CA1042573A - Method for precoating a filter with anion-cation exchange resins - Google Patents
Method for precoating a filter with anion-cation exchange resinsInfo
- Publication number
- CA1042573A CA1042573A CA229,434A CA229434A CA1042573A CA 1042573 A CA1042573 A CA 1042573A CA 229434 A CA229434 A CA 229434A CA 1042573 A CA1042573 A CA 1042573A
- Authority
- CA
- Canada
- Prior art keywords
- anion
- exchange resin
- resins
- cation exchange
- filter
- 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.)
- Expired
Links
Classifications
-
- 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
- B01J47/00—Ion-exchange processes in general; Apparatus therefor
- B01J47/12—Ion-exchange processes in general; Apparatus therefor characterised by the use of ion-exchange material in the form of ribbons, filaments, fibres or sheets, e.g. membranes
- B01J47/133—Precoat filters
Abstract
ABSTRACT OF THE DISCLOSURE
An improved method for precoating a filter with a mixture of anion and cation exchange resin particles in the size range of about 60 to 400 mesh is provided, wherein a floc of anion and cation exchange resins is formed by mixing these resins in aqueous suspension at elevated temperatures in the range of about 100 to 212°F. and coating these resins onto a filter.
An improved method for precoating a filter with a mixture of anion and cation exchange resin particles in the size range of about 60 to 400 mesh is provided, wherein a floc of anion and cation exchange resins is formed by mixing these resins in aqueous suspension at elevated temperatures in the range of about 100 to 212°F. and coating these resins onto a filter.
Description
SPECIFICATION
.. ~
The present invention relates to an improved method for precoating a filter with a mi~ture of anion and cation exchange resin particles.
In U. S. Patent No. 3,250,703, issued May 10, 1966, -and assigned to the assignee of this application, there is described a method and apparatus for removing impurities -from liquids by passing these liquids through a filter screen .... . ..
that has been precoated with lon exchanga resin particles in the size range of about 60 to 400 mesh. In U. S. Patent -~
No. 3,250,702, dated May 10, 1966, and assigned to the ~ -assignee of this application, there is described a method ~- ~ for purifying liquids by precoating such a filter screen with a mixture of both anion and cation exchange resin particles -in the size-range of about 60 to 400 mesh. Generally, this method is carried out by combining the two resins in aqueous suspension, causing the resins to agglomerate or "clump"
with one another to form larger particles. Because of the formation of these larger particles, a greater void space is provided in a bed of finely divided resin particles so that there is less resistance to flow of liquid through the filter bed, and therefore a lower pressure drop across the fiIters.
The "clumping" of the resins also produces a greater depth o~ filtration together with increased efficiency in removin~
suspended particles from the stream being filtered.
For a number o~ reasons, it is desirable to emplor as high a ratio of cation to anion exchange resin as possible in ca~rrying out the method described in the aforementioned patents. The primary reason for this is that the cation -exchange resin is significantly less expensive than the 30 anion exchange resin, and also has less of a tendency to , ~ degrade with age and exposure to heat. E~owever, it has been found that, with freshly manufactured resin, the maximum ratio of cation to anion exchange resin that produces an acceptable level of clumping for use in the aforementioned method and appar-atus is about 5 to 1 on a dry weight basis. Beyond this ratio, it has been found that a portion of the cation exchange resin does not clump, causing the pressure drop across the filter bed to become excessively high, so that the run length for the filter is shortened. As the resins age, it has been found that the proportion of cation exchange resin;that can be employed is reduced even further.
Generally, the present invention relates to an improved method for precoating a filter with a mixture of anion and cation exchange resin particles in the size range of about 60 to 400 mesh. In carrying out the method, a floc of the resins is formed by mixing the anion and cation exchange resin particles in aqueous suspension at elevated temperatures of about 100 to 212F whereby to cause said reslns to agglomerate with one ~-~
another to form larger particles, and then coating the resins ~20 onto a filter. When carrying out ~his method, the maximum ratio of cation to anion exchange resin is significantly in-creased, and this increase is particularly dramatic in the case of resins that have degraded because of aging.
.
More specifically, it has been found that complete "clumping" of anion and cation exchange resins at high cation:
anion resin ratios may be produced by combining the resin par-ticles in the si~e range of abo~t 60 to 400 mesh in aqueous suspension at elevated temperatures of about 100 to 212F.
and preferably to the range of about 125 to 212F. The pro-duction of csmplete clumping is observed by the absence offines in the supernate above the~clumped resin particles.
