Characterization of nanoporous materials prepared from montmorillonite clay and its application to the decolorization of mare's milk oil

Nanoporous materials have been prepared by leaching the purified montmorillonite clay with sulfuric acid (H2SO4) solution with varying concentrations (0.5–2 M) at 80°C for 0.5–4 h. Acid leaching causes partial amorphisation of the clay with depletion of MgO, Al2O3, CaO and Fe2O3 components mostly from interlayer and octahedral sites. This increases the specific surface area by more than 3 times, i.e. from 49.1 to 157 m2/g. The pore-size distribution curves calculated from the adsorption isotherms of the leached montmorillonite show that most of the pores are in the mesoporous region with their diameter ranging 3–4 nm. This material turns out to be appropriate for bleaching of the mare's milk oil. The chemical and structural changes of the acid-leached montmorillonite are discussed in terms of the decolorization capacity.