Chitin Derived Biochar To Activat Persulfate For Phenol Degradation

A kind of chitin biochar（N-BC）was prepared for activating persulfate（PDS）to quickly remove phenol in water.Firstly,the optimum preparation conditions of N-BC were explored and characterized by SEM,BET,FTIR,XPS and Raman spectra.Then,the practical application potential of N-BC/PDS system was tested.Finally,the mechanism of phenol degradation in the N-BC/PDS system was determined by EPR tests,quenching experiments and electrochemical experiments.The degradation products of phenol were analyzed by GC-MS.The main conclusions of this paper were as follows:（1）N-BC 600/PDS system had a benefit degradation effect on phenol.More than98%of 50 mg/L phenol can be removed by 0.4 g/L N-BC and 1.0 g/L PDS within two hours under 25℃and 200 rpm/min without p H adjustment.（2）The N-BC 600/PDS system maintained a high reaction activity in 15-45℃and the p H range of 3-11.The phenol degradation rate was almost unaffected by Cl^-,SO₄^2-,NO₃^-,HPO₄^2-,H₂PO₄^-,and HCO₃^-except CO₃^2-and humic acid.（3）The additional urea provided sufficient defect sites for chitin biochar,and the presence of graphite nitrogen promoted the activation effect of biochar on persulfate.The reaction was dominated by electron transfer pathway,which was transferred from phenol to PDS via N-BC 600.In addition,the free radical pathways（·OH and·O₂^-）played a supporting role in phenol degradation.However,phenol was not completely mineralized by N-BC 600/PDS system within 2 h.It was transformed into organic acids and large molecular alkanes,and then decomposed into formic acid,ethylene oxide and other small molecular substances.