Exploring the Potentials of Metal–Organic Frameworks as Adsorbents and Membranes for Separation of Hexane Isomers

Solanki, Vanaraj; Borah, Bhaskarjyoti

doi:10.1021/acs.jpcc.9b03240

Cited by 14 publications

(13 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Comparing with the profiles of n -hexane (Figure ), we can see that the energy barriers for propane are indeed lower than for n -hexane by about 10 kJ/mol, while the locations of the barriers and wells remain the same, which supports our argument. Similar correlations between barrier heights and diffusivities have also been observed in a recent high-throughput screening study on the diffusion of different hexane isomers in a database of MOFs …”

Section: Resultssupporting

confidence: 80%

See 1 more Smart Citation

Understanding the Loading Dependence of Adsorbate Diffusivities in Hierarchical Metal–Organic Frameworks

Chen

Snurr

2020

Langmuir

View full text Add to dashboard Cite

Using atomistic simulations, we studied the diffusion of n-hexane in a series of isoreticular hierarchical metal–organic frameworks (MOFs) NU-100x. Nonmonotonic diffusivity–loading relationships that depend on the pore sizes were observed, which can be explained by the spatial distribution of adsorbates at different loadings. For one of the MOFs in the series, NU-1000-M, the diffusivity–loading relationship is almost identical to the previously reported results of n-hexane diffusion in the hierarchical self-pillared pentasil (SPP) zeolite. Detailed analysis revealed that the similarity results from their similar micropore and window sizes, which was confirmed by free-energy mapping. The effects of temperature and adsorbate chain length on the diffusion were also studied, which supported our conclusion that the diffusivity in hierarchical nanoporous materials is primarily controlled by the sizes of the micropores and the connecting windows, particularly at relatively low loadings.

show abstract

Section: Resultssupporting

confidence: 80%

“…Similar correlations between barrier heights and diffusivities have also been observed in a recent high-throughput screening study on the diffusion of different hexane isomers in a database of MOFs. 55…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Understanding the Loading Dependence of Adsorbate Diffusivities in Hierarchical Metal–Organic Frameworks

Chen

Snurr

2020

Langmuir

View full text Add to dashboard Cite

show abstract

“…Recently, Solanki and Borah screened 4764 MOFs from the Computational Ready Experimental (CoRE) MOF database for separation of hexane isomers, and picked 11 of the most promising MOFs for more detailed pure component diffusivity simulations at infinite dilution to determine kinetic selectivity coefficients [204]. Solanki and Borah found that, among the different MOFs examined, the diffusivities of hexane isomers varied by more than an order of magnitude, indicating large kinetic selectivity to specific isomers.…”

Section: Multicomponent Diffusion In Metal-organic Frameworkmentioning

confidence: 99%

Connecting theory and simulation with experiment for the study of diffusion in nanoporous solids

et al. 2021

View full text Add to dashboard Cite

Nanoporous solids are ubiquitous in chemical, energy, and environmental processes, where controlled transport of molecules through the pores plays a crucial role. They are used as sorbents, chromatographic or membrane materials for separations, and as catalysts and catalyst supports. Defined as materials where confinement effects lead to substantial deviations from bulk diffusion, nanoporous materials include crystalline microporous zeotypes and metal–organic frameworks (MOFs), and a number of semi-crystalline and amorphous mesoporous solids, as well as hierarchically structured materials, containing both nanopores and wider meso- or macropores to facilitate transport over macroscopic distances. The ranges of pore sizes, shapes, and topologies spanned by these materials represent a considerable challenge for predicting molecular diffusivities, but fundamental understanding also provides an opportunity to guide the design of new nanoporous materials to increase the performance of transport limited processes. Remarkable progress in synthesis increasingly allows these designs to be put into practice. Molecular simulation techniques have been used in conjunction with experimental measurements to examine in detail the fundamental diffusion processes within nanoporous solids, to provide insight into the free energy landscape navigated by adsorbates, and to better understand nano-confinement effects. Pore network models, discrete particle models and synthesis-mimicking atomistic models allow to tackle diffusion in mesoporous and hierarchically structured porous materials, where multiscale approaches benefit from ever cheaper parallel computing and higher resolution imaging. Here, we discuss synergistic combinations of simulation and experiment to showcase theoretical progress and computational techniques that have been successful in predicting guest diffusion and providing insights. We also outline where new fundamental developments and experimental techniques are needed to enable more accurate predictions for complex systems.

show abstract

“…The segregation of the MOFs on the basis of hierarchy of adsorption of the hexane isomers is necessary in order to tune the membrane selectivity. In a recent work, we have observed that MOFs that show a normal hierarchy of adsorption are more selective toward the branched alkanes kinetically and vice versa . This leads to low membrane selectivity.…”

Section: Molecular Modeling and Computational Detailsmentioning

confidence: 99%

“…In a recent work, we have observed that MOFs that show a normal hierarchy of adsorption are more selective toward the branched alkanes kinetically and vice versa. 38 This leads to low membrane selectivity. Therefore, the segregation of the MOFs to these two categories of normal hierarchy and reverse hierarchy of adsorption followed by close observation of their structural properties might lead us to a way of tuning the membrane selectivity to a maximum value.…”

Section: ■ Introductionmentioning

confidence: 99%

Ranking of Metal–Organic Frameworks (MOFs) for Separation of Hexane Isomers by Selective Adsorption

Solanki

Borah

2019

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

The work presented in this article is aimed to assess the performances of 4763 Metal−Organic Frameworks (MOFs) for separation of hexane isomers using computer simulation methods. These MOFs, taken from the Computational Ready Experimental (CoRE) MOF database, are ranked on the basis of various performance metrics, namely, adsorption selectivity, working capacity, and regenerability. We investigated six binary mixtures, one three-component equimolar mixture, and one five-component equimolar mixture of hexane isomers at temperatures of 383, 433, 483, and 533 K. The MOFs were ranked separately for separation of each of these mixtures. The rankings with respect to these three metrics were found to be mostly different with only a few MOFs in common. We also carried out the rankings at different temperatures close to the typical isomerization reactor temperature. It is observed that the orders of the rankings at different temperatures are different. However, the majority of the MOFs are found to be common in the rankings at different temperatures. MOFs BIMDOR and WAMRIN01 perform the best with high adsorption selectivity for all the mixtures. It is observed that the MOFs with very high adsorption selectivity do not have high working capacity and regenerability. However, MOFs VEHJOJ, VEHJUP, and NAYGUR are found to be potential candidates for practical application of separation of the hexane isomers as they have regenerability >80% and reasonably high working capacity and adsorption selectivity. Further, we looked at various structures' property correlations. These correlations reveal that the largest cavity diameter and pore volume are crucial structural properties to be adjusted for obtaining the best performing MOF structure with high selectivity, high working capacity, and high regenerability. MOFs with a largest cavity diameter close to 10 Å show high values of selectivity, working capacity, and regenerability.

show abstract

Exploring the Potentials of Metal–Organic Frameworks as Adsorbents and Membranes for Separation of Hexane Isomers

Cited by 14 publications

References 55 publications

Understanding the Loading Dependence of Adsorbate Diffusivities in Hierarchical Metal–Organic Frameworks

Understanding the Loading Dependence of Adsorbate Diffusivities in Hierarchical Metal–Organic Frameworks

Connecting theory and simulation with experiment for the study of diffusion in nanoporous solids

Ranking of Metal–Organic Frameworks (MOFs) for Separation of Hexane Isomers by Selective Adsorption

Contact Info

Product

Resources

About