Understanding and Exploiting Window Effects for Adsorption and Separations of Hydrocarbons

Luna-Triguero, Azahara; Vicent-Luna, José Manuel; Dubbeldam, David; Gómez‐Álvarez, Paula; Calero, Sofı́a

doi:10.1021/acs.jpcc.5b05597

Cited by 18 publications

(43 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this study, we made use of the force field developed by the group of Sofia Calero to accurately describe vapor–liquid curves for alkanes and alkenes. As it has been successively tested in GCMC simulations of adsorption of hydrocarbons for a wide range of zeolites and MOFs, − we do not anticipate our choice of force field to be the source of significant differences between calculated and measured uptakes. We therefore attribute such differences to the nonrealistic, ideal structure of the Zr-fumarate-MOF used in the first set of GCMC calculations.…”

Section: Resultsmentioning

confidence: 99%

Role of Structural Defects in the Adsorption and Separation of C3 Hydrocarbons in Zr-Fumarate-MOF (MOF-801)

et al. 2019

View full text Add to dashboard Cite

An effective separation of propylene/propane mixtures is one of the most important processes in the petrochemical industry. Incidentally this separation is challenging due to the extensive similarities between both gases in terms of physicochemical properties such as, but not only limited to, boiling point, kinetic diameter and molecular weight. A drive to switch to less energy consuming processes, like adsorption or membrane separation, has highlighted several microporous metal organic frameworks as promising materials. In this work, we present a combined numerical and experimental investigation on propane and propylene adsorption in Zr-fumarate-MOF (also known as MOF-801), a small pore isoreticular analogue of UiO-66. Here, we demonstrate how the presence of structural defects can completely change the sorptive properties and separation performance of the Zr-fumarate-MOF, with enhanced capacity and gas diffusion rates for C3-sized hydrocarbons at the cost of kinetic selectivity. Extensive GCMC simulations performed on mixed defective supercells show that a percentage of missing cluster defects of around 1/8 th can best account for the experimental results. Furthermore, analysis of low-frequency phonon spectra is used to explain gaseous diffusion in the original pristine material. A slight preference for propane over propylene is highlighted in the defective sample, and confirmed through column breakthrough experiments, suggesting the potential applicability of the Zr-fumarate-MOF in this challenging separation. File list (3) download file view on ChemRxiv manuscript.pdf (3.98 MiB) download file view on ChemRxiv manuscript-SI.pdf (3.63 MiB) download file view on ChemRxiv structures.zip (60.21 KiB)

show abstract

Section: Resultsmentioning

confidence: 99%

Role of Structural Defects in the Adsorption and Separation of C3 Hydrocarbons in Zr-Fumarate-MOF (MOF-801)

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The relative stability of the two phases critically depends on the VDW parameters, and the MM3 dispersion interaction has the tendency to overstabilize the np phase. Una-Triguero et al [427] studied a similar breathing effect of ZJU-198 MOF. They predicted a structural phase transition from a np to a lp phase upon the adsorption of acetylene, ethene, and carbon dioxide.…”

Section: Mof Force Fieldsmentioning

confidence: 99%

Design, Parameterization, and Implementation of Atomic Force Fields for Adsorption in Nanoporous Materials

Dubbeldam

Walton

Vlugt

et al. 2019

Advcd Theory and Sims

View full text Add to dashboard Cite

Molecular simulations are an excellent tool to study adsorption and diffusion in nanoporous materials. Examples of nanoporous materials are zeolites, carbon nanotubes, clays, metal-organic frameworks (MOFs), covalent organic frameworks (COFs) and zeolitic imidazolate frameworks (ZIFs). The molecular confinement these materials offer has been exploited in adsorption and catalysis for almost 50 years. Molecular simulations have provided understanding of the underlying shape selectivity, and adsorption and diffusion effects. Much of the reliability of the modeling predictions depends on the accuracy and transferability of the force field. However, flexibility and the chemical and structural diversity of MOFs add significant challenges for engineering force fields that are able to reproduce experimentally observed structural and dynamic properties. Recent developments in design, parameterization, and implementation of force fields for MOFs and zeolites are reviewed.contain silicon and oxygen. They are readily available, very stable, and relatively cheap. The material should have the right combination of high adsorption selectivity, combined with adequate capacity for use in fixed-bed devices. Recently, new classes of nanoporous materials have been designed that have stability, high void volumes, and well defined tailorable cavities of uniform size. Example are metal-organic frameworks (MOFs), [1][2][3][4][5][6][7] covalent organic frameworks (COFs), [8,9] and zeolitic imidazolate frameworks (ZIFs). [10] These novel materials posses almost unlimited structural variety because of the many combinations of building blocks that can be imagined. The building blocks self-assembly during synthesis into crystalline materials that, after evacuation of the structure, can find applications in adsorption separations, air purification, gas storage, chemical sensing, and catalysis. [4,11] The judicious selection of building blocks allows the pore volume and functionality to be tailored in a rational manner. Because of the designprinciple underlying the synthesis, it is important to understand structure-properties relations, such as the mechanisms of gas separation as a function of shape and size of the pore system, in order to create "blueprints to MOF-design." Computer simulation is cost-effective, fast, and allows for rapid identification of important structural parameters affecting adsorption.Most of the published works on molecular simulation studying zeolites have used the Kiselev model. [12] In this model, zeolite atoms are fixed and interactions of guest atoms with silicon atoms is accounted for by an effective interaction only with the surrounding oxygen atoms. Interactions between sorbate molecules and the host are modeled by placing Lennard-Jones sites and partial charges on all framework atoms and sorbate molecules. The Kiselev model is attractive because of its simplicity and computational efficiency. This model has shown significant success, both in using the molecular dynamics method to compute, for example, the diffu...

