Effect of Si/Al Ratio in the Faujasite Structure on Adsorption of Methane and Nitrogen: A Molecular Dynamics Study

Moradi, Hojatollah; Azizpour, Hedayat; Bahmanyar, Hossein; Rezamandi, Nariman; Zahedi, Payam

doi:10.1002/ceat.202000356

Cited by 13 publications

(10 citation statements)

References 43 publications

(45 reference statements)

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“…225,226 Azizpour and co-workers studied the inuence of the Si/Al ratios in the FAU zeolite on the adsorption of CH 4 and N 2 and discovered that the adsorption capacity towards CH 4 was improved by decreasing the Si/Al ratios because of the formation of more acid sites in the Al-rich FAU zeolite. 227 As mentioned above, high-silica zeolite is hydrophobic and has the ability to adsorb organic compounds. 228 For example, ZSM-5 zeolite has the ability to adsorb methyl tert-butyl ether (MTBE) from water and the distribution coefficient K d is improved by increasing the Si/Al ratios.…”

Section: Methods For Determining the Si/al Ratios Of Zeolitesmentioning

confidence: 99%

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Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties

Gao

2023

Chem. Sci.

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Section: Methods For Determining the Si/al Ratios Of Zeolitesmentioning

confidence: 99%

“… 225,226 Azizpour and co-workers studied the influence of the Si/Al ratios in the FAU zeolite on the adsorption of CH 4 and N 2 and discovered that the adsorption capacity towards CH 4 was improved by decreasing the Si/Al ratios because of the formation of more acid sites in the Al-rich FAU zeolite. 227 …”

Section: Regulation Of the Si/al Ratios Of Zeolitesmentioning

confidence: 99%

Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties

Gao

2023

Chem. Sci.

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“…Generally, a lower Si/Al ratio is preferable since it increases the cation content because more Al atoms are substituted into the framework, thus enhancing the adsorption ability [53]. For example, Moradi et al [54] investigated the efect of Si/Al ratio in a faujasite structure on the adsorption of CH 4 . Tey observed an improvement in the CH 4 adsorption capacity when the Si/Al ratio was reduced from 3 to 1.…”

Section: Si/almentioning

confidence: 99%

The Production of Industrial-Grade Oxygen from Air by Pressure Swing Adsorption

Chin

Kamin

Bahrun

et al. 2023

International Journal of Chemical Engineering

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Oxygen, an odorless and colorless gas constituent of the atmosphere, is a vital gas component for the Earth, as it makes up 21% of the composition of the air we breathe. Apart from the importance of oxygen for human breathing, its highly pure form is demanding for industrial applications. As such, several technologies have been established to increase the oxygen purity from 21% to somewhat higher than 95%. One of the competitive technologies for producing this high-purity oxygen from the air is through pressure swing adsorption (PSA), which has the advantages of low cost and energy while being highly efficient. Also, PSA is a simple and flexible system due to its ability to start up and shut down more rapidly since its operation occurs at ambient temperature, which is enabled through the use of adsorbents to bind and separate the air molecules. The enhancement of the PSA’s performances was reported through the modification of PSA step cycles and material (zeolite) tailoring. A simplified complete set of a mathematical model is included for modelling the PSA system, aiming to ease the experimental burden of the process design and optimization of an infinite modification of PSA step cycles. Finally, some technological importance of oxygen production via PSA, particularly for onboard oxygen generation system and oxy-enriched incineration of municipal solid waste, was discussed. Continuous development of PSA will make significant contributions to a wide range of chemical industries in the near future, be it for oxygen production or other gas separation applications.

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“…In fact, different topologies might perform differently with different adsorbates, depending on their size and polarity. Besides, for a given topology, multiple Si/Al ratios and distributions of the aluminum atoms can also lead to different results. − The substitution of Si atoms with Al atoms leads to a negative net charge in the framework, which needs to be compensated by introducing extraframework cations. Because the cation distribution is highly dependent on the positions of the aluminum substitutions, these have an impact on the number and position of Bronsted acid sites, which determine the interactions between the zeolite and the adsorbates.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Carbon Dioxide in Non-Löwenstein Zeolites

2023

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We investigated the effect of the aluminum distribution in the adsorption properties of carbon dioxide in the MFI, MOR, and ITW zeolites. Because of its lack of experimental evidence and theoretical validation, Loẅenstein's rule was not generally imposed, and special attention was paid to the effect of the Al−O−Al linkages. To this end, we first generalized an existing transferable force field for CO 2 adsorption in non-Loẅenstein zeolites. By means of molecular simulations based on this force field, we showed that the carbon dioxide adsorption efficiency in MFI is determined by the number of Al atoms, rather than by their distribution in the framework. This was attributed to the small size of the CO 2 molecules compared to the 3D wide-channel topology of the structure. Conversely, we found that the Al distribution has a higher impact on the heat of adsorption in MOR. Although structures with a very high and very low number of non-Loẅenstein bonds presented significant differences, the bonds themselves do not affect the heat of adsorption directly. Instead, we found that an homogeneous distribution of the Al atoms in the sites forming the C-channel is more favorable. Finally, the small-pore distribution of the ITW zeolite led to high values of the heat of adsorption and wide error bars, which made the study feasible just for low aluminum concentrations. In that case, we report a small dependency of the heat of adsorption on the Al distribution.

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Effect of Si/Al Ratio in the Faujasite Structure on Adsorption of Methane and Nitrogen: A Molecular Dynamics Study

Cited by 13 publications

References 43 publications

Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties

Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties

The Production of Industrial-Grade Oxygen from Air by Pressure Swing Adsorption

Adsorption of Carbon Dioxide in Non-Löwenstein Zeolites

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