(123c) Development of Multi-Walled Carbon Nanotubes (MWNTs)/Polysulfone (PSF) Mixed Matrix Hollow Fiber Membranes for Enhanced Water Treatment

Due to the carbon nanotubes’ unique one-dimensional tubular structure and superior mechanical and chemical properties, we explored if the incorporation of oxidized multi-walled carbon nanotubes (MWNTs) into polysulfone (PSF) hollow fiber membranes could affect the membrane performance. Polyvinylpyrrolidone (PVP) and 1-Methyl-2-pyrrolidinone (NMP) were used as porogen and solvent, respectively, in the phase inversion spinning process, and deionized water was used as bore fluid and coagulant. MWNTs was first purified and oxidized in the mixed acid solution (H₂SO₄/HNO₃ = 3/1 in volume) and then used as the filler at concentrations ranging from 0 to 1 wt.% based on the amount of PSF. Results indicated that at three different PSF concentrations (15, 18, 20 wt.%), pure water flux of all membranes showed similar characteristics, with increasing MWNTs concentration, the flux first increased and then gradually decreased. The optimized blend membranes showed a significant increase of pure water flux (60% to 100%) while maintaining the same ability for solute rejection. The water contact angle of the mixed matrix membrane slightly decreased with increasing filler concentration, which indicated the improved membrane surface hydrophilicity, and the fouling resistance of the membrane to protein was also enhanced.