Home >
News > Molecular simulations of a CO₂/CO mixture in MIL-127
Molecular simulations of a CO₂/CO mixture in MIL-127
Summary:
The authors from Chulalongkorn University, University of Leipzig, Vienna Scientific Cluster and collaborating institutes developed the rigid Fe-based MOF MIL-127(Fe) with 5–7 Å channels and 10 Å cages, achieving a CO₂/CO adsorption selectivity of 15 and a predicted membrane selectivity of 12 at 233 K for gas-separation applications.
Background:
1. To address the separation of toxic CO from greenhouse CO₂, previous researchers measured single-gas adsorption isotherms in MIL-127(Fe) but lacked mixture data under technically relevant conditions.
2. The authors proposed an integrated Gibbs-Ensemble Monte Carlo plus Molecular Dynamics strategy to simulate equimolar CO₂/CO mixtures at 233–303 K and ≤12 bar, revealing strong temperature-dependent selectivity.
Research Content:
1. Synthesis: MIL-127(Fe) was computationally constructed from Fe³⁺ nodes and 3,3′,5,5′-azobenzenetetracarboxylate linkers; a 4×4×4 unit-cell supercell was used.
2. Characterizations:
1) BET-equivalent surface area and pore size distribution (5–7 Å channels, 10 Å cages) were extracted from the crystallographic model.
2) “Particle size” corresponds to the 4×4×4 unit-cell box (≈2.5 nm).
3) Radial distribution functions and mean-square-displacement analyses identified preferential adsorption sites (O_D and C_N atoms) and cluster formation of CO₂.
3. Application: GEMC predicted mixture adsorption isotherms; MD derived self-diffusion coefficients for CO₂ and CO at 233, 263 and 303 K; membrane selectivity was calculated as the product of adsorption and diffusion selectivities.
4. Mechanism: The quadrupole moment of CO₂ drives preferential adsorption on O_D/C_N sites; clustering of CO₂ molecules causes fluctuations; diffusion follows Arrhenius behavior with slightly higher mobility for CO.
Outlook:
MIL-127(Fe) is demonstrated as a promising rigid adsorbent/membrane for CO₂/CO separation, especially via low-temperature pressure-swing adsorption (adsorb at <233 K, >6 bar; desorb at >303 K, <0.5 bar).
Molecular simulations of a CO₂/CO mixture in MIL-127
Authors: Tatiya Chokbunpiam, Siegfried Fritzsche, Vudhichai Parasuk, Jürgen Caro, Suttichai Assabumrungrat
DOI: 10.1016/j.cplett.2018.02.032
Link: https://www.sciencedirect.com/science/article/pii/S0009261418301179
The above review is for academic progress sharing. For any errors or copyright issues, please contact us for correction or removal.
