2O and adjusting the pH value to 7-9.
- The As, Sb, Cd, Cr, Hg or Pb contents of the contaminated iron oxyhydroxide or of the solutions are determined using mass spectrometry (ICP-MS) according to DIN 38406-29 (1999) or by optical emission spectroscopy (ICP-OES) according to EN-ISO 11885 (1998), with inductively coupled plasma as excitation agent in each case.
- The mechanical and hydraulic abrasion resistance was assessed using the following method: 150 ml of demineralised water were added to 10 g of the granules to be tested, having particle sizes >0.1 mm, in a 500 ml Erlenmeyer flask, which was rotated on a LabShaker shaking machine (Kühner model from Braun) for a period of 30 minutes at 250 rpm. The >0.1 mm fraction was then isolated from the suspension using a screen, dried and weighed. The weight ratio between the amount weighed out and the amount weighed in determines the abrasion value in %.
- The invention is described in greater detail in the following by means of examples. The examples are intended to illustrate the process and do not constitute a limitation.
- 237 l of an aqueous iron sulfate solution with a concentration of 150 g/l FeSO4 were prepared at 24° C. 113 l of an aqueous NaOH solution (227 g/l) were then quickly added and the light blue suspension then oxidised with 40 l of air per hour and per mol of iron for 1.5 hours.
- The yellow suspension thus obtained was filtered out through a filter press and the solid washed until the residual filtrate conductivity was 1 mS/cm. The filter cake was in the form of a spreadable and kneadable paste, which was dried on metal sheets in a circulating air drying oven at 75° C. until the residual moisture content was 3 wt. %. The dried material was then roughly ground to produce particle sizes of between 0.5 and 2 mm. The hard pellets thus obtained were then placed directly in an adsorber tank.
- The product consisted of 100% α-FeOOH with an extremely short-needled habit, whereby the needles were congregated to form solid macroscopic agglomerates. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 15 and 35 nm, the needle lengths between 150 and 350 nm. The needles were extremely agglomerated.
- The BET specific surface area was 122 m2/g. The adsorption rate for NaAsO2 with an original concentration of 2.3 mg (As3+)/l was 2.14 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.7 mg (As5+)/l it was 2.29 mg(As5+)/g(FeOOH).h.
- 800 l of an aqueous iron sulfate solution with a concentration of 150 g/l FeSO4 were prepared at 29° C. and 147 l of an aqueous NaOH solution (300 g/l) added over 20 minutes with stirring. 2.16 kg of a nucleus modifier in the form of a 57% aqueous glycolic acid solution were then added to the grey-blue suspension formed in order to reduce the particle size of the nuclei, and oxidation was performed for 7 hours with 38 l of air per hour and per mol of iron.
- The dark brown suspension was filtered out through a filter press and the solid washed until the residual filtrate conductivity was 1 mS/cm. The filter cake was dried at 70° C. in a circulating air drying oven to a residual moisture of 5%, and the very hard blackish brown dry product was roughly ground in a roller crusher to particle sizes of up to 2 mm. The fine fraction <0.2 mm was separated out using a screen.
- An X-ray diffractogram showed that the product consisted of 100% α-FeOOH. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 15 and 20 nm, the needle lengths between 50 and 80 nm. The particles were extremely agglomerated. The BET specific surface area was 202 m2/g. The granules thus obtained were placed directly in an adsorber tank with no further treatment.
- The granules displayed an excellent adsorption performance in respect of the contaminants contained in the flowing water and demonstrated a high abrasion resistance, particularly when the adsorber tank is being back-flushed causing the granules to be whirled up strongly. The abrasion value after 30 minutes was only 1%.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.4 mg (As3+)/l was 1.0 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.8 mg (As5+)/l it was 2.07 mg(As3+)/g(FeOOH).h.
- 1.3 l of an aqueous 300 g/l NaOH solution were added to an α-FeOOH suspension obtained according to example 2 after a two-hour maturation at 30° C. with stirring, and post-oxidation was performed simultaneously for one hour with 190 l of air. The product was processed as described in example 2. Fine-particle needles of pure α-FeOOH with a BET specific surface area of 130 m2/g were obtained. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 15 and 20 nm, the needle lengths between 50 and 90 nm. The needles were extremely agglomerated. The granules proved to be very mechanically and hydraulically resistant, and the abrasion value was only 3.9%.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.3 mg/l was 1.1 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.8 mg/l it was 1.7 mg(As3+)/g(FeOOH).h.
- 306 l of an aqueous NaOH solution (45 g/l) were prepared at 31° C. and 43 l of an aqueous solution of FeCl2 (344 g/l) quickly added with stirring, and oxidation was then performed with 60 l of air per hour and per mol Fe. The dark yellow suspension thus obtained was processed in the same way as in example 1.
- An X-ray diffractogram showed that the product consisted of 100% α-FeOOH. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 15 and 50 nm, the needle lengths between 100 and 200 nm. The needles were extremely agglomerated. The BET specific surface area was 132 m2l/g.
