ION-EXCHANGE AND MOLECULAR ADSORPTION OF A CATIONIC SURFACTANT ON CLAY-MINERALS

The adsorption of hexadecylpyridinium chloride (HDPCl) from aqueous solution on to the clay minerals kaolinite, attapulgite, vermiculite, allevardite and monocationic montmorillonites was investigated. The organic ion exchange capacity was determined from the section of the adsorption isotherm characteristic of ion exchange adsorption. The values obtained were found to be related to the structures of the clay minerals. Adsorption of Cl- ions was observed in the section relating to molecular adsorption. The basal plane distances of swelling clay minerals were calculated from X-ray diffraction measurements. Formation of the adsorption layer could be explained by interlamellar expansion. Further, the dispersion properties of the organocomplexes of tenside clay minerals in toluene were investigated. A correlation was established between the swelling, disaggregation and structure-forming properties of the organocomplex dispersed in the organic liquid, and both tenside adsorption and X-ray diffraction data.