ADSORPTION OF NITROBENZENE AND N-PENTANOL FROM AQUEOUS-SOLUTION ON HYDROPHILIC AND HYDROPHOBIC CLAY-MINERALS

The sorption of nitrobenzene and n-pentanol from dilute aqueous soluti on on swelling clay minerals and their organophilized derivatives (org ano clays) was studied. Adsorption excess isotherms were obtained by t he immersion method. The basal spacings of the clay minerals were dete rmined by X-ray diffraction measurements. By combining these two indep endent methods, composition and structure of the interlamellar space c ould be calculated. On the hydrophilic surface of montmorillonite nega tive adsorption of the organic component was observed at low molar fra ctions of nitrobenzene or pentanol, i.e., water was preferentially ads orbed. On organophilized montmorillonite and vermiculite adsorption of nitrobenzene and pentanol was positive over the whole range of liquid composition. The amount of interlamellar alkyl chains which is determ ined by the Surface charge of clay mineral inversely affected the adso rption of both solutes.