EFFECTIVE CHARGE-DENSITY AND PORE STRUCTURE OF CHARGED ULTRAFILTRATION MEMBRANES

In the transport equation of charged ultrafiltration and reverse osmosis membranes which we proposed previously, the effective charge density and the membrane structure, that is, membrane thickness, tortuosity and the water content, are important transport parameters. In this study, these two parameters as determined from ultrafiltration experiments by using the previously proposed transport equation were compared with those obtained from other experiments. The effective charge density was determined from measurement of the membrane potential. It was strongly affected by the feed concentration and agreed well with that obtained from the filtration experiments. Moreover, the membrane structural parameter determined from filtration experiments was compared with that obtained from diffusion experiments. The two values showed good agreement. The measurement of membrane potential and the diffusion experiments were found to be useful for predicting the transport parameters of charged ultrafiltration membranes. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.