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

The heterogeneous catalyst Mackinawite (FeS) was applied to activate periodate (IO 4 − ) 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/IO 4 − system. The results showed that the BPAF was effectively degraded by FeS/IO 4 − 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 SO 4 2− , whereas CO 3 2− inhibited BPAF degradation. The radical scavenging tests and EPR indicated that singlet oxygen ( 1 O 2 ), superoxide radicals (O 2 − ) and SO 4 − were committed to the degradation of BPAF, among which O 2 − , 1 O 2 were predominant radicals. The separate experiments showed that Fe(Ⅱ) participated in the activation of periodate. Furthermore, the effects of sulfur species (including the S 2− , SO 3 2− ) on BPAF degradation by FeS/IO 4 − system were studied. The radical quenching tests suggested that S 2− and SO 3 2− were responsible for producing SO 4 − . 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.