Colloidal Stability of Aqueous Suspensions of Bentonite Clays from the Krantau Deposit. Analysis via Dynamic Light Scattering

The extent of pollution of natural waters forces the search for cheap and effective sorbents for heavy (ultimately toxic) and radioactive (totally dangerous) metal cations and their anionic forms. Clays are widely used due to the highly stable negative charge of the structural aluminosilicate framework, which creates selectivity for cationic forms. However, in the removal of inorganic pollutants in anionic forms, they have a poor sorption capacity. The most promising method of surface modification of natural sorbents is their organophilization with the use of cationic surfactants, which can significantly increase the sorption capacity in relation to the anionic forms of heavy metals and various types of organic toxicants. Modification processes have been the subject of numerous studies. Despite this, due to the issue’s complexity, some important details have not yet been elucidated. The study of processes at the clay–water interface in the systems of NaCl, CaCl2, cetyltrimethylammonium bromide, and methyl violet is the subject of this work, which relates to colloidal stability, coagulation, and compression of the electrical double layer. Comparison of electrolyte concentration function of zeta potential and rate of size increase and the identification of the regimes of colloidal stability and instability for bentonite clays (sodium montmorillonite) from the Krantau deposit are the features of this investigation.