Mechanism of palm oil bleaching by montmorillonite clay activated at various acid concentrations

The mechanism of bleaching by a nonswelling montmorillonite clay activated at various acid concentrations was studied in the bleaching of palm oil. Montmorillonite clay was activated by 2 parts of H 2 SO 4 at concentrations of 10‐40%. Chemical composition, bleaching ability, specific surface area and phosphorus content were studied. The study showed that an initial increase in bleaching ability by clay activated by an increasing addition of H 2 SO 4 was due to acid leaching of organic matter and impurities in the clay. The consequence of acid leaching in this case tends to expose active sites for adsorption. Acid leaching also removed Al 3+ , causing charge deficiency in the clay lattice and, hence, promoting the adsorption properties of the clay. A drop in bleaching efficiency at higher additions of H 2 SO 4 was observed. This was due to exces‐sive acid leaching of Al 3+ , causing collapse of the clay lattice struc‐ture.