WO1990011120A1 - Ultrafiltration membrane - Google Patents
Ultrafiltration membrane Download PDFInfo
- Publication number
- WO1990011120A1 WO1990011120A1 PCT/CA1990/000090 CA9000090W WO9011120A1 WO 1990011120 A1 WO1990011120 A1 WO 1990011120A1 CA 9000090 W CA9000090 W CA 9000090W WO 9011120 A1 WO9011120 A1 WO 9011120A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- membrane
- extrafiltrator
- solution
- water
- amount
- Prior art date
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 97
- 238000000108 ultra-filtration Methods 0.000 title claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 49
- 239000011148 porous material Substances 0.000 claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 20
- 239000000463 material Substances 0.000 claims abstract description 19
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 18
- XPFVYQJUAUNWIW-UHFFFAOYSA-N furfuryl alcohol Chemical compound OCC1=CC=CO1 XPFVYQJUAUNWIW-UHFFFAOYSA-N 0.000 claims abstract description 13
- HYBBIBNJHNGZAN-UHFFFAOYSA-N furfural Chemical compound O=CC1=CC=CO1 HYBBIBNJHNGZAN-UHFFFAOYSA-N 0.000 claims abstract description 10
- YLQBMQCUIZJEEH-UHFFFAOYSA-N Furan Chemical compound C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000003085 diluting agent Substances 0.000 claims abstract description 8
- 239000004014 plasticizer Substances 0.000 claims abstract description 8
- 238000000746 purification Methods 0.000 claims abstract description 8
- 239000002904 solvent Substances 0.000 claims abstract description 8
- -1 polypropylene Polymers 0.000 claims description 11
- 229920005989 resin Polymers 0.000 claims description 10
- 239000011347 resin Substances 0.000 claims description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 8
- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 claims description 8
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 239000000835 fiber Substances 0.000 claims description 6
- 239000001117 sulphuric acid Substances 0.000 claims description 6
- 235000011149 sulphuric acid Nutrition 0.000 claims description 6
- 239000004094 surface-active agent Substances 0.000 claims description 6
- KIWBPDUYBMNFTB-UHFFFAOYSA-N Ethyl hydrogen sulfate Chemical compound CCOS(O)(=O)=O KIWBPDUYBMNFTB-UHFFFAOYSA-N 0.000 claims description 5
- 239000004743 Polypropylene Substances 0.000 claims description 5
- 229920002678 cellulose Polymers 0.000 claims description 5
- 239000001913 cellulose Substances 0.000 claims description 5
- 230000008021 deposition Effects 0.000 claims description 5
- 229920001155 polypropylene Polymers 0.000 claims description 5
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 4
- 150000001298 alcohols Chemical class 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 claims description 4
- 239000004677 Nylon Substances 0.000 claims description 3
- 150000008430 aromatic amides Chemical class 0.000 claims description 3
- CSKNSYBAZOQPLR-UHFFFAOYSA-N benzenesulfonyl chloride Chemical compound ClS(=O)(=O)C1=CC=CC=C1 CSKNSYBAZOQPLR-UHFFFAOYSA-N 0.000 claims description 3
- 150000002148 esters Chemical class 0.000 claims description 3
- 239000007849 furan resin Substances 0.000 claims description 3
- 229920005546 furfural resin Polymers 0.000 claims description 3
- 229910017053 inorganic salt Inorganic materials 0.000 claims description 3
- 150000002576 ketones Chemical class 0.000 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- 229920001778 nylon Polymers 0.000 claims description 3
- 239000012466 permeate Substances 0.000 claims description 3
- 238000006116 polymerization reaction Methods 0.000 claims description 3
- DAJSVUQLFFJUSX-UHFFFAOYSA-M sodium;dodecane-1-sulfonate Chemical compound [Na+].CCCCCCCCCCCCS([O-])(=O)=O DAJSVUQLFFJUSX-UHFFFAOYSA-M 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 2
- 150000003242 quaternary ammonium salts Chemical class 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims 1
- 230000003247 decreasing effect Effects 0.000 claims 1
- 238000007865 diluting Methods 0.000 claims 1
- 239000012510 hollow fiber Substances 0.000 claims 1
- 238000001914 filtration Methods 0.000 abstract description 3
- 238000002360 preparation method Methods 0.000 abstract 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 9
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 235000019441 ethanol Nutrition 0.000 description 7
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 6
- 239000008213 purified water Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- 241000894006 Bacteria Species 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000008399 tap water Substances 0.000 description 3
- 235000020679 tap water Nutrition 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 235000020188 drinking water Nutrition 0.000 description 2
- 239000003651 drinking water Substances 0.000 description 2
- KIWBPDUYBMNFTB-UHFFFAOYSA-M ethyl sulfate Chemical compound CCOS([O-])(=O)=O KIWBPDUYBMNFTB-UHFFFAOYSA-M 0.000 description 2
- GQPLMRYTRLFLPF-UHFFFAOYSA-N nitrous oxide Inorganic materials [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 1
- 230000000711 cancerogenic effect Effects 0.000 description 1
- 231100000315 carcinogenic Toxicity 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 229960001701 chloroform Drugs 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 239000000645 desinfectant Substances 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 230000002070 germicidal effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 230000002335 preservative effect Effects 0.000 description 1
- 239000000941 radioactive substance Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L sodium sulphate Substances [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/106—Membranes in the pores of a support, e.g. polymerized in the pores or voids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/52—Polyethers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/02—Forward flushing
Definitions
- This invention relates to the field of filtration membranes for use in purification of water.
