Perspectives on Surface Functionalization of Polymeric Membranes with Metal and Metal-Oxide Nanoparticles for Water/Wastewater Treatment

Membrane filtration technology has been extensively applied in water/wastewater treatment to help address the issue of water shortage, in which polymeric membranes are most commonly used. However, the hydrophobic nature of polymeric membranes would contribute to membrane damage caused by accumulation of organic/inorganic fouling during filtration processes. The strategy of membrane surface functionalization with nanoparticles (NPs) has been investigated and utilized to effectively improve membrane performance. Herein, recent research efforts on surface functionalization of polymeric membranes with a variety of NPs for water/wastewater treatment were concisely reviewed, focusing on metal and metal-oxide NPs. Methods for the immobilization of NPs on membrane surface and their influences on membrane properties and performances were overviewed. Results and contributions achieved in the improvement of membrane performances through surface functionalization with NPs were summarized, and emphasis was given to membrane hydrophilicity, stability, as well as antifouling and antibacterial property. Furthermore, perspectives on the current challenges and future research needs in the development and application of surface functionalized polymeric membranes were discussed.