Pore‐structure analysis by using nitrogen sorption and mercury intrusion data

Tsakiroglou, Christos D.; Burganos, Vasilis N.; Jacobsen, Joachim

doi:10.1002/aic.10043

Cited by 22 publications

(37 citation statements)

References 56 publications

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“…A modeling exercise was performed on some select samples based on the application of a recently formulated porenetwork modeling methodology [37][38][39] to produce only one set of geometrical and topological parameters. This model suitably applies to porous systems comprised of sintered materials, palletized materials, and agglomerates that exhibit cusps rather than microroughness along pore walls.…”

Section: Appendix Amentioning

confidence: 99%

“…This model suitably applies to porous systems comprised of sintered materials, palletized materials, and agglomerates that exhibit cusps rather than microroughness along pore walls. The original work was done by Tsakiroglou et al 38 in an ATHENA visual workbench software environment, which involved a rigorous iterative simulation on experi mental sorption and porosimetry data in order to match experimental curves with analytical curves derived from the model. This report performs a similar modeling in a MATLAB 6 environment.…”

Section: Appendix Amentioning

confidence: 99%

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Impact of Porogens on the Pore Characteristics of Zirconia Particles Made by Polymer-Induced Colloid Aggregation

Pattanayak

Subramanian

2009

International Journal of Applied Ceramic Technology

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Zirconia particles were prepared from a 20% colloidal sol (ZrO2) by the polymer‐induced colloid aggregation (PICA) process, both in the presence and absence of porogens. Specifically, porous zirconia particles having varying porosity were prepared by a two‐step protocol wherein a porogen was first embedded during the particle synthesis, followed by its removal in a subsequent step. In this research study, the ability of four different types of porogens, viz. fumed silica, micronized high molecular weight polyethylene emulsion ME09730, and microcrystalline waxes ME48040M2 and ME98040M1, to impact the pore size, porosity, and pore area were investigated. Particle morphology and porosity of the resultant particles were characterized by scanning electron microscopy, mercury intrusion–extrusion porosimetry, and the nitrogen adsorption–desorption sorptometry. Optimal ratios of zirconia sol and porogen to yield the largest unimodal distribution of pores were determined. Porous zirconia particles were obtained after the removal of porogen, followed by a calcination and sintering protocol. Particle aggregates were typically 7–45 μm in diameter, with BET surface areas between 21 and 54 m2/g and pores ranging from 18 to 120 nm in diameter. The nitrogen sorptometry and mercury porosimetry data of these support particles were modeled to calculate surface fractal dimension, pore accessibility parameters, pore network, and pore geometry.

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Section: Appendix Amentioning

confidence: 99%

Section: Appendix Amentioning

confidence: 99%

Impact of Porogens on the Pore Characteristics of Zirconia Particles Made by Polymer-Induced Colloid Aggregation

Pattanayak

Subramanian

2009

International Journal of Applied Ceramic Technology

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“…Unless the initial guesses of the model parameters are close to the global minimum, the PNM parameters will not converge to it. Also, the initial conditions strongly affect the estimates of PNM parameters Tsakiroglou et al (2004).…”

Section: Hamiltonian Monte Carlomentioning

confidence: 99%

“…One approach is to use lattice networks in combination with indirect measurements made on real samples to characterise the pore network structures Tsakiroglou and Payatakes (1991); Portsmouth and Gladden (1991); Liu et al (1993); Ioannidis and Chatzis (1993); Matthews et al (1995); Tsakiroglou and Payatakes (2000); Moctezuma et al (2003); Radlinski et al (2004); Tsakiroglou et al (2004); Bekri and Vizika (2006); Tsakiroglou et al (2009) ;Tsakiroglou (2012). Hereafter, we will refer to these approaches as indirect methods.…”

Section: Introductionmentioning

confidence: 99%

Inversion of Lattice Network Structure Subjected to Carbonate Mercury Intrusion Capillary Pressure: Hamiltonian Monte Carlo Posterior Sampling

