Adsorption model for multi-component heavy metal ions on clay based on non-equilibrium thermodynamics

The adsorption behavior of clay particles is the key factor to control the solute transport, which can further affect the accurate evaluation of the long-term service performance of the seepage prevention barrier. Based on the single-component adsorption model, the theory of non-equilibrium thermodynamics and Ziegler's principle of maximal rate of dissipation, a non-equilibrium adsorption model for multi-components under non-ideal system is established by using the continuum mechanics method through setting up the dispersion-type free energy function and dissipation rate function. The proposed model is employed to describe the adsorption process of heavy metal ions. The results show that there is a good agreement between the model and experimental results, and it is indicated that the proposed non-equilibrium adsorption model can correctly reveal the kinetics mechanism of adsorption process for multi-components on clay.