Experimental Study On Solubilization/Desorption Of Petroleum In Soil Regulated By Surfactant

In the process of oil exploitation,the pollution of oil-field and surrounding soil caused by oil leakage is the main ecological environment problem faced by oil exploitation industry.Because of the high viscosity of oil and its aging effect under natural conditions,it is difficult to separate oil from soil.The process of oil entering(polluting)and leaving(removing or separating)in soil system is essentially the result of the complex interface behavior of oil-water-solid multiphase media.So far,taking the petroleum contaminated soil of Liaohe Oilfield in Panjin as the research object,this paper analyzes the characteristics of oil-solid-water three-phase distribution in the soil.On this basis,the commonly used surfactants were selected,including sodium dodecyl benzene sulfonate(SDBS),sodium dodecyl sulfate(SDS),Tween 80,Triton X-100 and rhamnolipid(Rham).The solubilization-desorption mechanism of different surfactants on oil-solid-water phases was discussed,and the sensitivity analysis of the effect of relevant process parameters on solubilization-desorption effect was carried out.The main conclusions are as follows:(1)The main forces between oil and soil particles include van der Waals force and chemical bond force.Because chemical bond force has strong bond energy,it plays a leading role in the relationship between oil and soil particles.In addition,the polarity of oil is weak,and the carbon element accounts for a relatively high proportion.The van der Waals force between oil and water molecules is difficult to break the hydrogen bond formed between water molecules,so the solubility of oil in water is low.(2)Surfactants play an important role in solubilization at the oil-water interface and desorption at the oil-solid interface.Due to the ability of anionic surfactant to reduce the work of adhesion between oil and soil is stronger,the desorption of Rham,SDS and SDBS is stronger.Due to the higher mass solubilization ratio of non-ionic surfactant,the solubilization of Triton X-100 and Tween 80 is stronger.This is related to their molecular structure and adsorption on soil.(3)The order of delta value of mean value and signal-to-noise ratio for surfactant type and concentration,equilibrium time,temperature is temperature > surfactant type > surfactant concentration > equilibrium time.From this point of view,temperature has the most important effect on the regulation of surfactant,so the optimal operating parameters should be selected.The sensitivity of surfactant type and concentration is moderate,and normal conditions can meet the requirements.For the equilibrium time with the least sensitivity,the most economical parameter can be chosen.