REVERSE-OSMOSIS MEMBRANES PREPARED FROM POTASSIUM PEROXYDISULFATE-MODIFIED POLY(VINYL ALCOHOL)

Poly(vinyl alcohol) (PVAL) was modified and insolubilized by reaction with potassium peroxydisulphate (K2S2O8) and used to make reverse osmo sis (RO) membranes on tubular poly(arylether sulphone) (PES) ultrafilt ration (UF) substrates. Prior to making the membranes, aqueous solutio ns of PVAL and K2S2O8 were aged. The effects of solution maturation ti mes on the salt retentions and permeate fluxes of the resultant membra nes were determined. Increased maturation times were found to lead to membranes with higher salt retentions. The K2S2O8-crosslinked PVAL mem branes were also tested with an industrial effluent. Changes which too k place in the maturing PVAL/K2S2O8 solutions were characterized by vi scometry, UV spectroscopy, H-1- and C-13-NMR spectroscopy, and pH meas urements. Only the most important results of these analyses are report ed here.