.. ~
The present invention relates to an improved method for precoating a filter with a mi~ture of anion and cation exchange resin particles.
In U. S. Patent No. 3,250,703, issued May 10, 1966, -and assigned to the assignee of this application, there is described a method and apparatus for removing impurities -from liquids by passing these liquids through a filter screen .... . ..
that has been precoated with lon exchanga resin particles in the size range of about 60 to 400 mesh. In U. S. Patent -~
No. 3,250,702, dated May 10, 1966, and assigned to the ~ -assignee of this application, there is described a method ~- ~ for purifying liquids by precoating such a filter screen with a mixture of both anion and cation exchange resin particles -in the size-range of about 60 to 400 mesh. Generally, this method is carried out by combining the two resins in aqueous suspension, causing the resins to agglomerate or "clump"
with one another to form larger particles. Because of the formation of these larger particles, a greater void space is provided in a bed of finely divided resin particles so that there is less resistance to flow of liquid through the filter bed, and therefore a lower pressure drop across the fiIters.
The "clumping" of the resins also produces a greater depth o~ filtration together with increased efficiency in removin~
suspended particles from the stream being filtered.
For a number o~ reasons, it is desirable to emplor as high a ratio of cation to anion exchange resin as possible in ca~rrying out the method described in the aforementioned patents. The primary reason for this is that the cation -exchange resin is significantly less expensive than the 30 anion exchange resin, and also has less of a tendency to , ~ degrade with age and exposure to heat. E~owever, it has been found that, with freshly manufactured resin, the maximum ratio of cation to anion exchange resin that produces an acceptable level of clumping for use in the aforementioned method and appar-atus is about 5 to 1 on a dry weight basis. Beyond this ratio, it has been found that a portion of the cation exchange resin does not clump, causing the pressure drop across the filter bed to become excessively high, so that the run length for the filter is shortened. As the resins age, it has been found that the proportion of cation exchange resin;that can be employed is reduced even further.
Generally, the present invention relates to an improved method for precoating a filter with a mixture of anion and cation exchange resin particles in the size range of about 60 to 400 mesh. In carrying out the method, a floc of the resins is formed by mixing the anion and cation exchange resin particles in aqueous suspension at elevated temperatures of about 100 to 212F whereby to cause said reslns to agglomerate with one ~-~
another to form larger particles, and then coating the resins ~20 onto a filter. When carrying out ~his method, the maximum ratio of cation to anion exchange resin is significantly in-creased, and this increase is particularly dramatic in the case of resins that have degraded because of aging.
.
More specifically, it has been found that complete "clumping" of anion and cation exchange resins at high cation:
anion resin ratios may be produced by combining the resin par-ticles in the si~e range of abo~t 60 to 400 mesh in aqueous suspension at elevated temperatures of about 100 to 212F.
and preferably to the range of about 125 to 212F. The pro-duction of csmplete clumping is observed by the absence offines in the supernate above the~clumped resin particles.
- 2 -~,-.
, , ~ ' : : ' ' ' ` ' ' :
:, .. . ~ ~ , ` , ¦ The clumping o~ anion and cation exchange resin particles is preferably carried out by combining the par- -ticles in aqueous suspension a-t a concentration of about 4~ dry resin by weight, although this concentration is by no means critical. The volume of the clumped resin is then measured by the "V/V ratio," which is determined by withdrawing one liter of the suspension in a graduated cylinder, and observing the percent of the cylinder volume that is filled with resin. In general, an acceptable range is 40-70~ resin volume/total volume of slurry. When complete clumping is produced, there is also an absence of cloudiness in the supernate above the clumped resin partlcles, indicating ` an absence of un-clumped particles or fines in aqueous sus-pension.
If an excessive V/V is produced, e., above 70~
the volume may be réduced in accordance with the method des-cribed in U. S. Patent No. 3,250,704, dated May 10, 1966, s ~ which is assigned to the assignee of this application. ~;
,,., ~
In some instances, a V/V below the level referred to above -is desired, i.e., when there is a very large concentration .,s ~ ::
of iron oxides in the liquid stream being treated, so that a higher pressure drop is desired. However, in general, it is desired to maintain the V/V in the 40-70~ range.
