Degradation of bisphenol A through transition metals activating persulfate process

Abstract In this study, the process of transition metals (Fe 2+ , Fe 0 , Ni 2 O 3 ) activating persulfate was attempted to degrade aqueous bisphonel A (BPA). Compared with thermal activation mode, significant degradation can be achieved at normal atmospheric temperature in transition metal activation mode. BPA removal in the transition metal-PS system can be divided into rapid phase (0–5 min) and slow phase (5–60 min). In rapid phase, 87.71% and 90.60% removal efficiencies were obtained in the Fe 2+ -PS and Ni 2 O 3 -PS systems, and the contaminant was almost completely oxidized after 60 min. There are many similarities between the Fe 2+ -PS and Fe 0 -PS systems, in particular the optimal removal efficiencies were achieved at n 0 (Fe 2+ ): n 0 (PS) = 1:2 and n 0 (Fe 0 ): n 0 (PS) = 1:2 rather than with maximum metal dosage. The Ni 2 O 3 dosage had positive correlation with BPA removal rate while the degradation efficiency of the Fe 2+ -PS system could be promoted by keeping n 0 (sodium citrate): n 0 (Fe 2+ ) below 1:1. Intermediate products of the Fe 2+ -PS system were analyzed by LC-MS and were predominantly phenol, p-hydroxyacetophenone, benzoquinone and propanedioic acid, therefore a possible oxidation degradation pathway was speculated.