Structure design on reinforced cellulose triacetate composite membrane for reverse osmosis desalination process

Non-woven fabric (NWF) has become one of the most important segments in filtration field. Herein, a new type of polyethylene-terephthalate (PET) NWF reinforced “sandwich” cellulose triacetate (CTA) composite reverse osmosis (RO) membrane (NCR membrane) was prepared by melting method. Moreover, the structure and performance of NCR membranes with different separation layer thickness were investigated by ATR-FTIR, SEM, and mechanical property and so on. The results indicated that the NWF supporting layer not only provided well interfacial bonding state with separation layer but also overcame the negative effect of CTA RO membrane's permeate flux loss, due to its easy compaction at a moderate or high operating pressure. Furthermore, all the same ATR-FTIR spectrum of NCR membranes indicated that NWF was wrapped up by CTA melt. Besides, the mechanical property exhibited that the tensile strength increased from 7.5 to 19.5 MPa when introducing the NWF into membrane matrix. Also, based on both membrane morphologies and performance, the optimal membrane thickness was 150 μm with adequate permeate flux and higher salt rejection. Finally, the long-term stable RO testing also exhibited that introducing NWF supporting layer with suitable thickness of separation layer was useful for compaction resistance and stable permeability of NCR membranes.