CTAB assisted preparation of cobalt oxide/biochar composite and its activation performance and mechanism of peracetic acid for the effective degradation of tetracycline in water

Application of the cobalt-based heterogeneous activators for peracetic acid (PAA) activation has attracted significant interests, though the efficacy limitations arise from delayed >Co(II)/>Co(III) redox cycling. The biochar-supported cobalt oxide (C-CoO/BC) composite prepared by cetyl trimithyl ammonium bromide (CTAB) assisted pyrolysis method possesses rich pore structure and surface functional groups, which can effectively promote the >Co(II)/>Co(III) redox cycle. Morphological and structural analyses confirm successful loading of cobalt oxide on biochar. The degradation performance results show that the C-CoO/BC/PAA system can achieve complete degradation of tetracycline (TC) within 5 min under neutral conditions, and exhibits excellent degradation performance in different water matrixes. The C-CoO/BC composite exhibits superior electron transfer performance than CoO and CoO/BC. The negligible influence of different ionic strength on TC abatement indicates the inner-sphere complexation between PAA and C-CoO/BC. The functional groups on the BC surface can continuously activate PAA through the >Co(II)/>Co(III) cycle to generate active species such as organic radical and 1 O 2 , achieving efficient TC abatement. According to the degradation intermediates, the TC degradation process mainly includes ring-opening, dehydroxylation and deamidation reaction with significantly reduced toxicity of the intermediate products. Finally, the system demonstrates strong interference resistance and reusability, as shown by its good TC degradation under varying factors and cyclic application. This study provides an efficient, stable and environmentally friendly technical solution for the treatment of antibiotic pollution in water bodies.