Cyclic closed system soil column test method for rapid determination of soil isotherm adsorption curve

Abstract

The invention discloses a cyclic closed system soil column test method for quickly measuring the isothermal adsorption curve of soil. It can infiltrate the soil through the pollutant solution to make the two adsorb and exchange, and form a closed system with constant quality of the pollutant solution and the soil in the form of recharging the effluent to the pollution source, and obtain the adsorption characteristics of the soil without digestion of the soil; The purpose of approaching the inflow and outflow solution concentrations quickly is realized, the adsorption equilibrium is easy to judge, and the equilibrium time of the soil column test is shortened. The invention overcomes the problem that there is a large difference between the adsorption characteristics of soil particles obtained by the batch test and the actual soil adsorption characteristics, and overcomes the problems that the conventional soil column test takes a long time, the adsorption balance is difficult to determine, and the numerical calculation boundary conditions are difficult to characterize. Authentically measure the adsorption characteristics of soil in the actual site.

Description

technical field [0001] The invention relates to an indoor test method for soil adsorption characteristics, in particular to a cyclic closed soil column testing device and method for isothermal adsorption curves of soil pollutants, which are used for analysis and simulation of pollutant migration in site soil and soil antifouling barriers Calculation of pollutant breakdown time. Background technique [0002] At present, my country's urbanization process is very fast, and the construction and operation management of industrial and municipal environmental protection infrastructure is relatively lagging behind, resulting in increasingly serious urban groundwater and soil pollution in my country. In order to deal with the increasingly serious problem of water and soil pollution, a large number of site treatment research and projects have been carried out at home and abroad for decades. Among them, the vertical barrier wall technology built with soil materials such as soil-bentoni...

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Problems solved by technology

However, this method has the following disadvantages: there is an obvious tailing phenomenon, that is, the concentration of the effluent solution cannot reach the source concentration level for a long time (up to several months) after it reaches a relatively stable level, making it difficult to accurately judge whether the pollutants in the soil and the solution have reached Adsorption balance; after the test, it is necessary to completely digest the soil to obtain the total adsorption capacity of the pollutants on the soil, but it is impossible to distinguish the distribution relationship between the pollutants adsorbed by the soil particles in the soil and the pollutants in the pore water; after the test, it is necessary to use Analytical solution or numerical calculation method simulates the pollutant outflow curve of the test to determine the relevant pollutant migration parameters, but the concentration of pollutants at the pollution source and the pollutant concentration at the inflow interface of the soil column are different due to molecular diffusion, and the boundary conditions used in calculation and analysis are generally difficult to characterize The actual inflow boundary conditions of conventional soil column tests lead to low accuracy of the determined pollution transport parameters

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