ESTABLISHMENT OF THE PARTICLE SIZE DISTRIBUTION OF BLEACHING EARTH FOR PALM OIL REFINING

Abstract

Palm oil has carotenoid pigments in them that limit their applications. The need to reduce the carotenoid pigments to improve the quality of the oil for industrial applications became serious concern to researchers. Chemical activated local clays have been used as adsorbents for adsorption bleaching to remove the carotenoid pigments, since Federal Government of Nigeria presently banned the importation of the adsorbent (fuller earth) and vegetable oil in the country. However, thermal activated local clay has not been popularly known but considered in this research as a better alternative. The clay sample was obtained from Umana – Ndiagu in Ezeagu L.G.A of Enugu State, Nigeria. The sample was pre-treated and classified into different particle sizes of 20?m, 40?m, 60?m, 80?m and 100?m using a set of vibrating sieves. Each particle size was thermally activated at different temperatures of 200^oC, 400^oC, 600^oC, 800^oC and 1000^oC in a muffle furnace. The chemical properties were determined using Atomic Absorption Spectrophotometer (model;210VGP). The bleaching procedures were carried out and colour reduction of the oil at various particle sizes and activation temperatures were measure by tintometer. In conclusion, the result shows that, carotenoid pigment or colour reduction was obtained at particle size of 100?m activated at a temperature of 800^oC which makes Palm oil suitable for industrial applications. Hence, it is recommended that the clay samples from the source for this research be packaged for commercial use in Nigeria. 

Key words: Thermal activation, bleaching earth, clay, adsorption, adsorbent