Degradation of bisphenol A in aqueous solution by persulfate activated with ferrous ion

Degradation of bisphenol A (BPA) in aqueous solution was studied with high-efficiency sulfate radical (SO4 (-center dot)), which was generated by the activation of persulfate (S2O8 (2-)) with ferrous ion (Fe2+). S2O8 (2-) was activated by Fe2+ to produce SO4 (-center dot), and iron powder (Fe-0) was used as a slow-releasing source of dissolved Fe2+. The major oxidation products of BPA were determined by liquid chromatography-mass spectrometer. The mineralization efficiency of BPA was monitored by total organic carbon (TOC) analyzer. BPA removal efficiency was improved by the increase of initial S2O8 (2-) or Fe2+ concentrations and then decreased with excess Fe2+ concentration. The adding mode of Fe2+ had significant impact on BPA degradation and mineralization. BPA removal rates increased from 49 to 97 % with sequential addition of Fe2+, while complete degradation was observed with continuous diffusion of Fe2+, and the latter achieved higher TOC removal rate. When Fe-0 was employed as a slow-releasing source of dissolved Fe2+, 100 % of BPA degradation efficiency was achieved, and the highest removal rate of TOC (85 %) was obtained within 2 h. In the Fe-0-S2O8 (2-) system, Fe-0 as the activator of S2O8 (2-) could offer sustainable oxidation for BPA, and higher TOC removal rate was achieved. It was proved that Fe-0-S2O8 (2-) system has perspective for future works.