New Ti/CNT/CNT-Ce-PbO2 anode synergy peroxymonosulfate activation for efficiently electrocatalytic degradation of p-aminobenzoic acid.

Abstract

Increased levels of p-aminobenzoic acid in aquatic environments, primarily utilized as UV filter in sunscreens, poses a serious threat to human and ecosystem health, while there is a dearth of exhaustive researches pertaining to the efficient and cost-effective elimination of p-aminobenzoic acid. Herein, a Ti/SnO₂-Sb/CNT-α-PbO₂/CNT-Ce-β-PbO₂, referred to Ti/CNT/CNT-Ce-PbO₂ electrode was constructed by incorporating CNTs into the middle layer of PbO₂ electrode, and simultaneously doping CNTs and Ce in the active layer. A series of tests signify that the target electrode is successfully fabricated, which exhibits higher particle density and smaller particle size, as well as exceptional degradation performance for p-aminobenzoic acid with a degradation rate of 99.7% within 30 min coupling with peroxymonosulfate activation. The optimal degradation performance was observed at a PMS dosage of 0.07 g, Na₂SO₄ concentration of 0.05 mol L^-1, current density of 120 mA cm^-2, and initial pH value of 6.94. Capture experiments, electron spin resonance test, liquid chromatography-mass spectrometry analysis, toxicity assessment and theoretical calculation were performed to clarify the main activate radicals, degradation pathways and intermediate toxicity. This study provides a new anode material, and conducted the first exploration of electrocatalysis integrating peroxymonosulfate activation for degradation p-aminobenzoic acid.