Chemically modified semipermeable membranes and their use in reverse osmosis and ultrafiltration

• US 4,690,765 A
• Filed: 01/22/1985
• Issued: 09/01/1987
• Est. Priority Date: 03/17/1981
• Status: Expired due to Fees

• Current Assignee: Aligena AG
• Original Assignee: Aligena AG
• Inventors: Linder, Charles, Perry, Mordechai, Kotraro, Reuven, Aviv, Gershon
• Primary Examiner(s): Sadowski, David
• Application Number:
  US06/693,321
• Time in Patent Office: 952 Days
• Field of Search: 210/490, 210/500, 210/506, 210/652, 210/653, 210/654, 210/500.28, 210/500.33, 210/500.34, 210/500.36, 210/500.37, 210/500.38, 210/500.39 , 210/500.41, 210/500.29, 210/500.42, 55/158, 428/305.5, 428/419, 428/315.5, 428/315.7, 428/315.9
• US Class Current: 210/654
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 67/0093 Chemical modification
• CPC Class Codes: B01D 69/10 Supported membranes; Membrane supports
• CPC Class Codes: B01D 71/68 Polysulfones; Polyethersulfones
• CPC Class Codes: C08G 65/48 Polymers modified by chemical after-treatment
• CPC Class Codes: C08G 75/20 Polysulfones
• CPC Class Codes: C08J 2379/06 Polyhydrazides; Polytriazoles; Polyamino-triazoles; Polyoxadiazoles
• CPC Class Codes: C08J 5/2256 based on macromolecular compounds obtained by reactions other than those involving carbon-to-carbon bonds, e.g. obtained by polycondensation

Abstract

Semipermeable membranes of modified polysulfones are provided which comprises repeating units of the formula

--M.sub.1 --R.sub.1 --M.sub.2 --R.sub.2 --SO.sub.2 --R.sub.3 --(1)

wherein M₁ and M₂ are independently a valence bond, --O-- or --NH--, R₁ is a valence bond or a group of the formula ##STR1## with the proviso that if R₁ is a valence bond, only one of M₁ and M₂ can be --O--, R₂ and R₃ are independently a group of the formula ##STR2## the aryl radicals R₁, R₂ and R₃ are optionally further substituted, R₄ is a valence bond, --O--, alkylene of 1 to 4 carbon atoms optionally substituted or interrupted by cycloalkyl(ene) or aryl(ene) of at most 7 carbon atoms, or alkylidene of 2 to 4 carbon atoms, R₅ to R₁₀ are independently hydrogen, or ##STR3## radicals, these radicals being modified through chemical reactions with (a) a monomeric compound containing at least two functional groups,

(b) a polyfunctional, linear or branched oligomer or polymer, and

(c) a non-ionic and/or ionic compound containing at least one, preferably two groups capable of reaction with (b),

--R₁₂ X or --R₁₃ CHO radicals, modified through chemical reaction with (b) and (c), or

--R₁₃ CN radicals, modified through chemical reaction with hydroxylamine, (a), (b) and (c),

R₁₁ is a valence bond, --CH₂ --, alkylene or arylene containing oxygen or nitrogen atoms (azo-groups), R₁₁^'"'"' constitutes the atoms necessary to form a heterocyclic ring condensed with the polymer backbone, R₁₂ is alkylene, R₁₃ is a valence bond or alkylene, R₁₃^'"'"' is arylazo, and X is halogen, the degree of substitution of substituents R₅ to R₁₀ --different from hydrogen--being between 0.05 and 3 milliequivalents/g.

The new membranes are suitable in reverse osmosis and ultrafiltration processes. They show good permeability (flux) and rejection characteristics combined with solvent and compaction resistance.

Claims

1. A semipermeable membrane of a modified polysulfone, which comprises repeating units of the formula

View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)

2. A membrane according to claim 1, wherein the modified polysulfone comprises repeating units of the formula

3. A membrane according to claim 2, wherein the modified polysulfone comprises repeating units of the formula

4. A membrane according to claim 3, wherein the polysulfone has repeating units of the formula ##STR54## wherein R₆₁ and R₇₁ have the meaning indicated in claim 8 and the degree of substitution of substituents R₆₁ and R₇₁ --different from hydrogen--being 0.3 to 3.5 meq/g.

