Performance Optimization Of Electric Fenton Reaction Based On Microchannel Carbon Cathode

The electric Fenton reaction produces H₂O₂ by reducing dissolved oxygen at the cathode,and then catalytically activating H₂O₂ to produce·OH to degrade organic pollutants in water.The important impactor of efficiency of degrading pollutants in the electric Fenton process is H₂O₂ and·OH rate.Currently,porous carbon materials are the most hopeful material for producing H₂O₂.The porous carbon cathodes are usually obtained by hot pressing of carbon powder or particles.The added binder will increase the resistivity,and the disordered channels increased the resistance to water flow.The ordered microchannel carbon electrode obtained from the carbonized natural pine block reported in the recent literature is expected to solve these two problems.Because the overall structure of the disordered binder has a resistivity comparable to that of graphite,its long straight ordered channel makes the water flow usually,relatively.The resistance to the disordered channel decreased significantly.In this thesis,an ordered microchannel carbon was used as the cathode to construct an electric Fenton reactor,and improve the efficiency of H₂O₂ and·OH produced by this new type of carbon cathode were studied.I hope that the research results can promote this new material in electricity The main contents of Fenton water treatment are as follows:The natural pine wood was calcined at 800°C under Ar to obtain microchannel carbon.The materials were characterized by thermogravimetry,scanning electron microscopy,and contact angle to determine that FeOCl has been loaded inside and on the electrode material.The effects of operating conditions were optimized.The best FeOCl loading is 3 g/L,the best voltage is-2.5 V,and the best hydraulic retention time is 90 s,The optimal pH is 3.0,and under this condition,the removal rate of 20 mg/L phenol reaches more than 99%.The 3h experiment shows that the system is stable.In order to further improve the efficiency of the obtained H₂O₂,the content of microchannel C=O and COOH is increased by the oxidation treatment method to improve the Faraday current efficiency of electrochemical reduction of oxygen,and then the generation rate of H₂O₂ increases.Place microchannel carbon in a beaker,gradually add 30mL of H₂O₂ solution with a mass fraction of 30%to treat microchannel carbon 30 min,and then dry.The H₂O₂ concentration of the 30 ml solution reached 3520?mol/L in the 30 min,which was 1.63??3520-1340?/1340=1.63?times higher than that microchannel carbon block?1340?mol/L?.The main reason why oxidation increased H₂O₂ production is that this way improved the current efficiency during the reaction and the reaction reacts faster to increase production.The CFD simulation is used to further design the electrode material at a theoretical level to improve·OH yield.The channel size and the number of active sites were simulated to change mass transfer and the degradation efficiency of pollutants.According to the simulation,it is found that the smaller the channel diameter,the greater the pressure drop and the faster the·OH yield,the optimal channel size is 30?m.However,the change of active sites obviously changes the concentration of pollutants,and the number of active sites can be increased by oxidation and activation to improve the removal efficiency of pollutants.In summary,microchannel carbon loaded with FeOCl has the ability to degrade phenol,and the removal rate has reached more than 99%.Oxidation increases the oxygen content of microchannel carbon to increase the output of H₂O₂.CFD simulation can design the material to improve the efficacy.The experimental results strongly promoted the application of wood carbon in electric Fenton.