Investigation on the selective adsorption and separation properties of coal mine methane in ZIF-68 by molecular simulations

Li, Qingzhao; Ruan, Maliang; Zheng, Yuannan; Mei, Xiaoning; Lin, Baiquan

doi:10.1007/s10450-016-9842-5

Cited by 8 publications

(5 citation statements)

References 53 publications

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“…Among the materials studied for this purpose, due to its amazing properties, metal-organic frameworks (MOFs) have been shown to present large adsorption and gas separation yields [13,14], these being among the most promising materials in this field. Their high specific surface area (even values up to 6255 m 2 /g [15]) combined with high total pore volume (1.303 cm 3 /g [16]) and great porosity (91.1% [17]) are responsible for the large adsorption capabilities, exceeding in the majority of cases other common materials [18].…”

Section: Introductionmentioning

confidence: 99%

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption

2020

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Metal-organic frameworks’ (MOFs) adsorption potential is significantly reduced by turning the original powder into pellets or granules, a mandatory step for their use at industrial scale. Pelletization is commonly performed by mechanical compression, which often induces the amorphization or pressure-induced phase transformations. The objective of this work is the rigorous study of the impact of mechanical pressure (55.9, 111.8 and 186.3 MPa) onto three commercial materials (Basolite C300, F300 and A100). Phase transformations were determined by powder X-ray diffraction analysis, whereas morphological changes were followed by nitrogen physisorption. Methane adsorption was studied in an atmospheric fixed bed. Significant crystallinity losses were observed, even at low applied pressures (up to 69.9% for Basolite C300), whereas a structural change occurred to Basolite A100 from orthorhombic to monoclinic phases, with a high cell volume reduction (13.7%). Consequently, adsorption capacities for both methane and nitrogen were largely reduced (up to 53.6% for Basolite C300), being related to morphological changes (surface area losses). Likewise, the high concentration of metallic active centers (Basolite C300), the structural breathing (Basolite A100) and the mesopore-induced formation (Basolite F300) smooth the dramatic loss of capacity of these materials.

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Section: Introductionmentioning

confidence: 99%

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption

2020

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“…Nowadays, the continuous consumption of fossil fuels has raised many issues-related to energy and environment, creating an increasing demand for the development of clean energy. Natural gas (the main component is methane, CH 4 ) is considered as an alternative energy source due to its clean and economical features and has become one of the fastest-growing energy source in the world. − A large amount of CH 4 is emitted from conventional natural gas and unconventional natural gas (such as landfill gas, shale gas, and coal bed methane). The latter resource with a substantial amount of CH 4 is very difficult to utilize directly because the high concentration of nitrogen (N 2 ) lowers the heat enthalpy.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it is of significance to efficiently separate the CH 4 /N 2 mixture, which is however a great challenge because of the very similar physical properties CH 4 and N 2 . , To date, several technologies have been used, such as cryogenic distillation, membrane separation, − and adsorption separation, where pressure swing adsorption (PSA) is regarded as an promising industrial and commercial technology, , due to the advantages of low investment cost, simple operation, flexibility, and energy conservation. , The key is suitable adsorbent. Different types of adsorbents have been investigated, while the separation performance is still very low so far, − especially for the integrated consideration of selectivity and productivity simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Microporous Metal–Organic Frameworks with Hydrophilic and Hydrophobic Pores for Efficient Separation of CH₄/N₂ Mixture

et al. 2019

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Highly selective removal of N2 from unconventional natural gas is considered as a viable way to increase the heat value of CH4 and reduce the greenhouse effect caused by the direct emission of CH4/N2 mixture. In this work, a three-dimensional Cu–MOF with two different types of micropores was synthesized, exhibiting a high selectivity for CH4/N2 (10.00–12.67) and the highest sorbent selection parameter value (65.73) among the reported materials. The CH4 molecule interacts with the framework to form multiple van der Waals interactions both in hydrophilic and hydrophobic pores, indicated by density functional theory calculations to gain a deep insight into the adsorption binding sites. In contrast, the weak polarity feature of the hydrophobic pore and the occupied open-metal sites in the hydrophilic pore result in a very low adsorption uptake of N2. The excellent separation performance combining the good stability and regenerability guarantees this Cu–MOF to be a promising adsorbent for an efficient separation of the CH4/N2 mixture.

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“…The isothermal heat of adsorption is an important parameter for describing the interaction between gas molecules and adsorbents. In addition, it is also an important parameter to characterize the energy variation law of the adsorption system [ 39 , 40 ]. The calculation method of isothermal adsorption heat is shown in Equation (3):

…”

Section: Resultsmentioning

confidence: 99%

Molecular Simulation on Competitive Adsorption Differences of Gas with Different Pore Sizes in Coal

et al. 2022

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Micropores are the primary sites for methane occurrence in coal. Studying the regularity of methane occurrence in micropores is significant for targeted displacement and other yield-increasing measures in the future. This study used simplified graphene sheets as pore walls to construct coal-structural models with pore sizes of 1 nm, 2 nm, and 4 nm. Based on the Grand Canonical Monte Carlo (GCMC) and molecular dynamics theory, we simulated the adsorption characteristics of methane in pores of different sizes. The results showed that the adsorption capacity was positively correlated with the pore size for pure gas adsorption. The adsorption capacity increased with pressure and pore size for competitive adsorption of binary mixtures in pores. As the average isosteric heat decreased, the interaction between the gas and the pore wall weakened, and the desorption amount of CH4 decreased. In ultramicropores, the high concentration of CO2 (50–70%) is more conducive to CH4 desorption; however, when the CO2 concentration is greater than 70%, the corresponding CH4 adsorption amount is meager, and the selected adsorption coefficient SCO2/CH4 is small. Therefore, to achieve effective desorption of methane in coal micropores, relatively low pressure (4–6 MPa) and a relatively low CO2 concentration (50–70%) should be selected in the process of increasing methane production by CO2 injection in later stages. These research results provide theoretical support for gas injection to promote CH4 desorption in coal pores and to increase yield.

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Investigation on the selective adsorption and separation properties of coal mine methane in ZIF-68 by molecular simulations

Cited by 8 publications

References 53 publications

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption

Microporous Metal–Organic Frameworks with Hydrophilic and Hydrophobic Pores for Efficient Separation of CH₄/N₂ Mixture

Molecular Simulation on Competitive Adsorption Differences of Gas with Different Pore Sizes in Coal

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Investigation on the selective adsorption and separation properties of coal mine methane in ZIF-68 by molecular simulations

Cited by 8 publications

References 53 publications

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption

Microporous Metal–Organic Frameworks with Hydrophilic and Hydrophobic Pores for Efficient Separation of CH4/N2 Mixture

Molecular Simulation on Competitive Adsorption Differences of Gas with Different Pore Sizes in Coal

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Microporous Metal–Organic Frameworks with Hydrophilic and Hydrophobic Pores for Efficient Separation of CH₄/N₂ Mixture