Sorption of Octyl-, Decyl-, and Dodecyltrimethylammonium Cations from Premicellar Solutions onto the Na-Form of Vermiculite

Essential differences were found in the mechanisms of adsorption of trimethyloctylammonium (TMOA), decyltrimethylammonium (DTMA), and dodecyltrimethylammonium (DDTMA) cations from premicellar aqueous solutions of their bromides onto the Na-form of Kovdor vermiculite. It was shown that the non-selective exchange of TMOA cations with sodium ions occurs preferentially at the external surface of the mineral. The adsorption of DTMA occurs by a mixed mechanism: part of its cations substitute the exchangeable Na + ions of the vermiculite, while the other part is sorbed in salt form. The DDTMA cations interact with the vermiculite by an ion-exchange mechanism with almost complete displacement of the Na + ions from the exchange complex of the mineral.