Study On The Treatment Of Aromatic Organic Pollutants By Heterogenous Electro-fenton

In this paper,the treatment of aromatic organic pollutants was studied by hetero-geneous electro-Fenton with iron/activated carbon.Taking phenol wastewater as a re-search object,the treatment effect of organic wastewater was studied.On this basis,a method which coupled heterogeneous electro-Fenton with gas absorption to treat or-ganic waste gases was proposed,and its feasibility for treating toluene waste gas was studied.Firstly,basic cathode material of electro-Fenton was selected,and its modification methods were studied.Graphite felt was selected as basic cathode material.Modified graphite felt was prepared by impregnating carbon black and polytetrafluoroethylene.When the mass ratio of carbon black to PTFE was 1:5,the modification result was optimal.Using modified graphite felt as cathode,the operating conditions for generat-ing H₂O₂ on cathode were optimized.With current density of 9 mA·cm^-2,initial elec-trolyte pH of 3 and air flow rate of 100 m L·L^-1,the generation of H₂O₂ could reach124.14 mg·L^-1 after 90 min reaction.Modified graphite felt showed good repeatability in recycling experiment.Secondly,the treatment performance of phenol wastewater by heterogeneous elec-tro-Fenton with iron/activated carbon catalyst was studied.The optimal operating con-dition was obtained when catalyst dosage was 0.7 g·L^-1,current density was 9 mA·cm^-2 and initial pH of electrolyte was 5.Under this operating condition,phenol could be greatly removed 95.94%after 90 min reaction.Consecutive experiments indicated that iron/activated carbon exhibited good stability.After 8 consecutive runs,the removal rate of phenol was still higher than 70%,and the total iron leaching ratio of iron/acti-vated carbon was lower than 18%.The process of phenol removal from wastewater was analyzed through experiments,including production of H₂O₂ on cathode,adsorption and catalytic oxidation of phenol by iron/activated carbon.Finally,based on the treatment of phenol wastewater by heterogeneous electro-Fenton with iron/activated carbon,the feasibility of this method for treating aromatic VOCs waste gases was studied.The treatment of aromatic VOCs waste gases by heter-ogeneous electro-Fenton was closely related to the gas solubility,gas velocity and VOCs concentration.With current density of 12 mA·cm^-2,initial electrolyte pH of 3,toluene waste gas flow of 150 m L·min^-1 and toluene concentration of 130 ppmv,tolu-ene removal rate was still higher than 65%after 120 min reaction,which showed that this method could achieve effective removal for toluene waste gas.