Thermodynamics and kinetics control of support layer synthesis for enhanced thin film composite membrane performance

Abstract

The desalination performance of a thin film composite (TFC) membrane hinges highly on the surface characteristics of support membrane. In this study, good wettability, regular pore size, and moderate roughness were identified as the critical surface properties of support membrane in forming a defect-free, uniform, and structurally stable polyamide film. These features were tailored by adjusting the thermodynamics and kinetics properties of the polymer solution via polysulfone (PSf)/polyvinylpyrrolidone (PVP) ratio as well as using N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide as co-solvent. It was found that the membrane formation was controlled kinetically by altering the PSf/PVP ratio but thermodynamically by using co-solvent. The TFC membrane with better desalination performance was achieved with the support membrane prepared at PSf/PVP ratio of 0.941 without any co-solvent. The resulting TFC membrane attained the highest permeability ratio of 0.691 bar−1 for water/NaCl filtration in this study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45802.