- ⁇ purifier for use in such systems.
- One such purifier is a fibre filter.
- Another such purifier is more comprehensive and includes an activated charcoal filter, a germicidal system which may use ultraviolet light and a hollow fibre extrafiltrator. Either of these purification systems are connected to a building's water system and the purified water is typically consumed after it has either been heated or cooled.
- the present invention provides an ultrafiltration membrane formed on an extrafiltrator for use in a water purification system, said ultrafiltration membrane comprising: a membrane material selected from the group of resins consisting of furan, furfural, furfurone, furfuronal and furfuryl alcohol; said membrane having a thickness of from 50 microns to 40,000 microns; said membrane having pores with a diameter of from 5 ⁇ A to lOOA; and, said membrane having been formed dynamically within the pores of said extrafiltrator.
- a method for forming an ultrafiltration membrane on an extrafiltrator comprising the steps of: preparing a membrane forming solution by dissolving a membrane forming material in a solvent and adding to the solution so obtained, a diluent, a plasticizer, a curing agent and a pore forming agent; and, passing said membrane forming solution through said extrafiltrator to cause a membrane to deposit within the pores of said extrafiltrator, and permitting the membrane so deposited to crosslink and fixate in said pores.
- a method for filtering water using an ultrafiltration membrane deposited on an extrafiltrator including the steps of: passing water through an extrafiltrator having an ultrafiltration membrane deposited thereon; and periodically stopping the flow of water into said extrafiltrator and allowing unfiltered water to drain from said extrafiltrator.
- Fig. 1 is a schematic diagram showing a process for membrane formation according to the present invention.
- Fig. 2 is a schematic diagram showing a water purification system using a membrane filter according to the present invention.
- a polymer material is used to form a membrane layer within the pores of the extrafiltrator of commercially available drinking water purification systems.
- the extrafiltrators may be any of the types comprising hollow fibres, spirally wound modules, or flat filters made from polypropylene, nylon, cellulose or aromatic amides having a pore diameter of from 0.02A to I.OA and being of a thickness from about 8 to 200 microns.
- the ultrafiltration membrane is an extra thick film which is able not only to remove low molecular weight organic substances that cannot be removed by the commercial extrafiltrator, but also the nitrous salts, metal salts, radioactive substances and suspended bacteria. Due to the thickness of the film, water can pass through with relatively small resistance thereby giving a relative high productivity per unit.
- a membrane forming material 1 is dissolved in a solvent 2, and a diluent 3, plasticizer 4, curing agent 5 and pore forming agent 6 are added to the solution 8.
- a commercial extrafiltrator 9 is connected by a pump 7 to the solution 8.
- the solution 8 is passed through the pores of the extrafiltrator and causes deposition of membrane forming material in the pores of the extrafiltrator.
- the membrane forming material condenses in the pores and is cross linked and fixated " therein. This results in an ultrafiltration membrane having a pore size significantly less than the original pore size of the extrafiltrator.
- the amount of polymerization of the pore forming agent and, accordingly, the size of the pore forming agent is controlled by controlling the pH of the membrane forming solution.
