Analysis of Equilibrium Electrocapillary Curves at the Interface between Hydrophobic Ionic Liquid, Trioctylmethylammonium Bis(nonafluorobutanesulfonyl)amide, and Aqueous Lithium Chloride Solutions

• Published in: Journal of chemical and engineering data 2010-10, Vol.55 (10), p.4463-4466
• Main Authors: Yasui, Yukinori, Kitazumi, Yuki, Nishi, Naoya, Kakiuchi, Takashi
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Gas-liquid interface and liquid-liquid interface; General and physical chemistry; Surface physical chemistry
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je100607w

Electrocapillary curves obtained under the thermodynamic equilibrium at the interface between trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide and aqueous lithium chloride have been analyzed to study the adsorption of Li+ and Cl− ions at the interface. The specific adsorption of Li+ and Cl− is negligible in almost the entire range of the polarized potential window. At the positive extreme where the excess surface charge density is greater than 3 μC·cm−2, the deviation of the experimental relative surface excesses of Li+ and Cl− from the Gouy’s theory was detected. This deviation suggests the coordination of adsorbed bis(nonafluorobutanesulfonyl)amide to Li+ in the aqueous side of the interface. The double layer capacitance on the ionic liquid side of the interface is deduced to be 125 μF·cm−2 at the potential of zero charge.