RESEARCH ARTICLE

Journal of Oil Palm Research Vol. 34 (2) June 2022, p. 337-347

INFLUENCE OF CHEMICAL COMPOSITION OF ACTIVATED CALCIUM BENTONITES AND SODIUM BENTONITES ON PALM OIL BLEACHING CAPACITY AND OIL QUALITY

DOLPHEN, R1; DHURAKIT, P2 and THIRAVETYAN, P2*

DOI: https://doi.org/10.21894/jopr.2021.0043
Received: 27 October 2020   Accepted: 25 August 2021   Published Online: 29 October 2021
ABSTRACT

The efficiency of clays in bleaching degummed palm oil depends on their unique characteristics. This study sheds new light on a novel characteristic which impacts on the quality and bleaching capacity of activated clay. Although bentonites may originate from different areas, their structural modifications can make them ideally suited for bleaching. Calcium (Ca)-bentonites and sodium (Na)-bentonites, including activated forms of both clays, were investigated in depth. Interestingly, X-ray fluorescence (XRF) spectrometry indicated that the high bleaching capacity of Na-bentonite was correlated with silica (SiO2) and alumina (Al2O3) contents in the range of 68.90%-85.20% and 8.96%-16.60% by weight (wt), respectively. The results showed that Na-bentonite treated with 1.5 M sulphuric acid (H2SO4) at a clay:acid ratio of 10:50 (w v–1) and refluxing time of 8 hr had a higher bleaching capacity (78.04%) than commercial clay (67.09%). These characteristics can provide a suitable reaction space at the interlayer for adsorption of pigments and impurities. Moreover, the specific surface area and total pore volume of this activated clay also increased. After bleaching by treated Na-bentonite with 1.5 M H2SO4, degummed palm oil appeared to be of good quality, leading to less deterioration and rancidity due to decreased free fatty acid (FFA), unsaturated fatty acid, iron (Fe) and phosphorus (P) contents.

KEYWORDS:


1 Pilot Plant Development and Training Institute,
King Mongkut’s University of Technology Thonburi,
Bangkok 10150, Thailand.

2 Division of Biotechnology,
School of Bioresources and Technology,
King Mongkut’s University of Technology Thonburi,
Bangkok 10150, Thailand.

* Corresponding author e-mail: paitip.thi@kmutt.ac.th