Hydraulic Conductivities and Effective Diffusion Coefficients of GeosyntheticClay Liners with Organobentonite Amendments

摘要

Laboratory diffusion and permeability tests were performed on GCLs amended withrntwo different types of organobentonites: benzyltriethylammonium-bentonite (BTEAbentonite)rnand hexadecyltrimethylammonium-bentonite (HDTMA-bentonite) andrncompared to results for a GCL constructed with conventional sodium bentonite.rnResults from the hydraulic conductivity testing indicate the addition of both types ofrnorganobentonite results in an increase in hydraulic conductivity. Only a smallrnincrease (less than one order of magnitude) in hydraulic conductivity was observedrnfor both types of GCLs amended with up to 20% organobentonite. At higherrnorganobentonite contents, measured hydraulic conductivity for both types of amendedrnGCLs increased by as much as three orders of magnitude. The effective diffusionrncoefficient measured for both the organobentonite-amended GCLs and the laboratoryconstructedrnsodium bentonite GCLs were similar and ranged from 2.67 x 10-10 torn4.17 ×10-10 m2/sec. Considering the strong sorption capacity of organobentonites forrnorganic contaminants, these results suggest that the ability of GCLs to retard therntransport of organic contaminants can be improved by substituting 10-20% of thernconventional bentonite with an organobentonite.