Photosynthetic membranes. VI. Characterization of ultrafiltration membranes prepared by photografting zeolite-epoxy-diacrylate resin composites onto cellulose

Abstract

Water permeability measurements were carried out at 20°C through membranes prepared by photochemically grafting an epoxy-diacrylate copolymer or one of its zeolite composites onto cellulose. A correlation between mean pore diameter and water flux per unit applied pressure drop has been established, the latter being in turn related to membrane thickness. In Poiseuille's laminary flow regime, with a normal Kozeny-Carman constant indicating a regular packing of isometrically shaped particles in the microporous medium, surface areas of zeolites 3A, 5A, and 13X could be evaluated as 628, 482, and 403 m 2-g − respectively, while a value of 102 m 2-g −1 resulted for the polymeric membrane. Rejection characteristics for poly(ethylene glycol) (PEG) polymers dissolved in water have been investigated. Linear relationships between water flux per unit applied pressure drop and molecular weight of PEG polymers at constant solute rejection have been obtained, independent of the kind of photosynthetic membrane, whether polymeric zeolite free or composite. Characterization of asymmetric membranes, prepared photochemically, by the methods used, gives consistent results as regards structural parameters and geometric configuration of these membranes.