Bentonite barrier compositions and related geosynthetic clay liners for use in containment applications

Abstract

The present invention relates to improved bentonite barrier compositions having enhanced low permeability over time in containment applications. Of the many embodiments provided herein, one embodiment includes a geosynthetic clay liner comprising: at least one geosynthetic layer; and a bentonite barrier composition comprising: bentonite and a polyanionic low molecular weight polymer.

1 . A geosynthetic clay liner comprising:
 at least one geosynthetic layer; and   a bentonite barrier composition comprising: bentonite and a polyanionic low molecular weight polymer.   
     
     
         2 . The geosynthetic clay liner of  claim 1  wherein the geosynthetic layer is a geotextile or a geomembrane. 
     
     
         3 . The geosynthetic clay liner of  claim 1  wherein the geosynthetic layer comprises a structure selected from the group consisting of: a nonwoven structure, a woven structure, and any combination thereof. 
     
     
         4 . The geosynthetic clay liner of  claim 1  wherein the geosynthetic layer is laminated with a geofilm or coated with a coating. 
     
     
         5 . The geosynthetic clay liner of  claim 1  wherein the bentonite barrier composition is adhered to the geosynthetic layer by an adhesive and/or by a mechanical means. 
     
     
         6 . The geosynthetic clay liner of  claim 1  further comprising a second geosynthetic layer that is a geotextile, a geofilm, or a geomembrane. 
     
     
         7 . The geosynthetic clay liner of  claim 1  wherein the bentonite barrier composition is present in an amount of about 0.25 to about 3 lb/ft 2  of the geosynthetic clay liner. 
     
     
         8 . The geosynthetic clay liner of  claim 1  wherein the polyanionic low molecular weight polymer comprises a polymer selected from the group consisting of: a guar, a hydrolyzed low molecular weight acrylamide, a polyacrylate, a polyanionic cellulose, poly(sodium styrene sulfonate), polyacrylic acid, pectin, carrageenan, an alginate, polyvinylpyrrolidone, and any combination of these. 
     
     
         9 . The geosynthetic clay liner of  claim 1  wherein the geosynthetic clay liner has a retained permeability of about 1×10 −8  cm/s or lower. 
     
     
         10 . The geosynthetic clay liner of  claim 1  wherein the geosynthetic clay liner has a retained permeability of about 1×10 −9  cm/s or lower. 
     
     
         11 . A sandwich geosynthetic clay liner comprising:
 a first geosynthetic layer;   at least a second geosynthetic layer; and   a bentonite barrier composition that is sandwiched between the first geosynthetic layer and the second geosynthetic layer comprising: bentonite and a polyanionic low molecular weight polymer.   
     
     
         12 . The sandwich geosynthetic clay liner of  claim 11  wherein the first geosynthetic layer or the second geosynthetic layer is a geotextile or a geomembrane. 
     
     
         13 . The sandwich geosynthetic clay liner of  claim 11  wherein at least one of the first geosynthetic layer or the second geosynthetic layer comprises a structure selected from the group consisting of: a nonwoven structure, a woven structure, and any combination thereof. 
     
     
         14 . The sandwich geosynthetic clay liner of  claim 11  wherein at least one of the first geosynthetic layer or the second geosynthetic layer is laminated with a geofilm or coated with a coating. 
     
     
         15 . The sandwich geosynthetic clay liner of  claim 1  wherein the bentonite barrier composition is adhered to at least one of the first geosynthetic layer or the second geosynthetic layer by an adhesive and/or a mechanical means. 
     
     
         16 . The sandwich geosynthetic clay liner of  claim 11  wherein the bentonite barrier composition is present in an amount of about 0.25 to about 3 lb/ft 2  of the sandwich geosynthetic clay liner. 
     
     
         17 . The sandwich geosynthetic clay liner of  claim 11  wherein the thickness of sandwiched bentonite barrier composition is about 0.01 inch to about 2 inches. 
     
     
         18 . A geosynthetic clay liner comprising:
 at least a first geosynthetic layer;   a bentonite barrier composition comprising: bentonite and a polyanionic low molecular weight polymer; and   an adhesive that at least partially bonds the bentonite barrier composition to the first geosynthetic layer.   
     
     
         19 . The geosynthetic clay liner of  claim 18  wherein the adhesive may comprise an acrylic polymer, polyvinyl acetate, waterborne polyurethane dispersions, or combination thereof. 
     
     
         20 . The geosynthetic clay liner of  claim 16  wherein the adhesive is present in an amount of about 2% to about 25% by weight of the bentonite.