TY - JOUR
T1 - Elucidating alkane adsorption in sodium-exchanged zeolites from molecular simulations to empirical equations
AU - García-Pérez, E.
AU - Torréns, I.M.
AU - Lago, S.
AU - Dubbeldam, D.
AU - Vlugt, T.J.H.
AU - Maesen, T.L.M.
AU - Smit, B.
AU - Krishna, R.
AU - Calero, Sofia
PY - 2005/10/31
Y1 - 2005/10/31
N2 - Configurational-bias Monte Carlo (CBMC) simulations provide adsorption isotherms, Henry coefficients and heats of adsorption of linear alkanes in sodium-exchanged MFI- and FAU-type zeolites. These simulations were carried out using our newly developed force field that reproduces experimental sodium positions in the dehydrated zeolites, and successfully predicts alkane adsorption properties over a wide range of sodium cation densities, temperatures, and pressures. We derived empirical expressions from the simulation data to describe the adsorption of linear alkanes in MFI- and FAU-type zeolites. These expressions afford a suitable substitute for complex CBMC simulations. In the low coverage regime we provide simple expressions that adequately describe the Henry coefficient and adsorption enthalpy of n-alkanes as a function of sodium density and temperature. The predicted Henry coefficients and heats of adsorption compare extremely well to available experimental data. In the high coverage regime we provide an expression for saturation capacities of linear alkanes in the zeolite. This expression, combined with the expression for the Henry coefficients, provides of the complete adsorption isotherms of pure adsorbents and mixtures, in good agreement with the adsorption isotherms obtained from CBMC.
AB - Configurational-bias Monte Carlo (CBMC) simulations provide adsorption isotherms, Henry coefficients and heats of adsorption of linear alkanes in sodium-exchanged MFI- and FAU-type zeolites. These simulations were carried out using our newly developed force field that reproduces experimental sodium positions in the dehydrated zeolites, and successfully predicts alkane adsorption properties over a wide range of sodium cation densities, temperatures, and pressures. We derived empirical expressions from the simulation data to describe the adsorption of linear alkanes in MFI- and FAU-type zeolites. These expressions afford a suitable substitute for complex CBMC simulations. In the low coverage regime we provide simple expressions that adequately describe the Henry coefficient and adsorption enthalpy of n-alkanes as a function of sodium density and temperature. The predicted Henry coefficients and heats of adsorption compare extremely well to available experimental data. In the high coverage regime we provide an expression for saturation capacities of linear alkanes in the zeolite. This expression, combined with the expression for the Henry coefficients, provides of the complete adsorption isotherms of pure adsorbents and mixtures, in good agreement with the adsorption isotherms obtained from CBMC.
KW - CBMC
KW - Empirical equations
KW - Molecular simulations
UR - http://www.scopus.com/inward/record.url?scp=26444527351&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2005.02.103
DO - 10.1016/j.apsusc.2005.02.103
M3 - Article
AN - SCOPUS:26444527351
SN - 0169-4332
VL - 252
SP - 716
EP - 722
JO - Applied Surface Science
JF - Applied Surface Science
IS - 3
ER -