The method o~ the present invention is applicable to any of the typical ion exchange resin particles. Typical cation exchange resin particles which may be employed in the present invention are the divinylbenzene-sLyrene copolymer type, the acrylic type, the sulfonated coal type, and the phenolic type. These may be used in the sodium, hydrogen, ;
ammonium, or hydrazine form, for example. Typical solid , I .
., ~
,, : ~ ' ,.. , ..................... . . . . ,' .
anion ~chan~ resin p~Lti~le~ th~t may be employed in the presen- invention are the yhenol-formal~ellyde tvpe, the divinylben_en~-styren~ copolymer type, tlle acrylic type, and the epo~y type. Tht~ anion resin narticles may be used in th~ hydro.~ide or chloride form, for exa~ple. These anion and cation e~chang~ resins are well Xnown in the art in the large oead form, i.e., in the si7e range of ~0-50 ~esh.
For e~ample, such resins are sold in the large bead form under the trade marks Amberlite IR-170 and IR~^~00, sold by Rohm ~ Haas Co., and Dowe~ HCR-S and SBR-P, sold by the Dow Chemical Company. The finely divided resins employed in the present invention are made by reducing the size of these --.~ well known large bead resins to the desired range. The .~. - finely divided resin particles are regenerated and washed prior to use, as with large bead resin particles.
The filter screens to which the precoat i~ applied may be of any shape without departing from the spirit of the present invention, although cylindrical, wound filter elements are generally employed. -The following e~amples are intended to illustrate the present invention, and should not be construed as ;
limitati~e.
.; .
:: .
- E~amDle I
In the following series of tests, the ma~imum c~tion `~ to anion e~change resin ratio that would produce complete f - clumping was determined, as evidenced by the presence of a cle~r supernate. In carrying out the tests 7 a total o~ -about 4 grams o~ cation and anion e~change resins ias em21Oyed.
., , .e~.- . I
. . .
; , . `. ~ , :
: ' . .~ , - .
' The tests were conducted in a one-liter beaker equipped with a heater, a thermometer, and a mechanical stirrer. The anion exchange resin was first placed in saspension and stirred for 5 minutes, after which the cation exchange resin was added, followed by stirring for another 5 minutes. The suspension was allowed to stand for 10 minutes, and the supernate was observed for clarity. The maximum cation:anion exchanqe resin ratio was the highest ratio that produced a clear supernate.
The resins employed were about 180 days old, and, as indicated below, produced a clear supernate at a maximum cation:
anion exchange ratio of only 3.8:1 on a dry weight basis at room temperature. The cation resin was a divinylbenzene-styrene co-polymer tYpe, having sulfonic acid active groups. The anion ~
exchange resin employed was also of the divinylbenzene-styrene -copolymer type, and having the quaternary ammonium acti~e groups. ~ -' The cation exchange resin was in the ammonium form and the anion -~i exchange resin was in the hydroxide form.
;Water Temperature (F.) Maximum Cation: Anion Ratio ,; .
70 ~ 3.8~
~`~ 20 100 4.8:1 125 5.9:1 155 8:1 As can be seen from the foregoing table, an increase in .
~ the temperature at which the anion and cation exchange resins , are mixed produces a substantial increase in the maximum - ratio of cation to anion exchange resin, enabling the economical . formation of high-e~ficiency precoats.
~: :
.
'~
~ - 5 -,~Atq`;
, ..~
, . . . . . . .
.;
.: ' .~ . . ' , .
104;~S73 A sIurry o~ ion e~change resin particles prepared as - above may be precoated onto 3 filter scre~n, such as a tubu-lar wound nylon Eilter elem~nt, b~ simply r~circulating the slurry through the element until the effluent stream is clear, according to methods tha; are well ~nown in the art. Such methods are described, for e~ample, in U. S. Patents ~os.
j,250,703 and ~,;7;,10i, which are assigned to the assignee of this application. Preferably, the filters are precoated by recirculating a slurry havino a reduced resin concentration 10 of about 0.5~. ~
':
Example II
A second series o tests was conducted with cation - and anion exchange resins of the same type as employed in --Example I. In this instance, the cation exchange resin was about two and one-half years old, while the anion exchanoe resin was about two months old. The cation e~change resin had therefore undergone a significant amount of age degrada-tion, as indicated by the impossibility of forming a clear supernate at room temperature with a a.9:1 ca;ion:anion ratio.
.
