Mechanistic insights into the adsorption and advanced oxidation behaviors of chlorotetracycline by iron-doped biochar from co-pyrolysis of steel sludge and wheat straw.

Steel mill wastewater sludge, rich in endogenous iron resources and heavy metals, can be converted into iron-doped biochar and reduce metal leaching through co-pyrolysis treatment. In this study, wheat straw was selected as the co-pyrolysis biomass for steel sludge, aiming to optimize the preparation of iron sludge/wheat straw co-pyrolysis biochar(FCB)without potential ecological risks, and it was applied in the adsorption and catalytic degradation of chlortetracycline (CTC), and its removal performance and mechanism were investigated. The results showed that the co-pyrolysis biochar (FCB3-800) showed a good removal performance of CTC. The adsorption process conforms to the pseudo-second-order kinetic model and the Langmuir isotherm model. FCB3-800 can effectively catalyze PDS to produce SO4˙-, ·OH and O2˙-, which can effectively catalyze the degradation of CTC through dehydroxylation, didemethylamino, ring opening, dehydration, C-C bond breaking, demethylation and amide reactions. The successful preparation of FCB3-800 provides a win-win solution for the resource utilization of solid waste and the treatment of antibiotic pollution.