Theoretical Evaluation of Pillared Clay Adsorbents: Part III: The Total Porosity and the Macrostructure of Al-Pillared Montmorillonite and Hectorite

As a new class of porous materials, pillared clays have been more and more investigated as a potential substituent or complement to zeolite materials. Despite of intensive research, real industrial applications are still lacking. Somehow, the porosity of these materials is lower than what was expected. To evaluate the potential of the pillared clays as adsorbent, theoretical calculations were carried out to obtain a better insight of the influence of the PILC's macrostructure on the micro-and mesoporosity. Assuming the layers to stack in a 3-dimensional brick-like fashion, the micro-and mesoporosity and interpillar free distance were calculated taking into account: the clay layer dimensions, interlayer free spacing, lateral distance between adjacent layers, partial pillaring/collapse and pillar symmetry. The calculations were performed for Al-pillared montmorillonite and hectorite and validated with experimental results.