Evolution of surface properties in a bentonite as a function of acid and heat treatments

Abstract

Abstract The evolution of surface properties, such as surface acid centres, porosity and specific surface area, in a bentonite from Almería (Spain) after acid and heat treatments (0.25–2.00 N H 2 SO 4 and 110–40°C) has been studied. The samples were characterized by mercury porosimetry and by X‐ray diffraction. The number of surface acid centres and micropore volume increase as the concentration of H 2 SO 4 used in the acid activation increases. Surface area has been determined from N 2 adsorption isotherms at 77.4K by applying the BET equation. Surface area values range from 88 m 2 g −1 to 292 m 2 g −1 , depending on the concentration of H 2 SO 4 used in the acid activation, the maximum value corresponding to the sample activated with 2.00 N H 2 SO 4 and heated at 100°C.