- Sodium hydroxide may be added at the outset to increase the pH of the solution which tends to suppress the molecular weight of the pore forming material.
- the pH of the solution is gradually reduced by the addition of sulphuric acid. This causes an increase in the amount of polymerization and, accordingly, an increase in the molecular weight of the pore forming material.
- the pore forming material will have the optimum molecular weight to deposit in the pores of the extrafiltrator to give a membrane of the desired separation qualities.
- an indicator such as phenolphthalein or xylenoblue may be added to the solution.
- the indicator concentration in the solution passing through the membrane may then be monitored, for example, using photometric means. Once the indicator concentration shows that the membrane has achieved the desired amount of separability, the passing of solution through the extrafiltrator is stopped.
- the membranes may be stored in a disinfectant and preservative solution.
- a suitable solution contains 1% ethyl alcohol, 5% glycerol and 1% formalin in water.
- Ultrafiltration membranes may be produced as described above using an extrafiltrator having the following properties as a substrate:
- Suitable membrane forming materials include furan resins such as furfural resin, furfuran resin, furfuronal resin, and furfuryl alcohol resin in concentrations of from 1 to 200 mg/1.
- Suitable diluents include lower alcohols and ketones such as Cl to C5 alcohols, in an amount of from 1 to 99% per volume of the membrane forming liquid.
- a suitable plasticizer is phthalic phosphoric ester in a concentration of from 0.5-500 mg/1.
- Suitable curing agents include benzene sulfonylchloride, ethyl sulfate and sulphuric acid in a concentration of from 0.9-5% by volume of the membrane forming solution.
- the pore forming agent may be a neutral soluble inorganic salt in a concentration of from 20-1500 mg/1 and a surfactant in a concentration of from 20-1500 mg/1.
- Suitable surfactants include alkyl sodium sulphate, quaternary ammonium salts and polyoxyethylene.
- a water purification system incorporating an ultrafiltration membrane as described above is illustrated in Figure 2.
- the system consists of a dynamically formed membrane module 10, three three-way electromagnetic valves 11, 12 and 13, a two-way electromagnetic valve 15 controlled by relay 14 for controlling water level, a relay or micro-computer 16 for controlling time, a water tank 17 and hot and cold water valves 18 and 19 respectively.
- relay 14 opens the two way electromagnetic valve 15 to permit tap water to pass therethrough.
- the tap water flows through the three-way electromagnetic valve 11 and into the membrane module 10.
- Purified water passing from the membrane module . 10 flows into the two three-way electromagnetic valves 12 and 13.
- Valve 13 is controlled by either a time relay or micro-computer indicated by reference 16.
- valve 13 For the first two to five minutes, the valve 13 is positioned so as to discharge water through a waste outlet 22 in order to flush the system. Once the system flushing time has expired, valve 13 is positioned so as to stop discharge through the waste outlet 22 and to cause purified water to drain into the tank 17 from the clean water outlet 23.
- Cool water is provided at outlet 18 through the use of water cooler 20.
- Hot water is provided at outlet 19 by means of water heater 21.
- the relay 14 for controlling water level will close the two-way electromagnetic valve 15 thereby shutting off water entry into the system from the water source.
- the three-way electromagnetic valves 11, 12 and 13 may periodically be activated so as to cause waste water from the membrane module 10 to be drained through the waste water outlet 22.
- Such periodic draining of the membrane module removes a portion of the contaminants from the non-filtered side of the module thereby reducing blockage and deposition of waste substances in the membrane module, increasing the life span of the module and optimizing both the flow rate through the module and the purified water quality.
- Example 1 The present invention may be further illustrated by reference to the following examples: Example 1
- the membrane forming solution 50 ppm furfurol alcohol was added to water. To this solution was added 1% ethyl alcohol, 0.1% polyoxyethylene. Sodium hydroxide was then added to this solution to adjust the pH to 8 and xylenoblue was added as an indicator. The pump was activated and operated at a pressure of 3 kg/cm 2 . After approximately 2-3 minutes, small amounts of sulphuric acid were added to lower the pH and the indicator concentration was measured with a photometer. After approximately 30 minutes, the solution had a pH of approximately 3 and the concentration of indicator in the permeate water as compared with the concentration of indicator remaining in the feedwater was approximately 95%.
- the extrafiltrator in this example contained a polypropylene hollow fibre module having a membrane thickness of 50 microns and a pore size of .6 microns.
