A natural bentonite sample from Argentina was activated by sulfuric acid in different concentrations (20 and 40 wt%) and different contact time (120 and 210 min), at the same temperature (90 °C) . The ratio of the mass of clay to the volume of acid solution was 1:10 (w/v). These materials were tested to verify its bleaching (decolorization) capacity of soybean oil, which was compared to a standard commercial bleaching material Fulmont Premiere. Differential thermal analysis and thermogravimetric techniques, infrared spectrometry and chemical analysis showed that the acid activation modified the clay material structural properties. Bleaching capacity was found to be dependent on the acid concentration and treatment time used. The activated Argentine material showed superior bleaching performance compared to the commercial clay used by vegetable oil refiners.
bentonite; acid activation; decolorization