Juri¹,

Dijke²,

Sorbie³

2014

Transp Porous Med

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The wide range of pore sizes in carbonates (differences of three to five orders of magnitude) aggravates the already difficult problem of multiple minima in pore network model (PNM) parameters. In this paper, we propose a method to estimate the PNM structural parameters. We have applied the method to four cases: one synthetic case and three carbonate rock samples. The PNM structural parameter estimates were conditioned to the mercury intrusion capillary pressure (MICP) via a stochastic inversion algorithm that uses molecular dynamics combined with stochastic steps using Hamiltonian mechanics. This algorithm, Hamiltonian Monte Carlo (HMC), allows for large moves in the phase space making use of the periodicity developed due to the Hamiltonian formulation, thus large modifications in the model parameters are possible. Additionally, we introduced a new estimator of the poresize distribution using MICP. The statistics of the stochastic inversion found the multiple local minima and the global minimum of the misfit function in a difficult case. The results for the synthetic case showed that the volume and fraction of small pores in the pore-size distribution can lead to multiple local minima. For the three carbonate rock samples, the model parameters clearly showed that the volume exponents are greater than zero, which contradicts the usual assumption and inferences made by other methods. As the pore-size distribution becomes multi-modal, the volume exponent decreases but is greater than zero. These results suggest that when microporosity is ignored the volume exponent will systematically tend to be strongly underestimated (values close to zero). Our findings demonstrate that lattice-type PNM parameter estimation is a difficult problem because of multiple minima. The HMC method was able to escape from those multiple minima, resulting in better estimates of the PNM parameters.

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“…This descriptor is used to understand the performance of such materials as heterogeneous catalyst pellets, adsorbents, chromatographic media, and many other applications. While the gas adsorption and mercury porosimetry methods are indirect, unique pore size distributions can be obtained for some materials using particular techniques for the simultaneous inversion of mercury intrusion and nitrogen sorption curves [1].…”

Section: Introductionmentioning

confidence: 99%

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

Rigby

Hasan

Hitchcock

et al. 2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1 normally requiring assumptions about the correct model for data analysis. In this work we present a novel method to both expand the range, and obtain greater accuracy, for the information obtained from the main boundary adsorption isotherms by using a combination of data obtained for two adsorptives, namely nitrogen and argon, both before and after mercury porosimetry. The method makes use of the fact that nitrogen and argon apparently 'see' a different pore geometry following mercury entrapment, with argon, relatively, 'ignoring' new metal surfaces produced by mercury porosimetry. The new method permits the study of network and pore-pore co-operative effects during adsorption that substantially affect the accuracy of the characteristic parameters, such as modal pore size, obtained for disordered materials. These effects have been explicitly quantified, for a typical sol-gel silica catalyst support material as a case study. The technique allowed the large discrepancies between modal pore sizes obtained from standard gas adsorption and mercury thermoporometry methods to be attributed to the network-based delayed condensation effect, rather than spinodal adsorption. Once the network-based delayed condensation effect had been accounted for, the simple cylindrical pore model and macroscopic thermodynamic Kelvin-Cohan equation were then found sufficient to accurately describe adsorption in the material studied, rather than needing a more complex microscopic theory. Hence, for disordered mesoporous solids, a proper account of inter-pore interactions is more important than that of intra-pore adsorbate density distribution, to obtain accurate pore size distributions. Detection of the Delayed Condensation Effect and Determination of its

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Pore‐structure analysis by using nitrogen sorption and mercury intrusion data

Cited by 22 publications

References 56 publications

Impact of Porogens on the Pore Characteristics of Zirconia Particles Made by Polymer-Induced Colloid Aggregation

Impact of Porogens on the Pore Characteristics of Zirconia Particles Made by Polymer-Induced Colloid Aggregation

Inversion of Lattice Network Structure Subjected to Carbonate Mercury Intrusion Capillary Pressure: Hamiltonian Monte Carlo Posterior Sampling

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

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