Acid Activation and Bleaching Performance of Turkish (Somas) Bentonite in Crude Soybean Oil

In this work, a bentonite clay from Turkey (Somas bentonite) was activated with different concentrations of H2SO4 and HCl at 70°–90°C and 5–8 h. Under these conditions several cations were removed from natural bentonite (Al, Mg, and Fe) and DTA-TGA and FT-IR curves of the solids obtained after acid treatment were examined. Treatment time and acid concentration increased the degree of destruction of the bentonite structure, which was determined by ICP. The specific surface area (S) and mesopore size distribution (PSD) of the samples were determined. Activated samples were tested in order to verify their capacity to bleach soybean oil and compared to standard commercial bleaching clays. The experimental results indicate that samples treated with H2SO4 show the same efficiency in bleaching crude soybean oil with the standards, and the sample treated with HCl is more efficient in bleaching than the commercial products. PSD values are mainly distributed between 7 and 60 Å, similar to standard commercial bleaching clays.

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