Strengthening of polysulfone membranes using hybrid mixtures of micro- and nano-scale modifiers

Abstract

Polysulfone (PSf) membranes were modified by either a new organic modifier (sulfonated poly(ether sulfide sulfone), SPESS) or a traditional modifier (rice hulk). These membranes were further reinforced with either multi-walled carbon nanotubes (MWCNTs) or silica nanoparticles. Having a dye rejection of 98.46%, the reinforced membranes increased more than 50% in strength but no change in solution flux was observed. The morphological and roughness studies were conducted using scanning electron microscopy and atomic force microscopy. Moreover, the PSF membranes were also characterized by differential scanning calorimetry. Modifying the membranes with organic modifier or nanofiller increases the glass transition temperature (T g ). The highest T g and strength were observed for the PSf-SPESSMWCNT membrane. SPESS decreases surface roughness but MWCNT increases roughness on the nanoscale. All membranes show a bimodal pore size distribution, whereas the PSf-SPESS-MWCNT membrane exhibits a relatively uniform distribution of macroscopic and microscopic pores.