` As in Example I, the tests were conducted in a one-liter beaker equipped with a heater, a thermometer, and a mechanical stirrer. The beaker contained about 700 ml of deioni7ed water, and 17.2 grams o~ anion e~change resin and 67 grams of cation e~ch~nge resin were added. A clear super-nate could not be produced at room temperature ~71F.)~
The hot plate was turned on, and the liquid was heated slowly with stirring until the supern~te was clear. This result was achieved at 160F. Enough cation e~chan~e resin 30 was then added to produce a supernate which appeared to have - ~ ~
.. .` ~ . , ~ , .. .
104'~573
, , ~ ' : : ' ' ' ` ' ' :
:, .. . ~ ~ , ` , ¦ The clumping o~ anion and cation exchange resin particles is preferably carried out by combining the par- -ticles in aqueous suspension a-t a concentration of about 4~ dry resin by weight, although this concentration is by no means critical. The volume of the clumped resin is then measured by the "V/V ratio," which is determined by withdrawing one liter of the suspension in a graduated cylinder, and observing the percent of the cylinder volume that is filled with resin. In general, an acceptable range is 40-70~ resin volume/total volume of slurry. When complete clumping is produced, there is also an absence of cloudiness in the supernate above the clumped resin partlcles, indicating ` an absence of un-clumped particles or fines in aqueous sus-pension.
If an excessive V/V is produced, e., above 70~
the volume may be réduced in accordance with the method des-cribed in U. S. Patent No. 3,250,704, dated May 10, 1966, s ~ which is assigned to the assignee of this application. ~;
,,., ~
In some instances, a V/V below the level referred to above -is desired, i.e., when there is a very large concentration .,s ~ ::
of iron oxides in the liquid stream being treated, so that a higher pressure drop is desired. However, in general, it is desired to maintain the V/V in the 40-70~ range.
The method o~ the present invention is applicable to any of the typical ion exchange resin particles. Typical cation exchange resin particles which may be employed in the present invention are the divinylbenzene-sLyrene copolymer type, the acrylic type, the sulfonated coal type, and the phenolic type. These may be used in the sodium, hydrogen, ;
ammonium, or hydrazine form, for example. Typical solid , I .
., ~
,, : ~ ' ,.. , ..................... . . . . ,' .
anion ~chan~ resin p~Lti~le~ th~t may be employed in the presen- invention are the yhenol-formal~ellyde tvpe, the divinylben_en~-styren~ copolymer type, tlle acrylic type, and the epo~y type. Tht~ anion resin narticles may be used in th~ hydro.~ide or chloride form, for exa~ple. These anion and cation e~chang~ resins are well Xnown in the art in the large oead form, i.e., in the si7e range of ~0-50 ~esh.
For e~ample, such resins are sold in the large bead form under the trade marks Amberlite IR-170 and IR~^~00, sold by Rohm ~ Haas Co., and Dowe~ HCR-S and SBR-P, sold by the Dow Chemical Company. The finely divided resins employed in the present invention are made by reducing the size of these --.~ well known large bead resins to the desired range. The .~. - finely divided resin particles are regenerated and washed prior to use, as with large bead resin particles.
The filter screens to which the precoat i~ applied may be of any shape without departing from the spirit of the present invention, although cylindrical, wound filter elements are generally employed. -The following e~amples are intended to illustrate the present invention, and should not be construed as ;
limitati~e.
.; .
:: .
- E~amDle I
In the following series of tests, the ma~imum c~tion `~ to anion e~change resin ratio that would produce complete f - clumping was determined, as evidenced by the presence of a cle~r supernate. In carrying out the tests 7 a total o~ -about 4 grams o~ cation and anion e~change resins ias em21Oyed.
., , .e~.- . I
. . .
; , . `. ~ , :
: ' . .~ , - .
' The tests were conducted in a one-liter beaker equipped with a heater, a thermometer, and a mechanical stirrer. The anion exchange resin was first placed in saspension and stirred for 5 minutes, after which the cation exchange resin was added, followed by stirring for another 5 minutes. The suspension was allowed to stand for 10 minutes, and the supernate was observed for clarity. The maximum cation:anion exchanqe resin ratio was the highest ratio that produced a clear supernate.