- the membrane solution contained 50 ppm furol, .7% dibutic phthalate, water, acetone, ethyl sulphate, sodium dodecyl sulfonate and phenolphthalein.
- the solution was made by dissolving furol in acetone, dibutic phthalate and ethyl sulphate to form a first solution.
- This first solution was poured into water to achieve the above concentration and sodium dodecyl sulfonate was dissolved in the solution while adding phenolphthalein.
- the pump was turned on and operated at a pressure of approximately 3 kg/cm 2 . The pump was operated for approximately 60 minutes and the concentration of indicator measured using a photometer.
- the indicator concentration in the permeate was approximately 95% of that in the feedwater.
- the pump was stopped and the membrane was treated with a preserving solution containing 1% ethyl alcohol, 5% glycerol and 1% formalin in water.
Abstract
An ultrafiltration membrane is formed on an extrafiltrator for use in a water purification system. The ultrafiltration membrane has a membrane material which may be furan, furfural, furfona, furfonal and furfuryl alcohol. The membrane has a thickness of from 50 microns to 40,000 microns and contains pores having a diameter of from 50 Å to 100 Å. A method for forming such a membrane dynamically within the pores of an extrafiltrator is also provided. The method includes the preparation of a membrane forming solution containing a membrane forming material, a solvent, a diluent, a plasticizer, a curing agent and a pore forming agent and passing the membrane forming solution through the extrafiltrator to cause a membrane to deposit within the pores of the extrafiltrator, to crosslink and fixate in the pores. A method for filtering water using such an ultrafiltration membrane is provided. The method includes the steps of passing water through an extrafiltrator having such an ultrafiltration membrane deposited thereon and periodically stopping the flow of water into the extrafiltrator to allow unfiltered water to drain from the extrafiltrator.
Description
Title: Ultrafiltration Membrane
FIELD OF THE INVENTION
This invention relates to the field of filtration membranes for use in purification of water.
BACKGROUND OF THE INVENTION
Commercial drinking water systems, such as those used in offices, generally consist of a water purifier and either a cooler or heater. There are two common types of purifier for use in such systems. One such purifier is a fibre filter. Another such purifier is more comprehensive and includes an activated charcoal filter, a germicidal system which may use ultraviolet light and a hollow fibre extrafiltrator. Either of these purification systems are connected to a building's water system and the purified water is typically consumed after it has either been heated or cooled.
The benefits of the previous systems include the removal of pigment, suspended matter and free chlorine. These systems however have some shortcomings. Firstly, eventually the ability of the activated charcoal to adsorb the organic substances will be diminished, necessitating replacement of the activated charcoal filter after adsorption saturation. Prior to replacement, however, harmful nitrous salts and more bacteria may be formed by long-term interaction between the activated charcoal in the filter and bacteria in contact therewith.
Another disadvantage with these prior systems is that the hollow fibre extrafiltrators presently commercially available are not able to remove the low molecular weight organic substances in the tap water completely. These may include potentially carcinogenic substances such as trichloromethane, tetrochloromethane and non polar organic materials.
SUMMARY OF THE INVENTION
The present invention provides an ultrafiltration membrane formed on an extrafiltrator for use in a water purification system, said ultrafiltration membrane comprising: a membrane material selected from the group of resins consisting of furan, furfural, furfurone, furfuronal and furfuryl alcohol; said membrane having a thickness of from 50 microns to 40,000 microns; said membrane having pores with a diameter of from 5θA to lOOA; and, said membrane having been formed dynamically within the pores of said extrafiltrator. A method is also provided for forming an ultrafiltration membrane on an extrafiltrator, said method comprising the steps of: preparing a membrane forming solution by dissolving a membrane forming material in a solvent and adding to the solution so obtained, a diluent, a plasticizer, a curing agent and a pore forming agent; and, passing said membrane forming solution through said extrafiltrator to cause a membrane to deposit within the pores of said extrafiltrator, and permitting the membrane so deposited to crosslink and fixate in said pores.
A method is provided for filtering water using an ultrafiltration membrane deposited on an extrafiltrator, said method including the steps of: passing water through an extrafiltrator having an ultrafiltration membrane deposited thereon; and periodically stopping the flow of water into said extrafiltrator and allowing unfiltered water to drain from said extrafiltrator.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described below with
reference to the appended drawings which form a part of the specification and in which:
Fig. 1 is a schematic diagram showing a process for membrane formation according to the present invention; and.
