Bentonite is a hydrous aluminum silicate that is mainly composed of montmorillonite. It is an important mineral with many industrial applications.

bentonite chemical formula consists of a combination of several chemical groups, and it can be classified into three categories: natural sodium bentonite, natural calcium bentonite and activated calcium (sodium-calcium) bentonite. These three categories differ in their proportion of exchangeable sodium and calcium cations, swelling index and pH value.

The cation exchange capacity of bentonite is also determined by its lattice parameters, which are related to the levels of isomorphous substitutions in the crystal lattice. This determines its swelling index, and the resulting amount of water it can absorb.

Bentonites can be formulated to absorb organic and inorganic contaminants, as well as amines, b-carotenes, N2 +, Ni2 + and Zn2+, phenols, ketones, pesticides, chlorophyll and phosphates. The adsorption process is generally divided into three stages: film diffusion, pore diffusion and surface interaction between the bentonite and the chemical agent.