Mussel-inspired polydopamine modification of polymeric membranes for the application of water and wastewater treatment: A review

Abstract Polymeric membranes are widely applied in water and wastewater treatment. During membrane filtration, membrane hydrophilicity is essential for both membrane flux and fouling resistance, and sufficient mechanical strength is also critical for enduring various operational condition. In the last 10 years, mussel-inspired chemicals have become a promising strategy for membrane modification due to their universality and versatility. Simply immersing membranes into a basic dopamine solution can induce a hydrophilic PDA layer on the membrane surface. Both the mechanical properties and the hydrophilicity of polymeric membranes are altered via this adhesion procedure. This review aims to expand the general vision on controlling PDA based hydrophilic modification, including influential factors of dopamine self-polymerization and the deposition behavior on different types of membranes. In addition, advanced dopamine-based hydrophilic modification is also reviewed where PDA serves as a filler or an intermediate layer to optimize the membrane separation performance. Finally, some critical unsolved challenges are discussed, and possible directions of further research on mussel-inspired PDA modification of polymeric membranes are proposed.