Preparation of Hollow Fibre Composite Reverse Osmosis Membrane

A novel thin-film composite (TFC) reverse osmosis (RO) membrane was developed by the interfacial polymerization (IP) of trimesoyl chloride (TMC) and m-phenylene diamine (MPD) on the hollow fibre ultrafiltration polysulphone (PS) membrane. The performance of the TFC membrane was optimized by studying the preparation parameters, which included monomer TMC concentration, monomer MPD concentration and alcohol additive in aqueous solution. The reverse osmosis performance of the resulting membrane was evaluated through permeation experiment with 1000 ppm NaCl at 0.7 MPa. The results showed that the optimum concentration of MPD and TMC were 0.5wt% and 3g/L, respectively. To improve flux, alcohol was added to the aqueous phase, when certain concentration of alcohol was added to the aqueous solution, the flux of the prepared membrane increased from 5.0 to 9.1 L/(m·h) without loss in salt rejection. The properties and structures of skin layer of RO composite membranes were characterized by AFM. It was found that IP had occurred and the separation layer was formed, and the novel reverse osmosis membrane appears to comprise a thicker, smoother and less cross-linking film structure. Additionally, the TFC membrane exhibits good long-term stability.