Novel chitosan-piperazine composite nanofiltration membranes for the desalination of brackish water and seawater

A novel chitosan (CS)-piperazine (PIP) composite nanofiltration (NF) membrane with satisfied characteristics for brackish water and seawater desalination was successfully developed. PIP was mixed with CS during the interfacial polymerization (IP) process to enhance the NF membrane permeate flux. The resultant NF membranes were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM), contact angle. Effects of CS concentration, trimesoyl chloride (TMC) concentration, reaction time and the mixing ratio of CS/PIP on NF membrane performance were investigated thoroughly. When PIP in the aqueous phase monomers reached to 25% (w/w), the PWF (60.6 L.m(-2).h(-1)) was synergistically improved by nearly 2 times without a significant reduction of Na2SO4 rejection (89.1%). Moreover, the NF membranes possessed excellent performance for the desalination of brackish water and seawater, which showed high potential to be applied in the desalination process for water treatment.