Degradation of a fluorescent tracer-PTSA in circulating cooling water: Kinetics, pathways, and degradation efficiency of a polycyclic aromatic hydrocarbon derivative

•UV-based AOPs was adopted to degrade PTSA in circulating cooling water.•The apparent kinetics constants of PTSA were inversely proportional to initial concentration.•The degradation pathways of PTSA were speculated through theoretical analysis and experiments.•The hydroxylation products of PTSA had stronger cytotoxicity than itself.