A novel vertical immobilized photocatalytic membrane reactor based on Bi2WO6-g-C3N4/PVDF for enhanced removal of atrazine, anti-fouling performance and long-term stability

Abstract

The high efficiency, anti-fouling performance and long-term stability of photocatalytic membrane reactors (PMRs) are critical in practical applications. Here, three flat-sheet immobilized PMRs based on Bi2WO6-g-C3N4/polyvinylidene fluoride (PVDF) photocatalytic membrane were constructed and compared for atrazine (ATZ) degradation under simulated sunlight. The photocatalytic removal rate of ATZ by the vertical PMRs was remarkable, at 78.98% in 6 h, and had a stable removal rate (about 65%) under continuous flow mode (18 h). Additionally, the reactor presented superior reusability and long-term stability with an ATZ removal rate of 65% even after at least 6 cycles in continuous flow mode. By filtering bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA) under simulated solar irradiation, it demonstrated good anti-fouling ability, which was further proved by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The degradation pathway and evolution of the intermediates were proposed by HPLC-QTOF-MS/MS and DFT calculations. The PMR in this work has great potential in the water treatment industry.