尿素-Na_2CO₃协同改性生物炭的表面自由基调控机制及PMS活化效能

To address the issue of treating refractory organic pollutants in water and to control environmental pollution, this study used aniline as a model pollutant and investigated the co-doping and synergistic modification of corn cob biochar with urea and sodium carbonate.The surface free radical regulation mechanism and the activation efficiency of peroxymonosulfate were explored.Modified biochar was prepared by varying nitrogen sources, urea dosage, sodium carbonate dosage and pyrolysis temperature, and analyzed for free radical generation, aniline removal efficiency, functional groups, and elemental composition.Incorporation of 30% urea resulted in a persistent free radical concentration of 5.339×109 spins/g, significantly higher than other nitrogen sources.When urea and sodium carbonate contents were 30% and 40%,respectively, the persistent free radical concentration and aniline removal efficiency were maximized, showing a positive correlation.As pyrolysis temperature increased from 300 to 900 ℃,the carbon content of biochar increased from 6.983% to 53.256%,hydrogen content initially increased and then decreased to 1.169%,oxygen content decreased to 20.065%,and nitrogen content peaked at 7.142%.Metal elements were enriched, with Fe concentration reaching 9 258.477 mg/kg.Functional groups in the modified biochar gradually decreased, especially oxygen-containing functional groups.Persistent free radicals and biochar the dosage were key factors affecting aniline removal, achieving an optimal removal rate of 97.6% under optimal conditions.Moreover, biochar prepared at 500 ℃ exhibited a moderate pore structure, stable surface functional groups, and good reusability.Urea-sodium carbonate synergistic modification effectively regulates surface free radicals, significantly enhance their activation efficiency, providing a new idea for the efficient treatment of refractory organic pollutants.