Study On The Migration And Transformation Of 2, 4-Dichlorophenol In The Loess Soil

2,4-dichlorophenol(2,4-DCP) is an important organic chemical intermediate products.It main used to produce pesticides,Pharmaceuticals,auxiliary products.Because of 2,4-DCP has long-term remains,bioaccumulation,semi-volatilized and high toxicity,it has been attributed to one of the Priority Pollutants in many countries.In the west of China,the Loess possesses a great share in the land distributions,thus the soil containing Loess is an important factors for the utilization of agriculture,forest,animal husbandry,urban construction and industrial development.Those subjects have very important theoretical and practical values,for instance, revealing the adsorption and migration laws of 2,4-dichlorophenol in the Loess,announcing the influence degree of 2,4-dichlorophenol on the groundwater,grasping migration and distribution laws of 2,4-dichlorophenol,evaluating the environmental hazards,reducing the pollution of groundwater,protecting the groundwater resources.In the present thesis,the structures,properties,resource and harm of 2,4-dichlorophenol have been gleaned,the adsorption and migration of 2,4-dichlorophenol in the soil/sediments has been reviewed.The detail items includes:the adsorption/desorption properties and laws of 2,4-dichlorophenol in the Loess have been ascertained by combination of static and dynamic method,the curves of adsorption dynamic and thermodynamic have been detected and determined.The migration transformation mathematical model of 2,4-dichlorophenol in the Loess and its model parameters have been obtained,and the result showed that the model parameters have a good cohererence with the experimental value,which further verify the validity of migration transformation mathematical model.The main conclusion of the study:1.The adsorption dynamic of 2,4-dichlorophenol in the Loess has better effect and less error,using least square method.Furthermore,the adsorption of 2,4-dichlorophenol in the Loess abides by the equation and the tow-parameters equations.The constant of adsorption quantity between 23.25μg/g and 37.5μg/g,the adsorption rate between 12.6μg/(g.h) and 18.75μg/(g.h).2.The adsorption of 2,4-dichlorophenol in the Loess accords with the liner model. Adsorption isotherm also can be described with Freundlich equation and Langmuir equation. The adsorption of 2,4-dichlorophenol in the Loess belongs to an exthermal spontaneous reaction,and the main force can be attributed to the hydrogen bond.3.The Loess soil has not a function for the enrichment of 2,4-dichlorophenol,and the 2,4-dichlorophenol penetrates the Loess soil easily.Inevitably,the groundwater will be contaminated by the 2,4-dichlorophenol.4.The migration of 2,4-dichlorophenol has been affected by the hydrodynamic diffusion, adsorption and degradation simultaneously.Moreover,the results determined form those modes has a well coherence with the experiments,which indicated that the diffusion modes can be used to simulate the migration of 2,4-dichlorophenol in the Loess soil well.