Abstract The effect of temperature on the equilibrium adsorption of Malachite green dye from aqueous solution using rectorite was studied. The equilibrium adsorption data were analyzed using three widely applied isotherms; Langmuir, Freundlich, and Redlich-Peterson isotherm. A nonlinear method was used for comparing the best fitting of the isotherms. Best fits were found to be Redlich-Peterson isotherm. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the Malachite green adsorption on rectorite was an endothermic and spontaneous process.
Keywords Malachite green, isotherm, thermodynamics, rectorite, equilibrium.