show abstract

“…It is vital to understand many related processes from scientific concepts to the industrial application to carry out deep molecular level characterization to the adsorption phenomenon in the nanopores. In this respect, molecular simulation is a powerful tool, which can be used to conduct detailed research to the molecular arrangement of the confined fluid . Jaramillo et al developed and performed a brand new force field to simulate the dynamics of HFCs in faujasite-type zeolites at the same time.…”

Section: Introductionmentioning

confidence: 99%

Competitive Adsorption Mechanism Study of CHClF₂ and CHF₃ in FAU Zeolite

Qin

Zhang

et al. 2018

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Separating and recovering CHF3 and CHClF2 greenhouse gases from exhausted gases is quite important for avoiding adverse impacts to the environment. In synthesizing chlorofluorocarbons substitutes, faujasite (FAU) is proved to be effective in separating the hydrofluorocarbons. Grand canonical ensemble Monte Carlo simulations were used without precedent in analyzing the competitive adsorption mechanism of CHF3/CHClF2 in Na58Al58Si134O384 (58Al), Na88Al88Si104O384 (88Al), and Na96Al96Si96O384 (96Al) FAU zeolite model from infinite dilution to saturation adsorption, so as to explore the overall competitive relationship as the adsorption amount increases. As a result, it has been found that the sodium migration degree is affected by the guest–host effect in the 58A1 model. However, the sodium migration is not discovered in 88Al and 96Al models with diversified CHF3 or CHClF2 loadings. The preferred binding site in all FAU zeolite models involves CHClF2 and CHF3 anchored by cations in sites II and site III′. Adsorption enthalpy predicted is highly correlated upon the adsorption site and the geometry structure of CHClF2 and CHF3 in FAU zeolite. The CHF3 molecule is preferentially adsorbed via the short-range force of its hydrogen center with the lattice oxygens of the FAU supercage. In addition, the CHF3 selectivity would be enhanced to a certain degree with ratios of Si/Al and adsorption temperatures being lowered. Through this computational study, the inherent competitive adsorption mechanism at the molecular level is clearly illustrated, thus providing an effective strategy of designing and screening adsorptive materials, so as to have a better separation and recovery of CHF3–CHClF2.

show abstract

Understanding and Exploiting Window Effects for Adsorption and Separations of Hydrocarbons

Cited by 18 publications

References 29 publications

Role of Structural Defects in the Adsorption and Separation of C3 Hydrocarbons in Zr-Fumarate-MOF (MOF-801)

Role of Structural Defects in the Adsorption and Separation of C3 Hydrocarbons in Zr-Fumarate-MOF (MOF-801)

Design, Parameterization, and Implementation of Atomic Force Fields for Adsorption in Nanoporous Materials

Competitive Adsorption Mechanism Study of CHClF₂ and CHF₃ in FAU Zeolite

Contact Info

Product

Resources

About

Understanding and Exploiting Window Effects for Adsorption and Separations of Hydrocarbons

Cited by 18 publications

References 29 publications

Role of Structural Defects in the Adsorption and Separation of C3 Hydrocarbons in Zr-Fumarate-MOF (MOF-801)

Role of Structural Defects in the Adsorption and Separation of C3 Hydrocarbons in Zr-Fumarate-MOF (MOF-801)

Design, Parameterization, and Implementation of Atomic Force Fields for Adsorption in Nanoporous Materials

Competitive Adsorption Mechanism Study of CHClF2 and CHF3 in FAU Zeolite

Contact Info

Product

Resources

About

Competitive Adsorption Mechanism Study of CHClF₂ and CHF₃ in FAU Zeolite