Fig. 2 is a schematic diagram showing a water purification system using a membrane filter according to the present invention.
BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS According to the present invention, a polymer material is used to form a membrane layer within the pores of the extrafiltrator of commercially available drinking water purification systems. The extrafiltrators may be any of the types comprising hollow fibres, spirally wound modules, or flat filters made from polypropylene, nylon, cellulose or aromatic amides having a pore diameter of from 0.02A to I.OA and being of a thickness from about 8 to 200 microns. The ultrafiltration membrane is an extra thick film which is able not only to remove low molecular weight organic substances that cannot be removed by the commercial extrafiltrator, but also the nitrous salts, metal salts, radioactive substances and suspended bacteria. Due to the thickness of the film, water can pass through with relatively small resistance thereby giving a relative high productivity per unit.
Referring to Figure 1, the process of dynamic membrane formation is illustrated. A membrane forming material 1 is dissolved in a solvent 2, and a diluent 3, plasticizer 4, curing agent 5 and pore forming agent 6 are added to the solution 8.
Generally, >a commercial extrafiltrator 9 is connected by a pump 7 to the solution 8. When the pump is activated, the solution 8 is passed through the pores of the extrafiltrator and causes deposition of membrane forming material in the pores of the extrafiltrator. The membrane forming material condenses in the pores and is
cross linked and fixated" therein. This results in an ultrafiltration membrane having a pore size significantly less than the original pore size of the extrafiltrator.
The amount of polymerization of the pore forming agent and, accordingly, the size of the pore forming agent, is controlled by controlling the pH of the membrane forming solution. Sodium hydroxide may be added at the outset to increase the pH of the solution which tends to suppress the molecular weight of the pore forming material. As the solution is passed through the extrafiltrator, the pH of the solution is gradually reduced by the addition of sulphuric acid. This causes an increase in the amount of polymerization and, accordingly, an increase in the molecular weight of the pore forming material. Eventually, the pore forming material will have the optimum molecular weight to deposit in the pores of the extrafiltrator to give a membrane of the desired separation qualities.
In order to monitor the separation ability of the membrane, an indicator such as phenolphthalein or xylenoblue may be added to the solution. The indicator concentration in the solution passing through the membrane may then be monitored, for example, using photometric means. Once the indicator concentration shows that the membrane has achieved the desired amount of separability, the passing of solution through the extrafiltrator is stopped.
After membrane formation has been completed, the membranes may be stored in a disinfectant and preservative solution. A suitable solution contains 1% ethyl alcohol, 5% glycerol and 1% formalin in water.
Ultrafiltration membranes may be produced as described above using an extrafiltrator having the following properties as a substrate:
thickness of substrate 8 - 200 microns; pore diameter of substrate 0.02-1 microns;
material of substrate polypropylene, nylon, cellulose, aromatic amide; and shape of substrate hollow fibre, spiral- wound module and flat. Such membranes typically have a thickness of from 50 microns to 40,000 microns and a pore size of from 5θA to lOOA. Suitable membrane forming materials include furan resins such as furfural resin, furfuran resin, furfuronal resin, and furfuryl alcohol resin in concentrations of from 1 to 200 mg/1.
Suitable diluents include lower alcohols and ketones such as Cl to C5 alcohols, in an amount of from 1 to 99% per volume of the membrane forming liquid.
A suitable plasticizer is phthalic phosphoric ester in a concentration of from 0.5-500 mg/1.
Suitable curing agents include benzene sulfonylchloride, ethyl sulfate and sulphuric acid in a concentration of from 0.9-5% by volume of the membrane forming solution.
Water is typically used as the solvent and forms from 1 to 99% by volume of the membrane forming solution. The pore forming agent may be a neutral soluble inorganic salt in a concentration of from 20-1500 mg/1 and a surfactant in a concentration of from 20-1500 mg/1. Suitable surfactants include alkyl sodium sulphate, quaternary ammonium salts and polyoxyethylene.
A water purification system incorporating an ultrafiltration membrane as described above is illustrated in Figure 2. The system consists of a dynamically formed membrane module 10, three three-way electromagnetic valves 11, 12 and 13, a two-way electromagnetic valve 15 controlled by relay 14 for controlling water level, a relay or micro-computer 16 for controlling time, a water tank 17 and hot and cold water valves 18 and 19 respectively.
