Sustainable removal of acetamiprid by a sludge-derived catalyst through catalytic wet peroxide oxidation: Performance, mechanism and toxicity assessment

The persistence of acetamiprid in aquatic environments, due to incomplete removal by conventional treatments, poses serious ecological and health concerns. This study investigated the Catalytic Wet Peroxide Oxidation (CWPO) treatment of acetamiprid using a sustainable iron-rich carbonaceous catalyst (FeBioAC) derived from sewage sludge. The catalyst exhibited high specific surface area (550 m²·g^-1) and thermal stability, enabling the efficient degradation of acetamiprid under mild conditions. CWPO experiments were conducted under varying concentrations (15-50 μg·mL^-1), temperatures (35-65 °C), and water matrices, including river samples and wastewater effluents. The optimal H₂O₂/acetamiprid ratio of 9.2 μg H₂O₂·μg ACE^-1 achieved 90 % removal in ultrapure water and above 84 % in real matrices, with high catalyst reusability over four cycles. Kinetic modelling revealed that a dual-reactant hyperbolic model best described the process (R² = 0.9863), with a notably low activation energy (12.56 kJ·mol^-1). Density Functional Theory (DFT) calculations provided mechanistic insights into the degradation pathways, highlighting dechlorination, hydroxylation, and decyanation as dominant reactions. Toxicity assessments confirmed that transformation products were substantially less harmful than the parent compound. These findings positioned FeBioAC as a sustainable and effective catalyst for removing emerging contaminants from complex aquatic environments.