Clays with adsorbent properties are used in one of the refining stages for the production of vegetable oil for human consumption. Those clays are often defined as discoloring clays, and their main function is to remove chlorophyll and carotenoid of the vegetable oil. Most of the commercial discoloring clays are obtained from smectites treated with strong inorganic acids. The acid treatment promotes the creation of acidic sites, increase of specific surface area, volume and pore size, dissolution of impurities and other changes that contribute to enhance the adsorbent properties of those materials.
discoloring clays; acid activation; adsorption
