Comparative evaluation of persulfate and peroxy monosulfate-based advanced oxidation processes for amoxicillin degradation: mechanisms, efficiency, and challenges
Harez R. Ahmed, Anu Mary Ealias
Abstract
The widespread occurrence of antibiotics in aquatic environments has raised serious concerns due to their persistence, toxicity, and contribution to the proliferation of antibiotic-resistant bacteria. Amoxicillin, one of the most frequently prescribed β-lactam antibiotics, is frequently detected in surface water, groundwater, and wastewater effluents due to its low biodegradability and incomplete removal by conventional treatment technologies. In this context, sulfate radical-based advanced oxidation processes (SR-AOPs) have emerged as highly effective alternatives for degrading antibiotics. This review critically evaluates activation-based AOPs using persulfate (PS) and peroxymonosulfate (PMS) for the degradation of amoxicillin, with emphasis on oxidant chemistry, radical generation mechanisms, redox properties, stability, and reaction kinetics. Various activation strategies, including thermal, UV/visible-light, transition-metal catalysis, carbonaceous material activation, and electrochemical/photoelectrocatalytic systems, are systematically compared with respect to efficiency, selectivity, operational conditions, and environmental implications. The advantages of sulfate radicals over hydroxyl radicals, including longer lifetimes, broader pH applicability, and enhanced selectivity for electron-rich antibiotic structures, are highlighted. Key challenges related to catalyst stability, metal leaching, energy consumption, and toxicity of transformation products are also discussed. Finally, future research directions are proposed to facilitate the scale-up and sustainable application of PS/PMS-based AOPs for treating antibiotic-contaminated water.