Experimental Study On Phenol Wastewater By Electro-Fenton Process

Electro-fenton process has become a hot point in wastewater treatment research field because of the unique advantage in treating hard degradation organic wastewater now. Using homemade electro-fenton experimental device,designing orthogonal experiment,the phenol wastewater was treated. The treating effect was evaluated synthetically by the indicators of BOD₅,COD,TOC,meanwhile the biochemical quality was analysed. The intermediate products were studied by HPLC,then the electro-fenton oxidative degradation way was inferred. Combining the electro-fenton oxidation mechanism and the organic molecules structural characteristics,the preliminary research about phenol electro-fenton oxidation degradation mechanism has done.The biochemical quality of phenol wastewater was studied by analysing the numerical value of BOD₅/COD. The intermediate products in the wastewater of phenol after electro-fenton oxidation were analyzed by HPLC. The method is that taking retention time as the basis of qualitative analysis and using standard addition method to notarize the sample. The intermediate products of phenol after electro-fenton oxidation were determined and the degradation way of phenol was inferred.Under certain conditions,after electro-fenton oxidation,the BOD₅ of phenol wastewater improved 45.1%,and the removal rate of COD achieved 87.3%,in the meanwhile,the TOC decreased 80.3%. At the same time,the biochemical quality of phenol wastewater has enhanced. The BOD₅/COD value was up to 0.68,improving 11.3 times compare with before. Therefore,as pretreatment before biological treatment,the electro-fenton process is feasible.It was found that in the experiment,the intermediate products of electro-fenton oxidation degradation phenol ( according to retention time order in HPLC chromatogram):Maleic acid(t_R=1.316min),Hydroquinone(t_R=1.702min),p-Quinone(t_R=2.196min). The electro-fenton oxidation degradation way of phenol was inferred:phenol→Hydroquinone→p-Quinone→Maleic acid→CO2 + H2O.Through the research in this paper , it is determined basically that the electro-fenton process is feasible as pretreatment before biological treatment. The study in the way and mechanism of phenol wastewater by electro-fenton process,was expected to provide some theoretical basis in treating phenol wastewater and other hard degradation organic wastewater by electro-fenton process.