Facile assembled N, S-codoped corn straw biochar loaded Bi2WO6 with the enhanced electron-rich feature for the efficient photocatalytic removal of ciprofloxacin and Cr(VI)

To the best of our knowledge, in few studies, biochar (BC)-based materials have been used as the photocatalyst for water purification, and their application is limited to a great extent due to catalyst agglomeration and inefficient electron migration. In this study, a novel Bi2WO6 loaded N, S co-doping corn straw biochar (Bi2WO6/NSBC) was successfully synthesized with a simple solvothermal method for the removal of ciprofloxacin (CIP) and Cr(VI) under visible light irradiation. The Bi2WO6/NSBC was featured with efficient and rapid catalytic removal toward CIP (5 mg/L) and Cr(VI) (10 mg/L), with efficiencies of ∼90.33% and ∼99.86% within 75 min, respectively. More attractively, this composite can be applied in a wide pH range (3.0–9.0) and with weak effects by coexisting ions (Cl−, CO32−, SO42−, and Ca2+). The facile synthesized porous graphitized structure demonstrates an outstanding performance of superior conductivity and promoted photoelectron transport. Meanwhile, it is found that N, S co-doping of the BC induces highly interconnected fibrous structures, high catalytic property, and favorable specific surface areas, which is considered to avoid agglomeration of Bi2WO6. The increased photocatalytic activity results from the synergistic effects of Bi2WO6 and NSBC by the optimized band gap and enhanced visible light response, due to higher migration and utilization efficiency of photoinduced carriers in photocatalytic reactions. In this approach, a cheap catalyst is provided, and at the same time, a synergistic effect of N, S co-doping is formed to rapidly remove contaminants in wastewater treatment.