REVERSE-OSMOSIS CELLULOSE-ACETATE MEMBRANES .1. RATE OF HYDROLYSIS

Measurements of hydrolysis rates of homogeneous porous and dense cellulose acetate membranes were analyzed in terms of external and internal mass transfer, and intrinsic chemical reaction. These results indicate that the external mass transfer controls the overall rate for porous membranes, while internal mass transfer and/or chemical reaction control the rate for dense membranes. By extending this analysis to asymmetric cellulose acetate membranes, the hydrolysis rate in the dense layer is shown to be much slower than the rate in porous layer.