Abstract: The adsorptive thermodynamics and kinetics of Methylene Blue on thermal-modified Attapulgite clay was investigated. It can be seen that the Methylene Blue equilibrium adsorption data were ?tted to Langmuir isotherm models and the adsorptive process as the Methylene Blue was in an initial concentration range of 50～600mg/L and the experimental temperature was in the range of 298～338K. The adsorption enthalpy changes and the adsorption Gibbs free energy changes are 1.92KJ/mol and -25.429～-29.097 KJ/mol independently. The positive values of adsorption entropy changes illustrate the adsorption of the Methylene Blue onto thermal-modified Attapulgite clay is endothermic and spontaneous. The adsorptive kinetics data were in good agreement with the pseudo-second rate equation. The apparent adsorption activation energy of the thermal-modified Attapulgite clay is 13.5676KJ/mol. It suggests this adsorption may involve the combined control of chemical adsorption and film diffusion.

Key words: attapulgite clay , thermal-modification , adsorption thermodynamics , adsorption kinetics