5. A membrane according to claim 4, wherein R₆₁ and/or R₇₁ are independently hydrogen, or ##STR55## radicals, modified through chemical reaction by steps (a), (b) and (c), wherein

in step (a) said monomeric compound is an organic compound that contains reactive multiple bonds or epoxide, aziridine, aldehyde, imidate, isocyanate, isothiocyanate, hydroxyl , anhydride, acyl halide, carbonic acid imide halide or N-methylol groups or is a compound containing substituents detachable as tertiary amines or as anions, or is a compound containing a combination of these groups and/or substituents,

in step (b) said oligomer or polymer is a hydrophilic polyfunctional, aliphatic or aromatic oligomer or polymer containing amino, hydroxyl or thiol groups, and

in step (c) said ionic compound contains at least one sulfonic acid group, or carboxylic group, optionally in the form of their salts, or ammonium group.

6. A membrane according to claim 1, wherein the modified polysulfone comprises repeating units of the formula

7. A membrane according to claim 6, wherein the modified polysulfone comprises repeating units of the formula ##STR56## wherein R₈ is independently hydrogen or a ##STR57## radical, modified through chemical reaction by steps (a), (b) and (c), Y'"'"' being a valence bond, --O-- or --NH--, the degree of substitution of substituents R₈ --different from hydrogen--being between 0.3 and 3.5 milliequivalents/g.

8. A membrane according to claim 7 or 5, wherein said oligomer or polymer comprises a member selected from the group consisting of polyethyleneimines, polyvinyl alcohols, cellulose derivatives, polyvinylamines, polyvinylanilines, polypiperidines, polydialkylamines, amino modified polyepihalohydrines, condensation products of dicyandiamide, amine or ammonium salts and formaldehyde, diamino condensation products of polyanhydrides, aminoalkyl polysulfones or aminoalkyl polyphenylene oxides.

9. A membrane according to claim 7 or 5, wherein said monomeric compound is a cyclic carbonic acid imide halide or a compound containing isocyanate, isothiocyanate or N-methylol groups.

10. A membrane according to claim 9, wherein said monomeric compound is a halogenodiazine or -triazine containing at least 2 reactive substituents and optionally ionic groups.

11. A membrane according to claim 10, wherein said monomeric compound is cyanuric chloride or tetrachloropyrimidine.

12. A membrane according to claim 7 or 5, wherein said ionic compound is a colored compound.

13. A membrane according to claim 12, wherein said ionic compound is a reactive azo dye containing sulfonic acid groups, carboxyl groups and/or ammonium groups.

14. A membrane according to claim 13, wherein said ionic compound is a reactive azo dyestuff containing sulfonic acid (--SO₃ H) or carboxyl (--COOH) groups and as reactive groups monochlorotriazinyl, dichlorotriazinyl, 2,4-dichloropyrimidinyl, vinyl sulfonyl, β

-sulfatoethylsulfonyl, β

-chloroethylsulfonyl or β

-sulfatoethylaminosulfonyl radicals.

15. A membrane according to claim 7 or 1, wherein said non-ionic compound is a colorless cyclic carbonic acid imide halide, a dihalide of dicarboxylic acids, a dialdehyde or a trihalide of tricarboxylic acids.

16. A membrane according to claim 5, wherein said ionic compound is a colorless compound containing ionic groups and halotriazinyl or halopyrimidyl radicals.

17. A membrane according to claim 5, wherein said non-ionic and/or ionic compound contains two groups capable of reaction with the product of step (b).

18. A membrane according to claim 1, wherein the modified polysulfone comprises repeating units of the formula

19. A membrane according to claim 1, wherein said modified polysulfone is supported as a thin film by a porous support.

20. A membrane according to claim 1, wherein said non-ionic and/or ionic compound contains two groups capable of reaction with the product of step (b).

21. A process for concentrating a solution with a solute which comprises disposing on one side of a semipermeable membrane according to claim 1 a solution with a solute, said solution having an osmotic pressure, and filtering said solution by applying a hydraulic pressure against said solution and said membrane, said hydraulic pressure being greater than the osmotic pressure of said solution.

22. A process for purifying a solution with a solute which comprises disposing on one side of a semipermeable membrane according to claim 1 a solution with a solute, said solution having an osmotic pressure, and applying a hydraulic pressure against said solution and said membrane, said hydraulic pressure being greater than the osmotic pressure of said solution.

23. A process according to claim 22, wherein effluents obtained from dye production are purified by separating off dyes.

24. A process for separating components dissolved in a solution which comprises disposing on one side of a semipermeable membrane according to claim 1 a solution with a solute, said solution having an osmotic pressure, and applying a hydraulic pressure against said solution and said membrane, said hydraulic pressure being greater than the osmotic pressure of said solution.

25. A process according to claim 24, which comprises separating monovalent ions of low ionic weight from polyvalent ions of low or relatively high ionic weight and monovalent ions of high ionic weight.

26. A process according to claim 25, wherein organic and metal-organic ionic substances are separated from by-product inorganic salts in a reaction mixture.

27. A process according to claim 26, wherein inorganic salts are separated from organic dyestuffs.