Turkish Journal of Chemistry

Abstract: Thermodynamic parameters provide clues for finding the spontaneity of a given process at a given temperature. In the present work, the Temkin adsorption model was applied for evaluation of the thermodynamic parameters of cadmium adsorption studied on sand. The lateral interaction energy parameter was found to be unity, which showed that the heat of adsorption is directly proportional to the fraction of free adsorption sites. The values of D H° and D S° were --4.8 kJ mol^-1 and 42 J mol^-1 K^-1, respectively. The value of D G° was negative, indicating the spontaneity of cadmium adsorption on sand.

Key Words: Thermodynamic parameters, spontaneity, Temkin adsorption model, cadmium, sand, modified isotherm