Sodium bentonite expands when wet, absorbing as much as several times its dry mass in water. Because of its excellent colloidal properties,it is often used in drilling mud for oil and gas wells and boreholes for geotechnical and environmental investigations.The property of swelling also makes sodium bentonite useful as a sealant, since it provides a self-sealing, low permeability barrier. It is used to line the base of land fills, for example. Various surface modifications to sodium bentonite improve some rheological or sealing performance in geo environmental applications, for example, the addition of polymers.

Sodium bentonite expands when wet, absorbing as much as several times its dry mass in water. Because of its excellent colloidal properties,it is often used in drilling mud for oil and gas wells and boreholes for geotechnical and environmental investigations.The property of swelling also makes sodium bentonite useful as a sealant, since it provides a self-sealing, low permeability barrier. It is used to line the base of land fills, for example. Various surface modifications to sodium bentonite improve some rheological or sealing performance in geo environmental applications, for example, the addition of polymers.