Research On Microwave Remediation Technology Of Petroleum Contaminated Soil

With the rapid development of the petroleum industry,the pollution problem caused by the entry of petroleum and its products into the soil is becoming more and more serious.Microwave soil remediation technology has the advantages of uniform heating,low energy consumption,short remediation time and low risk of secondary pollution.It has become the current research hotspot.This topic selects the typical semi-volatile organic compound Naphthalene（Nap）as the target pollutant in petroleum-contaminated soil.On the basis of discussing the enhancement effect of sensitizer on the microwave heating of contaminated soil,single factor method and response surface method（RSM）were used to study the effect of different influencing factors on the removal of petroleum pollutants in the soil by microwave.At the same time,the pilot effect of microwave soil remediation-microwave catalytic combustion device was investigated.The main conclusions are as follows:1)Experiments on the enhancement effect of different sensitizers on the microwave heating of contaminated soil show that the enhancement effect of granular activated carbon on the microwave heating of contaminated soil is significantly stronger than that of Si C and Al₂O₃.Add 5 wt%GAC to 20 g of soil and irradiate it with 720 W microwave power for 20 min.The soil temperature can reach 350°C.2)Single factor experiments show that microwave power,irradiation time,soil thickness,and water content have significant effects on the removal efficiency of Naphthalene.The best value range of the experimental parameters:microwave power is540～720 W,processing time is 15～25 min,the thickness of the soil layer is 3～5 cm,and the soil moisture content is 13%～19%.3)Using the Box-Behnken experimental design in the RSM method to optimize the experimental conditions of microwave soil remediation,a quadratic multiple regression equation model was established,and the analysis of variance（ANOVA）results showed that the model reached an extremely significant level,and the best experimental parameters predicted:The microwave power is 750.27 W,the treatment time is 18.04 min,the soil thickness is 4.28 cm,and the water content is 15.98%.Under these conditions,the removal rate of Naphthalene in the soil is 98.15%.The verification experiment result is96.87%,which is only compared with the predicted result.The deviation of 1.28%indicates that the model fits well.4)Under the condition that the initial concentration of Naphthalene in the contaminated soil is 57.37 mg·kg^-1,the soil moisture content is 16%,and the soil thickness is 4 cm,the contaminated soil is irradiated with 750 W microwave for 20 minutes.The pilot experiments show that the removal rate of Naphthalene in contaminated soil is 95.6%,and the exhaust gas purification efficiency of the microwave catalytic combustion device is 92.7%.