In use, when the tank 17 is empty, relay 14 opens the two way electromagnetic valve 15 to permit tap water to pass therethrough. The tap water flows through the three-way electromagnetic valve 11 and into the membrane module 10. Purified water passing from the membrane module . 10 flows into the two three-way electromagnetic valves 12 and 13. Valve 13 is controlled by either a time relay or micro-computer indicated by reference 16. For the first two to five minutes, the valve 13 is positioned so as to discharge water through a waste outlet 22 in order to flush the system. Once the system flushing time has expired, valve 13 is positioned so as to stop discharge through the waste outlet 22 and to cause purified water to drain into the tank 17 from the clean water outlet 23.
Cool water is provided at outlet 18 through the use of water cooler 20.
Hot water is provided at outlet 19 by means of water heater 21. When the water tank 17 is filled with purified water, the relay 14 for controlling water level will close the two-way electromagnetic valve 15 thereby shutting off water entry into the system from the water source.
The three-way electromagnetic valves 11, 12 and 13 may periodically be activated so as to cause waste water from the membrane module 10 to be drained through the waste water outlet 22. Such periodic draining of the membrane module removes a portion of the contaminants from the non-filtered side of the module thereby reducing blockage and deposition of waste substances in the membrane module, increasing the life span of the module and optimizing both the flow rate through the module and the purified water quality.
The present invention may be further illustrated by reference to the following examples: Example 1
An extrafiltrator made of the cellulose hollow
fibres manufactured in U.S.A. by Microgon and having a thickness of 50 microns and a pore size of .02 microns was used.
To make the membrane forming solution, 50 ppm furfurol alcohol was added to water. To this solution was added 1% ethyl alcohol, 0.1% polyoxyethylene. Sodium hydroxide was then added to this solution to adjust the pH to 8 and xylenoblue was added as an indicator. The pump was activated and operated at a pressure of 3 kg/cm2. After approximately 2-3 minutes, small amounts of sulphuric acid were added to lower the pH and the indicator concentration was measured with a photometer. After approximately 30 minutes, the solution had a pH of approximately 3 and the concentration of indicator in the permeate water as compared with the concentration of indicator remaining in the feedwater was approximately 95%.
At this point, the pump was stopped and a solution of 1% ethyl alcohol, 5% glycerol and 1% formalin was introduced into the membrane. Example 2
The extrafiltrator in this example contained a polypropylene hollow fibre module having a membrane thickness of 50 microns and a pore size of .6 microns.
The membrane solution contained 50 ppm furol, .7% dibutic phthalate, water, acetone, ethyl sulphate, sodium dodecyl sulfonate and phenolphthalein. The solution was made by dissolving furol in acetone, dibutic phthalate and ethyl sulphate to form a first solution. This first solution was poured into water to achieve the above concentration and sodium dodecyl sulfonate was dissolved in the solution while adding phenolphthalein. The pump was turned on and operated at a pressure of approximately 3 kg/cm2. The pump was operated for approximately 60 minutes and the concentration of indicator measured using a photometer. After approximately 60 minutes the indicator concentration in the permeate was approximately 95% of that in the feedwater. The pump was stopped and the
membrane was treated with a preserving solution containing 1% ethyl alcohol, 5% glycerol and 1% formalin in water.
It is to be understood that variations to the embodiment described above may be apparent to persons skilled in the relevant arts without departing from the spirit and scope of the invention as set out in the appended claims. It is to be understood that such variations or modifications are intended to be covered by this specification.
Claims
1. An ultrafiltration membrane formed on an extrafiltrator for use in a water purification system, said ultrafiltration membrane comprising: a membrane material selected from the group of resins consisting of furan, furfural, furfurone, furfuronal and furfuryl alcohol; said membrane having a thickness of from 50 microns to 40,000 microns; said membrane having pores with a diameter of from 5θA to lOOA; and, said membrane having been formed dynamically within the pores of said extrafiltrator.
2. An ultrafiltration filter as claimed in claim 1, wherein said membrane formation is achieved by passing a solution containing a membrane forming material, a solvent, a diluent, a plasticizer, a curing agent and a pore forming agent through said extrafiltrator; said extrafiltrator is made from a material selected from the group consisting of polypropylene, nylon, cellulose and aromatic amides; said extrafiltrator has a thickness of from 8 to 200 microns and a pore size of from .02 to 1 microns.
