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

摘要

Semipermeable membranes of modified polysulfones are provided which comprises repeating units of the formula -M1-R1-M2-R2-SO2-R3-(1) wherein M1 and M2 are independently a valence bond, -O- or -NH-, R1 is a valence bond or a group of the formula 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 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 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), -R12X or -R13CHO radicals, modified through chemical reaction with (b) and (c), or -R13CN 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.