Journal of Colloid and Interface Science, Vol.280, No.1, 131-138, 2004
Investigation of the properties of oil at the bleaching unit of an oil refinery
Color removal from neutralized Sunflower oil was studied with different kinds of commercial bleaching earths. The effect of changes in time (25 and 35 min), temperature (80-125 degreesC), and bleaching earth dosage (0.1-0.9% by weight) on color, chlorophyll and carotene concentrations, and oxidation degree were investigated. To obtain adsorption Curves from coloring compounds adsorbed onto activated bleaching earths, the Langmuir and Freundlich equations was used, the constant parameters and correlation coefficient R were calculated for each type of bleaching earth, and color changes were explained by both adsorption isotherms. It was observed that an increase in bleaching earth dosage decreases color. Its effect oil oxidation state, however, is complex and related to both primary and secondary oxidation products. In addition, ail increase in temperature seems to decrease chlorophyll and carotene adsorptions. Generally, time beyond equilibrium is considered useless for the removal of unwanted components. This Study also confirms this claim and reveals that the pet-oxide value does not indicate the oxidation state of the oil completely. (C) 2004 Elsevier Inc. All rights reserved.
Keywords:bleaching adsorption;Freundlich equation;chlorophylls;carotenes;relative absorbance;activated bleaching earth