Abstract

The effectiveness of adsorbents (unactivated and acid activated) developed from local raw materials - clay and diatomaceous earth samples - sourced from various geographical locations in northern Nigeria for use in the adsorptive bleaching of palm oil was studied. Two acids namely hydrochloric and sulphuric acids of varying strengths 20, 30 and 45% were used for the activation. A batch adsorption process of operation was employed in the bleaching step. Results obtained in which the performance of these locally prepared adsorbents were expressed in terms of percentage colour reductions showed that, the acid-activated samples were more effective in the adsorptive bleaching of palm oil. As much as 96.5 and 98% colour reductions were attained in the first and second sequences of the bleaching steps respectively. This performance compares very well with those of well-known commercial adsorbents (fuller’s earth and activated carbon).

Key words: Adsorptive bleaching, acid-activated clay, palm oil refining, degumming, neutralization.