- The granules thus obtained were placed in an adsorber tank with no further treatment. The granules displayed an excellent adsorption performance in respect of the contaminants contained in the water and demonstrated a high abrasion resistance, particularly when the adsorber tank is being back-flushed causing the granules to be whirled up strongly. The abrasion value after 30 minutes was only 12 wt. %.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.4 mg (As3+)/l was 2.11 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.7 mg (As5+)/l it was 2.03 mg(As5+)/g(FeOOH).h.
- 124 l of an aqueous NaOH solution (114 g/l) were prepared at 24° C. and 171 l of an aqueous solution of FeSO4 (100 g/l) quickly added with stirring, and oxidation was then performed with 10 l air per hour and per mol Fe. Immediately upon completion of oxidation, 56 l of an aqueous solution of Fe2(SO4)3 (100 g/l) were added and stirred for 30 minutes. The yellowish brown suspension thus obtained was processed in the same way as in example 1.
- An X-ray diffractogram showed that the product consisted of 100% α-FeOOH. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 15 and 35 nm, the needle lengths between 70 and 180 nm. The needles were extremely agglomerated. The BET specific surface area was 131 m2/g. The abrasion value after 30 minutes was only 7 wt. %.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.3 mg (As3+)/l was 1.7 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.7 mg (As5+)/l it was 1.2 mg(As5+)/g(FeOOH).h.
- 7905 kg FeSO4 were prepared, dissolved with water to a volume of 53.3 m3, the solution cooled to 14° C. and 1000 kg MgSO4.7 H2O added to this solution. The prepared solution was then diluted at 14° C. with 5056 kg NaOH as a solution with approx. 300 g/l and then oxidised with 4000 m3/h air to a precipitation degree of >99.5%. The batch was washed on a filter press until the residual filtrate conductivity was <1000 μS/cm and the paste pushed through a perforated metal sheet with hole diameters of 7 mm, causing it to be formed into strands. The strands were dried on a belt dryer to a residual moisture of approx. 3%. An X-ray diffractogram showed that the product consisted of 100% α-FeOOH with very short needles. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 30 and 50 nm. The needle lengths could not be clearly determined as the needles were too greatly agglomerated. The BET specific surface area was 145 m2/g. The abrasion value after 30 minutes was only 6%.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.5 mg (As3+)/l was 1.8 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.9 mg (As5+)/l it was 1.5 mg(As5+)/g(FeOOH).h.
- 4096 kg NaOH (as solution with approx. 300 g/l) were prepared and diluted with water to 40 m3. 4950 kg FeSO4 were dissolved with water to form 48.5 m3 solution, cooled to 15° C. and then pumped into the prepared NaOH over 1 h. The suspension was then oxidised with 1500 m3/h air over approx. 2 h. Approx. 2 m3 of the nucleus suspension was washed on a filter press to obtain a filtrate conductivity <1000 μS/cm, the filter cake was dried in a drying oven at 75° C. and the dried material roughly ground to particle sizes <1.5 mm. The fine fraction <0.5 mm was separated out using a screen. The material thus obtained had a BET specific surface area of 153 m2/g and consisted of 100% α-FeOOH. Using a scanning electron micrograph e.g. at a magnification of 60000:1, the needle widths were measured at between 15 and 35 nm, the needle lengths between 50 and 100 nm. The needles were extremely agglomerated.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.7 mg (As3+)/l was 1.7 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.8 mg (As5+)/l it was 1.4 mg(As5+)/g(FeOOH).h.
- 3100 kg NaOH (as solution with approx. 100 g/l) were measured out and diluted with cold water to 31 m3. The temperature of the solution was 26° C. 3800 kg FeSO4 were dissolved with water to form about 38 m3 solution, cooled to 13-14° C. and then pumped with stirring into the prepared NaOH. The suspension was then oxidised with 2500 m3/h air in approx. 75 min. 18.2 m3 FeSO4 solution (100 g/l) were added at a rate of 150 l/min to this suspension with stirring and gassing. The suspension was filtered on a filter press and washed until the residual filtrate conductivity was <1000 μS/cm, the paste was pushed through a perforated metal plate and were dried on a belt dryer to a residual moisture of less than 20%. The dry pellets were roughly ground to obtain a particle size of less than 2 mm. The portion of the particles with less then 0.5 mm was removed. The material thus obtained had a BET specific surface area of 145 m2/g and consisted of 100% α-FeOOH.
- An aqueous solution of FeSO4 (100 g/l) was added at room temperature to 1600 g of the alkaline nucleus suspension prepared according to example 7 (2.7% FeOOH) with stirring and simultaneous aeration with 130 l/h of air until a pH of 8 was obtained. The nucleus suspension obtained was filtered, washed and the filter cake dried at 75° C. and roughly ground to particle sizes of between 0.5 and 2 mm as described in example 7. The material thus obtained had a BET specific surface area of 163 m2/g and according to the X-ray diffractogram consisted of 100% α-FeOOH. The scanning electron micrograph, e.g. at a magnification of 60000:1, showed that the needles are extremely agglomerated. Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.7 mg (As3+)/l was 2.0 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.7 mg (As5+)/l it was 1.9 mg(As5+)/g(FeOOH).h, for KSb(OH)6 (original concentration 3.0 mg (Sb5+)/l) the adsorption was 2.5 mg (Sb5+)/g (FeOOH).h, for Na2CrO4 (original concentration 47 μg (Cr6+)/l) 42 μg (Cr6+)/g(FeOOH).h were adsorbed, for PbCl2 (original concentration 0.94 mg (Pb2+)/l) 0.46 mg (Pb2+)/g(FeOOH).h were adsorbed.
