Water-mediated potassium acetate intercalation in kaolinite as revealed by molecular simulation

Abstract

Molecular simulations are suitable tools to study the adsorption and intercalation of molecules in clays. In this work, a recently proposed thermodynamically consistent force field for inorganic compounds (INTERFACE, Heinz H, Lin TJ, Mishra RK, Emami FS (2013) Langmuir 29:1754-1765), which enables accurate simulations of inorganic-organic interfaces, was tested for a two-sheet type clay mineral. All-atom NpT molecular dynamics simulations were used to describe the characteristics (basal spacing, loading, molecular orientation) of some intercalate complexes of kaolinite with potassium acetate and the results were compared with the available experimental data. The most probable structural configurations of the kaolinite/potassium acetate intercalate complexes were determined from the simulations. Our examinations confirmed some supposed (single- or double-layered) arrangements of guest molecules. The need of interlayer water in the intercalate complex, which can be produced by the basic synthesis procedure in air atmosphere, was verified.

Two-Dimensional Ordering of Ionic Liquids Confined by Layered Silicate Plates via Molecular Dynamics Simulation

“…The pressure coupling is semi-isotropic in that only pressures in x-and y-directions are isotropic while different in z-direction. 35 …”

Combined experimental and theoretical investigation of interactions between kaolinite inner surface and intercalated dimethyl sulfoxide

“…To address such issues, molecular dynamics (MD) simulations have become an effective way for the study of interfacial systems by providing the atomic level information in many aspects complementary to the experimental data. To our best knowledge, only a few MD simulation studies have been reported on high polar organics intercalated into the galleries of kaolinite [23][24][25][26][27][28]. However, the kaolinite intercalation complexes in these researches were constructed according to the ideal model system.…”

Simulation study of intercalation complexes of kaolinite with simple amides as primary intercalation reagents

“…For all the amides, we detected a second stable state (type-2) at higher guest molecule contents, but the identification of this state is subject to higher uncertainty. Although the reality of these complexes is still an open question, it is indirectly confirmed by the experimentally proven existence of a second kaolinite intercalation complex with potassium (and also ammonium) acetate [23,25,27].…”

“…Adsorption and intercalation of molecules in clays are effectively studied by means of such techniques [19][20][21][22][23][24], uncovering material features that are currently not available from experiments. In our earlier studies we provided predictions by molecular simulations for intercalation complexes with potassium and ammonium acetates [25][26][27], methanol [28], and cetyltrimethylammonium chloride [29], using the standard allatom force field, CHARMM [30], and its highly realistic extension for kaolinite, INTERFACE [31].…”