Investigating the Molecular Structure of Modified Bentonite in Geosynthetic Clay Liners: Insights from Molecular Dynamics Simulations

Abstract

Geosynthetic clay liners (GCLs) are integral components of landfill containment systems, relied upon for their ability to prevent the migration of hazardous contaminants into the surrounding environment. A key constituent of GCLs is modified bentonite, whose structural properties significantly influence the liner's effectiveness. This study employs molecular dynamics (MD) simulations to probe the molecular structure of modified bentonite within GCLs, offering invaluable insights into its behavior under various environmental conditions. By constructing a computational model representative of GCLs, including parameters mimicking landfill conditions, we investigate the interplay between modified bentonite and surrounding components. Our simulations reveal alterations in the interlayer spacing and hydration properties of modified bentonite due to the incorporation of polymers or chemical additives. Furthermore, we examine the interactions between modified bentonite and adjacent materials, such as geotextiles and geomembranes, elucidating their collective influence on GCL performance. Through MD simulations, we unveil the molecular mechanisms underlying the swelling behavior and barrier formation capabilities of modified bentonite, offering critical insights for optimizing GCL design and functionality.