Applying a novel advanced oxidation process of activated peracetic acid by CoFe2O4 to efficiently degrade sulfamethoxazole

In this study, peracetic acid (PAA) is successfully activated by cobalt ferrite (CoFe 2 O 4 /PAA) to remove sulfamethoxazole (SMX). Increasing either PAA (25–200 μM) or CoFe 2 O 4 (25–200 mg/L) dose accelerated SMX degradation in the CoFe 2 O 4 /PAA system, and the best removal of SMX (87.3%) was acquired with 200 μM PAA and 0.1 g/L CoFe 2 O 4 at neutral condition. Addition of humic acid or HCO 3 – inhibited SMX removal, whereas Cl – had little impact. The redox cycle of ≡Co 3+ /≡Co 2+ on the CoFe 2 O 4 surface dominated PAA activation to produce organic radicals (R-O • ) including CH 3 C(O)O • and CH 3 C(O)OO • accounting for SMX degradation. Based on the density functional theory (DFT) calculation and identified oxidation products, SMX transformation pathway was proposed to be initiated by electron transfer reaction with R-O • . The insignificant variation of acute toxicity, the fine CoFe 2 O 4 stability and the good removal of some other micro-organic pollutants suggested the potential applicability of the CoFe 2 O 4 /PAA system in degrading micro-organic pollutants.