STUDY OF POROUS STRUCTURE OF PILLARED CLAYS - 1 - MONTMORILLONITE FIXED BY CHROMIUM(III) OXIDE

The porous structure of montmorillonite fixed by chromium oxide was st udied by nitrogen, water vapor, and benzene adsorption. The adsorption data obtained were analyzed in detail by the alpha(s)-method and the theory of volume filling of micropores. The fixation of acid-treated m ontmorillonite K10 by hydroxochromium cations resulted in the formatio n of the pillared clay with considerable mesoporosity. Additional micr opores appeared, and new polar adsorption sites were formed. The role of new absorption sites belongs to hydroxochromium cations or chromium oxide clusters localized in the interlayer space of the pillared clay . A microporous material was found to be formed mostly by the fixation of Oglanli bentonite. The calcination of the synthesized pillared cla ys at 673 K resulted in an increase in the average width of their micr opores and mesoporosity. The porous montmorillonite structure fixed by chromium oxide can be purposefully formed using clays of different ch emical composition and physical and chemical properties.