- 6.4 l of an aqueous solution of NaOH (100 g/l) were prepared at 29° C. with stirring and 12.2 l of an aqueous iron(II) sulfate solution (100 g/l) were added with simultaneous introduction of air until a pH of 9 was obtained. The suspension thus obtained was processed in the same way as in example 1. The material had a BET specific surface area of 251 m2/g and according to the X-ray diffractogram consisted of 100% α-FeOOH. The scanning electron micrograph shows short, stumpy needles, which are extremely agglomerated. Abrasion performance: 5%.
- Adsorption performance: The adsorption rate for NaAsO2 with an original concentration of 2.7 mg (As3+)/l was 1.1 mg(As3+)/g(FeOOH).h, for Na2HAsO4 with an original concentration of 2.7 mg (As5+)/l it was 1.0 mg(As5+)/g(FeOOH).h.
- Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Claims (18)
1. A unit suitable for the through-flow of a fluid medium, at least partially filled with particles agglomerated from fine-particle iron oxide and/or iron oxyhydroxide, wherein the fine-particle iron oxide and/or iron oxyhydroxide displays a particle size of up to 500 nm and a BET surface area of 50 to 500 m2/g.
2. The unit of claim 1 wherein the medium comprises a gas.
3. The unit of claim 1 wherein the medium comprises a liquid.
4. The unit of claim 3 , wherein the liquid comprises water.
5. A water treatment plant comprising the unit of claim 4 .
6. A waterwork comprising the water treatment plant of claim 5 .
7. The unit of claim 1 wherein the fine-particle iron oxide and/or iron oxyhydroxide displays a BET surface area of 80 to 200 m2/g.
8. The unit of claim 1 wherein the agglomerates further comprise iron oxide pigments with particle sizes above 500 nm and BET surface areas below 50 m2/g, whereby the maximum content of these is such that the resistance of the charge to the forces exerted upon it by the flowing medium is sufficiently great that the stress exerted on the charge by the flowing medium does not lead to an undesirable abrasion of the charge material.
9. A process for the production of particles from fine-particle iron oxide and/or iron oxyhydroxide comprising the steps of producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m2/g, and removing the water and dissolved constituents by
either
I) a) first removing only the water from the suspension, b) introducing the residue thus obtained in water, c) filtering the material obtained, d) washing the residue, and e) either e1) completely dehydrating the filter cake obtained as residue and comminuting the material thus obtained to the desired shape and/or size or e2) partially dehydrating the filtercake to obtain a paste, shaping the paste and subsequently additionally drying the paste until a pellet is obtained,
or
II) a) filtering the suspension, b) washing the residue, c) either c1) completely dehydrating the filter cake obtained as residue in the form of a solid to semisolid paste and then comminuting the material thus obtained to the desired shape and/or size or c2) partially dehydrating the filtercake to obtain a paste, shaping the paste, and subsequently additionally drying the paste until a pellet is obtained.
10. The process of claim 9 further comprising a step of subjecting the pellet to a further comminution by grinding or rough grinding.
11. The process of claim 9 wherein the BET surface area is 80 to 200 m2/g.
12. The process of claim 9 wherein I) a) the water is removed by evaporation.
13. The process of claim 9 comprising I d) washing the residue until it is free from salts.
14. The process of claim 9 comprising II b) washing the residue until it is low in salts.
15. A process comprising treating fluid medium by contacting the gas or liquid in a unit according to claim 1 with particles obtained by a process for the production of particles from fine-particle iron oxide and/or iron oxyhydroxide comprising the steps of producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m2/g, and removing the water and dissolved constituents by
either
I) a) first removing only the water from the suspension, b) introducing the residue thus obtained in water, c) filtering the material obtained, d) washing the residue, and e) either e1) completely dehydrating the filter cake obtained as residue and comminuting the material thus obtained to the desired shape and/or size or e2) partially dehydrating the filtercake to obtain a paste, shaping the paste and subsequently additionally drying the paste until a pellet is obtained,
or
II) a) filtering the suspension, b) washing the residue, c) either c1) completely dehydrating the filter cake obtained as residue in the form of a solid to semisolid paste and then comminuting the material thus obtained to the desired shape and/or size or c2) partially dehydrating the filtercake to obtain a paste, shaping the paste, and subsequently additionally drying the paste until a pellet is obtained.
16. The process of claim 15 wherein the fluid medium comprises water.
17. The process of claim 15 comprising removing a heavy metal, phosphorus, antimony, beryllium, selenium, tellurium or cyano compound from water.
