Clay from Ukpor was acid activated (at various concentrations) to improve its adsorptive capacity by increasing the specific surface area. The activated samples were used to adsorb colour pigments from palm oil. To study the adsorption capacity of the activated clay samples, the effects of temperature, contact time, adsorbent dosage and particle size were studied. The experimental data were analyzed using the established kinetic models of Pseudo-first order, Pseudo-second order, Elovich, and intra-particle diffusion. The data fitted very well to the Pseudo-second order kinetic model with a regression coefficient of 0.995. Equilibrium isotherms were analyzed by Langmuir, Freundlich, and Temkin adsorption models. The data conformed to the Freundlich isotherm model with regression coefficient of 0.998. The activation energy was calculated as 18kJ/mol, while the other thermodynamics parameters were determined as ΔS = 0.075J/mol, ΔH = 43.565J/mol, and ΔG = -74.347kJ/mol. These values indicate that the removal of colour pigment from refined palm oil by acid activated Ukpor clay is exothermic and can be attributed to a physico-chemical adsorption process.
