Is the bet equation applicable to microporous adsorbents?

Rouquérol, J.; Llewellyn, Philip; Rouquérol, F.

doi:10.1016/s0167-2991(07)80008-5

Cited by 974 publications

(733 citation statements)

References 7 publications

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“…For pore size distributions, N2 isotherms of the materials were measured at 77 K in a Micromeritics ASAP 2020 (Micromeritics Instrument Corporation, Georgia, USA). The method to calculate BET surface areas was consistent with the BS ISO 9277:2010, which uses the consistency criteria reported by Rouquerol [30,31]. To obtain the microporous and total pore volume of the materials, Dubinin-Radushkevich (DR) and Horvath-Kawazoe (HK) methodologies were used [32,33].…”

Section: Methodsmentioning

confidence: 99%

Structure–property relationships in metal-organic frameworks for hydrogen storage

Noguera-Díaz

Bimbo

Holyfield

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Experimental hydrogen isotherms on several metal-organic frameworks (IRMOF-1, IRMOF-3, IRMOF-9, ZIF-7, ZIF-8, ZIF-9, ZIF-11, ZIF-12, ZIF-CoNIm, MIL-101 (Cr), NH2-MIL-101 (Cr), NH2-MIL-101 (Al), UiO-66, UiO-67 and HKUST-1) synthesized in-house and measured at 77 K and pressures up to 18 MPa are presented, along with N2 adsorption characterization. The experimental isotherms together with literature high pressure hydrogen data were analysed in order to search for relationships between structural properties of the materials and their hydrogen uptakes. The total hydrogen capacity of the materials was calculated from the excess adsorption assuming a constant density for the adsorbed hydrogen. The surface area, pore volumes and pore sizes of the materials were related to their maximum hydrogen excess and total hydrogen capacities. Results also show that ZIF-7 and ZIF-9 (SOD topology) have unusual hydrogen isotherm shapes at relatively low pressures, which is indicative of "breathing", a phase transition in which the pore space increases due to adsorption. This work presents novel correlations using the modelled total hydrogen capacities of several MOFs. These capacities are more practically relevant for energy storage applications than the measured excess hydrogen capacities. Thus, these structural correlations will be advantageous for the prediction of the properties a MOF will need in order to meet the US Department of Energy targets for the mass and volume capacities of on-board storage systems. Such design tools will allow hydrogen to be used as an energy vector for sustainable mobile applications such as transport, or for providing supplementary power to the grid in times of high demand.

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Section: Methodsmentioning

confidence: 99%

Structure–property relationships in metal-organic frameworks for hydrogen storage

Noguera-Díaz

Bimbo

Holyfield

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…The samples were degassed under high vacuum at 180°C for 8 h in order to remove any adsorbate and residual solvent within the material. BET surface areas were determined from the data using the British Standard BS IS0 9277:2010 [25], although the range of P/P 0 (where P is the absolute J Mater Sci (2017) 52:3862-3875 pressure and P 0 the vapour pressure of the adsorptive at the isotherm temperature) chosen was determined using the consistency criteria provided by Rouquerol et al [26] to better reflect the expected microporous nature of the material. Both the surface area and PSD were calculated in Micromeritics MicroActive 1.01 software.…”

Section: Gas Adsorption Studymentioning

confidence: 99%

Mechanical characterisation of polymer of intrinsic microporosity PIM-1 for hydrogen storage applications

et al. 2016

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Polymers of intrinsic microporosity (PIMs) are currently attracting interest due to their unusual combination of high surface areas and capability to be processed into free-standing films. However, there has been little published work with regards to their physical and mechanical properties. In this paper, detailed characterisation of PIM-1 was performed by considering its chemical, gas adsorption and mechanical properties. The polymer was cast into films, and characterised in terms of their hydrogen adsorption at -196°C up to much higher pressures (17 MPa) than previously reported (2 MPa), demonstrating the maximum excess adsorbed capacity of the material and its uptake behaviour in higher pressure regimes. The measured tensile strength of the polymer film was 31 MPa with a Young's modulus of 1.26 GPa, whereas the average storage modulus exceeded 960 MPa. The failure strain of the material was 4.4%. It was found that the film is thermally stable at low temperatures, down to -150°C, and decomposition of the material occurs at 350°C. These results suggest that PIM-1 has sufficient elasticity to withstand the elastic deformations occurring within state-of-the-art high-pressure hydrogen storage tanks and sufficient thermal stability to be applied at the range of temperatures necessary for gas storage applications.

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“…The specific surface area was calculated using the BET methodology and micropore volume was determined using the Dubinin-Radushkevich (DR) equation, according to the procedure described by (12). The total pore volume was obtained from the N 2 volume adsorbed at a relative pressure of 0.95.…”

mentioning

confidence: 99%

Improvement in the Adsorption of Anionic and Cationic Dyes from Aqueous Solutions: A Comparative Study using Aluminium Pillared Clays and Activated Carbon

Aguiar

Bezerra

Siqueira

et al. 2014

Separation Science and Technology

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The aim of this work was evaluate the adsorption properties of anionic dye Reactive Black 5 (RB5) and cationic dye Methylene Blue (MB) from salted aqueous solution using natural clay, aluminum pillared clay (Al-PILC) and activated carbon. The textural properties of the materials were obtained by N 2 adsorption at 77 K and structural properties of natural and pillared clays were determined by Xray diffraction. The effect of pH, contact time, initial concentration of dye and influence of the addition of NaCl were evaluated by batch adsorption. Adsorption isotherms of Al-PILC, in different salt concentration, were compared with natural clay and activated carbon. The adsorption isotherms were well fitted by Langmuir and Langmuir-Freundlich models. The process of pillaring only improved the adsorption of the anionic dye RB5. Depending on the system adsorbent/adsorbate analyzed, the salt concentration can either help or hinder dye adsorption. We found that a special morphology formed during the process of pillaring greatly increased adsorption of the MB cationic dye in the range of high salt concentrations. This unexpected result may help in developing new pillarization strategies to treat effluents with high salt content.

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Is the bet equation applicable to microporous adsorbents?

Cited by 974 publications

References 7 publications

Structure–property relationships in metal-organic frameworks for hydrogen storage

Structure–property relationships in metal-organic frameworks for hydrogen storage

Mechanical characterisation of polymer of intrinsic microporosity PIM-1 for hydrogen storage applications

Improvement in the Adsorption of Anionic and Cationic Dyes from Aqueous Solutions: A Comparative Study using Aluminium Pillared Clays and Activated Carbon

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