Uncertainty in pore size distribution derived from adsorption isotherms: I. Classical methods

Madani, S. Hadi; Badalyan, Alexander; Biggs, Mark J.; Pendleton, Phillip

doi:10.1016/j.micromeso.2015.04.026

Cited by 10 publications

(8 citation statements)

References 45 publications

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“…Determining the surface chemistry and PSD (Pore Size Distribution) is part of the characterization of porous materials and the interaction of the solid with different molecules complements its knowledge [22]. To carry out the study of PSD with the data obtained from the gas isotherms at low temperatures, different methods are used which can be classified into two groups: classic methods and those with an integral approach of adsorption [22][23][24]. The classic methods are based on thermodynamic treatments, while the integral approach of adsorption is based on molecular modeling, mainly using the method of density functional theory (DFT) and statistical mechanics [22,25,26].…”

Section: Introductionmentioning

confidence: 99%

Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry

2020

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In this work, the textural parameters of graphene oxide (GO) and graphite (Gr) samples were determined. The non-local density functional theory (NLDFT) and quenched solid density functional theory (QSDFT) kernels were used to evaluate the pore size distribution (PSD) by modeling the pores as slit, cylinder and slit-cylinder. The PSD results were compared with the immersion enthalpies obtained using molecules with different kinetic diameter (between 0.272 nm and 1.50 nm). Determination of immersion enthalpy showed to track PSD for GO and graphite (Gr), which was used as a comparison solid. Additionally, the functional groups of Gr and GO were determined by the Boehm method. Donor number (DN) Gutmann was used as criteria to establish the relationship between the immersion enthalpy and the parameter of the probe molecules. It was found that according to the Gutmann DN the immersion enthalpy presented different values that were a function of the chemical groups of the materials. Finally, the experimental and modeling results were critically discussed.

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Section: Introductionmentioning

confidence: 99%

Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry

2020

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“…This ambiguity is due to disagreements in the validity of calculated specific surface areas and disagreements in the applicability of the models used for PSD reduction from adsorption isotherm data. This latter characterization method typically results from complex models containing several simplifying, model‐dependent assumptions . Several model‐independent techniques including adsorption calorimetry, immersion calorimetry, TEM, XRD, SANS, TPD, and XPS are often used as supporting characterization techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Thisl atter characterization method typically results from complex modelsc ontaining severals implifying, modeldependent assumptions. [2,3] Several model-independent techniques includinga dsorption calorimetry,i mmersion calorime-try,T EM, XRD, SANS, TPD, and XPS [4] are often used as supporting characterization techniques. Of these,i mmersion calorimetry provides the option to evaluateb oth specific surface area and PSD.…”

Section: Introductionmentioning

confidence: 99%

Immersion Calorimetry: Molecular Packing Effects in Micropores

et al. 2015

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Repeated and controlled immersion calorimetry experiments were performed to determine the specific surface area and pore-size distribution (PSD) of a well-characterized, microporous poly(furfuryl alcohol)-based activated carbon. The PSD derived from nitrogen gas adsorption indicated a narrow distribution centered at 0.57±0.05 nm. Immersion into liquids of increasing molecular sizes ranging from 0.33 nm (dichloromethane) to 0.70 nm (α-pinene) showed a decreasing enthalpy of immersion at a critical probe size (0.43-0.48 nm), followed by an increase at 0.48-0.56 nm, and a second decrease at 0.56-0.60 nm. This maximum has not been reported previously. After consideration of possible reasons for this new observation, it is concluded that the effect arises from molecular packing inside the micropores, interpreted in terms of 2D packing. The immersion enthalpy PSD was consistent with that from quenched solid density functional theory (QSDFT) analysis of the nitrogen adsorption isotherm.

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“…Furthermore, the accuracy of such thermodynamic, macroscopic methods is limited, because of the assumption that the pore fluid has similar thermophysical properties as the bulk fluid (Madani et al 2015).…”

Section: Resultsmentioning

confidence: 99%

Structural Characterization of Heat Treated Poplar Wood

Monteiro

2018

UPjeng

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Wood has been very useful in many fields due to its excellent properties. However, it also has less attractive characteristics, like high hygroscopicity and low bioconversion efficiencies. Heat treatment has been proved to improve these properties making lignocellulosic materials a stronger alternative to non-renewable sources to produce energy and other products. This study focused on the structural changes of heat treated poplar (populus) wood specimens treated under different temperature conditions. Nitrogen adsorption, pore size distribution and specific surface area of heat treated wood were studied. Increasing the temperature of treatment leads to a change on the characteristics of the nitrogen adsorption isotherms. The volume of pores for samples treated at higher temperatures is much greater comparing with samples below 400 oC BET specific surface areas were generally low for samples at temperatures until 400 oC, after this a great increase occurred while increasing temperatures up to 500 oC (413,06 m2/g).

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Uncertainty in pore size distribution derived from adsorption isotherms: I. Classical methods

Cited by 10 publications

References 45 publications

Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry

Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry

Immersion Calorimetry: Molecular Packing Effects in Micropores

Structural Characterization of Heat Treated Poplar Wood

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