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Influence of Chemical Composition of Activated Sodium Bentonites on Degummed Palm Oil Bleaching
  • Rujira Dolphen,
  • Prapai Dhurakit,
  • Paitip Thiravetyan
Rujira Dolphen
King Mongkut's University of Technology Thonburi
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Prapai Dhurakit
King Mongkut's University of Technology Thonburi
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Paitip Thiravetyan
King Mongkut's University of Technology Thonburi
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Abstract

The efficiency of clays in bleaching degummed palm oil depended on their unique characteristics. The characteristics of bentonites and Na-bentonites, including activated forms of both clays, were investigated in depth to determine their bleaching capacity. The results showed that Na–bentonite treated with 1.5 M H2SO4 at a clay:acid ratio of 10:50 (w/v) and refluxing time of 8 h had higher bleaching capacity (78.04%) than commercial clay (67.09%). X-Ray Diffraction (XRD) patterns of bentonites and Na-bentonites activations show peaks similar to montmorillonite. Meanwhile, X-ray Fluorescence Spectrometry (XRF) indicated a correlation between the SiO2 and Al2O3 contents of clays and their bleaching capacity. Interestingly, the high bleaching capacity of Na–bentonite was correlated with SiO2 and Al2O3 contents in the range of 72.30–85.20% and 8.96–13.30% by weight, respectively. Moreover, the specific surface area and total pore volume of this activated clay also increased. In addition, after bleaching by Na–bentonite treated with 1.5 M H2SO4, the degummed palm oil appeared to be of good quality, leading to less deterioration and rancidity. Moreover, the bleached palm oil had lower yellowish colour, moisture content, and peroxide values than the degummed palm oil.