The Adsorption And Transportion Of Petroleum Hydrocarbons In Soil?s Micropores And Molecular Simulation

The problem of soil pollution is becoming more and more serious with the rapid development of economy.More and more attention have be paid to the remediation of petroleum hydrocarbon contaminated soil.Once released into the environment,the transport processes for the contaminants included volatilization,oxidation,dissolution,biotransformation,accumulation within the soil biota,and sequestration within the organic matter fractions.The soil organic solvent leaching is one of the most commonly used soil remediation technologies at home and abroad,which is one of the hot spots in the field.However,the mechanism of soil remediation,especially the destruction of soil organic matter and soil degradation has not been paid much attention.Based on the discussion of the possible damage to soil structure caused by organic solvent,the possible adsorption model of petroleum hydrocarbon in soil was put forward.The effect of humic acid on the migration of petroleum hydrocarbons was discussed from the molecular scale by Gromacs molecular simulation software.The same time,We reaserched on the diffusion of petroleum hydrocarbons and humic acids under the electric force from the molecular scale.The conclusion are as follows:(1)In this paper,the contaminated soil was extracted by organic solvent for crude oil adsorption experiment.Porosity and SEM of soils were used to analyze the change of soil structure.The results show that soil porosity decreased after solvent extraction.Soils were contaminated by solvent extraction.There is a close relationship between soil's ability of readsorbing petroleum hydrocarbons and soil porosity.The adsorption curves showed that the adsorption of petroleum hydrocarbons in soil was in accordance with the Freundich equation.The monolayer adsorption model does not accord with the adsorption behavior of petroleum hydrocarbons in soils.T-herefore,The constituents of crude oil may be flocculated and adsorbed on the soil pores.(2)Through the GROMACS molecular simulation software,it is found that the soil humic acid(LHA)and aromatic hydrocarbon(ANT)will appear wrapped flocculation.The more the number of LHA molecules in the system,the slower the diffusion of saturated hydrocarbons(ANT).(3)The influence of the electrokinetic effect on the Transport of aromatic hydrocarbon and humic acid was investigated from the molecular point of view:(1)The diffusion and flocculation of aromatic hydrocarbons(ANT)and humic acids(LHA)are affected by the electric force.The electric field strength only in a certain range can reflect the promotion of diffusion.Is not the bigger the electric field strength is beneficial to the diffusion of petroleum hydrocarbons.This provides a theoretical basis for the practical work of electric power.(2)The amount of humic acid in the system greatly affects the diffusion and the flocculation of the aromatic hydrocarbon by electric power.When the number of LHA is small in the system,the electric field intensity in a certain range greatly promotes the diffusion of ANT,and if the electric field intensity is too large,it will promote the flocculation of ANT itself and cause the ANT diffusion to slow down.When the number of LHA is large in the system,the diffusion of ANT is mainly affected by the flocculation of LHA and.The influence of electric field is not very obvious,and the flocculation of ANT-LHA is promoted when the electric field intensity increases,which makes the ANT and LHA's diffusion decreased.