Oxidation of bisphenol A by persulfate via Fe3O4-α-MnO2 nanoflower-like catalyst: Mechanism and efficiency

A novel and high-efficiency Fe 3 O 4 -α-MnO 2 nanoflower-like catalyst was synthesized using a two-step hydrothermal method. The catalyst was used to activate persulfate (PS) to degrade bisphenol A (BPA) in aqueous phase. The mechanism of the Fe 3 O 4 -α-MnO 2 /PS system was investigated. X-ray photoelectron spectra and cyclic voltammograms showed that the mixed valence of Fe 3 O 4 -α-MnO 2 was favorable to electron transfer between Fe and Mn elements. Apparently, this process promoted the circulation of Fe 2+ /Fe 3+ and Mn 3+ /Mn 4+ , increasing the effectiveness of the catalyst to activate the PS. In addition, with ATR-FTIR analysis, the influence of phosphate confirmed the presence of OH groups on the Fe 3 O 4 -α-MnO 2 surface. Thus, these groups played crucial roles in the PS activation . Sulfate radicals were reacting species of great importance in BPA degradation. The degradation intermediates were also detected via GC–MS analysis, and the possible BPA degradation pathway was proposed.