Degradation Of Tetracycline By Activated Persulfate Using Biochar Prepared From Agricultural Waste As Precursor

Antibiotics are secondary metabolites produced in the process of biological life.They have the ability to interfere with the development of biological cells and are widely used in the treatment of human and animal diseases.In fact,China is the first country to use tetracycline,and tetracycline hydrochloride（TC-H）is the most common antibiotic.TC-H in water is difficult to decompose naturally,which is harmful to human health.Moreover,it can increase the drug resistance of bacteria and greatly reduce the effect of tetracycline.Therefore,the effective management of tetracycline has always been a problem to be solved.In recent years,advanced oxidation processes（AOPs）have made remarkable progress in the treatment of antibiotic wastewater.Among them,sulfate based AOPs（SR AOPs）have been widely and deeply studied.At the same time,biochar as a catalyst in the field of advanced oxidation has been widely concerned.In this paper,biochar prepared from agricultural waste was used as catalyst to activate persulfate to degrade tetracycline hydrochloride.The specific research is as follows:（1）Soybean dregs were used as raw materials in nitrogen atmosphere.The raw biochar was obtained by pyrolysis of soybean residue with carbon dioxide,and then the raw biochar was modified by ball milling assisted alkali activation to prepare the biochar material MKBC.The effects of catalyst concentration,PDS concentration,TC-H concentration and p H value on the degradation of TC-H in MKBC/PDS system were investigated in detail.Firstly,the production of active substances（radicals and non-radicals）in the reaction process was obtained by combining the radical quenching experiment and EPR test.The total organic carbon（TOC）analysis and liquid chromatography-mass spectrometry（LC-MS）were used to prove the mineralization of TC-H and analyze its possible degradation pathways.The possible mechanism of TC-H degradation in the MKBC/PDS system was explored。（2）Using agricultural waste cotton hull as raw material,through a simple preparation process,named CBC was prepared by pyrolysis of waste cotton hull.The effects of catalyst concentration,PDS concentration,initial p H and TC-H concentration on the degradation of TC-H in CBC/PDS system were also discussed in detail.Furthermore,the results of radical quenching experiment and EPR test showed that SO₄^·-,·OH and ¹O₂were produced during the degradation reaction,which suggested the possible mechanism of CBC catalyzed PDS degradation of TC-H.