Aromatic-cycloaliphatic polyamide thin-film composite membrane with improved chlorine resistance prepared from m-phenylenediamine-4-methyl and cyclohexane-1,3,5-tricarbonyl chloride

Aromatic-cycloaliphatic polyamide thin-film composite (TFC) reverse osmosis (RO) membranes with improved chlorine resistance as well as good RO performance were developed by the interfacial polymerization of m-phenylenediamine-4-methyl (MMPD) and cyclohexane-1,3,5-tricarbonyl chloride (HTC) on polysulfone supporting film. Parametric studies were carried out to optimize the performance of the TFC membrane. The RO performance including salt rejection and water flux of the resultant membrane was evaluated through permeation experiment, the properties of TFC membrane were characterized by AFM, SEM, XPS, ATR-IR and contact angle measurement, and the chlorine resistance was studied by measuring the chlorine uptake rate of the polyamide and the evaluation of membrane performance before and after hypochlorite exposure. The results reveal that the TFC membrane prepared from MMPD and HTC exhibits higher chlorine resistance and better-matched water flux compared with that prepared from m-phenylenediamine (MPD) and trimesoyl chloride (TMC) at the expense of some salt rejection. The desired membrane prepared under the optimum condition exhibits a typical salt rejection of 97.5% and a water flux of 53.0 l/m2 h for brackish water desalination, and an attractive chlorine resistance of more than 3000 ppmh Cl. The high chlorine resistance is attributed to the reduced probability of N-chlorination and Orton-rearrangement by using monomer MMPD.