The adsorption of poly(1-vinylimidazole) (PVI) on Na-bentonite from aqueous solutions was investigated as a function of some parameters such as pH, ionic strength, and temperature. The adsorption of PVI increased with increasing pH and decreasing ionic strength and temperature. The electrophoretic mobility of Na-bentonite dispersions was measured at different PVI concentrations and pH. The results have shown that Na-bentonite can be used for adsorption of PVI from aqueous solutions. The second-order kinetic equation best fit the experimental data. (c) 2012 Elsevier B.V. All rights reserved.