Study On The Properties Of Carbon Cathode And Electric Fenton Prepared By Gas Sludge,Pistia Stratiotes And Alternanthera Philoxeroides

Dye synthesis,textiles,printing and dyeing and other industries use a large number of synthetic dyes,resulting in the discharge of wastewater from these industries also contains dyes,dye-containing colored wastewater becomes an environmental problem.Therefore,the removal of dyes from aqueous solutions has great potential in the field of environmental engineering.This thesis first reviews the classification of synthetic dyes and their effects on the water environment and introduces methods for treating wastewater containing dyes,such as precipitation,adsorption,electrocoagulation,advanced oxidation,etc.,among which Electron Fenton?Electro-Fenton,E-Fenton?technology has attracted people's attention,because the high mineralization efficiency of E-Fenton technology,which can directly oxidize organic matter into carbon dioxide and water and can generate hydrogen peroxide?H₂O₂?in situ,avoiding H₂O₂ transportation and storage risks.The research on E-Fenton mainly focuses on the combination with other technologies,the use of heterogeneous catalysts,the modification of iron-containing functional cathodes and non-metallic carbon cathodes.These applications are aimed at increasing the production of H2O2,widening the pH range of E-Fenton applications and reducing the addition of exogenous iron.In this thesis,gas sludge,pistia stratiotes and alternanthera philoxeroides were selected as three materials.Carbon materials were prepared by different treatment methods and prepared into carbon electrodes.The degradation,H₂O₂ formation and production of hydroxyl radicals?·OH?were investigated as cathodes in E-Fenton.Four samples of gas sludge,S300,S500 and S900 were prepared by treating gas sludge.X-ray photoelectron spectroscopy?XPS?characterization shows that Fe in gas sludge mainly exists in Fe³⁺oxides,while Fe in S900 treated at high temperature mainly exists in Fe²⁺oxides.N₂ adsorption and desorption tests show that there are mesopores in the material.In the degradation X3B experiment,the gas sludge electrode had the worst degradation effect,and it degraded by 90%in 45 minutes.The S900 had the best degradation effect and degraded 90%in 20 minutes.The amount of H₂O₂ produced by gas sludge electrode is the largest,producing 2mM in 45 minutes,but the amount of iron dissolved is the least,dissolving 0.07mM in 60 minutes;the amount of H₂O₂ produced by S900 electrode is the least,generating 0.8mM in 50minutes,but the amount of iron dissolved is the largest,dissolving 0.25mM in 30minutes.The amount of H₂O₂ and the intensity of·OH production are negatively correlated with the amount of iron dissolved,because Fe²⁺can react with H₂O₂ to produce·OH,which consumes part of H2O2.The application of gas sludge carbon cathode in E-Fenton is feasible.The molten salt zinc chloride activated pistia stratiotes to prepare carbon materials and explored the influence of temperature and zinc chloride ratio on carbon materials,then carbon materials prepared them into electrodes.XPS test showed that the surface N and P contents of the carbon materials prepared by pistia stratiotes were2.20%and 1.06%respectively,N₂ adsorption and desorption test showed that the carbon material prepared was mesoporous material and the specific surface area ranging from 350 cm ².g^-10 to 720 cm².g^-1.X3B degradation experiments of prepared water pistia stratiotes material electrodes showed that the removal rates of X3B exceeded 90%in 20 minutes and the kinetic constants of pistia stratiotes were the largest by kinetic fitting.By measuring the output of H₂O₂ and analyzing the current efficiency,it was found that the activated carbon material at 500?had a better effect,and the·OH intensity of pistia stratiotes with the ratio of 1:1 to zinc chloride was the highest when coumarin was used to capture·OH.After eight repeated degradation experiments,the electrode still has good experimental results and good electrode stability.Carbon materials activated by double molten salts were prepared.The ratio of peanut,zinc chloride and Mg₅?OH?₂?CO₃?₄ was 1:3:1.In addition,carbon materials of 1:3:0,1:0:1 and 1:0:0 were prepared for comparison.Through SEM and N₂adsorption and desorption test,it is proved that the material 1:3:1 synthesizes carbon materials with multi-layer pore structure with micropores,mesopores and macropores;XPS characterization shows that N on the surface of the four materials is mainly graphitized nitrogen?G-N?.The linear sweep voltammetry?LSV?and electrochemical impedance spectroscopy?EIS?electrochemical characterization show that the material 1:3:1 has good oxygen reduction performance and suitable charge transfer resistance.The four kinds of synthetic alternanthera philoxeroides materials have good effect on degrading X3B,and the degradation efficiency reaches 90%in 20minutes,which is consistent with the first-order reaction kinetics model.Comparing the H₂O₂ production of four kinds of alternanthera philoxeroides material electrodes,the H₂O₂ production of electrode material 1:3:1 is the highest,producing 0.9 mM in30 minutes and its current efficiency is 42%.Coumarin was used to detect the content of·OH.It was found that·OH strength of materials 1:0:1 and 1:0:0 was the highest.In a word,double molten salt activated alternanthera philoxeroides carbon has multi-layered pore structure and the electrode also has good E-Fenton performance.Compared with the E-Fenton system of pistia stratiotes and alternanthera philoxeroides,the E-Fenton system of gas sludge electrode does not need additional iron source.The dissolution of iron has a positive effect on the E-Fenton system of gas sludge electrode.In addition,the stability of gas sludge electrode is not as good as that of pistia stratiotes and alternanthera philoxeroides electrode.