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

Abstract 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 Co 3 (PO 4 ) 2 /Ag 3 PO 4 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 Co 3 (PO 4 ) 2 /Ag 3 PO 4 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 Ag 3 PO 4 and Co 3 (PO 4 ) 2 . The reduction of antimicrobial activity for 8%Co 3 (PO 4 ) 2 /Ag 3 PO 4 reached 88.8% after 5 min of sunlight irradiation. CONCLUSION Co 3 (PO 4 ) 2 played a critical role in suppressing carrier recombination and provided a large number of photogenerated holes and • O 2 − 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 Co 3 (PO 4 ) 2 /Ag 3 PO 4 . Therefore Co 3 (PO 4 ) 2 /Ag 3 PO 4 is an attractive candidate for the removal of OFX. © 2019 Society of Chemical Industry

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