ZnS/Ag2S decorated PES membrane with efficient near-infrared response and enhanced photocatalysis for pollutants photodegradation on high-turbidity water

Abstract

By the combination of photocatalysis with membrane separation technology, a concurrent strategy of near-infrared (NIR) photocatalytic degradation and flow-through filtration for the treatment of antibiotics and dye effluent are proposed. After the deposition of homogeneous polyether sulfone (PES) layer with zinc acetate seeds as zinc oxide (ZnO) precursor on PES substrate membrane fabricated by non-solvent induced phase separation (NIPs), a photocatalytic membrane comprising of zinc sulfide (ZnS), silver sulfide (Ag2S), and PES substrate (ZnS/Ag2S@PES) was fabricated using successive ion layer adsorption and reaction (SILAR) and ion exchange method based on the conversion of ZnO into ZnS. ZnS/Ag2S@PES photocatalytic membrane with UV–vis-NIR full-spectrum response ability due to the construction of p-Ag2S/n-ZnS heterojunction can fulfil high pollutant photodegradation efficiency (methylene blue (MB) ∼ 70 % & tetracycline (TC) ∼ 58 %) in dead-end filtration by single pass. By simply two successive repeating units in flow-through filtration, more than 95 % of photodegradation efficiency for MB and TC can be achieved. More importantly, under NIR irradiation by the penetration of high-turbidity media and real turbidity wastewater, 68 % and 72 % of MB photodegradation efficiency can be respectively reached by only one unit within 1 h, which is expected to achieve the catalytic degradation to high-turbidity real industrial wastewater.