Highly effective antifouling performance of N-vinyl-2-pyrrolidone modified polypropylene non-woven fabric membranes by ATRP method

In this paper, a hydrophilic polymer, poly(N-vinyl-2-pyrrolidone) (PNVP), was grafted on the surface of polypropylene non-woven fabric (PP-NWF) membrane via ozone surface activation and surface-initiated atom transfer radical polymerization (ATRP). The grafting degree of PNVP on the membrane surface can be modulated in a wide range through the variation of grafting time. Chemical and morphological changes of the PNVP-modified membrane surface were characterized in detail by Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy and scanning electron microscopy (SEM). The hydrophilicity of the membrane increased upon modification with the water contact angle decreasing from 113.0 ± 1.2° to 52.1 ± 3°. Permeation experiments of water and supernatant solution of active sludge were conducted to evaluate the antifouling property of the PNVP-modified membranes, which results indicated that the modified membranes had higher permeation fluxes with enhanced rejection rates, lower flux loss and better antifouling property than those of the original NWF membrane. Bacterial adhesion on the studied membrane surfaces was also investigated, which showed that bacteria were restrained from growing on PNVP-modified membranes, and adhesion of bacteria was reversible due to the enhanced hydrophilicity.