Study On The Extraction And Detection Method Of Petroleum Hydrocarbons In Soil

In recent years,with the rapid development of industry,people use more and more petroleum,resulting in the inevitable serious pollution of soil,water and atmosphere caused by petroleum products.The pollutants in the water and the atmosphere will migrate to the soil,making the petroleum hydrocarbon pollution in the soil more serious.Therefore,the pollution monitoring of the soil is an important part of environmental protection.For the determination of petroleum hydrocarbons in soil,the choice of extraction solvent and the method of pretreatment will have a great influence on the results of the determination.In this paper,gas chromatography is selected as the detection method,and the extraction agent with higher extraction efficiency and environmental friendliness of petroleum hydrocarbons is selected by comparing the extraction effects of different solvents.optimization,thereby establishing an accurate and efficient method for the detection of petroleum hydrocarbons in soil.In this paper,the extraction effects of five extractants including n-hexane,ethyl acetate,carbon disulfide,petroleum ether and acetone on soil petroleum hydrocarbons(C₁₀-C₄₀)were studied.Among them,carbon disulfide had the highest extraction efficiency,reaching 91.72%,followed by n-hexane and acetone.,followed by ethyl acetate,petroleum ether is the lowest;because carbon disulfide is highly toxic and environmentally unfriendly,it is replaced by a complex solvent.The composite solvents of n-hexane,ethyl acetate,petroleum ether and acetone were experimentally analyzed,in which n-hexane/acetone composite solvent（volume ratio 4:1）and n-hexane/petroleum ether composite solvent（volume ratio 1:4）The extraction effect of soil petroleum hydrocarbons was better,which were86.77%and 89.24%,respectively.The extraction rate of petroleum hydrocarbons by other composite solvents was relatively low,because acetone was a precursor solvent and was not easy to buy.In this experiment,the volume ratio of n-hexane and petroleum ether was 1:4 as the extraction solvent of soil petroleum hydrocarbons(C₁₀-C₄₀).In this study,the single factor experiment and response surface method were used to optimize the three conditions of extraction agent dosage,extraction time and extraction times of ultrasonic extraction.First,the single factor method is used to determine the approximate range of the three conditions that have a great influence on the extraction of petroleum hydrocarbons,and then the response surface method is used for the final optimization.The extraction time was 20.5min,the amount of extractant was 21m L,and the extraction effect was the best under the condition of 4 cycles of extraction,and the average extraction rate reached 92.40%,which was basically consistent with the predicted value of the calculation model of the software Design-Expert 10.0.7.Using the optimized ultrasonic extraction conditions,field sampling of decommissioned soil blocks from a printing and dyeing plant was used for petroleum hydrocarbon pollution detection and analysis.The determination of soil petroleum hydrocarbons will establish a certain foundation in the future.