PREADSORPTION OF ORGANIC-COMPOUNDS ON IRON OXIDE-PILLARED CLAYS

Iron(III) oxide-pillared clays were prepared by a reaction of Na+-montmorillonite with base-hydrolyzed solutions of Fe3+ salts and a subsequent thermal conversion of the intercalated polycations. Those pillared clays have low micropore volumes (0.04 cm(3)/g) and surface areas (95 m(2)/g). The low porosity is due to a high density of Fe pillars between the clay sheets. This disadvantage can be overcome by a preadsorption of amines between the clay sheets prior to pillaring with the iron precursor. As a result, the pillar density decreases because a part of the interlayer space is occupied by the amine. During calcination, the pillaring precursor is converted into rigid iron oxide pillars, and the organic compound is removed. This results in a micropore volume and surface area 2.5 times higher reflecting an important increase of the adsorption capacity.