3. An ultrafiltration filter as claimed in claim 1 or 2, wherein said dynamically formed membrane material is a resin selected from the group consisting of furan resin, furfural resin, furfurone resin, furfuronal resin and furfuryl alcohol resin in a concentration of from 1 to 200 mg/1; said diluent is selected from the group consisting of lower alcohols and ketones in an amount of from 1 to 99% by volume of the membrane forming liquid; said plasticizer is phthalic phosphoric ester in a concentration of from 0.5 to 500 mg/1;
said curing agent is selected from the group comprising benzene sulfonyl chloride, ethyl sulfate, sulphuric acid in an amount from 0.9 to 5% by volume of the membrane forming solution; said solvent is water in an amount of from
1 to 99% of said membrane forming solution; and, said pore forming agent is a neutral soluble inorganic salt in a concentration of from 20 to 1500 mg/1 and a surfactant in a concentration of from 20 to 1500
4. A method for forming an ultrafiltration membrane on an extrafiltrator, said method comprising the steps of: preparing a membrane forming solution by combining a membrane forming material, a solvent, a diluent, a plasticizer, a curing agent and a pore forming agent; and, passing said membrane forming solution through said extrafiltrator to cause a membrane to deposit within the pores of said extrafiltrator, to crosslink and to fixate in said pores.
5. A method according to claim 4 wherein: said membrane material is a resin selected from the group consisting of furan resin, furfural resin, furfurone resin, furfuronal resin and furfuryl alcohol resin in an amount of from 1 to 200 mg/1; said diluent is selected from the group consisting of lower alcohols and ketones in an amount of from 1 to 99% by volume of said membrane forming solution; said plasticizer is phthalic phosphoric ester in an amount of from 0.5 to 500 mg/1. said curing agent is selected from the group consisting of benzene sulfonyl chloride, ethyl sulfate and sulphuric acid in an amount of from 0.9 to 5% by volume of said membrane forming solution; said solvent is water in an amount of from 1 to
99% by volume of said membrane forming solution; and said pore forming agent is a neutral soluble inorganic salt in an amount of from 20 to 1500 mg/1 and a surfactant in an amount of from 20 to 1500 mg/1.
6. A method according to claim 5 wherein: said surfactant is selected from the group consisting of alkylsodium sulfate, quaternary ammonium salt and polyoxyethylene; and the pH of the membrane forming solution is adjusted during membrane deposition to gradually increase the amount of polymerization of the membrane forming material.
7. A method according to claim 6 wherein an indicator is further added to the membrane forming solution and the indicator concentration in the membrane forming solution permeating through the extrafiltrator is monitored to determine the completeness of membrane deposition.
8. A method according to claim 7 wherein: said extrafiltrator is a cellulose hollow fiber module having a thickness of about 50 microns and a pore size of about 0.02 microns; said surfactant is polyoxyethylene in an amount of about 1% by weight of the membrane forming solution; sodium hydroxide is added to the membrane forming solution to give an initial pH of approximately 8; and, during membrane deposition the pH of the membrane forming solution is decreased to approximately 3 by the addition of sulphuric acid.
9. A method for forming an ultrafiltration membrane on an extrafiltrator which is a polypropylene hollow fibre module having a thickness of about 50 microns and a pore
size of about 6 microns, said method comprising the steps of: diluting furol with acetone, dibutic phthalate and ethyl sulfate to form a first solution which is subsequently combined with water to give a concentration of 50 ppm furol, .7% dibutic phthalate; 2% acetone and
1.5% ethyl sulfate; dissolving 1000 ppm sodium dodecyl sulfonate in said first solution and adding phenolphthalein to give a second solution; passing said second solution through said extrafiltrator at a pressure of about 3 kg/cm2; photometrically measuring the concentration of said indicator permeating through said extrafiltrator; ceasing passing of said second solution through said extrafiltrator when the concentration of indicator in said permeate reaches a desired value.
