Fabrication and performance of polysulfone/H2O2-g-C3N4 mixed matrix membrane in a photocatalytic membrane reactor under visible light irradiation for removal of natural organic matter

Abstract

The coupling of photocatalysis with membrane technology, which is known as photocatalytic membrane reactors (PMRs), has received great consideration in recent years and become a promising approach with the high potential to improve the fouling of membranes. In this paper, the photocatalyst of g-C3N4 treated with H2O2 was incorporated with a polysulfone membrane to enhance the anti-fouling properties of the membrane. AFM, FE-SEM images, porosity, and contact angle analysis indicated that the membrane properties like hydrophilicity, porosity, and surface roughness were improved. Also, UV–visible DRS, PL spectra, EIS analysis confirmed that the treated g-C3N4 (H2O2-g-C3N4) had high light absorption and low electron-hole recombination rate. The polysulfone/H2O2-g-C3N4 membrane with photocatalytic influences improved the removal of humic acid and anti-fouling properties under light conditions. Also, this incorporating was enhanced the water permeability from 266.6 to 412.1 L m−2 h−1 bar−1 in the optimum condition. To a considerable extent, the modified membranes maintained the humic acid solution fluxes during long-time experiments under visible light irradiation, so that after a 10 h run, the flux decline of the modified membrane was 21.9% compared to the initial flux, while for the pristine membrane was 53% in the same condition. The unique properties of polysulfone/H2O2-g-C3N4 membrane, like photocatalytic activity, led to a reduction in fouling resistances, especially block resistance. These results demonstrated the high potential of the polysulfone/H2O2-g-C3N4 mixed matrix membrane exposed to light irradiation for treating humic acid solution.