BACKGROUNDOfloxacin 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. RESULTSCo3(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 Co-3(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 Co-3(PO4)(2). The reduction of antimicrobial activity for 8%Co-3(PO4)(2)/Ag3PO4 reached 88.8% after 5min of sunlight irradiation. CONCLUSIONCo3(PO4)(2) played a critical role in suppressing carrier recombination and provided a large number of photogenerated holes and O-center dot(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(PO4)(2)/Ag3PO4. Therefore Co-3(PO4)(2)/Ag3PO4 is an attractive candidate for the removal of OFX. (c) 2019 Society of Chemical Industry