The resins employed were about 180 days old, and, as indicated below, produced a clear supernate at a maximum cation:
anion exchange ratio of only 3.8:1 on a dry weight basis at room temperature. The cation resin was a divinylbenzene-styrene co-polymer tYpe, having sulfonic acid active groups. The anion ~
exchange resin employed was also of the divinylbenzene-styrene -copolymer type, and having the quaternary ammonium acti~e groups. ~ -' The cation exchange resin was in the ammonium form and the anion -~i exchange resin was in the hydroxide form.
;Water Temperature (F.) Maximum Cation: Anion Ratio ,; .
70 ~ 3.8~
~`~ 20 100 4.8:1 125 5.9:1 155 8:1 As can be seen from the foregoing table, an increase in .
~ the temperature at which the anion and cation exchange resins , are mixed produces a substantial increase in the maximum - ratio of cation to anion exchange resin, enabling the economical . formation of high-e~ficiency precoats.
~: :
.
'~
~ - 5 -,~Atq`;
, ..~
, . . . . . . .
.;
.: ' .~ . . ' , .
104;~S73 A sIurry o~ ion e~change resin particles prepared as - above may be precoated onto 3 filter scre~n, such as a tubu-lar wound nylon Eilter elem~nt, b~ simply r~circulating the slurry through the element until the effluent stream is clear, according to methods tha; are well ~nown in the art. Such methods are described, for e~ample, in U. S. Patents ~os.
j,250,703 and ~,;7;,10i, which are assigned to the assignee of this application. Preferably, the filters are precoated by recirculating a slurry havino a reduced resin concentration 10 of about 0.5~. ~
':
Example II
A second series o tests was conducted with cation - and anion exchange resins of the same type as employed in --Example I. In this instance, the cation exchange resin was about two and one-half years old, while the anion exchanoe resin was about two months old. The cation e~change resin had therefore undergone a significant amount of age degrada-tion, as indicated by the impossibility of forming a clear supernate at room temperature with a a.9:1 ca;ion:anion ratio.
.
` As in Example I, the tests were conducted in a one-liter beaker equipped with a heater, a thermometer, and a mechanical stirrer. The beaker contained about 700 ml of deioni7ed water, and 17.2 grams o~ anion e~change resin and 67 grams of cation e~ch~nge resin were added. A clear super-nate could not be produced at room temperature ~71F.)~
The hot plate was turned on, and the liquid was heated slowly with stirring until the supern~te was clear. This result was achieved at 160F. Enough cation e~chan~e resin 30 was then added to produce a supernate which appeared to have - ~ ~
.. .` ~ . , ~ , .. .
104'~573
3 particle concelltr~tion oE about i0 ppm. SLow heating was then continu~d until the superna-e ~gain be~me cle~r. This procedure was repe~ted until, ~bove a temper~ture of 207F., the productioll of bubbles in the w3ter disrupted and avitated the resin so th3t a cle~r supernate could not be produced.
The temp~ratures, together with the cation:anion e~change resin ratio (dry weight basi~l that produced a clear super-nate are shown in the following table: :
Water Tem~erature (F.~ Cation:Anion Ratio 10160 3.9:1 167 5.0:1 180 6.3:1 1~ 7.0:1 9 7.7:1 195 8.1:1 ., .
207 ~ 8.5:1 After the foregoing series of tests was completed, ~; the liquid was periodically agitated ~hile being allowed to -~
cool to room temperature. It was noted that the floc remained ~ -,~. . . . .
stable., as indicated by a clear supernate, down to a tempera-ture of 87F. Thus, a floc may be formed at high temperatures in accordance with the present invention and may then be precoated onto a filter without the floc becoming unstable Y~ turing moderate temperature drops or during the filtration ; of liquids having a temperature only slightly above room temper~ture.
. Obviou~ly, many modifications and variations of the invention as hereinbefore set forth will occur to those skilled in the ~rt, and it is intended to cover in the appended claims a0 all such modific3tions 3nd vari3tions ~s f~ll within the tru~
spirit and scope of the invention.
" ~ , A'-- ~ ` ,. .
. . . . .
The temp~ratures, together with the cation:anion e~change resin ratio (dry weight basi~l that produced a clear super-nate are shown in the following table: :
Water Tem~erature (F.~ Cation:Anion Ratio 10160 3.9:1 167 5.0:1 180 6.3:1 1~ 7.0:1 9 7.7:1 195 8.1:1 ., .
