| In electro-Fenton reaction,H2O2 is in-situ generated through oxygen reduction reaction,and then converted into hydroxyl radicals by the catalysis of ferrous ions.the organic matter in the wastewater is oxidized and degraded by hydroxyl radicals.However,the addition of ferrous ions causes problems such as narrow p H range applicable to the reaction and subsequent treatment technology of iron-containing sludge.Therefore,it is worth trying to improve the performance of electrocatalytic production of H2O2,and to continue to catalyze in-situ H2O2 to generate hydroxyl radicals without introducing metal ions.So as to achieve in-situ generation of Fenton reagents,which is also the key to the development of electro-Fenton technology in the future.In view of this,this paper designed a dual-cathode electro-Fenton system without external reagents,in order to achieve efficient and stable generation of H2O2,and the conversion of H2O2 to OH.Conductive polymer PEDOT was electropolymerized on carbon cloth.O2 was reduced to generate H2O2 on PEDOT/CC through 2-electron ORR.At-0.9V vs.Ag/Ag Cl,H2O2 was generated in-situ after 120min electrolysis,and the yield of H2O2was 243.1mg/L,which was increased to 2 times of the original,and the current efficiency was 77.0%.Hydroxyl radicals were generated by the reduction of H2O2 in-situ by the second cathode stainless steel mesh（SSM）electrode.The mechanism of·OH generation was analyzed by fluorescence spectroscopy and EPR measurement.Dye wastewater containing Rh B,MB and AO7 was oxidized and degraded by a dual-cathode electro-Fenton system.Results show that the PEDOT/CC voltage of-0.9 V,under the condition of SSM voltage of-0.8 V,after 120 min,electrolytic degradation efficiency were 99.7%,98.3%,97.5%,respectively.Among them,for Rh B dye wastewater,TOC removal efficiency was 54.3%in the 120 mins,illustrating the system of decolorization of wastewater with high concentration of dye and the effect of mineralization.After five cycles,the degradation efficiency remains above 90%.In this paper,a simple and feasible modification method was put forward.The use of engineering materials PEDOT and stainless steel mesh,which are cheap and easy to get,replace external added reagent..Accomplishing the best conditions for removing organic pollutants by adjusting the reaction conditions of O2-H2O2-·OH two-step method.There is no ferrous ion leaching and no iron sludge in the experiment.By using air aeration,economic anode to replace pure oxygen and nobal metal,the removal efficiency can still reach a higher,which provides a reference for practical operation. |
