Industrial organic wastewater has become a challenge in the field of environmental management due to its high carcinogenicity,recalcitrance and high environmental hazard.Advanced Oxidation Processes(AOPs)degrade pollutants by producing highly reactive substances such as hydroxyl radicals(·OH)in the wastewater.Among them,Electrochemical Oxidation Processes(EOPs),as one of the representative technologies of AOPs,has many advantages such as high degradation rate,simple operation and low cost,and is very promising in the field of treatment of refractory organic wastewater.Among the developed anode materials,antimony-doped titanium-based tin dioxide electrode(Ti/SnO2-Sb)is potentially an ideal material for EOPs due to its high oxygen evolution potential,excellent electrocatalytic activity,low manufacturing cost and good electrical conductivity.However,the short service life severely limits its industrial application.To address the problem of short lifetime of Ti/SnO2-Sb electrode,this article uses electrodeposition preparation technique to replace the traditional brush preparation method of Ti/SnO2-Sb electrode.And by changing the deposition liquid system and introducing additives,the stability was enhanced as much as possible while taking into account its catalytic activity.Two main studies were carried out:on the one hand,Ti/Ce-Mn/meso-SnO2-Sb electrodes were prepared by stepwise electrodeposition method using aqueous solution as the electrodeposition liquid system with surfactant Pluronic F127 based on the use of Ce-Mn composite interlayer;on the other hand,the deep eutectic solvent(DES)system of choline chloride+urea was used as the electrodeposition liquid.The Ti/CNT-Ni-SnO2-Sb-DES electrode was prepared by electrodeposition using the acid-washed carbon nanotubes(CNTs)as the template agent for the growth of metal oxides and Ni/Sb as the dopant.The following conclusions were reached based on the experimental results.(1)The Ti/Ce-Mn/meso-SnO2-Sb electrode prepared by stepwise electrodeposition had a higher specific surface area(68.37 m2·g-1)and oxygen evolution potential(2.16 V).Its phenol degradation rate was 91.83%and the COD removal rate was 81.25%within 120 min.The high specific surface area provided more in situ active sites for electrocatalysis,which creates good conditions for the generation of·OH.Meanwhile,phenol can quickly diffuse into the mesoporous channels,increasing the opportunity to interact with·OH and achieving a fast electrocatalytic reaction.The stability test results showed that the accelerated lifetime of the Ti/Ce-Mn/meso-SnO2-Sb electrode reached 172.5 min at 1.0 mol/L H2SO4,0.5A/cm2current density.The stepwise electrodeposition method and the introduction of the Ce-Mn composite intermediate layer as the active layer carrier not only increased the binding force between the active layer and the intermediate layer,but also refined the SnO2grain size.Moreover,it refined the SnO2grains and improved the overall thickness and coverage uniformity of the electrode,which in turn significantly improved the service life of the electrode.(2)The Ni/Sb co-doped Ti/CNT–Ni–SnO2–Sb–DES electrode using DES as the electrodeposition solution and the acid-washed CNT as the metal oxide growth template had a higher oxygen evolution potential(2.29 V),the degradation rate of phenol increased to 98.09%and the COD removal rate increased to 85.36%within 120min.Accelerated lifetime test showed that the accelerated lifetime of Ti/CNT-Ni-SnO2-Sb-DES electrode reached 208 min(1 mol/L H2SO4,1 A/cm2).It was found that the DES electrodeposition system effectively prevented the damage of the electrode coating caused by the hydrolysis of metal ions and the hydrogen evolution reaction during the electrodeposition process.Meanwhile,CNTs provided a guiding template for the growth of tin-antimony-nickel oxides,which avoided the agglomeration of metal oxides to the greatest extent and ensured the dense and uniform electrode coating.Finally,both Sb and Ni entered the SnO2lattice in the form of ions,replacing Sn4+.This co-doping accelerated the charge transfer rate,reduced energy consumption,corrected the SnO2lattice charge imbalance caused by Sb5+doping,and prolonged the electrode lifetime. |