207 ~ 8.5:1 After the foregoing series of tests was completed, ~; the liquid was periodically agitated ~hile being allowed to -~
cool to room temperature. It was noted that the floc remained ~ -,~. . . . .
stable., as indicated by a clear supernate, down to a tempera-ture of 87F. Thus, a floc may be formed at high temperatures in accordance with the present invention and may then be precoated onto a filter without the floc becoming unstable Y~ turing moderate temperature drops or during the filtration ; of liquids having a temperature only slightly above room temper~ture.
. Obviou~ly, many modifications and variations of the invention as hereinbefore set forth will occur to those skilled in the ~rt, and it is intended to cover in the appended claims a0 all such modific3tions 3nd vari3tions ~s f~ll within the tru~
spirit and scope of the invention.
" ~ , A'-- ~ ` ,. .
. . . . .
Claims (6)
1. A method for precoating a filter with a mixture of anion and cation exchange resin particles in the size range of about 60 to 400 mesh comprising: mixing said anion and cation exchange resins in aqueous suspension at a temperature of about 100 to 212°F., whereby to cause said resins to agglomerate with one another to form larger particles; and coating said resins onto a filter.
2. A method as defined in Claim 1 wherein said temperature is about 125 to 212°F.
3. The method as defined in Claim 1 wherein the ratio of said cation exchange resin to said anion exchange resin is at least about 5:1 on a dry weight basis.
4. The method as defined in Claim 3 wherein said temperature is about 125 to 212°F.
5. A method for precoating a filter with a mixture of anion and cation exchange resin particles comprising:
mixing cation and anion exchange resin particles in aqueous suspension at a temperature of at least about 100 to 212°F., said resin particles being in the size range of about 60 to 400 mesh, and said resins being of the styrene-divinylbenzene copolymer type, said cation exchange resin having sulfonic acid active groups and said anion exchange resin having quaternary ammonium active groups, the ratio of said cation exchange resin to said anion exchange resin being at least about 5:1 on a dry weight basis, whereby to cause said resins to agglomerate with one another to form larger particles;
and coating said resins onto a filter.
mixing cation and anion exchange resin particles in aqueous suspension at a temperature of at least about 100 to 212°F., said resin particles being in the size range of about 60 to 400 mesh, and said resins being of the styrene-divinylbenzene copolymer type, said cation exchange resin having sulfonic acid active groups and said anion exchange resin having quaternary ammonium active groups, the ratio of said cation exchange resin to said anion exchange resin being at least about 5:1 on a dry weight basis, whereby to cause said resins to agglomerate with one another to form larger particles;
and coating said resins onto a filter.
6. The method as defined in Claim 5 wherein said temperature is in the range of about 1.25 to 200°F.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/492,465 US4007301A (en) | 1974-07-29 | 1974-07-29 | Method for precoating a filter with a mixture of anion and cation exchange resin particles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1042573A true CA1042573A (en) | 1978-11-14 |
Family
ID=23956364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA229,434A Expired CA1042573A (en) | 1974-07-29 | 1975-06-16 | Method for precoating a filter with anion-cation exchange resins |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4007301A (en) |
| CA (1) | CA1042573A (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4267039A (en) * | 1977-12-05 | 1981-05-12 | Ecodyne Corporation | Fluid filtration method and apparatus |
| US4200695A (en) * | 1978-09-19 | 1980-04-29 | Rohm And Haas Company | Flocs for filtration and deionization prepared from cationic and anionic emulsion ion exchange resins |
| US4238329A (en) * | 1979-09-14 | 1980-12-09 | Industrial Filter Corporation | Process for recovering heavy metal using insoluble starch-xanthates |
| US4313832A (en) * | 1980-06-12 | 1982-02-02 | Rohm And Haas Company | Method for treatment of aqueous solutions with ion exchange fibers |
| US4704256A (en) * | 1980-09-23 | 1987-11-03 | California Institute Of Technology | Apparatus for the sequential performance of chemical processes |
| US4603114A (en) * | 1980-09-23 | 1986-07-29 | California Institute Of Technology | Method for the sequential performance of chemical processes |
