The adsorption equilibrium of dark-coloured compounds from apple juice has been investigated as a function of several variables including activation conditions of bentonite (heat and acid treatments), clay concentrations (2×10 −3 –8×10 −3 kgclay/dm 3 apple juice) and temperature (range of 296–336K). The adsorption efficiency with acid-activated bentonite was greater than that with heat-activated and native bentonite, depending on surface properties; specific surface areas were 95.31, 71.95 and 71.76m 2 /g, respectively.Absorbance data at 420nm were fitted reasonably well with the Langmuir and Freundlich isotherms. The parameters K, Q 0 , K fr and n were determined for different temperatures. Thermodynamic parameters such as Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) change of adsorption were determined as about −3.125, 9.43 and 0.039kJmol −1 K −1 , respectively, for acid-activated bentonite. These parameters were also determined for native and heat-activated bentonites. It was shown that the adsorption process was endothermic, spontaneous and controlled by physical mechanism. The adsorption and desorption rate constants (k a and k d ) were obtained separately by applying a geometric approach to the first-order Langmuir model. k a varied from 5.717×10 −4 to 20.667×10 −3 s −1 and k d from 1.425×10 −4 to 7.473×10 −3 s −1 . The results showed that acid-activated bentonite is more suitable for the adsorption of dark compounds from apple juice.