Mechanism of biochar composite (BN3Z0.5BC) activated peracetic acid for efficient antibiotic degradation: Synergistic effect between free radicals and non-free radicals

Abstract

This study utilized corn straw as the feedstock to synthesize biochar (BC) loaded with cobalt-zeolitic imidazolate framework nanoparticles and boron nitride quantum dots. The prepared BC composite, named BN₃Z_0.5BC, efficiently activated peracetic acid (PAA), resulting in the degradation of 94.8% of sulfadiazine (SDZ) in five minutes. Compared to pure BC, the SDZ removal rate increased nearly 5-fold. Mechanism analysis revealed that the main degradation pathway involves synergism between free and non-free radicals. The defect structure on the BC surface possesses a high charge density, stimulating PAA to produce more active species, while nitrogen-oxygen vacancy formation significantly promotes charge transfer. Besides, the unique structure of BC ensures good stability and recyclability, effectively controlling metal leaching. The BN₃Z_0.5BC/PAA system shows promising applicability across various water matrices, indicating a favorable application outlook.

Keywords: Defect structure; Singlet oxygen; Sulfadiazine; Superoxide radical; Water treatment.