| US5626820A (en) * | 1988-12-12 | 1997-05-06 | Kinkead; Devon A. | Clean room air filtering |
| US5582865A (en) * | 1988-12-12 | 1996-12-10 | Extraction Systems, Inc. | Non-woven filter composite |
| US5354476A (en) * | 1989-05-24 | 1994-10-11 | Toray Industries, Inc. | Method of treating water |
| US5346624A (en) * | 1993-01-11 | 1994-09-13 | The Graver Company | Method and apparatus for treatment of aqueous solutions |
| US5585171A (en) * | 1993-01-11 | 1996-12-17 | Graver Chemical | Adsorbent filter bed with pliant and stiff members |
| US5607647A (en) * | 1993-12-02 | 1997-03-04 | Extraction Systems, Inc. | Air filtering within clean environments |
| US5830361A (en) * | 1996-01-18 | 1998-11-03 | Demartino; Roberto | Method to improve performance in precoat filter demineralizers when applied as unique condensate treatment system in BWR condensate treatment system |
| JP2944504B2 (en) * | 1996-04-03 | 1999-09-06 | 三菱電機株式会社 | Insulating paint and printed wiring board having coating film of the paint |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2961417A (en) * | 1956-09-04 | 1960-11-22 | Dow Chemical Co | Method of manufacturing non-agglomerating mixed bed ion exchange resins and productsthereof |
| US3262891A (en) * | 1962-07-09 | 1966-07-26 | Diamond Alkali Co | Agglomeration prevention in anion exchange and mixed exchange resins using finely divided bentonite |
| US3250705A (en) * | 1963-03-08 | 1966-05-10 | Union Tank Car Co | Method of removing impurities from water at elevated temperatures |
| US3250703A (en) * | 1963-03-08 | 1966-05-10 | Union Tank Car Co | Process and apparatus for removing impurities from liquids |
| US3250704A (en) * | 1963-11-12 | 1966-05-10 | Union Tank Car Co | Method for removing impurities from water streams |
| GB1095267A (en) * | 1964-05-06 | 1967-12-13 | Permutit Co Ltd | Treatment of ion-exchange resins |
| US3339743A (en) * | 1964-07-16 | 1967-09-05 | Morris A Bealle | Portable water purifier |
| AU434130B2 (en) * | 1967-11-22 | 1973-03-27 | Commonwealth Scientific And Industrial Research Organization | Improved ion-exchange resins |
| US3558744A (en) * | 1968-01-05 | 1971-01-26 | Amicon Corp | Process for making polyelectrolyte complex resin |
| US3674686A (en) * | 1970-02-24 | 1972-07-04 | Laval Turbine | Filter precoating method |
-
1974
- 1974-07-29 US US05/492,465 patent/US4007301A/en not_active Expired - Lifetime
-
1975
- 1975-06-16 CA CA229,434A patent/CA1042573A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4007301A (en) | 1977-02-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1042573A (en) | Method for precoating a filter with anion-cation exchange resins | |
| US5855790A (en) | Magnetic particles, a method for the preparation thereof and their use in the purification of solutions | |
| US3573277A (en) | Cellulosic ion exchange materials and method of making | |
| US5346624A (en) | Method and apparatus for treatment of aqueous solutions | |
| US3250704A (en) | Method for removing impurities from water streams | |
| JP5934738B2 (en) | Method for granulating adsorbent and adsorbent granules produced by the method | |
| EP0103875B1 (en) | Packing for chromatography | |
| US3254034A (en) | Aluminosilicate processing | |
| Bauman et al. | Dowex 50 | |
| US2460516A (en) | Ion-exchange resin | |
| US3717594A (en) | Stabilizing cation resins | |
| JP3594492B2 (en) | Condensate desalination equipment | |
| US3441515A (en) | Method for manufacturing improved perlite filteraid products | |
| EP0428868B1 (en) | Materials for removing suspended impurities | |
| US5308876A (en) | Materials for removing suspended impurities and use thereof | |
| US3409566A (en) | Method of grinding strong base ion exchange resins in the hydroxide form | |
| CA1171839A (en) | Process for the preparation of adsorbent materials | |
| US2400465A (en) | Catalytic conversion of hydrocarbons | |
| CA1247762A (en) | Method for treating aqueous solutions with weakly acidic cation exchange resins | |
| US3433748A (en) | Process for forming silica-alumina hydrocarbon conversion catalysts | |
| US4313844A (en) | Inorganic ion exchanger | |
| EP0149792B1 (en) | Method for treating aqueous solutions with weakly acidic cation exhange resins | |
| US4568466A (en) | Method for pretreating aqueous solutions with weakly acidic cation exchange resins | |
| JPH03232528A (en) | Adsorbent and method for removing suspended impurities | |
| US4548717A (en) | Method for treating aqueous solutions with weakly acidic cation exchange resins |