Enhanced polysulfone ultrafiltration membrane performance through fullerol Addition: A study towards optimization

In this study, we have prepared and characterized polysulfone (PSF) ultrafiltration membranes, via a phase inversion method, which incorporate oxidized fullerenes (fullerols as C60(OH)x(ONa)y, with x + y = 24 and y = 6 to 8). Fullerol addition, at relatively low loadings (≤2.5 wt%), has significant impact on the resulting membrane structure, permeability, anti-fouling, and mechanical properties. Fullerol modified membranes have enlarged, open-ended pores and enhanced (surface) hydrophilicity. When optimized, incorporation of fullerol breaks the traditional trade-off between membrane permeability and selectivity (i.e., rejection of bovine serum albumin (BSA)), as both are improved with 1.5% fullerol (wt/wt), from 23.9 to 191.9 LMHB and 89% to 93%, respectively. Recovery measurements and protein adsorption tests also indicate that anti-fouling properties are enhanced via fullerol incorporation, which is likely due to decreased membrane roughness and increased surface-based electrostatic repulsion. Mechanical strength measurements indicate an optimal incorporation ratio at 0.5% fullerol/PSF (w/w). Taken together, results clearly demonstrate the potential of fullerol as a novel and effective, yet simple, PSF membrane modifier.