Comparative study on the degradation of sucralose by UV/persulfate and UV/periodate processes: Performance, dechlorination, and technical feasibility

Sucralose (SUC) pose a potential threat to the aquatic environment and human health. In the study, SUC degradation by UV/persulfate (UV/PS) and UV/periodate (UV/PI) was compared from different perspectives. The results showed that both processes were effective in degrading SUC within 15 min, but the degradation rate of UV/PI was much higher than that of UV/PS due to higher radical concentrations. UV/PS and UV/PI are more suitable for the degradation of SUC under neutral and alkaline conditions. The presence of Cl^- and HCO₃^- mainly inhibited SUC degradation by UV/PI, while NO₃^- was more likely to inhibit SUC degradation by UV/PS. •OH and SO₄•^- in UV/PS degraded SUC mainly by hydroxylation, hydrogen atom abstraction, dehydration, and direct oxidation. In UV/PI, in addition to the above-mentioned actions, IO₃• initiates a deep oxidation process by destroying the ether bonds. After 15 min of oxidation, dechlorination of SUC by UV/PI and UV/PS was 35.1 % and 22.9 %. Dechlorination is mainly achieved by the chlorine atoms abstraction from •OH and the single electron transfer of IO₃•. UV/PI is recommended as a SUC degradation process with lower cost (55.8 % lower) and safer inorganic product (isometric IO₃^-) than UV/PS with similar detoxification effect.