Polysulfone/amino-silanized poly(methyl methacrylate) dual layer hollow fiber membrane for uremic toxin separation

A new strategy to recycle dialysate within a system is needed to foster the progress of developing wearable artificial kidney as an alternative to conventional hemodialysis practices. This study presents an attractive approach to collectively remove uremic toxins by combining membrane filtration and adsorption process. In this work, dual layer hollow fiber (DLHF) membranes consisting of polysulfone (PSf) inner layer well attached to PSf/amino-silanized poly(methyl methacrylate (N-PMMA) outer layer were prepared via co-extrusion spinning process based on non-solvent induced phase separation. The PSf/N-PMMA DLHF membranes were characterized and evaluated in terms of urea adsorption capacity and filtration performance. It was revealed that the urea adsorption onto N-PMMA is a non-spontaneous physical process that follows Freundlich isotherm model and pseudo-second-order kinetic model. Results showed that the membrane exhibited urea adsorption capacity of up to 27.6 mg/g depending on N-PMMA content. Under dynamic filtration condition, the membranes demonstrated significant urea removal (39.2%) and showed desired sieving characteristics for other solutes. The design of DLHF membrane with adsorptive property is an exciting prospect that would become a key solution for dialysate regeneration.