Degradation of UV-filter benzophenone-3 in aqueous solution using persulfate catalyzed by cobalt ferrite

Abstract The occurrence of benzophenone-3 (BP-3) in aquatic environments constitutes a potential risk to the environment and human health due to its phytotoxicity, carcinogenicity and endocrine disrupting effects. In this work, cobalt ferrite (CoFe 2 O 4 ) prepared by chemical co-precipitation method was used as a catalyst for the degradation of BP-3. The catalyst was characterized by SEM, TEM, XRD, XPS, BET and FT-IR spectroscopy, and its catalytic activity on BP-3 removal by persulfate (PS) was then evaluated at different operating parameters (catalyst loading, reaction temperature, solution pH and PS dose). The removal of BP-3 (1.31 μM) in 6 h reached 91% under the condition of [BP-3] 0 : [PS] 0  = 1: 1000, initial pH = 7.0, T = 25 °C and catalyst load = 500 mg L −1 . In addition to the satisfactory catalytic performance, the CoFe 2 O 4 also showed high stability and excellent recyclability. Electron paramagnetic resonance and radical quenching tests showed that sulfate radicals predominated in the decomposition of BP-3 by PS/CoFe 2 O 4 , while hydroxyl radicals also contributed to the catalytic oxidation process. Fifteen degradation products were identified by liquid chromatography-mass spectrometry (LC-MS), and two reaction pathways involving hydroxylation, demethylation, direct oxidation and benzene ring opening were proposed. This study could provide useful information for the potential application of CoFe 2 O 4 activated PS technology to treat water and wastewaters containing BP-3.