Influence of the preparation parameters (particle size and aluminium concentration) on the textural properties of Al-pillared clays for a scale-up process

In this work, a natural Spanish clay, from La Serreta de Nijar (Almeria), with neither additional refining nor preexchange, was used to study the intercalation of aluminium polymeric species. Successful intercalations were obtained for all the samples, and a slight decrease in textural properties (surface area and pore volumes) for increasing Al and clay concentrations in the final intercalation medium was found. One surface area increase from 85 to 358 m(2) g(-1) was obtained in a preparation using 47 g l(-1) of clay in the final medium and to 245 m(2) g(-1) in the higher concentration of 142.8 g l(-1). The particle size of the clay, up to 320 mu m, showed no influence at all on the final properties of the pillared material. This result is related to the actual structure of the particle formed by aggregates of elemental particles that disintegrates during the intercalation process. The success obtained using big particles of an unmodified natural clay in a very concentrated intercalation medium opens up new possibilities for the industrial application of these types of material. (C) 1998 Elsevier Science B.V. All rights reserved.