18. The process of claim 15 comprising removing arsenic compounds from water.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/217,971 US7651973B2 (en) | 2000-09-26 | 2008-07-10 | Contact and adsorbent granules |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2000147997 DE10047997A1 (en) | 2000-09-26 | 2000-09-26 | Flow-through apparatus useful for e.g. water treatment comprises lumps of adsorbent/reactant comprising iron oxide and/or oxyhydroxide bound with metal oxides and/or (oxy)hydroxides |
DE10047997.9 | 2000-09-26 | ||
DE10115415.1 | 2001-03-29 | ||
DE2001115415 DE10115415A1 (en) | 2001-03-29 | 2001-03-29 | Filtration unit for removing pollutants from fluids, especially water, comprises agglomerates of finely divided iron oxide and oxyhydroxide |
DE10129304.6 | 2001-06-18 | ||
DE2001129304 DE10129304A1 (en) | 2001-06-18 | 2001-06-18 | Filtration unit for removing pollutants from fluids, especially water, comprises agglomerates of finely divided iron oxide and oxyhydroxide |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/217,971 Division US7651973B2 (en) | 2000-09-26 | 2008-07-10 | Contact and adsorbent granules |
Publications (1)
Publication Number | Publication Date |
---|---|
US20020070172A1 true US20020070172A1 (en) | 2002-06-13 |
Family
ID=27214086
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/962,935 Abandoned US20020070172A1 (en) | 2000-09-26 | 2001-09-25 | Contact and adsorbent granules |
US12/217,971 Expired - Lifetime US7651973B2 (en) | 2000-09-26 | 2008-07-10 | Contact and adsorbent granules |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/217,971 Expired - Lifetime US7651973B2 (en) | 2000-09-26 | 2008-07-10 | Contact and adsorbent granules |
Country Status (12)
Country | Link |
---|---|
US (2) | US20020070172A1 (en) |
EP (1) | EP1328476B1 (en) |
JP (1) | JP5113975B2 (en) |
KR (1) | KR100788118B1 (en) |
CN (1) | CN1466548B (en) |
AT (1) | ATE503726T1 (en) |
AU (1) | AU2002212269A1 (en) |
BR (1) | BR0114178B1 (en) |
CA (1) | CA2423174C (en) |
DE (1) | DE50115834D1 (en) |
TW (1) | TWI255735B (en) |
WO (1) | WO2002026632A1 (en) |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030209495A1 (en) * | 2002-03-12 | 2003-11-13 | Andreas Schlegel | Mixtures of adsorber materials |
US20040178135A1 (en) * | 2003-03-13 | 2004-09-16 | Beplate Douglas K. | Filtering device incorporating nanoparticles |
US20040258609A1 (en) * | 2003-01-28 | 2004-12-23 | Boren Richard M. | Oxides of manganese processed in continuous flow reactors |
US20050074380A1 (en) * | 2003-07-31 | 2005-04-07 | Boren Richard M. | Metal oxide processing methods and systems |
WO2005056164A1 (en) * | 2003-12-05 | 2005-06-23 | Jayalekshmy Ayyer | A catalyst useful for h2s removal from gas stream preparation thereof and use thereof |
US20050252863A1 (en) * | 2004-05-05 | 2005-11-17 | Bernd Wurth | Foams for removing pollutants and/or heavy metals from flowable media |
WO2006032727A1 (en) * | 2004-09-24 | 2006-03-30 | Kemira Oyj | Process for the preparation of an adsorbent material containing iron oxyhydroxide, adsorbent material and the use thereof |
US20060170332A1 (en) * | 2003-03-13 | 2006-08-03 | Hiroto Tamaki | Light emitting film, luminescent device, method for manufacturing light emitting film and method for manufacturing luminescent device |
US20080098614A1 (en) * | 2006-10-03 | 2008-05-01 | Wyeth | Lyophilization methods and apparatuses |
US20080272054A1 (en) * | 2000-09-26 | 2008-11-06 | Andreas Schlegel | Adsorption vessels |
US20090028770A1 (en) * | 2005-02-16 | 2009-01-29 | Japan Science And Technology Agency | Method for producing iron oxyhydroxide and adsorbing material comprising iron oxyhydroxide |
US20100230360A1 (en) * | 2006-06-29 | 2010-09-16 | Createrra Inc. | Anion adsorbent, water or soil cleanup agent and process for producing the same |
US20150101980A1 (en) * | 2013-10-10 | 2015-04-16 | Nano And Advanced Materials Institute Limited | Household water filter element for removing radioactive substances |
EP2039658B1 (en) * | 2007-09-20 | 2020-01-01 | Ulrich Kubinger | Use of a coagulant and flocculent comprising nanoparticles for treating water and water treatment method |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6849187B2 (en) | 2002-12-10 | 2005-02-01 | Engelhard Corporation | Arsenic removal media |
