Removal of Ibuprofen via the O3/H2O2 Oxidation System: Performance, Degradation Mechanism, and Toxicity Evaluation

Abstract

Ibuprofen (IBF), as a representative emerging contaminant, poses urgent environmental and ecological risks that demand efficient removal technologies. This study employed an O3/H2O2 catalytic oxidation process to degrade IBF in aqueous systems and systematically investigated the effects of reactant ratios, pH, and reactive species on the degradation efficiency. The results demonstrated that O3-dominated oxidation significantly outperformed H2O2 alone in IBF removal, with an optimal dosage ratio of c(O3):c (H2O2) = 6:1 and a removal efficiency of 94.75% at pH > 7. Radical quenching experiments confirmed that •OH served as the dominant reactive species, the concentration and stability of which directly governed the degradation kinetics. Combined density functional theory (DFT) calculations and mass spectrometry analysis revealed that the benzene ring and carboxyl groups in IBF were vulnerable to radical attack, with degradation pathways involving hydroxylation, decarboxylation, and ring-opening reactions, yielding 13 intermediate products. The toxicity assessment indicated that over 70% of these intermediates exhibited low or negligible toxicity. Remarkably, IBF removal efficiencies exceeded 99.4% in real water matrices (raw, filtered, and finished water), validating the robust anti-interference capability of the O3/H2O2 system. This process, characterized by high efficiency and low ecological risk, provides a feasible solution for eliminating trace emerging contaminants in advanced drinking water treatment.