The degradation of the artificial sweetener acesulfame (ACE) was investigated using an ultraviolet (UV)365-activated peroxydisulfate (PDS) process. The results demonstrated that the ACE reaction rate with the UV/PDS process followed pseudo first-order kinetics (R2 > 0.9) under various conditions. A high dosage of PDS, alkaline condition, and the existence of NO3- and Cl- enhanced ACE degradation; however, a high dosage of ACE, the existence of HCO3-, humic acid, and fulvic acid, and a real water matrix did not facilitate the degradation of ACE. Four types of transformation products were detected in the degradation of ACE by UV/PDS, and the primary degradation pathways were oxidation, hydroxyl substitution, hydrolysis, and hydration. The hydroxyl radicals played a predominant role (71.31%) in the degradation of ACE by the UV/PDS process, followed by sulfate radicals (14.57%) and UV photolysis (8.83%). Both the degradation and mineralization rates of ACE using the UV/PDS process had significant advantages over that of the UV/H2O2 process regarding ACE degradation, indicating that the UV/PDS process is more promising for treating water containing ACE.
Keywords: Acesulfame; Artificial sweetener; Degradation; Ultraviolet/peroxydisulfate.
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