Characterisation of acid activated montmorillonite clay from Tuulant (Mongolia)

The characteristics of an acid-leached montmorillonite-containing clay from Tuulant (Mongolia) were studied by XRD, DTA-TG, FTIR and N2 adsorption techniques. Sample aliquots (2 g) were treated with 50 ml 2 M hydrochloric acid at 80 °C for various times. Leaching caused the surface area of the clay to increase 3-fold to 93.9 m2/g reflecting the formation in the porous silica product of 3–5 nm micropores and 6–10 nm mesopores, the latter resulting from a delaminated card-house structure rather than from the condensation of the micropores. Differences between the surface area of the present leached samples and those reported for other montmorillonite clays reflect the mineralogical composition of the clay, particularly the presence of non-clay constituents.