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Direct Simulation of Ternary Mixture Separation in a ZIF‐8 Membrane at Molecular Scale
Author(s) -
Namsani Sadanandam,
Ozcan Aydin,
Yazaydın A. Özgür
Publication year - 2019
Publication title -
advanced theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.068
H-Index - 17
ISSN - 2513-0390
DOI - 10.1002/adts.201900120
Subject(s) - chemistry , ternary operation , molecular dynamics , membrane , selectivity , thermodynamics , diffusion , separation process , chromatography , computational chemistry , catalysis , organic chemistry , biochemistry , physics , computer science , programming language
Separation of H 2 in a ZIF‐8 membrane from a syngas mixture composed of CO 2 , H 2 , and N 2 at 300 K and 35 atm is simulated with the concentration gradient driven molecular dynamics (CGD‐MD) method. Steady‐state fluxes are computed to predict the H 2 selectivity of the ZIF‐8 membrane using four different flexible force fields developed for ZIF‐8. The permselectivities predicted by the CGD‐MD method are compared with those obtained from the grand canonical Monte Carlo+equilibrium molecular dynamics (GCMC+EMD) approach, which is based on the solution‐diffusion model and widely used to predict permselectivities for mixture separations. The permselectivities obtained by using the CGD‐MD method accurately predict that ZIF‐8 is H 2 selective over CO 2 and N 2 . On the other hand, permselectivities predicted with the GCMC+EMD approach are found to be incorrect, that is, ZIF‐8 not selective for H 2 . The study suggests that a reliable non‐equilibrium molecular dynamics approach should be employed in order to obtain accurate predictions for the permselectivity of a membrane for a multicomponent mixture separation process which happens at moderate or high pressure conditions.