A model for ion transfer through liquid|liquid interfaces

Abstract

Using a lattice-gas model we calculate the potential of mean force experienced by a single ion in the vicinity of a liquid|liquid interface. Typically, this potential exhibits both a maximum and a minimum; ion transfer is therefore an activated process involving the transfer over a barrier. An explicit expression for the rate constant is derived. Model calculations show that in most situations the reaction will follow a Butler-Volmer type law. Double layer corrections are shown to be inappropriate.