Study On Remediation Of Petroleum Hydrocarbon Contaminated Soil By Modified And Electric Fenton Technology

Oil may leak into the soil and cause pollution to the soil during exploration,development,transportation,transportation and storage.At present,the soil contaminated by petroleum hydrocarbons in China is increasing by more than 100million tons per year.This poses a serious threat to the ecological environment.Therefore,the situation of oil-contaminated soil remediation is severe.The paper mainly treats petroleum hydrocarbon contaminated soil by modified Fenton method and electric Fenton method.The effects of modified Fenton method and electric Fenton method on the recovery of petroleum hydrocarbon contaminated soil under different factors were studied.Analysis of the causes and mechanisms of various factors on the reaction process,in order to determine the optimal processing conditions.The main conclusions are drawn through experiments:Adding Fenton reagent to the soil mud system,the TPH degradation rate of the reaction can reach 70.13%in 12 hours when the ratio of H₂O₂ to FeSO₄ is 200:1.The higher the initial TPH concentration of the soil,the higher the removal rate under the same treatment conditions within the range of 0.7%to 4.97%.Adding citric acid complexing agent allows the reaction to proceed in a neutral environment.Compared with the non-added citric acid complexing agent,the degradation rate of TPH increased by 7.37%¹4.4%in soil with an initial concentration of 0.7%to 3.01%.In the cathodic method of electric Fenton experiment,the orthogonal experiment was designed to determine the extent of the effect of removing soil TPH:Fe²⁺concentration>pH>voltage>plate spacing>aeration.Exploring the influencing factors according to the single factor optimization experiment,the optimal combination level of TPN in the removal of soil by the cathode method is as follows:the plate spacing is 4cm;the mud pH is 3;the voltage is 8V;the Fe²⁺ion concentration is 1.4mmol/L;the blast air aeration is 5L/min.The soil TPH removal rate was higher in the first 2 hours of the reaction,and the TPH removal rate reached 71.69%at 6 hours.The kinetic fitting of the change process of soil TPH content was found to be consistent with the second-order kinetics.The soil degradation process of different initial TPH concentrations was investigated to verify that the reactions of each group were consistent with the second-order kinetics.Besides,the degradation rate of low concentration soil?1.32%².46%?was higher than that of high concentration soil?4.97%⁶.10%?.In the anodic Fenton experiment,the orthogonal experiment was designed to determine the effect of removing TPH from soil:pH>H₂O₂ dosage>voltage>plate spacing.Through the single factor optimization experiment,the influencing factors were explored.The optimal combination level of the anode Teflon to remove soil TPH was obtained:the plate spacing is 5cm;the mud pH is 2.5;the voltage is 3V;the H₂O₂dosage is 4mmol/L;blast aeration is 5L/min.The soil TPH removal rate reached 46.70%after 1 hour of reaction,then the degradation rate gradually decreased and gradually stabilized after 5 hours,and the 6-hour TPH removal rate reached 82.01%.The process of soil TPH degradation was fitted,and the degradation process was consistent with the second-order kinetics.The use of stainless steel as the cathode material can improve the degradation rate of TPH in the initial stage of the reaction.However,the TPH removal rate of the overall reaction process is lower than the TPH removal rate when the graphite felt is used as the cathode.By comparing the electro-Fenton of the anode method and the electro-Fenton of the cathode method,it is concluded that the pH values of the two reaction systems will gradually increase.Among them,the anode method Fenton can be increased to near neutral without adjusting the pH?pH=6.2?.Therefore,it is necessary to adjust the pH value of the mud regularly.Comprehensive comparison of various conditions of the cathode method of electric Fenton and anode electric Fenton,it is concluded that the anode method electric Fenton is more suitable for the repair of petroleum hydrocarbon contaminated soil.