Enhanced BiFeO/BiFeO/HO heterogeneous system for sulfamethoxazole decontamination: System optimization and degradation pathways.

Sulfonamides as the major antibiotic have become emerging contaminants worldwide in aquatic environments. Herein, a heterogeneous Fenton-like oxidation driven by a novel BF-PMCs bismuth ferrites reported firstly for efficient degradation of sulfamethoxazole (SMX) in which the possible degradation pathways are thoroughly analyzed through identifying some of key intermediates (i.e., CHNOS, CHNO, etc.) using liquid chromatography-mass spectrum (LC-MS), monitoring organic acids (i.e., acetic acid, pyruvic acid) and inorganic anions (i.e., sulfate, nitrate) using ion chromatography (IC), and detecting radical species (i.e., HO) using both chemical quenchers and fluorescence technique, simultaneously. The optimal operations in BF-PMCs/HO system for SMX degradation are recommended at the conditions of initial pH ~4.5, 1.5 mg L [SMX], 70 mM [HO], and BF-PMCs loading of 0.2 g L. The degradation rates (kinetic value of k) for SMX, azoxystrobin, bisphenol A, and 2,4-dichlorophenol are 9.5 × 10, 13.6 × 10, 7.3 × 10, and 5.9 × 10 min, respectively. Meanwhile, the degradation rates in BF-PMCs/HO system for SMX degradation are slightly slower in the presence of inorganic anions (e.g., Cl, NO) and NOM (e.g., humic acid). Based on an overall consideration, the BF-PMCs/HO system has great potential for degradation of emerging organic pollutants (EOPs) in natural water systems.