Waste Natural Pyrite Activation of Peroxymonosulfate for Degradation of Artificial Sweetener Acesulfame Potassium: Efficiency, Influencing Factors, Degradation Mechanisms, and Toxicity Evaluation

Acesulfame potassium (ACE) is an emerging pollutant with the potential to induce a range of health hazards. In this study, waste natural pyrite (with some oxides on its surface) was washed and used as an activator to activate potassium peroxomonosulfate (PMS) to degrade ACE in water. The experimental results demonstrate that waste natural pyrite with an oxidized layer exhibited a significant degradation effect on ACE. Under conditions of 0.7 g/L pyrite and 60 μM PMS, a degradation rate of 99.3% for ACE was achieved within 15 min, and the mineralization rate reached 15.3% within 30 min. In addition, concerning its applicability, waste natural pyrite demonstrates strong activation ability within a pH range of 3 to 7. It is important to note that while HCO3−and Ca2+can influence the effectiveness, other common anions and cations do not significantly affect the degradation process. Mechanistic studies reveal that the primary active species in the waste natural pyrite/PMS system were sulfate radicals (SO4•−) as well as hydroxyl radicals (•OH), which contributed 50.6% and 36.9%, respectively. In addition, the analysis of ACE degradation products indicates that no highly toxic intermediates were generated during the degradation process. Overall, this study underscores the outstanding performance of waste natural pyrite as an activator, providing a safe, efficient, and cost-effective approach for degrading organic pollutants like ACE.