Flower-spherical Ag-Bi2WO6 photocatalytic degradation of sulfamethazine

Abstract

5 %A-Bi₂WO₆ (5 %A-BW) photocatalysts with a flower-spherical structure were synthesised by hydrothermal technique at 120 °C for 24 h. This photocatalyst was used to degrade sulfamethazine in wastewater. It was found that 50 ml of sulfamethazine at a concentration of 5 mg/L and pH 6.0 was degraded by 92.7 % when 25 mg of the 5 % A-BW sample underwent exposure to a 500-watt Xenon light at the wavelength of 420 nm for 90 min. This is a 47.7 % improvement over the degradation rate of Bi₂WO₆ (0 % A-BW). This improvement was credited to the efficient inhibition of photogenerated e⁻-h⁺ pair recombination by Ag doping, which enhanced photocatalysis. Through the analysis of ESR characterization and quenching studies, it can be determined that O₂⁻, OH and h⁺ all contribute to the photocatalytic process, with O₂⁻ playing the largest role. In conclusion, the 5 % A-BW composites exhibited excellent photocatalytic activity, which can provide a reference for the future application of photocatalytic technology to treat organically polluted wastewater.