Coupling photocatalytic water oxidation on decahedron BiVO4 crystals with catalytic wet peroxide oxidation for removing organic pollutions in wastewater

Abstract

Catalytic wet peroxide oxidation (CWPO) is widely used to remove organic pollutants in industrial wastewater, however, the remained challenges in circulating Fe3+/Fe2+ ions, inevitably forming iron sludge and massively consuming H2O2 limit its applications. Herein, the coupling of CWPO and photocatalytic water oxidation on decahedron BiVO4 crystals was reported to solve the above challenges. Using spatial photogenerated charge separation between different facets of BiVO4, efficiently circulating Fe3+ to Fe2+ was realized with a selectivity of ~100%, which greatly inhibits the formation of iron sludge. Moreover, in-situ formation of H2O2 through two-hole-involved photocatalytic water oxidation on BiVO4 replenishes the H2O2 consuming in the CWPO process. The coupling system exhibits a much higher total organic carbon (TOC) removal than the CWPO process in various pollutants, giving an improvement of rate constant to more than 10 times. This work provides a potential coupling route for advanced degradation of organic pollutants in wastewater treatment.