Acid-treated clays are employed industrially as catalysts, catalyst supports and adsorbents. A relatively new market for activated clay is in animal feed where it absorbs mycotoxins. In terms of consumption, the most important use of the activated clays is in the purification, decolorization and stabilization of vegetable oils. They are used to remove phospholipids, soaps, trace metals, organic compounds (for example, chlorophyll) and their degradation products, which impart undesirable colors to the edible oils. The adsorptive capacity of these materials is significantly increased by treatment with strong inorganic acids, particularly sulfuric and hydrochloric acid. In this work, two bentonite clays with different mineralogical compositions from Mendoza, Argentine, were activated with H_2SO_4 solutions of 4 and 8 N at 90 °C for 3.5 hours. These treatment effects under clay structural properties were tested by thermogravimetry, infrared spectrometry and chemical analysis. The activated samples were tested in order to verify their bleaching capacity for castor, cottonseed, and soybean oils and were compared to a standard commercial bleaching clay. Bleaching efficiency was strongly dependent on acid concentration used for clay activation. The treated samples have shown a bleaching capacity compared to the standard. The mineralogical composition of natural clays have has influenced the properties of treated clays (or activated clays) and these properties increased its bleaching capacity.
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