Assessing the impact of membrane support and different amine monomer structures on the efficacy of thin-film composite nanofiltration membrane for dye/salt separation

Abstract

The right choice of porous support and diamine monomer is crucial in fabricating TFC membranes with improved performance. In this study, the effect of the supporting layer and diamine monomer structure in preparing TFC membranes for dye/salt separation was investigated. Supports used are polysulfone (PSf), polyacrylonitrile (PAN), and hydrolyzed PAN (mPAN) while diamine monomers used are piperazine (PIP), 1,3-diaminopropane (DAPE), and 1,4-bis(3-aminopropyl) piperazine (BAPP). Changing the porous substrate and monomer not only affects membrane physical and chemical morphology but also the performance of TFC NF membranes. Characterization and NF tests revealed that the TFC membrane prepared using mPAN as support and PIP as diamine monomer had most hydrophilic, roughest surface, and lowest crosslinking degree, and it delivered the optimum NF performance: J = 127.66 ± 12.61 LMH; R_{Brilliant Blue} = 99.28 ± 0.57% R_{Congo Red} = 99.21 ± 0.08%; R_NaCl = 14.00 ± 6.16%.