Layered double hydroxide nanoparticle modified forward osmosis membranes via polydopamine immobilization with significantly enhanced chlorine and fouling resistance

Abstract

Currently, the degradation of polyamide (PA) layers in thin-film composite (TFC) membranes due to chlorine-based chemical cleaning is still the major obstacles to the development of reverse and forward osmosis (FO) technologies. In this study, layered double hydroxide (LDH) nanoparticles were bound on the TFC membranes by virtue of a polydopamine (PDA)-induced immobilization process to enhance its chlorine and fouling resistance. Two modification strategies as deposition and dip-coating were compared. The accelerated chlorination experiments using 1000ppm NaOCl indicated the excellent chlorine-resistant performance of the deposition-modified TFC membrane, the chlorine-resistant time was improved about 96 times than the control membrane. The LDH layer served as a barrier to protect the PA layer from chlorination. Moreover, the LDH-modified membrane exhibited a better resistance to organic fouling. Also, the bound LDH layer succeeded to reduce the attachment of bacteria, indicating a promising anti-fouling capability. In general, the modification using the LDH nanoparticles effectively improved the chlorine and fouling resistance of the TFC membranes, suggesting promising applications in various areas.