Review of polymer-amended bentonite: Categories, mechanism, modification processes and application in barriers for isolating contaminants

Abstract

Polymer-amended bentonite is a kind of high-performance bentonite material, which has been widely researched and applied in barrier engineering. This paper summarizes the modification mechanism and process of polymer-amended bentonite in previous studies and discusses its modification effect for impermeability and isolating capacity as barrier materials. Conclusions are drawn as follows: Polymer enhance the performance of bentonite/barrier mainly through adsorption, filling, bonding, and anti-erosion effects; The common modification processes do not balance well between modification effect and complexity, and they could be improved according to the extrusion-pre-hydration method (refer to dense pre-hydrated GCL); Nonionic and anionic polymer-amended bentonite are applicable to the contaminated environments with inorganic salt and heavy metals, while cationic polymer-amended bentonite is suitable for isolating organic and some anionic contaminations.