Adsorption and Kinetic Studies of the Intercalation of Some Organic Compounds onto Na+-Montmorillonite

The adsorption and the kinetics of the intercalation of metanil yellow dye, p-aminodiphenylamine (p-NH2-DPA), and benzidine by colloidally dispersed Na+-montmorillonte (Na+-MMT) have been studied. The adsorption isotherm parameters confirmed the occurrence of chemical adsorption that is based on the cation-exchange process. The selectivity of these compounds toward Na+-MMT follows the order metanil yellow p-NH2-DPA>benzidine. The rate of oxidation has been quantitatively measured using a stopped-flow spectrophotometer. The rate constant follows the order benzidineallyle acetate shows inhibiting effect on the reaction rate. The rate of cation exchange process between the radical cation of the organic molecule and the Na+-ion in the Na+-MMT has been monitored by using the stopped-flow instrument with an electrical conductivity detection unit. The activation energy of the electron transfer reaction is less than that of cation exchange process and has the order metanil yellowbenzidine. X-ray diffraction, IR, and differential scanning colorimetry (DSC) measurements confirmed the intercalation process.