Specific adsorption of acetate ions at the mercury-lithium acetate (AQ) interface

Abstract

Specific adsorption of acetate ions at the mercury-lithium acetate (aq) interface has been investigated using both differential capacity and electrocapillary measurements. Variation of charge due to surface excess of lithium ions (q+) and of charge due to specifically adsorbed acetate ions (q-1 with electrode charge (qM) have been discussed. Such discussion inferred superequivalent adsorption of acetate ions at all positive charges for concentrations of lithium acetate ≥0.20 M whereas Esin-Markov plots predicted the absence of specific adsorption; the prediction of Esin-Markov plots has been shown to be faulty under certain conditions. The plots of φM-2vs q-1 at constant qM for acetate ion resembled the corresponding plots for F- and BF-4 ions; the slope of these plots is negative up to coverages corresponding to 0.20 M lithium acetate. The identification of the isotherm parameter, (∂φM-2/∂q-1)q with the reciprocal of inner layer capacity at constant charge (-1Ci) has been questioned. © 1978.