Economical synthesis strategy of RHO zeolites with fine-tuned composition and porosity for enhanced trace CO2 capture

Ke, Quanli; Sun, Tianjun; Wei, Xiaoli; Guo, Yang; Xu, Shutao; Wang, Shudong

doi:10.1016/j.cej.2018.11.098

Cited by 25 publications

(12 citation statements)

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“…These processes essentially involve moleculeswhich may enter, remain outside, or leave the pores according not only to trivial relative size considerations, but also thanks to the flexibility of both molecular species and host framework. Such flexibility may help rationalize various technologically important phenomena in zeolites, such as catalytic performances of Lewis-acid sites (Luo et al 2016), window effects (Balestra et al 2015;Coudert and Kohen 2017;Ke et al 2019), fabrication of functional materials (Tabacchi et al 2015(Tabacchi et al , 2016b or hybrid nanocatalysts (Zendehdel et al 2018). All these phenomena essentially involve correlated vibrational motions of guest molecules and zeolite framework, and collective oscillations of Arletti, R., Fois, E., Gigli, L., Vezzalini, G., Quartieri, S., and Tabacchi, G. (…”

Section: Discussionmentioning

confidence: 99%

Computer modeling of apparently straight bond angles: The intriguing case of all-silica ferrierite

Trudu

Tabacchi

Fois

2019

American Mineralogist

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The relationships between synthetic zeolites and their natural counterparts that have been unveiled by theoretical studies have contributed to improving the properties and applications of zeolite-based materials in strategic areas such as industrial catalysis, environmental protection, and solar energy harvesting. To pinpoint the role of modeling in zeolite science, we discuss an example of computationally driven problem solving: can tetrahedral frameworks sustain straight (i.e., 180°) Si-O-Si bond angles? The true crystal symmetry of zeolite ferrierite (FER), especially in its all-silica form, had been intensely debated for 30 years before being solved in the Pmnn space group. Yet there are indications that an Immm structure with energetically unfavorable linear Si-O-Si linkages could be formed at high temperature. To gather insight, we perform density functional theory (DFT) optimizations and frequency calculations of all-silica ferrierite in both the Pmnn and Immm space groups. Our results indicate that Pmnn is more stable than Immm, in line with experiments. While the Pmnn structure is a true minimum in the energy profile of ferrierite, the Immm structure has four imaginary frequency vibrations, three of which are localized on the 180° Si-O-Si angles. This suggests that ferrierites with Immm symmetry may be classified as metastable phases. Such a designation is also supported by first-principles molecular dynamics on Immm FER, showing that the average value of 180° actually results from Si-O-Si angle inversion. An implication of this study with interesting geological and technological consequences is the association of straight Si-O-Si angles experimentally detected in open-framework or low-density silicates to an angle-inversion process occurring at the femtosecond scale. Such flexibility of the apparently flat Si-O-Si linkages might play an important role in sorption phenomena, which are ubiquitous in geological processes and industrial applications alike.

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Section: Discussionmentioning

confidence: 99%

Computer modeling of apparently straight bond angles: The intriguing case of all-silica ferrierite

Trudu

Tabacchi

Fois

2019

American Mineralogist

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“…[23,24] Due to their relatively low cost, good thermal stability, shape selectivity (pore diameter and aperture) as well as their ability of easily exchanging extra-framework cations, zeolite materials have found many applications in adsorption and catalytic processes. [25][26][27][28][29][30][31][32][33] Low aluminum loaded zeolites (BEA with Si/Al = ∞) were found to be the most efficient ones for the removal of phenol in wastewater, mainly because of the competitive adsorption of water molecules on zeolite acid sites. [34][35][36] Recently, faujasite (FAU)-type zeolites were used for the selective adsorption of phenol from alkane solutions, with a high adsorption capacity and a good regeneration ability.…”

Section: Introductionmentioning

confidence: 99%

Biofuel purification: Coupling experimental and theoretical investigations for efficient separation of phenol from aromatics by zeolites

Khalil

Jabraoui

Lebègue

et al. 2020

Chemical Engineering Journal

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The purification of second-generation biofuels is becoming an urgent issue due to the toxicity of the combustion products of residual phenol in these biofuels. The use of solid sorbents such as zeolites appears as a promising solution for ensuring the selective sorption of phenol towards aromatics (the main components of biofuel). In the present work, we have adopted a bottom-up approach for removing phenol from a synthetic biofuel feed containing isooctane, 1 wt.% phenol, 1 wt.% n-nonane and 40 wt.% toluene, using faujasitetype Y zeolites with Si/Al ratio = 2.5. The adsorption modes of the molecules involved have been assessed by comparing theoretical and experimental infrared spectra. In addition, coupling molecular modeling with breakthrough curves has revealed the important role of protons embedded in zeolites for the selective removal of phenol.

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“…4c) and the H form RHO zeolite. [21] Elemental analysis shows that the exchange degree of Na + in Na-SAPO-RHO is ca. 87.13%, leaving 12.87% of H + Please do not adjust margins Please do not adjust margins balancing the negative charge of the framework of SAPO-RHO.…”

Section: Resultsmentioning

confidence: 99%

The inorganic cation-tailored “trapdoor” effect of silicoaluminophosphate zeolite for highly selective CO₂ separation

et al. 2021

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Economical synthesis strategy of RHO zeolites with fine-tuned composition and porosity for enhanced trace CO2 capture

Cited by 25 publications

References 53 publications

Computer modeling of apparently straight bond angles: The intriguing case of all-silica ferrierite

Computer modeling of apparently straight bond angles: The intriguing case of all-silica ferrierite

Biofuel purification: Coupling experimental and theoretical investigations for efficient separation of phenol from aromatics by zeolites

The inorganic cation-tailored “trapdoor” effect of silicoaluminophosphate zeolite for highly selective CO₂ separation

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Economical synthesis strategy of RHO zeolites with fine-tuned composition and porosity for enhanced trace CO2 capture

Cited by 25 publications

References 53 publications

Computer modeling of apparently straight bond angles: The intriguing case of all-silica ferrierite

Computer modeling of apparently straight bond angles: The intriguing case of all-silica ferrierite

Biofuel purification: Coupling experimental and theoretical investigations for efficient separation of phenol from aromatics by zeolites

The inorganic cation-tailored “trapdoor” effect of silicoaluminophosphate zeolite for highly selective CO2 separation

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Product

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The inorganic cation-tailored “trapdoor” effect of silicoaluminophosphate zeolite for highly selective CO₂ separation