Four Layer Complexation Model for Ion Adsorption at Electrolyte/Oxide Interface: Theoretical Foundations

Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

“…Because hydronium has a uniquely high mobility, a factor of ∼ 5 higher than common salt ions, in bulk solutions, it is found that hydronium ions begin to dominate the electrical conductivity when the salt concentration is lower than ∼ 5 × 10 −6 M. Furthermore, hydronium is also known to interact with the confining walls of the electrolyte. For oxide walls, most prominently silica, numerous studies have shown how hydronium affects the electrical properties of the wall-electrolyte interface and leads to a wall surface charge that depends on salt concentration [33][34][35][36][37][38][39][40][41][42][43][44] including our own recent study [26]. Finally, at sufficiently low salt concentration, this surface charge is found to dominate the conductance of electrolyte-filled nanochannels [8,11,19,24,27,28,32,45].…”

“…8 in a recent review paper [2]. However, this is in contrast to the observed nonmonotonic conductance graphs with a minimum, and therefore, we choose to base our analysis on the other well-known class of modeling, where the surface charge is governed dynamically by chemical reaction constants of the proton dissociation processes in the bulk electrolyte and at the wall [26,[32][33][34][35][36][37][38][39][40][41][42][43][44].…”

“…[26,[33][34][35][36][37][38][39][40][41][42][43][44], we model the solid/liquid interface as the layered structure shown in Fig. 1 …”

Interpretation of Chromatographic Retention Based on Electrostatic Theories

“…The G-C and G-C-Stern theory have been successfully utilized not only to electrochemical phenomena but also to electrophoretic behaviors of colloids 11 , membrane separation of ions 29 , and behaviors of ions at surface of metal oxides 14,30 , at ion-exchange resin surface [31][32][33][34][35] , or on the surface membrane. 13,15 However, the applications of these theories to chromatography have been very few.…”

“…This assumption predicts the following strange relation. Assuming that monovalent ions B and C are separated by a monovalent eluent A, a selectivity coefficient between A and C can be written as (14) where capital letters represent concentrations, and A -and C -are the concentrations in a resin phase. A capacity factor for C is represented by (15) where f is a phase ratio.…”