Preparation And Electrochemical Oxidation Performance Of Catalytic Graphite Felt Electrode

Electrochemical oxidation degradation efficiency of organic pollutants in wastewater through direct oxidation and indirect oxidation has been influenced greatly by the materials of the electrode.The research of anode materials has been relatively mature,but the cathode has been concerned by more and more people.The cathode can improve the efficiency of indirect oxidation by strong oxidizing substances which were produced by the reduction of oxygen.In this issue,catalytic graphite felt cathodes modified by anthraquinones were prepared by impregnation method.With catalytic graphite felt as cathode and Ti/RuO₂-IrO₂ electrode as anode,the catalytic performance of the anthraquinones was studied through electrochemical oxidation degradation of acid red B.The optimal operating conditions and the optimal catalytic cathode were determined.The oxidizability and applicability of the optimal electrochemical system were tested through electrochemical degradation of cephalosporins synthetic wastewater.The main experimental conclusion is as follows:1)Anthraquinone-modified graphite felt and 2-ethyl-anthraquinone-modified graphite felt were characterized by SEM,XRD and CV.The results showed that graphite felt had good microporous and surface structure.Anthraquinone crystals and2-ethyl-anthraquinone crystals could be observed on anthraquinone-modified graphite felt and 2-ethyl-anthraquinone-modified graphite felt,respectively.Anthraquinone and2-ethyl-anthraquinone could promote the progress of degradation through producing oxidizing substances.2)Acid red B?200mg/L?was treated by electrochemical oxidation system using Ti/RuO₂-IrO₂ electrode as anode and graphite felt,anthraquinone-modified graphite felt or2-ethyl-anthraquinone-modified graphite felt as cathode,respectively.The results showed that optimum cathode was 2-ethyl-anthraquinone-modified graphite felt.Under the condition of current density was 90mA·cm-2,electrolytic time was 30 min,Na2SO4concentration was 0.2mol·L-1,electrode distance was 2cm,and initial pH was 3.0,the efficiency of the electrochemical oxidation acid red B was 99% and electrochemical energy consumption was 0.19kWh·g-1.3)Electrochemical oxidation treatment of cephalosporin synthesis wastewater using Ti/RuO₂-IrO₂ electrode as anode and 2-ethyl-anthraquinone-modified graphite felt ascathode.When the condition of current density was 150mA·cm-2,electrolytic time was 50 min,Na2SO4 concentration was 0.1mol·L-1,electrode distance was 2 cm,and initial pH was 7.0,and the initial quality index of cephalosporin synthesis wastewater included COD25 000³0 000mg·L-1,BOD5 7 100⁷ 950mg·L-1,chroma 2 300² 680 degree,ammonia nitrogen 850¹ 300mg·L-1,the removals of COD,chroma and ammonia nitrogen could reach 40%,68% and 30%,and the BOD5/COD increased from 0.27 to 0.42.