Fabrication of a thin film nanocomposite hollow fiber nanofiltration membrane for wastewater treatment

Abstract

A thin film nanocomposite (TFN) hollow fiber membrane containing nanoporous SAPO-34 nanoparticles was prepared on the dual-layer (PES/PVDF) hollow fiber substrate. The nanoparticle exposed TFN membrane (TFN(DOX)) was fabricated via the co-solvent (dioxane) assisted interfacial polymerization process. The TFN(DOX) had a larger nanoporosity and a higher crosslinking degree, which simultaneously led to an increased pure water permeability but a decreased salt permeability than the TFN membrane. The larger nanoporosity of TFN(DOX) membrane was ascribed to the effective exposure of nanoparticles, proved by the less PA coverage and the stable dispersion of nanoparticles in organic solution. Contributed by the exposed nanoparticles, the TFN(DOX) showed superior hydrophilicity and lower streaming potential than the TFN membrane. Compared to the NF-90, the TFN(DOX) membrane simultaneously improved the water flux and the rejections against tris(2-chloroethyl) phosphate, tris(1-chloro-2-propyl) phosphate and tris(1,3-dichloro-2-propyl) phosphate molecules. In addition to the elevated pure water permeability of 20.1Lm−2h−1bar−1, the newly developed TFN(DOX) hollow fiber nanofiltration membranes have high rejections to both the multivalent electrolytes and micropollutant molecules, showing the potential applications in industrial wastewater treatment and drinking water purification.