Adsorption of Carotene from Crude Palm Oil by Activated Achalla Clay

Abstract

High costs of imported bleaching earths have led to the need for alternative local sources. The effectiveness of acid-activated Achalla clay in crude palm oil bleaching was examined. The clay sample was collected, sun-dried, manually ground, and activated with the hydrochloric acid solution. Characterization of the raw and activated clay samples was carried out using X-ray fluorescence (XRF), Scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) analyses. The factors that were varied during the bleaching process were temperature, contact time, and adsorbent dosage. The adsorption kinetics, adsorption isotherm, and thermodynamics studies were also investigated. The XRF, SEM, and FTIR characterization results showed that the clays were kaolinites with some significant increase in the number of microporous surfaces and some changes in the functional groups. The results also indicated that the process performance improved at higher temperatures. The highest bleaching efficiency of the bleaching process was 85.6%. The pseudo-first-order model described the adsorption process from the experimental data with higher correlation coefficients than the pseudo-second-order, first-order, and Intra-particle diffusion models. The equilibrium isotherm data were described better by the Temkin model than Langmuir and Freundlich models due to higher R2 values. The enthalpy and entropy values were determined to be 26,968.12 J/mol and 78.2273 J/mol respectively. The Gibb’s free energy was found to vary between -1.428.39 to 1,700.70 J/mol. The results of the thermodynamic parameters showed that it was a spontaneous chemical adsorption process and endothermic. This study has revealed that acid-activated Achalla clay can be used for the bleaching of crude palm oil at higher temperatures.