Asymmetric semi-permeable membrane - formed from poly:aryl:ether:sulphone and used for reverse osmosis or ultrafiltration

摘要

The support layer and active layer are both formed from the same sulphonated polyarylethersulphone (I) where the membrane has a salt rejection and flux such that the ratio Flux (m/day)/(100-% salt rejection) (A) has a value of at least 0.05 (0.5). Also claimed is a sulphonated polysulphone deriv. contg. repeat units of formula (II) together with those of formula (III) and opt. a minor proportion of repeat units of formula (IV). -Ph1-O-Ph2-O-Ph1-SO2- (II) -Ph1-O-Ph1-SO2-Ph1-O-Ph1-SO2- (III) -Ph1-O-Ph1-O-Ph1-SO2- (IV) Ph1=phenylene residue Ph2=phenylene residue having one or two -SO3M1 gps.; and M1=divalent metal in a proportion sufficient to combine with the unsatis. valencies of the -SO3 gps.