Work

pH/Temperature tuning selective generation of SO4•−/HO•/FeⅣ in Fe2+-activated peroxide water systems

Year: 2025

Type: article

Abstract: Active species (AS) are key in Fenton/Fenton-like reactions. The unclear AS category and generation order of SO 4 •− and HO • in the reaction of peroxymonosulfate (PMS) and Fe 2+ , as well as the quantity of SO 4 •− produced in the Fe 2+ /peroxydisulfate (PDS) system, limiting the practical application of selective AS generation for targeted pollutant degradation. Understanding the pathway of PMS/PDS/H 2 O 2 activated by Fe 2+ for SO 4 •− , HO • , and Fe Ⅳ generation is critical for the selective generation of AS by adjusting reaction conditions of pH or temperature. Results suggested that SO 4 •− was the sole PMS active product at T < 340 K and pH < 12, subsequently driving HO • generation from H 2 O, while Fe Ⅳ O 2+ was rapidly generated due to the chemical interaction between Fe 2+ and PMS. In Fe 2+ /PDS system, one SO 4 •− instead of reputed two SO 4 •− was generated since the coactions of Fe 2+ and SO 4 moiety, while Fe Ⅳ O 2+ is generated when H 2 O acts as reactant at pH 0 −7. In Fe 2+ /H 2 O 2 system, Fe Ⅳ O 2+ can only be formed stem from the pre-reaction of HO • generation. Furthermore, Tuning the reactant concentration could convert the AS category. This work advances the cognition of Fenton/Fenton-like microcosmic reactions, and is positive to the future design of experimental and industrial processes.

Source: Journal of Hazardous Materials

DOI: 10.1016/j.jhazmat.2025.139481