Electro-Assisted Fe³⁺/Persulfate System for the Degradation of Bezafibrate in Water: Kinetics, Degradation Mechanism, and Toxicity

In this study, an electrochemical-assisted ferric ion/persulfate (EC/Fe3+/PS) process was proposed to degrade bezafibrate (BZF), a widespread hypolipidemic drug, in water. By promoting the reduction of Fe3+ to Fe2+ at the cathode, the introduction of an electric field successfully overcomes the limitation of non-regenerable Fe2+ inherent in Fe2+/PS systems, significantly improving the degradation efficiency of BZF. The predominant reactive species identified were •OH and SO4●−, with 1O2 also playing a role. Various key operational parameters were investigated and optimized, including the current intensity, Fe3+ dosage, PS concentration, and initial pH. With a current intensity of 50 mA, an Fe3+ concentration of 50 μΜ, a PS dosage of 50 μM, and an initial pH of 3, the degradation efficiency of BZF demonstrated an exceptional achievement, reaching up to 98.8% within 30 min. The influence of anions and humic acid was also assessed. An LC/TOF/MS analysis revealed four major degradation pathways of BZF: hydroxylation, amino bond cleavage, dechlorination, and fibrate chain removal. The acute and chronic toxicities of BZF and its degradation intermediates were then assessed using the ECOSAR program. These findings highlight the wide-ranging applications of the EC/Fe3+/PS system and its potential for remediating water contaminated with micropollutants.