In order to enhance the use and stability of edible oil, it needs to refine crude oil in several stages. Bleaching is one of the most important steps in refining. Although the main purpose of bleaching is ?-carotene and chlorophyll removal, but some other impurities such as free fatty acids, peroxide value and phosphorus would be removed. Bleaching not only makes the oil customer-friendly, but also increases its stability and shelf life. Among the effective factors on bleaching, third of them, including bleaching earth, reaction temperature, and time are most significant. Different bleaching earth are using that one of them is bentonite. Sepiolate is also one of the clay types that its mine was first discovered and extracted in 2010 in Iran. Due to the high active surface it can be used as bleaching clay. In this study acid- activated sepiolite was used as bleaching earth. BET analysis showed that during acid activation, Sepiolites surface area changed from 105 m 2 /g to 168 m 2 /g. to optimize the condition of oil bleaching, the factors of amount of bleaching clay, bleaching time and temperature were considered and optimum point was obtained response surface methodology (RSM). The results showed that there was no significant difference between real condition and predicted data by software. Clay Amount had the highest effect on the removal of pigments and free fatty acids and the optimum bleaching condition was bleaching earth 3%, time 42/46 and temperature 110 ° C. then bleaching activity of sepiolite was compared with clays used in industry, in two condition of optimum point and the one applied in factory. The findings should that sepiolite was the most effective clay in removed of FFA, peroxide and phosphorus and could reduce 98.15 and 21 % of ?-carotene and chlorophyll contents, respectively. Generally, due to higher content of bleaching clay optimum point was more effective than industrial condition. in spite of insignificant differences in some bleaching indices, sepiolate could be used as a proper substitute to imported bleaching earth. Keyword: Bleaching, Sepiolite, Optimization, Acid Activation.
