Study On Modification Of Electro-fenton Cathode Materials And Degradation Of Organic Matter In Coking Tail Water

Coking wastewater is a kind of typical refractory industrial wastewater,and the effluent from biochemical treatment can not meeting the discharge standards well.Electric Fenton technology applies the electrical energy as the driving force for the production of H₂O₂ through the cathodic oxygen reduction reaction,which has the advantages such as efficient,environmentally friendly and so on.Oxygen reduction reaction activity of traditional electro-Fenton materials always is suppressed,which has the disadvantages of low current efficiency and a low H₂O₂yield.Therefore,the development of cathode materials with good per formance has become a research hotspot.In order to improve the catalytic ability of the oxygen reduction reaction on the cathode surface,the material have been modified by metal doping method which applied nickel foam as the matrix in this study.The effect of parameters on the removal of organic matter and the removal characteristics of organic matter in coking tail water have been discussed which combined with material characterization and electrochemical performance test,and the degradation of coking tail water by electric Fenton to investigate the reaction.Bamboo powder was used as raw material to prepare carbon material by thermal decomposition method in this paper,and it was modified by metal doping,and foamed nickel was used as matrix,and modified cathode material have obtained by coating and baking.Scanning electron microscopy tests were conducted on the material and the results showed that the carbon material has a porous structure and is stable in structure.The catalytic layer of the cathod e material has a porous structure,and the amounts of the surface active sites have increased,which promoted the mass transfer process of oxygen on the cathode surface and reduced the dissolution of nickel foam.And the results of EDS showed that the metal content is consistent with the added amount.Electrochemical performance testing of the electrode showed by the CV curve that the current response potential shifted positively,and the modified electrode material have extended the electrical activation area and improved the surface oxygen reduction ability of the material.From the LSV curve,it can be known that the modified material electrode improved the oxygen reduction current response value,and enhanced the electrode's catalytic ability,which was beneficial to the generation of H₂O₂.Single factor experiment was carried out on the initial pH value,current size,Fe²⁺concentration and reaction time in the electric Fenton system by the response value of the coking tail water TOC removal rate.The optimal reaction conditions were:pH was 3 and current size 200 mA?Fe²⁺concentration was 100mg/L,reaction time was 90min.And the Cu-Pr/C electrode and Cu-Ce/C electrode TOC,COD removal rate reached 83.70%?78.35%and 95.23%?94.57%,UV₂₅₄ The values dropped to 0.238 and 0.305 respectively under optimal reaction conditions.During the COD removal process in the coking tail water,the reaction kinetics have been fitted,and the reaction kinetic constant was significantly improved.After 10 times repeated use of the modified cathode material,it still has a high catalytic capacity.Analysis of the removal efficiency of organic matter in coking tail water,and the results of UV-Vis showed that with the increase of reaction time,the characteristic absorption peak intensity decreased significantly,aromatic compounds have been degraded effectively,and the concentration of organic matter also have decreased.FTIR showed that coking tail water and outflow of E-fenton both contained O-H stretching vibration,unsaturated double bond and triple bond C?N stretching vibration,sulfur hydrogen C-S stretching vibration and sulfur hydrogen C=S stretching vibration and other unsaturated structure double bond and aromatic compounds.The vibration frequency of functional groups and chemical bonds have decreased with the increase of reaction time.The results of 3D-EEM showed that water there were tyrosine-like,tryptophan-like,soluble microbial by-products,humic acid-like and fulvic acid-like substances in the coking tail.After treatment with the electric Fenton system,the fluorescence peak intensity have significantly reduced,some fluorescence peaks have disappeared,and there were no other fluorescent substances produced.GC-MS analysis showed that the coking tail water contained a large amount of aromatic organic substances such as alcohols,phenols,organic acids and esters.The organic substances were mainly existed as oxygenated heterocycles,benzene series,alcohols and esters and other macromolecular organic substances.The characteristic peaks decreased significantly,and the macromolecular organics were converted into small molecular organics dominated by alkanes after the treatment by the electric Fenton systems.The studies showed that carbon materials doped with active metals modified the electric Fenton cathode oxygen reduction performance,improve d the processing efficiency and reduced the power consumption effectively.The results showed that the modified electrode has a good removal effect on organic matter contained in coking tail water,which provides technical support for the removal of refractory organic matter in wastewater by metal modified cathode materials,and this improved materials and treatment technology do has a bright application prospect.