Enhanced BiFeO₃/Bi₂Fe₄O₉/H₂O₂ heterogeneous system for sulfamethoxazole decontamination: System optimization and...

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., C₈H₁₁N₃O₄S, C₄H₄NO₂, 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/H₂O₂ system for SMX degradation are recommended at the conditions of initial pH ~4.5, 1.5 mg L^-1 [SMX], 70 mM [H₂O₂], and BF-PMCs loading of 0.2 g L^-1. The degradation rates (kinetic value of k_app) for SMX, azoxystrobin, bisphenol A, and 2,4-dichlorophenol are 9.5 × 10^-3, 13.6 × 10^-3, 7.3 × 10^-3, and 5.9 × 10^-3 min^-1, respectively. Meanwhile, the degradation rates in BF-PMCs/H₂O₂ system for SMX degradation are slightly slower in the presence of inorganic anions (e.g., Cl^-, NO₃^-) and NOM (e.g., humic acid). Based on an overall consideration, the BF-PMCs/H₂O₂ system has great potential for degradation of emerging organic pollutants (EOPs) in natural water systems.