Study On The Mechanism Of Corn Cob Biochar Activating Persulfate To Degrade Organic Pollutants

Organic solid waste is a potential resource.Utilizing it as a resource can alleviate resource shortages,reduce greenhouse gas emissions,and solve a series of environmental pollution problems caused by organic solid waste.A large number of complex organic pollutants can be discharged into the water environment through different channels（such as industrial and agricultural household sewage）,so the water organic pollution has become a difficult problem in water environment control.At present,adsorption,chemical oxidation and degradation techniques have become the most commonly used countermeasures for water environment remediation.Persulfate-based advanced oxidation processes have been paid more attention because of its strong oxidation and high degradation efficiency,but it still needs to find efficient and environmentally friendly catalysts to activate persulfate.As a new kind of porous carbon material,biochar has the potential to activate persulfate,and has the advantages of low preparation cost and abundant raw materials without secondary pollution.However,how to prepare efficient functional materials of biochar and reveal the mechanism of activation of persulfate remains to be studied.Therefore,this work mainly focuses on the preparation of biochar materials degradation reaction conditions optimization reaction mechanism and other aspects of the discussion.Based on solid waste recycling,we prepared a metal-free corn cob biochar（CCBC）using discarded corn cob as raw material.The pathway of activation of persulfate（PDS）by CCBC was also analyzed.Pyrolysis temperature played a key role in regulating the structure and properties of biochar.The pore and defect structure of CCBC prepared at 800°C was relatively richer,so it showed the best adsorptive and catalytic ability to five typical organic pollutants（2,4-dichlorophenol,Tetracycline hydrochloride,Ciprofloxacin,Methyl orange and Rhodamine B）.The treatment of pharmaceutical wastewater showed that the metal-free catalyst has good application potential.CCBC/PDS induced a compound activation mechanism,in which the contribution of radical pathway accounted for 58%,and that of non-radical pathway accounted for 42%.More importantly,further redox experiments manifested that the carbon framework（defects,sp²-hybrid carbon,etc.）only made a contribution to the free radical pathway,while the ketone group（C=O）of CCBC was proved to be mainly responsible for the non-radical pathway,namely the generation of singlet oxygen（¹O₂）.The effective degradation of a variety of organic pollutants by CCBC showed its universality.It also presented good catalytic activity in a wide p H range and in actual pharmaceutical wastewater treatment,which indicated that the catalyst would have good potential for practical application.