Investigation of mechanical and thermal behavior of polydopamine added polymeric composite membranes and application to water treatment

Recently, the use of polymeric membranes in the treatment of drinking water, domestic wastewater and industrial wastewater has become rapidly widespread. Polymeric membranes are preferred in water treatment due to their ease of production, cost efficiency and high effluent quality. Polymeric materials used in membrane production are the most important elements for high-performance membrane production. The most commonly used organic polymers in commercial scale are: Polysulfone (PSf), Polyethersulfone (PES), Polyacrylonitrile (PAN) etc. In this study, three different types of polymeric membranes were produced and characterized as PSf membranes without dopamine additive, PSf membranes with dopamine additive and PSf membranes coated with PDA solution. In order to increase membrane performance and mechanical strength, composite membranes were produced by adding Polydopamine (PDA) into the polymers. In membrane production, PSf, PVP and dopamine ratios were kept constant as 15%, 5% and 0.2%, respectively, and the phase inversion method was used. The characterization analysis of the produced membranes included FTIR, SEM, water retention capacity, porosity, contact angle, DMA and DSC tests. Pure water and lake water flux tests were performed on the membranes with dead-end filtration system and the repeat performances of the fouled membranes were evaluated. The results showed that the PDA-doped membranes improved their mechanical, thermal and chemical properties. Especially PSf/PVP/Tris/dopamin membranes exhibited the highest performance in pure water and lake water flux, but a decrease in performance was observed after fouling. This study demonstrated the potential use of dopamine-doped and PDA-coated membranes in water treatment applications.