Influence of surface charge and solution pH on the performance characteristics.pdf

Science and Technology of Advanced Materials 6 (2005) 246–250 /locate/stam Influence of surface charge and solution pH on the performance characteristics of a nanofiltration membrane a a,* b Cao Van Chung , Ngo Quoc Buu , Nguyen Hoai Chau aInstitute of Materials Science, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi, Vietnam bInstitute of Environmental Technology, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi, Vietnam Received 12 January 2005; revised 23 February 2005; accepted 23 February 2005 Available online 15 July 2005 Abstract Acetyl cellulose nanofiltration membrane (NF) was manufactured by a dry/wet phase inversion process and studied on its performance characteristics for the electrolyte solutions NaCl, MgCl , Na SO with a concentration range of 10 K3–10 K2 N at various pH values. It was 2 2 4 shown that the multivalent cation Mg2 C or sulfate anion SO2K present in non-symmetrical electrolytes makes the membrane more positively 4 or negatively charged as a result of their adsorption on the amphoteric pore surface, which greatly increases the membrane selectivity up to 85–95% for these electrolyte solutions. Meanwhile, with respect to 1:1 electrolyte solution NaCl the rejection capacity is low (R Z30–40%) because there is essentiall