An automated, high precision unit for low-pressure physisorption

Borghard, W.S.; Sheppard, E. W.; Schoennagel, H.J.

doi:10.1063/1.1142216

Cited by 23 publications

(16 citation statements)

References 6 publications

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“…The micropore volume accessible to N 2 , CH 3 OH, and C 2 H 5 OH adsorbates was determined by analyzing the semilog derivative plots of adsorption isotherms (∂( V ads /g)/∂(log( P / P 0 )) vs. log ( P / P 0 )). The relative pressure at which the micropore filling transition occurs in microporous solids is given by the first maximum of ∂( V ads /g)/∂(log( P / P 0 )); in turn, the local minimum that follows immediately corresponds to the end of micropore filling . The total H 2 O uptakes reported in Table correspond to the volume of H 2 O adsorbed at P / P 0 =0.2 for comparison purposes, because micropore filling transitions were not detected for H 2 O isotherms on hydrophobic materials.…”

Section: Experimental Methodsmentioning

confidence: 99%

Beyond shape selective catalysis with zeolites: Hydrophobic void spaces in zeolites enable catalysis in liquid water

2013

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Zeolites confine active sites within void spaces of molecular dimension. The size and shape of these voids can be tuned by changing framework topology, which can influence catalytic reactivity and selectivity via coupled reaction‐transport phenomena that exploit differences in transport properties among reactants and/or products that differ in size and shape. The polarity and solvating properties of intrazeolite void environments can be tuned by changing chemical composition and structure, ranging from hydrophobic defect‐free pure‐silica surfaces to silica surfaces containing hydrophilic defect sites and/or heteroatoms. Here, we discuss how the polarity of zeolite voids influences catalytic reactivity and selectivity via the partitioning of reactant, product, and solvent molecules between intrazeolitic locations and external fluid phases. These findings provide a conceptual basis for developing selective catalytic processes in aqueous media using hydrophobic zeolites that are able to adsorb organic reactants while excluding liquid water from internal void spaces. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3349–3358, 2013

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Section: Experimental Methodsmentioning

confidence: 99%

Beyond shape selective catalysis with zeolites: Hydrophobic void spaces in zeolites enable catalysis in liquid water

2013

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“…The spherical-shaped pore model was employed next to deduce the PSD of Faujasite from the argon isotherm data of Ž . Borghard et al 1991 . Figure 15 shows the distribution of pores as calculated by the four models.…”

Section: Spherical Pore Model Faujasite Zeolitementioning

confidence: 95%

“…K has been given by Borghard et al 1991 . This type of zeolite actually has a spherical cavity and the results using the modified HK model for spherical pores will be subsequently shown.…”

Section: Faujasite Zeolitementioning

confidence: 99%

Corrected Horváth‐Kawazoe equations for pore‐size distribution

2000

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“…The accuracy of the gravimetric method for supercritical CO 2 sorption has recently been discussed by Pini et al 6 The focus of the present article is the accuracy of the manometric method. The accuracy of the manometric method far below [22][23][24][25][26][27] and far above [28][29][30][31] the critical point has been discussed in the literature. However, no literature regarding the quantification of the accuracy of near critical manometric sorption measurements could be found.…”

Section: Introductionmentioning

confidence: 99%

Improved manometric setup for the accurate determination of supercritical carbon dioxide sorption

Hemert

Bruining

Rudolph

et al. 2009

Review of Scientific Instruments

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An improved version of the manometric apparatus and its procedures for measuring excess sorption of supercritical carbon dioxide are presented in detail with a comprehensive error analysis. An improved manometric apparatus is necessary for accurate excess sorption measurements with supercritical carbon dioxide due to the difficulties associated with the high sensitivity of density for pressure and temperature changes. The accuracy of the apparatus is validated by a duplicate measurement and a comparison with literature data. Excess sorption and desorption of CO 2 on Filtrasorb 400 at 318.11 K up to 17 069 mole/ m 3 ͑15.474 MPa͒ were selected for this validation. The measured excess sorption maximums are 7.79Ϯ 0.04 mole/ kg at 2253 mole/ m 3 for the first sorption isotherm and 7.91Ϯ 0.05 mole/ kg at 2670 mole/ m 3 for its subsequent desorption isotherm. The sorption and desorption peaks of the duplicate experiment are 7.92Ϯ 0.04 mole/ kg at 2303 mole/ m 3 and 8.10Ϯ 0.05 mole/ kg at 2879 mole/ m 3 , respectively. Both data sets show desorption data being higher than the sorption data of the same data set. The maximum discrepancy between the desorption and sorption isotherms of one data set is 0.15 mole/kg. The discrepancy between the two excess sorption isotherms is 0.12 mole/kg or less. The a priori error of the excess sorption measurements is between 0.02 and 0.06 mole/kg. The error due to He contamination is between 0.01 and 0.05 mole/kg. The difference between the a priori uncertainty and the observed maximum discrepancies is considered to be acceptable. The sorption isotherms show identical qualitative behavior as data in the literature. The quantitative behavior is similar but the peak height and the linear decrease in excess sorption at high gas densities are 10% higher. A plot of the excess sorption versus the density can be used to obtain the sorbed phase density and the specific micropore volume. These sorbed phase densities are in excellent agreement with the data in the literature. Furthermore, the excess sorption data scaled to this specific micropore volume in this work and in the literature collapse on a single curve when plotted versus gas density.

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An automated, high precision unit for low-pressure physisorption

Cited by 23 publications

References 6 publications

Beyond shape selective catalysis with zeolites: Hydrophobic void spaces in zeolites enable catalysis in liquid water

Beyond shape selective catalysis with zeolites: Hydrophobic void spaces in zeolites enable catalysis in liquid water

Corrected Horváth‐Kawazoe equations for pore‐size distribution

Improved manometric setup for the accurate determination of supercritical carbon dioxide sorption

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