Modeling of cesium transport through sand-bentonite mixtures

Abstract

The sorption and transport of Cs through mixture of Ca/Mg-bentonite and sand have been studied using five column experiments with different bentonite/sand ratio, initial Cs concentration and column height. For comparison the batch experiments with small m/V ratio and high Cs concentration were performed. The results showed that Cs removal from aqueous solution by bentonite is controlled by ion-exchange reaction between Cs and Ca/Mg initially sorbed on bentonite and that there is a consistency between the results obtained from batch equilibrium data and the results obtained from column experiments verified in the environment of PHREEQC.

Investigations of the Fundamental Surface Reactions Involved in the Sorption and Desorption of Radionuclides

“…Most of the researchers report us ing linear adsorption isotherm models [12] [10] [17] but som e employed nonlinear adsorption isotherm (Langmuir and Freundlich isotherms) [14] [15]. Few have studied the sp ecific radionuclide transport and adsorption on Nevada test soil despite the need for info rmation for the Nevada Test Site regulatory.…”

“…The aim of this study was to perf orm laboratory experiments using NTS soil and t o incorporate an "Advective Dispersion React ive model" [10] [24] [17] along with…”

“…The sorption and ion-exchange are class ified under heterogeneous class of reactions or (17) This sorption mechanism slows the contam inate transport through porous m edium. It is assumed that the concen tration of the solute in the liqu id phase is in eq uilibrium with solid phase.…”

“…The uniqueness of this model is that it readily couples a nonlinear adsorption isotherm with the "advective dispersion transport equation" which is an improvement over the lim itation constrained to line ar adsorption [12][10] [17].…”

Uptake of Ce(III) and Ce(IV) on montmorillonite

“…Pb, Cd, Zn), cationic pollutants (e.g. dyes) from various wastes as well as for retention of RE, clay minerals were also used (Torstenfelt et al, 1982;Weiss et al, 1998;Kraus et al, 2006;Bergaya et al, 2006aBergaya et al, , 2006bKlika et al, 2007Klika et al, , 2011Vopálka et al, 2015). Uptake and factors influencing retention of La, Ce, Sm, Gd, Er, and Y on montmorillonite were investigated and it was found that montmorillonite in aqueous dispersion modifies their pH and therefore the precipitation of RE(III) hydroxides begins already at pH 5 (Bruque et al, 1980).…”