Preparation Of Electrocatalytic Oxidation Anode And Its Degradation Of Drilling Wastewater

In this study,drilling wastewater was treated by electrocatalytic oxidation technology.The electrocatalytic activity and stability of typical electrocatalytic anodes were compared and analyzed,and the paths of electrocatalytic reactions with different electrodes were explored;The antimony doped tin dioxide electrode（Ti/Sn O₂-Sb）on titanium substrate was optimized.The electrode performance and the treatment effect of drilling wastewater were investigated by electrode characterization and wastewater characterization.Firstly,the electrochemical test,indirect oxidation performance test and pollutant degradation ability of titanium based platinum electrode（Ti/Pt）,titanium based ruthenium iridium electrode（Ti/Ru-Ir）,titanium based tin antimony electrode（Ti/Sn O₂-Sb）and boron doped diamond electrode（BDD）were carried out;The results showed that Ti/Sn O₂-Sb electrode had good indirect oxidation performance,the oxygen evolution potential was 1.81 V（vs.Ag/Ag Cl）,the internal resistance of the reactor was only 22.1Ω/cm²,less side reactions and high current efficiency;Ti/Pt and Ti/Ru-Ir mainly rely on direct oxidation to remove organic matter,and the reaction is relatively slow and incomplete.Ti/Sn O₂-Sb and BDD mainly rely on indirect oxidation to remove organic matter,and the reaction is relatively fast and complete;Ti/Sn O₂-Sb had strong electrocatalytic ability of,simple instrument and low cost in preparation,and has high engineering popularization value.Secondly,the substrate layer,catalytic layer material and preparation method of Ti/Sn O₂-Sb were further optimized;Six kinds of ordinary titanium based tin antimony electrodes（10%-P-PEG,10%-M-PEG,5.8%-P-PEG,5.8%-M-PEG,P-EG,M-EG）and three kinds of adsorption titanium based tin antimony electrodes（AD10-EG,AD30-EG and AD50-EG）were prepared.The results showed that AD50-EG electrode had the densest surface and the strongest indirect oxidation performance.After 8 hours of reaction,the phenol degradation efficiency was 100%,the COD degradation efficiency was 96.6%,the cell voltage increased only 0.45 V,and the reaction rate constant was 0.447 h^-1.SEM,EDS and XRD results showed that the above electrodes had successfully loaded the catalytic layer,and there was a catalytic layer in the pores of the adsorption electrode.Finally,AD50-EG electrode was applied to the treatment of drilling wastewater.The results showed that the electrode can effectively degrade the pollutants in drilling wastewater,and 2403 components can be removed after 3 h of reaction.The polyoxycompounds with aromatic ring,sulfur-containing heterocyclic compounds and nitrogenous compounds in the wastewater were effectively removed and transformed into saturated compounds and aliphatic compounds with higher O/C.The degradation efficiency increased with the decrease of wastewater concentration,and the electrocatalytic performance of the electrode was excess in the degradation of low concentration wastewater.Under the conditions of electrocatalytic oxidation with current density of 10 m A/cm²,clean titanium plate as cathode,plate electrode spacing of 20 mm and reaction temperature at room temperature,the degradation efficiency of COD was71.4%,the degradation efficiency of TOC was 62.2%and the oxidation rate constant was0.428 h^-1.