Feasibilty of Kaolin and Mica as Bleaching Earths for the Removal of Organic Compounds From Crude Palm Oil

Abstract

This paper describes the feasibility of use of locally available kaolin and mica for refining crude palm oil (CPO) and compares their performance with commercially available bleaching earth (Attapulgite) which is commonly used in the palm oil industry. The materials were characterized for chemical composition, surface area, pore size and pore volume, functional groups, and microstructure. The performance of refining was determined by measuring the removal of color, phosphorous, free fatty acids (FFA), and peroxide from palm oil. Attapulgite, kaolin and mica mainly contained silica, alumina and ferrous oxide and they were mesoporous materials with surface area of 89.932, 4.889, and 8.195 m2/g respectively. Functional group analysis showed decrease in the intensity of peaks due to adsorption of phosphorous which was in the order of attapulgite>mica>kaolin. Microstructural analysis showed heterogenous behavior of adsorbents with the presence of particles of different size. The refining of CPO results indicated that both kaolin and mica were able to adsorb impurities from the CPO. Attapulgite had the highest bleaching efficiency followed by mica and kaolin. Based on the obtained results, mica has the potential of refining of CPO and its performance could be further improved by activation using different agents.