Mixed gas adsorption of carbon dioxide and methane on a series of isoreticular microporous metal–organic frameworks based on 2-substituted imidazolate-4-amide-5-imidates

Abstract

In this work the adsorption of CO 2 and CH 4 on a series of isoreticular microporous metal-organic frameworks based on 2-substituted imidazolate-4-amide-5-imidates, IFP-1-IFP-6 (IFP ¼ Imidazolate Framework Potsdam), is studied firstly by pure gas adsorption at 273 K. All experimental isotherms can be nicely described by using the Toth isotherm model and show the preferred adsorption of CO 2 over CH 4 . At low pressures the Toth isotherm equation exhibits a Henry region, wherefore Henry's law constants for CO 2 and CH 4 uptake could be determined and ideal selectivity a CO 2 /CH 4 has been calculated. Secondly, selectivities were calculated from mixture data by using nearly equimolar binary mixtures of both gases by a volumetric-chromatographic method to examine the IFPs. Results showed the reliability of the selectivity calculation. Values of a CO 2 /CH 4 around 7.5 for IFP-5 indicate that this material shows much better selectivities than IFP-1, IFP-2, IFP-3, IFP-4 and IFP-6 with slightly lower selectivity a CO 2 /CH 4 ¼ 4-6. The preferred adsorption of CO 2 over CH 4 especially of IFP-5 and IFP-4 makes these materials suitable for gas separation application.

In situ synthesis of amide-imidate-imidazolate ligand and formation of metal-organic frameworks: Application for gas storage

“…Therefore, the Co centres in IFP-10 have a higher potential to polarize CO 2 molecules than the Zn based IFP-9. This behavior was previously also observed for the Co-based isostructural IFP-5 [41,46].…”

“…Additionally, binary adsorption was predicted using the IAST (Ideal Absorbed Solution Theory) in comparison with the pure gas adsorption Tóth isotherm model for spreading pressure calculations [46]. The partial molar loadings are given in Fig.…”

Study of the Discrepancies between Crystallographic Porosity and Guest Access into Cadmium–Imidazolate Frameworks and Tunable Luminescence Properties by Incorporation of Lanthanides

“…To investigate the adsorption properties at higher pressures, CO 2 and CH 4 adsorption isotherms on IFP‐1 and IFP‐6 were reported at 273 K up to 50 bar . A significant amount is adsorbed by IFP‐6 at high pressure; this is comparable to IFP‐1.…”

“…To investigate the adsorption properties at higherp ressures, CO 2 and CH 4 adsorption isotherms on IFP-1 and IFP-6 were reporteda t2 73 Ku pt o5 0bar. [27] As ignificant amount is adsorbedb yI FP-6 at high pressure;t his is comparable to IFP-1. Interestingly,I FP-6 maintained crystallinity after high-pressure gas uptake (Figure 2), whereas at least part of the IFP-6f ramework broke down during the activation process to create an instabilityo ft he surface.…”

Controlled synthesis of conjugated polycarbazole polymers via structure tuning for gas storage and separation applications

“…The CO 2 or CH 4 uptake shows a almost linear increase with the increasing pressure, whereas that of nitrogen has no apparent increase trend (ESI, Figure S10 ). From the available single-gas adsorption isotherms, the selectivity in the adsorption of CO 2 , CH 4 and N 2 from CO 2 -N 2 , CO 2 -CH 4 , and CH 4 -N 2 gas mixtures was estimated by Ideal Adsorption Solution Theory (IAST), which has been widely used to predict gas mixture adsorption behavior in the porous materials 52 , 53 . Under simulated flue gas streams (typically 15% CO 2 and 85% N 2 ), N 4 CMP-3 exhibits the highest selectivity for CO 2 /N 2 among the five polymers (53.8 at 273 K and 1.05 bar) (Fig.…”