CN100462311C (en) * | 2003-12-23 | 2009-02-18 | Ihe代尔夫特 | Method for the removal of metals from a metal-containing aqueous medium |
DE102004016601A1 (en) * | 2004-04-03 | 2005-10-13 | Bayer Chemicals Ag | Stable adsorber granules |
WO2006132321A1 (en) * | 2005-06-09 | 2006-12-14 | J-Pharma Co., Ltd. | Agent for preventing, ameliorating and treating phosphorus-induced disorder, oral preparation for adsorbing phosphate ion in food, drink or drug and method of producing the same |
US20080047902A1 (en) | 2006-08-28 | 2008-02-28 | Basf Catalysts Llc | Media for the removal of heavy metals and volatile byproducts from drinking water |
EP1932807A1 (en) * | 2006-12-14 | 2008-06-18 | Novartis AG | Inorganic compounds |
JP5451623B2 (en) * | 2007-10-03 | 2014-03-26 | スリーエム イノベイティブ プロパティズ カンパニー | Microbial concentration process |
US20110056887A1 (en) | 2009-09-08 | 2011-03-10 | Lanxess Deutschland Gmbh | Removal of oxo anions from water |
US8404031B1 (en) | 2009-10-06 | 2013-03-26 | Michael Callaway | Material and method for the sorption of hydrogen sulfide |
US8759252B1 (en) | 2010-10-06 | 2014-06-24 | Michael D. and Anita Kaye | Material and method for the sorption of hydrogen sulfide |
CN103232103A (en) * | 2013-04-09 | 2013-08-07 | 北京建筑工程学院 | Method for removing phosphorus from reclaimed water by using ferric hydroxide produced through iron salt coagulant in-situ hydrolysis |
CN105107480A (en) * | 2015-09-06 | 2015-12-02 | 武汉理工大学 | Preparation method of mesoporous ferric hydroxide adsorbent used for adsorbing highly toxic pollutant Cr(VI) |
KR20200098860A (en) * | 2019-02-13 | 2020-08-21 | 주식회사 엘지화학 | Cathode for lithium secondary battery comprising goethite, and lithium secondary battery comprising the same |
KR20210006243A (en) * | 2019-07-08 | 2021-01-18 | 엘지전자 주식회사 | filter for water purifier and water purifier using thereof |
KR102134292B1 (en) * | 2020-02-11 | 2020-07-15 | 주식회사 에스엔텍솔루숀 | Plasma low temperature oxidation adsorption catalyst deodorizer and deodorization method |
EP4015459A1 (en) | 2020-12-21 | 2022-06-22 | LANXESS Deutschland GmbH | Method for the production of iron oxyhydroxide |
CN112940795A (en) * | 2021-02-23 | 2021-06-11 | 湖北华特尔净化科技股份有限公司 | Iron-based desulfurizer for blast furnace gas and preparation method thereof |
WO2023094608A1 (en) | 2021-11-25 | 2023-06-01 | Lanxess Deutschland Gmbh | Adsorbent materials for mineral soils |
CN116870670B (en) * | 2023-09-06 | 2023-12-19 | 振华新材料(东营)有限公司 | Butadiene recovery device of butadiene rubber device |
Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3332737A (en) * | 1965-01-28 | 1967-07-25 | Kurt A Kraus | Process for separating inorganic anions with hydrous oxide anion exchangers |
US3804945A (en) * | 1970-05-27 | 1974-04-16 | Atomic Energy Authority Uk | Processes for extracting metal values from solutions |
US3931007A (en) * | 1972-12-19 | 1976-01-06 | Nippon Electric Company Limited | Method of extracting heavy metals from industrial waste waters |
US4383980A (en) * | 1980-12-09 | 1983-05-17 | Occidental Research Corporation | Process for extracting tungsten and molybdenum values from solution |
US4459370A (en) * | 1981-08-07 | 1984-07-10 | Veg Gasinstituut N.V. | Process for the preparation of an iron(III) oxide catalyst or absorbent |
US4481087A (en) * | 1981-12-23 | 1984-11-06 | Occidental Chemical Corporation | Process for removing chromate from solution |
US4515756A (en) * | 1980-12-09 | 1985-05-07 | Occidental Research Corporation | Process for extracting tungsten or molybdenum from solution |
US5369072A (en) * | 1988-05-10 | 1994-11-29 | University Of Washington | Granular media for removing contaminants from water and methods for making the same |
US5502021A (en) * | 1990-10-29 | 1996-03-26 | Walhalla-Kalk Entwicklungs-Und Vertriebsgesellschaft | Highly reactive reagents and compositions for purifying exhaust gases and wastewater, production and use thereof |
US5601721A (en) * | 1994-04-29 | 1997-02-11 | Union Oil Company Of California | Method for reducing the selenium concentration in an oil refinery effluent |
US5948726A (en) * | 1994-12-07 | 1999-09-07 | Project Earth Industries, Inc. | Adsorbent and/or catalyst and binder system and method of making therefor |
US6093236A (en) * | 1998-05-30 | 2000-07-25 | Kansas State University Research Foundation | Porous pellet adsorbents fabricated from nanocrystals |
