Fabrication Of A Novel Type Of Sb-doped Tin Dioxide Electrode And Its Application In The Treatment Of Dye Water

Compared with other metal oxide electrodes,Sb doped SnO₂ is regarded as one of the most promising materials to remove organic pollutants from wastewater.However,the short service lifetime and low conductivity have limited its commercial applications.At the same time,its' oxygen evolution potential?OEP?and electro-catalytic ability also need improve.In this paper,A new type of Ti/SnO₂-Sb electrode?Nb-Ti/Nb-TiO₂-NTs/SnO₂-Sb?is prepared by pulse electrochemical deposition and modified by highly ordered Nb doped TiO₂ nanotubes?Nb-TiO₂-NTs?,which can serve as excellent carriers for the further loading of catalyst with high conductivity,by anodizing Nb-Ti alloy.Compared with the titanium analogue?Ti/SnO₂-Sb and Ti/TiO₂-NTs/SnO₂-Sb?prepared by pulse electrochemical deposition,the electrode modified by Nb-TiO₂-NTs has a larger surface area and smaller crystallite particles obtained from the analysis of scanning electron microscopy?SEM?and X-ray diffraction?XRD?.Moreover,the new electrode has the higher oxygen evolution potential?OEP?of 2.29V?vs.Ag/AgCl?,and the lower charge transfer resistance number for Ti and Nb,which decreased by 65% and 79%.The service lifetime of Nb-Ti/Nb-TiO₂-NTs/SnO₂-Sb is 4.9 times longer than that of Ti/SnO₂-Sb and 1.9 times longer than that of Ti/Ti O₂-NTs/SnO₂-Sb.The new electrode is electrochemically oxidized Acid Red 73,a model organic pollutant.The AR73 removal and kinetic rate constant are increased due to the introduction of NbTiO₂-NTs.Besides,the energy consumption reduces 37.2% and 31.4% in contrast with Ti/SnO₂-Sb and Ti/TiO₂-NTs/SnO₂-Sb.Then,Nb-Ti/Nb-TiO₂-NTs/SnO₂-Sb was applied in the treatment of Acid Red 73 aqueous wastewater.The parameters such as current density,initial AR73 concentrations,electrolyte and pH values affecting the efficiency of electro-catalytic oxidation degradation were also investigated and optimized.It was found that the electro-catalytic oxidation of AR73 on this electrode could be achieved by the formation of hydroxyl radicals and the electrode was non-active electrode.The optimized current density was 50mA·cm-2.When the AR73 concentrations beyond 1.5 g·L-1,it could not be degraded efficiently by this electrode.The optimized electrolyte was Na2SO4 and this method could be applied in a wide range of pH values.After that,Nb-Ti/Nb-TiO₂-NTs/SnO₂-Sb,as the anode,was applied into the synergetic process of electrocatalytic and nanofiltration to treat the dye water.The introduction of novel electrode caused significantly increase of permeation flux by reducing membrane fouling and concentration polarization.Hence,Nb-Ti/Nb-TiO₂-NTs/SnO₂-Sb can be regarded as one of the most promising materials for dye water treatment.