THE USE OF IRAQI RAW MATERIAL IN BLEACHING OF VEGETABLE OIL

This study is carried out to determine the possibility of using the Iraqi Bentonite raw material for bleaching the cottonseed oil and to study the effect of treatment with acid and caustic on the process of bleaching as well as the effect of the particle size, the degree of temperature and the time required for the process.The Iraqi local material was examined by X-ray diffraction (XRD) and infrared spectroscopy (IR) techniques, also chemical and mineral analysis were used to determine the clay characteristic.Two methods of adsorption were used the physical and chemical adsorption. For the physical adsorption method, two groups of Bentonite samples were prepared (A&B). For group A, the Bentonite with percentage (70%, 75%, 80%, 85%, and 90%) mixed with sulfuric acid (H₂SO₄) using different percentage (30%, 25%, 20%, 15%, and 10%) with concentration 4N for 6 hours. While sample of group B different concentration of H₂SO₄ with normality 4N and 8N were mixed with a specific amount of Bentonite for a time 3.5 hours and 6 hours. In the second group (C), the Bentonite treated with (Na₂CO₃) to get the following values of pH (8.5, 9.5, 10.5, and 12.5) for a time 3.5 hours and of pH (10.5, 12.5, and 14.5) for a time 6 hours. The process of bleaching of cottonseed oil then performed by using all the groups A,B, and C using concentration 0.3% and 0.7% for time periods 3.5 hours and 6 hours.The red color degree for the cottonseed oil was measured using Lovibond color glasses before and after bleaching. Also the free fatty acid (F.F.A), the pH of the treated Bentonite, and the pH, density of bleached oil. The value of the physical and chemical adsorption were calculate using two equations, Frendlich and Langmuir, and the constant of the equations were determined, the result of the study reveals that the best color was obtained by using the chemical adsorption method (group C). As the color degree of cottonseed oil changed from (16-red) before bleaching to (7-red) after bleaching with the sample (C₇) of the pH value 7.6. In the case of using the physical adsorption method. The best value of color (9.01-red) was produce using sample A₁ with concentration 0.7% and pH value 1.45 for a time 3.5 hours. While in group B, the best value produce by using sample B₄, where the degree of color was (9.2-red) using concentration 0.7% with pH value 1.5 and time 3.5 hours.