Abstract: In order to find a way to solve the problem of heavy metal pollution with high efficiency，low cost and no pollution，and with the sodium montmorillonite (Na-mnt) after purification and Na-modification as adsorbent，the Cu²⁺ adsorption experiments were carried out based on analyzing its characteristics.Influences of Cu²⁺ initial concentration，initial pH of solution，adsorption temperature and adsorption time on Cu²⁺ adsorption performance were investigated.The adsorption mechanism of Na-mnt on Cu²⁺ was analyzed through the isotherm adsorption model of Langmuir and Freundlich and the kinetic equations from views of the thermodynamics and the kinetics.The results showed that the adsorption equilibrium data of Cu²⁺ on Na-mnt conforms to the Langmuir isothermal model.The adsorption process is a non-spontaneous exothermic reaction process，which conforms to the pseudo-second-order kinetic equation.

Key words: Na-montmorillonite, Cu²⁺, Kinetics, Thermodynamics, Adsorption