US6531065B2 (en) * | 1999-11-12 | 2003-03-11 | San Diego State University Foundation | Perchlorate removal methods |
US6994792B2 (en) * | 2002-03-12 | 2006-02-07 | Bayer Aktiengesellschaft | Mixtures of adsorber materials |
Family Cites Families (31)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5144719B2 (en) * | 1972-08-19 | 1976-11-30 | ||
DE2313331C2 (en) * | 1973-03-17 | 1986-11-13 | Merck Patent Gmbh, 6100 Darmstadt | Mica flake pigments containing iron oxide |
JPS55132633A (en) | 1979-03-30 | 1980-10-15 | Agency Of Ind Science & Technol | Adsorbent for arsenic |
DE3120891A1 (en) | 1981-05-26 | 1982-12-23 | Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe | METHOD FOR REMOVAL OR PARTIAL REMOVAL OF INTERESTING SUBSTANCES CONTAINED IN A FLOWING WATER, AND DEVICE FOR IMPLEMENTING THE METHOD |
US4459276A (en) * | 1981-09-17 | 1984-07-10 | Agency Of Industrial Science & Technology | Yellow iron oxide pigment and method for manufacture thereof |
JPS6013975B2 (en) * | 1981-09-17 | 1985-04-10 | 工業技術院長 | yellow iron oxide pigment |
EP0105873A1 (en) * | 1982-04-15 | 1984-04-25 | Occidental Research Corporation | Hydrous iron adsorbent, process for preparing the same and process for using the same in the extraction of tungsten and/or molybdenum from solution |
DE3224325A1 (en) * | 1982-06-30 | 1984-01-05 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING NEEDLE-SHAPED, FERRIMAGNETIC IRON OXIDES |
US4514216A (en) * | 1983-04-30 | 1985-04-30 | Toda Kogyo Corp. | Acicular ferromagnetic alloy particles for magnetic recording and process for producing the same |
DE3402734A1 (en) * | 1984-01-27 | 1985-08-01 | Basf Ag, 6700 Ludwigshafen | MOLDED IRON CATALYST, THEIR PRODUCTION AND USE |
DE3800873A1 (en) | 1987-01-15 | 1988-07-28 | Hoelscher Richard | Method for binding pollutants and absorbent for pollutants |
JPH06122519A (en) * | 1991-05-27 | 1994-05-06 | Toda Kogyo Corp | Hydrated amorphous ferric oxide particle powder and its production |
DE4214487C2 (en) | 1992-05-07 | 1994-08-04 | Wahnbachtalsperrenverband | Process and reactor for removing contaminants from water |
DE4235946A1 (en) * | 1992-10-23 | 1994-04-28 | Bayer Ag | Process for the production of pure iron oxide direct red pigments and their use |
DE4235944A1 (en) * | 1992-10-23 | 1994-04-28 | Bayer Ag | Color-pure iron oxide direct red pigments, process for their preparation and their use |
DE4235945A1 (en) * | 1992-10-23 | 1994-04-28 | Bayer Ag | Transparent iron oxide pigments, processes for their production and their use |
EP0604849B1 (en) * | 1992-12-29 | 1996-10-16 | Ishihara Sangyo Kaisha, Ltd. | Cobalt-containing magnetic iron oxide and process for producing the same |
DE4320003A1 (en) | 1993-06-11 | 1994-12-15 | Jekel Martin Prof Dr Ing | Process for removing dissolved arsenic by means of solid iron hydroxide in water purification |
JPH0824634A (en) * | 1994-07-13 | 1996-01-30 | Ishihara Sangyo Kaisha Ltd | Phosphorus adsorbent |
JP3427856B2 (en) * | 1994-08-23 | 2003-07-22 | 戸田工業株式会社 | Granular goethite fine particle powder, method for producing the same, and method for producing granular iron oxide fine particle powder using the fine particle powder |
DE19601412C2 (en) * | 1996-01-17 | 1999-07-22 | Emtec Magnetics Gmbh | Ferromagnetic pigments |
DE19804109A1 (en) * | 1998-02-03 | 1999-08-12 | Cerdec Ag | Red-brown color bodies burning out, process for their production and their use |
DE19814080A1 (en) * | 1998-03-30 | 1999-10-07 | Basf Ag | Catalyst for the dehydrogenation of hydrocarbons, in particular for the dehydrogenation of ethylbenzene to styrene, and process for its preparation |
DE69925903T2 (en) * | 1998-04-01 | 2006-05-04 | Alcan International Ltd., Montreal | WATER TREATMENT METHOD |
DE19826186B4 (en) | 1998-06-04 | 2004-12-23 | Ingenieurbüro Dr. Fechter GmbH | Process for producing an iron hydroxide and a polymer-containing adsorbent / reactant and its use |
JP2002053903A (en) * | 2000-08-07 | 2002-02-19 | Toda Kogyo Corp | Secondarily aggregated body of metallic magnetic grain for magnetic recording and its production method |
ATE503727T1 (en) * | 2000-09-26 | 2011-04-15 | Lanxess Deutschland Gmbh | CONTACT AND ADSORBER GRANULES |
EP1328478B1 (en) * | 2000-09-26 | 2011-03-30 | LANXESS Deutschland GmbH | Contacting and adsorbent granules |
