Is there really any special influence of lithium ion on the specific adsorption of anions at the mercury—aq. Solution interface?

Abstract

Specific adsorption of chloride ions at the mercury—LiCl(aq) interface has been studied through both differential capacity and electrocapillary measurements in order to investigate whether there is really any special role of lithium ion in the double layer as reported by Barradas and Herrman. Electrocapillary data were obtained by maximum “bubble” pressure method, which being independent of contact angle guaranteed accurate values. A comparison of q + vs q M plots has been made with the corresponding plots of Barradas and Herrman. The large discrepancy between the two plots observed at lower concentrations and positive charges, has been attributed to the error in measurement of interfacial tensions by Barradas and Herrman, owing to the development of a contact angle between glass and mercury inside the straight capillary of the electrometer. q + and q −1 data for 0.10 m LiCl (present work) agreed with the corresponding data for 0.10 m KCl obtained by Grahame and Soderberg within the error limits of evaluation of these parameters. Constant charge isotherms for LiCl are exactly similar to those for KCl. Finally, it has been concluded that the specific adsorption of anions is independent of the nature of cation present when the cationic specific adsorption is negligible and that there is no special role of lithium ion on specific adsorption of anions.