Surface modification of a poly(vinyl chloride) membrane by UV irradiation for reduction in sludge adsorption

N-vinyl-2-pyrroldinone was grafted by the UV-irradiation process onto the porous surface of poly(vinyl chloride) (PVC) membrane to increase the surface wettability and to decrease the adsorptive fouling. The graft yield of the modified PVC membrane was maximum at 5 min UV exposure time and 20 wt% aqueous NVP solution. The specific resistance (alpha(c)) of the adsorbed cake layer decreased with the increase of the grafting degree of NVP. In the dead-end filtration performances of membranes, although the mutual repulsive interaction between sludge and the surface of the PVC-g-PNVP membrane was weak with the increase of the grafting degree, the low adsorption of sludge with the increase of NVP grafting was affected by the contribution of the higher hydrophilicity due to grafting NVP rather than by the contribution of interaction between sludge and the membrane surface.