Bisphenol A degradation by base-activated persulfate using steel slag

Steel slag was firstly employed as a solid activator for a peroxydisulfate activation system, in which the degradation efficiency of BPA was evaluated. About 74% of BPA(50 μg/L) can be effectively removed within 1 hour under the adopted condition ([peroxydisulfate]0=2g/L, [Steel Slag]=3g/L, T=25℃). The components and surface morphology of unused and recycled steel slag were analyzed by scanning electron microscopy, X-ray diffraction and X-ray fluorescence, demonstrating the gradual decrease of CaO and FeO. Radical scavenger studies confirmed that all of the O2•-, S O4•- and •OH contributed to the BPA degradation with the contribution of 68.97%, 9.52% and 21.51%, respectively. The degradation efficiency was enhanced in tap water due to the existence of HCO3- and was weakened in municipal wastewater effluent due to the radical scavenge by other organics. A redox mechanism was proposed and claimed that both the base oxides and iron oxides of steel slag were responsible for the peroxydisulfate activation. The degradation products of BPA included quinone and carboxylic acid, which were identified by LC/MS. © 2019, Editorial Board of China Environmental Science. All right reserved.