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In this paper,with K+,Ca2+and Fe3+as the objects of study,retardation of soil–bentonite(SB)barrier materials for metal ions with different valences is investigated,and the adsorption mechanism,migration patterns and permeation behavior are explored so as to provide a theoretical basis for their application.The results show that the adsorption process for metal ions with different valences by SB barrier materials is fast,and the higher the valence,the greater the adsorption capacity.The ftting of the adsorption process conforms to pseudo-second-order adsorption kinetics and Langmuir–Freundlich adsorption equation,which explains that chemical adsorption is the dominating state and that the SB surface has certain heterogeneity.The permeability coeffcient of K+,Ca2+and Fe3+in SB each has a maximum and the higher the valence,the sooner the maximum appears.Also the higher the valence,the more obvious the effect on SB retardation performance;and the sooner the ion breaks through the barrier wall completely,that is,the wall’s retardation performance for higher valent ions may decline.
In this paper, with K +, Ca2 + and Fe3 + as the objects of study, retardation of soil-bentonite (SB) barrier materials for metal ions with different valences is investigated, and the adsorption mechanism, migration patterns and permeation behavior are explored so as to provide a theoretical basis for their application. The results show that the adsorption process for metal ions with different valences by SB barrier materials is fast, and the higher the valence, the greater the adsorption capacity. The ftting of the adsorption process conforms to pseudo-second-order adsorption kinetics and Langmuir-Freundlich adsorption equation, which explains that chemical adsorption is the dominating state and that the SB surface has certain heterogeneity. The permeability coeffcient of K +, Ca2 + and Fe3 + in SB each has a maximum and the higher the valence, the sooner the highest the. als the higher the valence, the more obvious the effect on SB retardation performance; and the sooner the ion breaks through the barri er wall completely, that is, the wall’s retardation performance for higher valent ions may decline