Degradation of bisphenol AF in water by periodate activation with FeS (mackinawite) and the role of sulfur species in the generation of sulfate radicals

Abstract

The heterogeneous catalyst Mackinawite (FeS) was applied to activate periodate (IO4−) to degrade endocrine disruptors bisphenol AF (BPAF). This study investigated the influence of FeS dosage, periodate dosage, BPAF concentration, initial pH value and inorganic ions on BPAF degradation by FeS/IO4− system. The results showed that the BPAF was effectively degraded by FeS/IO4− system. The acidic pH exhibited higher efficiency in BPAF degradation compared with alkaline and neutral conditions. Furthermore, the BPAF degradation was dramatically promoted in the presence of Cl− and SO42−, whereas CO32− inhibited BPAF degradation. The radical scavenging tests and EPR indicated that singlet oxygen (1O2), superoxide radicals (O2−) and SO4− were committed to the degradation of BPAF, among which O2−, 1O2 were predominant radicals. The separate experiments showed that Fe(Ⅱ) participated in the activation of periodate. Furthermore, the effects of sulfur species (including the S2−, SO32−) on BPAF degradation by FeS/IO4− system were studied. The radical quenching tests suggested that S2− and SO32− were responsible for producing SO4−. The findings of this study elucidated an approach for the removal of micro-pollutants in the water environment through heterogeneous activation of periodate by FeS.