Main content area

Co3(PO4)2/Ag3PO4 with enhanced simulated sunlight photocatalytic activity toward ofloxacin degradation and mechanism insight

Geng, Zhi, Yang, Min, Qi, Xin, Li, Zhaoyang, Yang, Xia, Huo, Mingxin, Crittenden, John C
Journal of chemical technology and biotechnology 2019 v.94 no.5 pp. 1660-1669
antimicrobial properties, byproducts, dealkylation, decarboxylation, effluents, irradiation, lighting, methyl orange, optical properties, photocatalysis, photocatalysts, solar radiation, superoxide anion, surface water, wastewater treatment
BACKGROUND: Ofloxacin is a frequently detected fluoroquinolone antibiotic in wastewater treatment plant effluents, sea waters and surface waters. Photocatalytic technology is considered to be the most promising treatment technology for the removal of ofloxacin. However, it is a big challenge to exploit a novel sunlight‐driven photocatalyst and reveal the mechanism of ofloxacin degradation. RESULTS: Co₃(PO₄)₂/Ag₃PO₄ composites were prepared using a facile hydrothermal synthesis method. The structural, morphological and optical properties of the composites were well characterized. Both the degradation efficiency and cyclical stability of the Co₃(PO₄)₂/Ag₃PO₄ composites increased significantly under simulated sunlight irradiation when ofloxacin (OFX) or methyl orange (MO) was used as the target molecule, as compared with single‐phase Ag₃PO₄ and Co₃(PO₄)₂. The reduction of antimicrobial activity for 8%Co₃(PO₄)₂/Ag₃PO₄ reached 88.8% after 5 min of sunlight irradiation. CONCLUSION: Co₃(PO₄)₂ played a critical role in suppressing carrier recombination and provided a large number of photogenerated holes and •O₂⁻ to oxidize OFX or MO. The OFX degradation mechanism included piperazinyl dealkylation, decarboxylation and defluorination. The reduction of antimicrobial activity for degradation byproducts was obvious after simulated sunlight irradiation over Co₃(PO₄)₂/Ag₃PO₄. Therefore Co₃(PO₄)₂/Ag₃PO₄ is an attractive candidate for the removal of OFX. © 2019 Society of Chemical Industry