CO2 adsorption in mono-, di- and trivalent cation-exchanged metal-organic frameworks a molecular simulation study

CO2 adsorption in mono-, di- and trivalent cation-exchanged metal-organic frameworks : a molecular simulation study

© 2012 American Chemical Society

Bibliographische Detailangaben
Veröffentlicht in:Langmuir : the ACS journal of surfaces and colloids. - 1992. - 28(2012), 8 vom: 28. Feb., Seite 3903-10
1. Verfasser: Chen, Y F (VerfasserIn)
Weitere Verfasser: Nalaparaju, A, Eddaoudi, M, Jiang, J W
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2012
Zugriff auf das übergeordnete Werk:Langmuir : the ACS journal of surfaces and colloids
Schlagworte:Journal Article
Beschreibung
Zusammenfassung:© 2012 American Chemical Society
A molecular simulation study is reported for CO(2) adsorption in rho zeolite-like metal-organic framework (rho-ZMOF) exchanged with a series of cations (Na(+), K(+), Rb(+), Cs(+), Mg(2+), Ca(2+), and Al(3+)). The isosteric heat and Henry's constant at infinite dilution increase monotonically with increasing charge-to-diameter ratio of cation (Cs(+) < Rb(+) < K(+) < Na(+) < Ca(2+) < Mg(2+) < Al(3+)). At low pressures, cations act as preferential adsorption sites for CO(2) and the capacity follows the charge-to-diameter ratio. However, the free volume of framework becomes predominant with increasing pressure and Mg-rho-ZMOF appears to possess the highest saturation capacity. The equilibrium locations of cations are observed to shift slightly upon CO(2) adsorption. Furthermore, the adsorption selectivity of CO(2)/H(2) mixture increases as Cs(+) < Rb(+) < K(+) < Na(+) < Ca(2+) < Mg(2+) ≈ Al(3+). At ambient conditions, the selectivity is in the range of 800-3000 and significantly higher than in other nanoporous materials. In the presence of 0.1% H(2)O, the selectivity decreases drastically because of the competitive adsorption between H(2)O and CO(2), and shows a similar value in all of the cation-exchanged rho-ZMOFs. This simulation study provides microscopic insight into the important role of cations in governing gas adsorption and separation, and suggests that the performance of ionic rho-ZMOF can be tailored by cations
Beschreibung:Date Completed 13.06.2012
Date Revised 28.02.2012
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1520-5827
DOI:10.1021/la205152f