Mohagir AM, Syed S, Bup N D, Kamga, R and Kapseu C
Keywords: Shea butter, decolourisation, tonsil fuller earth, adsorption isotherm, Freundlich, Langmuir.
Abstract: The objective of this paper was to study the adsorption isotherms of decolourisation of shea butter. The adsorption of pigments from aqueous extracted shea butter using tonsil fuller earth was carried out. The absorbance of crude and decolourised black and yellow shea butter using 1, 2, 3, 4 and 5 mass % of the adsorbent at different temperatures (55, 65, 65, 75, 85 and 95°C ) were measured. The experimental data obtained were analysed and fitted to Freundlich and Langmuir equations. Langmuir adsorption isotherm model fitted well the decolourisation of yellow shea butter at 95°C, while Freundlich model significantly fitted the decolourisation of black shea butter at 65°C. Gibbs free energy, enthalpy and entropy of adsorption were generated from the experimental data. The absolute value of enthalpy of adsorption showed that the decolourisation process of shea butter is a physical phenomenon, whereas the negative values of Gibbs free energy suggested that, the adsorption is spontaneous process.
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