Highly efficient photocatalytic removal of multiple refractory organic pollutants by BiVO4/CH3COO(BiO) heterostructured nanocomposite

Abstract

Highly efficient photocatalytic degradation of refractory organic contaminants in wastewater remains a great challenge due to low quantum efficiency and poor solar energy utilization of the currently employed photocatalysts. Herein, a novel BiVO4/CH3COO(BiO) heterojunction photocatalyst is designed and prepared by a simple one-pot solvothermal method, and characterized by various techniques. By using this photocatalyst, degradation efficiency of four kinds of emerging refractory organic pollutants (sulfamethoxazole, bisphenol A, 4‑aminoantipyrine and ibuprofen) in water is investigated under simulated solar irradiation. Then, total organic carbon is measured to determine the mineralization degree, and degradation intermediates of the pollutants are identified to propose their degradation pathway. It is found that under the given conditions, complete degradation of the pollutants is observed within the irradiation of 5–24 h, and 81–96% mineralization degree is achieved in 24 h. Furthermore, it is shown that the degradation kinetics can be described by pseudo-first order model. Based on the detected intermediates during the degradation process of 4‑aminoantipyrine and ibuprofen, the degradation pathways of these two pollutants are suggested to involve cleavage of side chain, heterocyclic ring opening and hydroxylation of aromatic ring. In addition, the application of the BiVO4/CH3COO(BiO) heterojunction photocatalyst in the purification of the spiked real wastewater is also investigated.