Durability and adsorption of heavy metal ions of glass-geogrid-reinforced geosynthetic clay liners

Abstract

Geosynthetic clay liners (GCLs) are commonly used in engineering to prevent seepage. These liners’ surface fabric often suffers damage, especially in toxic environments and under high pressure. To mechanically strengthen the GCLs, this study proposes reinforcement by using needle bonding and glass geogrid to establish glass-geogrid-reinforced GCLs (i.e., GGCLs), consisting of glass geogrid, bentonite layer, and 0.3 mm thick melt-blown nonwoven fabric. Tensile durability of GGCLs was determined by exposing them to thermal oxidation and UV degradation. Hydraulic conductivity and heavy metal ions adsorption of GGCLs was explored to simulate the damage caused by garbage leachate. Tensile strengths of polyamide (PA)- and polyethylene terephthalate (PET)-contained GGCLs retained greater than 73% and 90%, respectively, even after 20 h thermal oxidation at 100°C and 60 h UV degradation. Improvement of hydraulic conductivity after 2 h adsorptions of Cu2+, Ni2+, and Pb2+ reached 51.09, 51.04, and 45.56%. The absorptions of Cu2+ and Ni2+ conformed to the quasi-secondary dynamics model, but that of Pb2+ followed both the quasi-first-order and quasi-secondary dynamics models. The mechanical properties and impermeability of the resulting GGCLs declined under the simulated conditions. This study provides a basic theory to predict the durability and adsorption of heavy metal ion of landfill GGCLs under natural and severe weather conditions.