Preparation Of Graphene Oxide Electrode And Study On The Performance Of Electrocatalytic Degradation Of 2-chloro-5-nitrophenol

Chloronitrophenol compounds(CNPs)are widely used in industrial and agricultural production.It was found in water and soil environments during the general survey of water and soil environments.Due to the stable chemical properties of CNPs,such as the presence of multiple electron-absorbing groups,high lipophilicity and high toxicity,the research on the degradation of CNPs has attracted wide attention from researchers.Electrocatalytic oxidation technology has the advantages of needless to add oxidizing reducing agent,mild reaction conditions,simple equipment,strong coupling,low treatment cost,etc.,which could be used as an effective technology to degrade CNPs.Graphene oxide has used in electrocatalytic electrode materials due to its excellent electrical conductivity and affinity for polar substances.The electrochemical method of stripping carbon fibers to prepare graphene oxide has a low price,more economical and environmentally friendly than traditional graphene oxide preparation methods,the simple and easy preparation steps to control,needless adding a variety of mixed strong oxidants,green,safe and non-toxic advantages.Based on this,this study first prepared graphene oxide electrode materials with excellent corrosion resistance and electrical conductivity,and then studied the effectiveness of the prepared electrode materials to degrade 2-chloro-5-nitrophenol(2C5NP).The graphene oxide was prepared by electrochemical oxidation stripping of carbon fibers with weak current electrochemical method.The effects of different electrolytes,different current densities and different electrolysis times on the electrochemical stripping of carbon fibers to produce graphene oxide were studied.XRD,XPS,FTIR,UV-Vis,SEM and other modern analysis and testing technologies were used to characterize the stripped products;the stripped graphene oxide was coated on the carbon fiber cloth to obtain the graphene oxide coated carbon fiber cloth;The graphene oxide/carbon fiber cloth electrode was used as the anode to study its electrocatalytic degradation of 2-chloro-5-nitrophenol(2C5NP).Explored the influence of different graphene oxide coating amount,electrolyte,applied current,initial concentration,pH and other factors on the degradation of 2C5NP;UV-Vis,HPLC,LC/MS/MS and other testing techniques was used to detect the intermediate products.Quantitative and qualitative analysis was carried out to speculate the possible mechanism of 2C5NP degradation.The study found:XRD results showed that under the condition of electrolyte H2SO4,current density 3mA/cm2,electrolysis time 5 days,the electrochemical stripping of carbon fibers can effectively oxidize the carbon fiber boundaries and expand the carbon fiber layer spacing,and the diffraction peak of graphene oxide prepared by electrochemical stripping of carbon fiber appears near 2? at 11°.FT-IR results showed that graphene oxide had abundant oxygen-containing functional groups,including five kinds of oxygen-containing functional groups including-C=O,-CO,-C(O)C-,-COH,and-CH(O)CH-.There ware the most types of oxygen groups contained at H2SO4 as the electrolyte.The UV-Vis absorption peak appeared at 235.5nm,and the C-C/C=C conjugate structure containing ?-?*electron transition and the C=O conjugate structure of n-?*charge transfer;XPS results indicated C/O in graphene oxide was 1.974,and the percentages of C-C,C-O and C=O binding bonds were 57.46%,36.32%and 6.21%,respectively.SEM observation of graphene oxide was thin wing-shaped,with large wrinkles on the surface,curling around,and a transparent flocculent sheet.(2)The 2C5NP electrocatalytic degradation was carried out in an open environment.The results showed that graphene oxide as a catalyst can effectively improve the efficiency of the electrocatalytic system.Under the optimal experimental conditions:electrolyte is NaCl,graphene oxide coating amount 70mg,the applied current density 1.2mA/cm2,and the initial concentration of 2C5NP 20mg/L,the pH=5,the degradation rate of 2C5NP reached 95.15%after 4 h,and the degradation rate was 98.3%at 6 h.Free radical trapping experiments show that· OH plays a leading role in the process of electrocatalytic oxidative degradation.(3)Analysis of samples by UV-Vis?HPLC and LC/MS/MS indicated that during the 2C5NP electrocatalytic degradation process,a variety of intermediate products were generated and degraded,such as 2-chloro-5-nitrophenol,chlorohydroquinone,hydroquinone,1,2,4-benzenetriol,4-hydroxymuconic semialdehyde,maleylacetate,oxalic acid,pentanediol,valeric acid et al.,speculated possible 2C5NP degradation pathway.