Cascade degradation of organophosphorus pollutant by photoenzymatic integrated nanocatalyst

BACKGROUND As visible-light photocatalytic semiconductors, BiOBr-based catalysts have a promising application prospect for the degradation of dyes and pollutants in wastewater. Enzyme catalysis has become a promising technology in the degradation of organophosphorus pollutants due to excellent activity and specificity. Herein, a photoenzymatic integrated nanocatalyst of organophosphorus hydrolase (OPH) immobilized on BiOBr (OPH@BiOBr) was successfully synthesized for the cascade degradation of methyl parathion under visible light. RESULTS The obtained OPH@BiOBr could degrade methyl parathion into para -nitrophenol (p-NP) by hydrolyzing the P  S bond using OPH, and then converting the produced p-NP into a less toxic substance through photocatalysis of BiOBr. After 3 h of reaction, methyl parathion was degraded into hydroquinone and nearly 80% of the produced p-NP was further degraded at the same time. The OPH@BiOBr nanocatalyst could be recycled five times and still retained 83% of its initial activity. CONCLUSIONS A novel photoenzymatic integrated nanocatalyst was developed for cascade degradation of methyl parathion under visible light. This represents the first attempt at eliminating pesticide residues by combining enzyme with photocatalyst through a cascade reaction. Considering the fact that wastewater may have pesticide residues, photoenzymatic integrated catalysts will be useful for the degradation of pollutants. The unique flower-like structure of the nanocatalyst could not only improve photocatalytic activity but also protect enzyme molecules so as to complete the cascade degradation. In addition, with the development of enzyme engineering and photocatalysis, the integrated nanocatalysts that combine photocatalyst with enzyme will have more and more application in the fields of energy and the environment. © 2020 Society of Chemical Industry