Bleaching of Crude Palm Oil by Activated Nise Clay: Process Kinetics, Isotherm and Thermodynamic Studies

Alkaline-activated Nise clay was applied in the bleaching of crude palm oil as an adsorbent.The FTIR, SEM and XRF analyses were carried out on the raw and activated (ANIC) clay samples.The experimental process was carried out to determine the efficiency of ANIC in bleaching the crude palm oil.Adsorption kinetics and equilibrium isotherm studies were carried in other to understand and implement the adsorption process.The results obtained after analyses of the morphological properties, the elements and minerals present and the characteristic functional groups showed that the clay was kaolinite.The activation of the clay also brought about some changes in the morphological structure of the clay and also changed the functional groups.The efficiency of the bleaching process was observed to increase with increase in temperature.The optimum bleaching efficiency was 87.6% and was obtained at optimum conditions of 100 oC, 3.5 g and 50 mins.The kinetic adsorption studies indicated that the intra-particle diffusion model best described the bleaching process.The isotherm studies revealed that the Temkin isotherm model gave the best fitting using the experimental data because it gave the highest R 2 values of >0.98 at all the operating temperatures.The thermodynamic parameters indicated that the bleaching process became spontaneous between 353 and 373 K.The positive value of entropy (ΔS 0 ) obtained showed that the affinity of the adsorbent towards the adsorbate was high.The value of ΔH 0 was higher than 40 KJ.mol -1 indicating that the bleaching process was a chemisorption process.