Abstract: The chemosmosis performance for long-term solute permeation in the geosynthetic clay liner (GCL) is obvious. The laboratory test of permeation with solute is introduced. And the test result indicates that the cation exchange has largely effect on the hydraulic conductivity of GCL. The hydraulic conductivity of GCL is up to 2.5×10-11 m/s and 5.6×10-11 m/s permeated with 10 mM and 30 mM CaCl2 solution respectively. The time of solute breakthrough the GCL decreases with the solution concentration increasing. The change of the hydraulic conductivity of the GCL is impacted largely on the presaturation reagent. The effect of the hydraulic conductivity of GCL by using the distilled water for presaturated sample is much smaller than that using the CaCl2 solution. Considering the effect of the membrane behavior and cation exchange, the coupling dynamic model of solute transport has been developed. And the coupling model is applied to modeling the variation of the solute concentration in permeation process. The Ca2+ concentration is anastomotic by data match from the test and simulation result; and the reliability of the coupling model is approved. The chemosmosis in GCL is important, which can effectively delay the solute transport velocity described by the breakthrough curve of Ca2+ concentration and flux. Moreover, the level of the retardation effect by chemosmosis becomes obviously with decreased of the solute concentration. Therefore, the effect of the chemosmosis should be taken into account for analysis of the solute transport in GCL.

Key words: solute permeation, geosynthetic clay liner, chemosmosis, coupling model, breakthrough