US20020074292A1 (en) * | 2000-09-26 | 2002-06-20 | Andreas Schlegel | Adsorption vessels |
DE102004016601A1 (en) * | 2004-04-03 | 2005-10-13 | Bayer Chemicals Ag | Stable adsorber granules |
DE102004022766A1 (en) * | 2004-05-05 | 2005-12-01 | Bayer Chemicals Ag | Foams for removing pollutants and / or heavy metals from flowable media |
-
2001
- 2001-09-21 BR BRPI0114178-3A patent/BR0114178B1/en not_active IP Right Cessation
- 2001-09-21 DE DE50115834T patent/DE50115834D1/en not_active Expired - Lifetime
- 2001-09-21 CN CN018162916A patent/CN1466548B/en not_active Expired - Lifetime
- 2001-09-21 EP EP01980422A patent/EP1328476B1/en not_active Expired - Lifetime
- 2001-09-21 AT AT01980422T patent/ATE503726T1/en active
- 2001-09-21 AU AU2002212269A patent/AU2002212269A1/en not_active Abandoned
- 2001-09-21 JP JP2002530422A patent/JP5113975B2/en not_active Expired - Lifetime
- 2001-09-21 WO PCT/EP2001/010926 patent/WO2002026632A1/en active Application Filing
- 2001-09-21 CA CA2423174A patent/CA2423174C/en not_active Expired - Lifetime
- 2001-09-21 KR KR1020037004282A patent/KR100788118B1/en active IP Right Grant
- 2001-09-25 US US09/962,935 patent/US20020070172A1/en not_active Abandoned
- 2001-09-25 TW TW090123514A patent/TWI255735B/en not_active IP Right Cessation
-
2008
- 2008-07-10 US US12/217,971 patent/US7651973B2/en not_active Expired - Lifetime
Patent Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3332737A (en) * | 1965-01-28 | 1967-07-25 | Kurt A Kraus | Process for separating inorganic anions with hydrous oxide anion exchangers |
US3804945A (en) * | 1970-05-27 | 1974-04-16 | Atomic Energy Authority Uk | Processes for extracting metal values from solutions |
US3931007A (en) * | 1972-12-19 | 1976-01-06 | Nippon Electric Company Limited | Method of extracting heavy metals from industrial waste waters |
US4515756A (en) * | 1980-12-09 | 1985-05-07 | Occidental Research Corporation | Process for extracting tungsten or molybdenum from solution |
US4383980A (en) * | 1980-12-09 | 1983-05-17 | Occidental Research Corporation | Process for extracting tungsten and molybdenum values from solution |
US4459370A (en) * | 1981-08-07 | 1984-07-10 | Veg Gasinstituut N.V. | Process for the preparation of an iron(III) oxide catalyst or absorbent |
US4481087A (en) * | 1981-12-23 | 1984-11-06 | Occidental Chemical Corporation | Process for removing chromate from solution |
US5369072A (en) * | 1988-05-10 | 1994-11-29 | University Of Washington | Granular media for removing contaminants from water and methods for making the same |
US5502021A (en) * | 1990-10-29 | 1996-03-26 | Walhalla-Kalk Entwicklungs-Und Vertriebsgesellschaft | Highly reactive reagents and compositions for purifying exhaust gases and wastewater, production and use thereof |
US5601721A (en) * | 1994-04-29 | 1997-02-11 | Union Oil Company Of California | Method for reducing the selenium concentration in an oil refinery effluent |
US5948726A (en) * | 1994-12-07 | 1999-09-07 | Project Earth Industries, Inc. | Adsorbent and/or catalyst and binder system and method of making therefor |
US6093236A (en) * | 1998-05-30 | 2000-07-25 | Kansas State University Research Foundation | Porous pellet adsorbents fabricated from nanocrystals |
US6531065B2 (en) * | 1999-11-12 | 2003-03-11 | San Diego State University Foundation | Perchlorate removal methods |
US6994792B2 (en) * | 2002-03-12 | 2006-02-07 | Bayer Aktiengesellschaft | Mixtures of adsorber materials |
Cited By (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7942953B2 (en) | 2000-09-26 | 2011-05-17 | Lanxess Deutschland Gmbh | Adsorption vessels |
US20080272054A1 (en) * | 2000-09-26 | 2008-11-06 | Andreas Schlegel | Adsorption vessels |
US20030209495A1 (en) * | 2002-03-12 | 2003-11-13 | Andreas Schlegel | Mixtures of adsorber materials |
US6994792B2 (en) | 2002-03-12 | 2006-02-07 | Bayer Aktiengesellschaft | Mixtures of adsorber materials |
US20040258609A1 (en) * | 2003-01-28 | 2004-12-23 | Boren Richard M. | Oxides of manganese processed in continuous flow reactors |
US20080317650A1 (en) * | 2003-01-28 | 2008-12-25 | Boren Richard M | Oxides of Manganese Processed in Continuous Flow Reactors |
EP1606042A2 (en) | 2003-03-13 | 2005-12-21 | Douglas K. Beplate | Filtering device incorporating nanoparticles |
