Potentially Exploitable Base-Metal Containing Bentonite Clay Minerals of Ibeshi-Ikorodu South-Western Nigeria for Oil Bleaching

The experiment has been undertaken to evaluate the bleaching capacity of Ibeshi Montmorillonite-Bentonite clay to be used on soya bean oils (edible oils). The clay capacity for bleaching was evaluated before and after acid activation processes. The acid-activated Bentonite was prepared from raw Bentonite with sulphuric acid of concentrations 6 M, 7 M, and 8 M; this is because availability of hydrogen is a competitor at ions exchange site. Acid activation promotes catalytic activities by increasing the number of active sites of the clay samples. The results from AAS, GC-MS analysis and the spectra of the raw clay indicated that the dominant components present were Al2O3, MgO, CaO, Na2O, and K2O together with Fe2O3, TiO2, MnO2 and P2O5. The ratio of Na2O:CaO is 0.24-0.30, a value less than one, indicative the presence of montmorillonite, and the SiO2 : Al2O3 between ratio of 1.12-1.50 greater than one. The optimum acid concentration for industrial bleaching is 6 M H2SO4. However, the exchange capacity was observed at pH 7. The work has shown that activated montmorillonite/Bentonite clay has other useful organic compounds such as organic complexes 2, 4-Nonadienal; up to 8% α-Tocopherol. Tests for bleaching performance evaluation confirmed that the clay has moderately bleaching action as shown by percentage colour reduction. The colour reduction for natural clay was 9.1%, this value increases to 27.3% after 8M H2SO4 activation. Other properties include the structural characteristics, free fatty acid value, viscosity were also recorded. The availability of Bentonite across Nigeria makes it a potential industrial mineral for the economy development.Keyword: Bentonite, clay, dominant, components, acid-activate