Synthesis and performance analysis of oil palm ash (OPA) based adsorbent as a palm oil bleaching material

Abstract

Bleaching is a vital step in crude palm oil (CPO) processing due to its importance for both decolourisation and removal of impurities present in the oil. The commonly used material for CPO bleaching is bleaching earth. However, there are associated environmental issues due to its disposal without pre-treatment, and the retention of significant quantities of oil during the bleaching process. It is therefore imperative to research into viable alternative bleaching materials which are economical, readily available and able to undergo successive regeneration while minimizing oil loss. The present work probed the performance of enhanced oil palm ash (OPA), as an alternate bleaching adsorbent. The performance of the bleaching process was investigated by engineering critical process parameters such as stirring speed, adsorbent dosage, regenerability and ash particle sizes. The effective particle size of OPA was determined to be 212–300 μm, resulting in a maximum bleaching efficiency of 97.3%. A stirring speed of 800 rpm was optimal irrespective of the adsorbent particle size. In addition, a high adsorbent-to-CPO dosage ratio was identified to be effective for successive numbers of regeneration with less retention of oil. Indications from this analyses are that a higher bleaching performance can be obtained by optimizing relevant process conditions of OPA as an adsorbent.