Co <sub/>3</sub> (PO <sub/>4</sub> ) <sub/>2</sub> /Ag <sub/>3</sub> PO <sub/>4</sub> with Enhanced Simulated Sunlight Photocatalytic Activity toward Ofloxacin Degradation and Mechanism Insight

摘要： BACKGROUND: Ofloxacin is a frequently detected fluoroquinolone antibiotic in wastewater treatment plants effluents, sea waters and surface waters. Photocatalytic technology is considered to the most promising treatment technology for the removal of ofloxacin. However, it is a big challenge to exploit the novel sunlight driven photocatalyst and reveal the mechanism of the ofloxacin degradation. RESULTS: Co3(PO4)2/Ag3PO4 composites were prepared using a facile hydrothermal synthesis method. The structural, morphological, 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 to single-phase Ag3PO4 and Co3(PO4)2. The reduction of antimicrobial activity for 8%Co3(PO4)2/Ag3PO4 reached to 88.8% after 5 min sunlight irradiation. CONCLUSIONS: Co3(PO4)2 played a critical role in suppressing carrier recombination and provided a large number of photogenerated holes and ?O2- to oxide OFX or MO. The OFX degradation mechanism included piperazinyl dealkylation, decarboxylation, 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.