MULTI-ELECTROLYTE TRANSPORT THROUGH NANOFILTRATION MEMBRANES CHARACTERISED BY THE ELECTROSTATIC AND STERIC-HINDRANCE MODEL

摘要

Nanofiltration (NF) is one of the most recently developed pressure driven membrane process. One of the major advantages of NF is its operation pressure can be much lower than reverse osmosis (RO) with high solution permeate flux, which shows great industrial application potential in desalination or drinking water treatment. In order to fully realize the potential of NF and to properly predict membrane separation performance, it is important to have a mathematical model, particularly for mixed ions system. Such predictive models will reduce development risk and time, thus promoting the wider use of membrane technology in process industries. Comparing with typical industrial integrated membrane process of RO, the modeling of NF membrane process is harder due to the structure and property of NF membranes. Most of the commercial NF membranes are thin-film composites made of synthetic polymers (typically polyamide, polyethersulphone, etc.). It possesses two separation features: one is the intermediate molecular weight cut-off between reverse osmosis and ultrafiltration; the other is salt rejection due to its charge characterization.