Preparation and performance of poly(4-vinylpyridine)-b-polysulfone-b-poly (4-vinylpyridine) triblock copolymer/polysulfone blend membrane for separation of palladium (II) from electroplating wastewaters

In order to separate palladium (II) from electroplating wastewaters, poly(4-vinylpyridine)-b-polysulfone-b-poly (4-vinylpyridine) (P4VP-PSF-P4VP) / polysulfone blend membranes were fabricated by combining non-solvent induced phase separation, surface segregation and self-assembly of block copolymer. Amphiphilic P4VP-PSF-P4VP was used as the membrane base material, which was synthesized by introducing the functional monomer of 4-vinylpyridine (4-VP), and polysulfone as the additive. Effects of blend ratio and 4-VP content on membrane performance, such as structure, hydrophilicity, pure water flux and adsorption capacity towards Pd (II), were investigated. The membranes exhibited dense surface structure and low roughness due to surface segregation and self-assembly of P4VP-PSF-P4VP. The presence of 4-VP increased hydrophilicity and water flux of membrane, and it also provided good adsorption capacity towards Pd (II) (up to 103.1 +/- 5.15 mg/g). Further, the membrane was used to separate Pd (II) from simulated wastewaters during filtration. It showed good rejection ability and high selectivity towards Pd (II) in co-existence of Cu (II) and Ni (II), and selectivity coefficients of Pd/Cu and Pd/Ni are 41.9 +/- 1.88 and 97.8 +/- 4.32, respectively. In filtration process of actual electroplating wastewater, the membrane also exhibited excellent rejection performance (Pd (II) rejection reached up to 96.8 +/- 2.71%). Perhaps it is suitable for future practice applications.