10. A method for purifying water using an ultrafiltration membrane deposited on an extrafiltrator, said method including the steps of: passing water through an extrafiltrator having an ultrafiltration membrane deposited thereon; and periodically stopping the flow of water into said extrafiltrator and allowing unfiltered water to drain from ultrafiltration membrane deposited on said extrafiltrator.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU53354/90A AU5335490A (en) | 1989-03-18 | 1990-03-16 | Ultrafiltration membrane |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN89101659.7A CN1045756A (en) | 1989-03-18 | 1989-03-18 | Full-automatic dynamically forms the film water cleaning systems |
EP89101659.7 | 1989-03-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1990011120A1 true WO1990011120A1 (en) | 1990-10-04 |
Family
ID=4854374
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA1990/000090 WO1990011120A1 (en) | 1989-03-18 | 1990-03-16 | Ultrafiltration membrane |
Country Status (2)
Country | Link |
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CN (1) | CN1045756A (en) |
WO (1) | WO1990011120A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7025885B2 (en) | 1998-11-23 | 2006-04-11 | Zenon Environmental Inc. | Water filtration using immersed membranes |
US7842637B2 (en) | 2008-05-23 | 2010-11-30 | Lumimove, Inc. | Electroactivated film with polymer gel electrolyte |
US7993495B2 (en) | 2005-06-21 | 2011-08-09 | Crosslink Polymer Research, a division of Lumimove, Inc. | Signal activated decontaminating coating |
USRE42669E1 (en) | 1995-08-11 | 2011-09-06 | Zenon Technology Partnership | Vertical cylindrical skein of hollow fiber membranes and method of maintaining clean fiber surfaces |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102397751A (en) * | 2011-11-30 | 2012-04-04 | 江苏南极机械有限责任公司 | Microfiltration film filter |
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US2593540A (en) * | 1945-09-01 | 1952-04-22 | American Viscose Corp | Semipermeable membrane |
US3849305A (en) * | 1972-05-23 | 1974-11-19 | S Manjikian | Reverse osmosis water purifying system for household use |
US3926798A (en) * | 1974-10-17 | 1975-12-16 | Us Interior | Reverse osmosis membrane |
US4187333A (en) * | 1973-05-23 | 1980-02-05 | California Institute Of Technology | Ion-exchange hollow fibers |
US4214020A (en) * | 1977-11-17 | 1980-07-22 | Monsanto Company | Processes for coating bundles of hollow fiber membranes |
WO1985001222A1 (en) * | 1983-09-12 | 1985-03-28 | Memtec Limited | Treatment of porous membranes |
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- 1989-03-18 CN CN89101659.7A patent/CN1045756A/en active Pending
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US2593540A (en) * | 1945-09-01 | 1952-04-22 | American Viscose Corp | Semipermeable membrane |
US3849305A (en) * | 1972-05-23 | 1974-11-19 | S Manjikian | Reverse osmosis water purifying system for household use |
US4187333A (en) * | 1973-05-23 | 1980-02-05 | California Institute Of Technology | Ion-exchange hollow fibers |
US3926798A (en) * | 1974-10-17 | 1975-12-16 | Us Interior | Reverse osmosis membrane |
US4214020A (en) * | 1977-11-17 | 1980-07-22 | Monsanto Company | Processes for coating bundles of hollow fiber membranes |
WO1985001222A1 (en) * | 1983-09-12 | 1985-03-28 | Memtec Limited | Treatment of porous membranes |
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PATENT ABSTRACTS OF JAPAN, Volume 6, No. 158 (C-120) (1036, 19 August 1982, & JP-A-5778908 (Kuraray K.K.) 17 May 1982 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USRE42669E1 (en) | 1995-08-11 | 2011-09-06 | Zenon Technology Partnership | Vertical cylindrical skein of hollow fiber membranes and method of maintaining clean fiber surfaces |
US7025885B2 (en) | 1998-11-23 | 2006-04-11 | Zenon Environmental Inc. | Water filtration using immersed membranes |
US7993495B2 (en) | 2005-06-21 | 2011-08-09 | Crosslink Polymer Research, a division of Lumimove, Inc. | Signal activated decontaminating coating |
US7842637B2 (en) | 2008-05-23 | 2010-11-30 | Lumimove, Inc. | Electroactivated film with polymer gel electrolyte |
US7959773B2 (en) | 2008-05-23 | 2011-06-14 | Lumimove, Inc. | Electroactivated film with electrocatalyst-enhanced carbon electrode |
Also Published As
Publication number | Publication date |
---|---|
CN1045756A (en) | 1990-10-03 |
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