Adsorption of Dicarbollylcobaltate(III) Anion {(π-(3)-1,2-B9C2H11)2Co(III)−} at the Water/1,2-Dichloroethane Interface. Influence of Counterions' Nature

• Published in: Journal of colloid and interface science 2001-04, Vol.236 (1), p.20-27
• Main Authors: Popov, Alexander, Borisova, Tatjana
• Format: Article
• Language: English
• Subjects: Chemistry; dicarbollylcobaltate(III) anion; drop-volume method; Exact sciences and technology; Gas-liquid interface and liquid-liquid interface; General and physical chemistry; interface adsorption; interfacial tension; monolayer; Surface physical chemistry
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1006/jcis.2000.7339

Interfacial tension has been used to study the adsorption at the water/1,2-dichloroethane interface of dicarbollylcobaltate(III) {(π-(3)-1,2-B9C2H11)2Co(III)−} of the monovalent and bivalent metals. At the limiting coverage, the area per dicarbollylcobaltate(III) anions in the monolayer found experimentally is equal to 95±8 Å2. It can be assumed that the symmetry axis of the adsorbed anions is arranged parallel to the interface surface. By their effects on the surface activity of the dicarbollylcobaltate(III) anions, cations can be arranged in the following order: Mg2+≈Ba2+≈Pb2+≥Li+≈Na+>K+>NH+4>Rb+Tl+≈Ag+≈Cs+. The parameters of Frumkin and the virial isotherms have been calculated. There is a rather strong repulsion among the adsorbed anions. To define the energy of the specific interaction between the anions and the adsorbed monolayer, the technique of E. Goddard et al. (J. Colloid Interface Sci.24, 297 (1967)) was applied. Its application for two-phase systems permits us to define the parameters of the ion exchange reaction on the basis of measurements of interfacial tension. The ion exchange constants calculated by various methods have been compared.