Prediction of K-Ca-Mg ternary exchange from binary isotherms in volcanic soils using the Rothmund-Kornfeld approach

Abstract

The Gaines-Thomas formulation of the Rothmund-Kornfeld equation was used to predict the K-Ca-Mg exchange in variable surface charge soils. Binary and ternary equilibria were carried out at 25°C and at constant ionic strength of 0.050 mol/L. The selectivity sequence K > Ca > Mg was observed in binary isotherms. The experimental ternary isotherms are well described from binary data. When experimental v. calculated equivalent fractions were plotted, slopes between 0.901 and 1.051, and correlations between 0.970 and 0.986, were obtained. The design used assures in volcanic soils that no, or minor, changes in surface charge, cation exchange capacity, and selectivity occur, but the predicted ternary values are restricted to the same binary experimental conditions employed.

Disposal of domestic sludge and sludge ash on volcanic soils

“…The leaching of exchangeable bases behaves as predicted by cation exchange selectivity previously reported [17]. Phosphate is leached in very low amounts (<0.1%), even though sewage sludge and sludge ash present large P contents; this is due to the specific PO 4 adsorption, which is a characteristic of Chilean volcanic soils [12].…”

Compositional constraints to identifying ternary interactions in ion‐exchange equilibria

“…One method that can eliminate compositional incoherence is to use log-ratio models as used for illite previously (Reynolds, 2015). The Rothmund-Kornfeld model is also widely applied to ion-exchange thermodynamics and is a type of log-ratio model (Bond, 1995;Bond & Verberg, 1997;Rad & Towfighi, 2020;Reynolds, 2015;Escudey et al, 2002;Yakubu & Agbenin, 2010).…”

A Rothmund–Kornfeld model of Cs+–K+–Na+ exchange on spherical resorcinol-formaldehyde (sRF) resin in Hanford nuclear waste

“…They found that the Rothmund-Kornfeld model was the most effective of those available for a wide range of ions and resins. The Rothmund-Kornfeld model continues to be used extensively [23][24][25][26][27][28][29][30][31]. The Rothmund-Kornfeld model predicts the logratio of the ions in one phase from the log-ratio of the ions in another phase.…”