EP2281622A1 (en) | 2003-03-13 | 2011-02-09 | Applied Nanoscience Inc. | Filtering device incorporating nanoparticles |
US20040178135A1 (en) * | 2003-03-13 | 2004-09-16 | Beplate Douglas K. | Filtering device incorporating nanoparticles |
US20060170332A1 (en) * | 2003-03-13 | 2006-08-03 | Hiroto Tamaki | Light emitting film, luminescent device, method for manufacturing light emitting film and method for manufacturing luminescent device |
US7923918B2 (en) * | 2003-03-13 | 2011-04-12 | Nichia Corporation | Light emitting film, luminescent device, method for manufacturing light emitting film and method for manufacturing luminescent device |
US20100059428A1 (en) * | 2003-07-31 | 2010-03-11 | Boren Richard M | System for Removal of Metals from Aqueous Solutions |
US20050074380A1 (en) * | 2003-07-31 | 2005-04-07 | Boren Richard M. | Metal oxide processing methods and systems |
WO2005056164A1 (en) * | 2003-12-05 | 2005-06-23 | Jayalekshmy Ayyer | A catalyst useful for h2s removal from gas stream preparation thereof and use thereof |
US20050252863A1 (en) * | 2004-05-05 | 2005-11-17 | Bernd Wurth | Foams for removing pollutants and/or heavy metals from flowable media |
US20080257823A1 (en) * | 2004-09-24 | 2008-10-23 | Kemira Ojy | Process for the Preparation of an Adsorbent Material Containing Iron Oxyhydroxide, Adsorbent Material and the Use Thereof |
WO2006032727A1 (en) * | 2004-09-24 | 2006-03-30 | Kemira Oyj | Process for the preparation of an adsorbent material containing iron oxyhydroxide, adsorbent material and the use thereof |
US20090028770A1 (en) * | 2005-02-16 | 2009-01-29 | Japan Science And Technology Agency | Method for producing iron oxyhydroxide and adsorbing material comprising iron oxyhydroxide |
US20100230360A1 (en) * | 2006-06-29 | 2010-09-16 | Createrra Inc. | Anion adsorbent, water or soil cleanup agent and process for producing the same |
US8231790B2 (en) | 2006-06-29 | 2012-07-31 | Createrra Inc. | Process for producing an anion adsorbent and anion adsorbent produced by said process |
US20080098614A1 (en) * | 2006-10-03 | 2008-05-01 | Wyeth | Lyophilization methods and apparatuses |
EP2039658B1 (en) * | 2007-09-20 | 2020-01-01 | Ulrich Kubinger | Use of a coagulant and flocculent comprising nanoparticles for treating water and water treatment method |
US20150101980A1 (en) * | 2013-10-10 | 2015-04-16 | Nano And Advanced Materials Institute Limited | Household water filter element for removing radioactive substances |
US9731227B2 (en) * | 2013-10-10 | 2017-08-15 | Nano And Advanced Materials Institute Limited | Household water filter element for removing radioactive substances |
Also Published As
Publication number | Publication date |
---|---|
KR100788118B1 (en) | 2007-12-21 |
TWI255735B (en) | 2006-06-01 |
WO2002026632A1 (en) | 2002-04-04 |
AU2002212269A1 (en) | 2002-04-08 |
BR0114178A (en) | 2003-07-22 |
CN1466548B (en) | 2013-01-02 |
ATE503726T1 (en) | 2011-04-15 |
CA2423174C (en) | 2012-10-23 |
US20080274043A1 (en) | 2008-11-06 |
CA2423174A1 (en) | 2003-03-21 |
JP2004509752A (en) | 2004-04-02 |
EP1328476A1 (en) | 2003-07-23 |
KR20030036832A (en) | 2003-05-09 |
JP5113975B2 (en) | 2013-01-09 |
EP1328476B1 (en) | 2011-03-30 |
BR0114178B1 (en) | 2011-12-27 |
US7651973B2 (en) | 2010-01-26 |
DE50115834D1 (en) | 2011-05-12 |
CN1466548A (en) | 2004-01-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7651973B2 (en) | Contact and adsorbent granules | |
US7767001B2 (en) | Contact and adsorbent granules | |
US7811360B2 (en) | Contact and adsorbent granules | |
US7942953B2 (en) | Adsorption vessels | |
CA2423178C (en) | Adsorption container and iron oxide adsorber | |
DE10115415A1 (en) | Filtration unit for removing pollutants from fluids, especially water, comprises agglomerates of finely divided iron oxide and oxyhydroxide | |
DE10129304A1 (en) | Filtration unit for removing pollutants from fluids, especially water, comprises agglomerates of finely divided iron oxide and oxyhydroxide |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: BAYER AKTIENGESELLSCHAFT, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SCHLEGEL, ANDREAS;REEL/FRAME:012583/0636 Effective date: 20011024 |
|
AS | Assignment |
Owner name: LANXESS DEUTSCHLAND GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BAYER AG;REEL/FRAME:018584/0319 Effective date: 20061122 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |