Bimetallic metal-organic framework as a high-performance peracetic acid activator for sulfamethoxazole degradation

A novel 3D bimetallic metal-organic framework (MOF(Fe–Co)) was successfully prepared and its performance on sulfamethoxazole (SMX) removal in advanced oxidation process (AOP) based on peracetic acid (PAA) was evaluated. MOF(Fe–Co) exhibited an efficient catalytic performance on PAA activation for SMX degradation under neutral condition. Increasing PAA concentration could enhance SMX removal, while the variation of MOF(Fe–Co) dosage from 0.05 to 0.2 g/L had an inappreciable effect on SMX removal. According to the results of inductively coupled plasma mass spectrometry analyses and X-ray photoelectron spectroscopy, catalytic reactions mainly occurred on the surface of MOF(Fe–Co). Organic radicals (i.e., CH3C(O)OO• and CH3C(O)O•) were demonstrated to be the predominant reactive radicals for SMX degradation by MOF(Fe–Co)/PAA through radical quenching experiments. The presence of Cl− could enhance the degradation of SMX by MOF(Fe–Co)/PAA, while HCO3− and natural organic matter inhibited SMX degradation severely. Five identified degradation products were detected in this system and four possible SMX transformation pathways were proposed, including amino oxidation, S–N bond cleavage, coupling reaction and hydroxylation.