Advanced textural characterization of biogenic silica by nitrogen physisorption, positron annihilation lifetime spectroscopy and hyperpolarized 129Xe NMR spectroscopy

Schneider, Denise; Attallah, Ahmed G.; Wassersleben, Susan; Wenzel, Marianne; Matysik, Jörg; Krause‐Rehberg, R.; Enke, Dirk

doi:10.1016/j.micromeso.2020.110515

Cited by 8 publications

(13 citation statements)

References 45 publications

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“…Several models were introduced in the literature for that purpose. 18,19 Smaller pore sizes or, to be consistent with the model introduced by Fraissard et al, a reduced mean free path of the xenon atoms inside the sample 32 lead to decreased shielding, which results in higher chemical shifts. This includes a neglectable xenonsurface interaction and low partial pressure to reduce xenonxenon interactions.…”

Section: Pore Systemmentioning

confidence: 69%

“…17 This method provides several independent parameters to be analyzed: The 129 Xe chemical shift reports the mean pore size based on a pore geometry model in combination with a wisely chosen reference material. 18,19 The peak shape provides information about the uniformity of the pores throughout the sample, which is hardly accessible with other techniques. 20 Variable-temperature experiments allow heats of adsorption to be extracted from the Xenon chemical shifts.…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic insight into post-synthetic surface modification of porous glass beads as a silica model system

Wenzel

Eckert

Müller

et al. 2022

Phys. Chem. Chem. Phys.

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Section: Pore Systemmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Spectroscopic insight into post-synthetic surface modification of porous glass beads as a silica model system

Wenzel

Eckert

Müller

et al. 2022

Phys. Chem. Chem. Phys.

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“…According to IUPAC, this type of hysteresis is typical for aggregates of plate-like particles, giving rise to slitshaped pores [47,48]. Furthermore, larger mesopores that are only accessible by smaller pores can theoretically take the shape of ink-bottle pores [46]. The isotherm shape and hysteresis loop size for the AAZ (0.47)/S sample indicated only a low total volume and low mesopore volume, respectively, compared to the other samples.…”

Section: N 2 Physisorptionmentioning

confidence: 95%

“…In type IV isotherms, we can distinguish four types of hysteresis. The measured isotherms of the S samples showed the H3 loop, which did not show any limiting adsorption (plateau) at a high P/P0, indicating larger mesopores and macropores [46]. According to IUPAC, this type of hysteresis is typical for aggregates of plate-like particles, giving rise to slit-shaped pores [47,48].…”

Section: N₂ Physisorptionmentioning

confidence: 96%

Influence of the Addition of Blast Furnace Slag to Alkali-Activated Mixtures Based on Natural Zeolites

et al. 2021

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This study focuses on a comparison of alkali-activated materials based on natural zeolites without and with the addition of blast furnace slag and their subsequent modification by acid leaching. The addition of slag to alkali-activated mixtures is generally used to increase the strength. The subsequent modification of its chemical, textural and mechanical properties by acid leaching makes this material usable in other industries, especially in the chemical industry. This study aimed to examine the influence of the addition of blast furnace slag to alkali-activated mixtures based on natural zeolites and observe the effect of subsequent acid leaching on the chemical, textural and mechanical properties and CO2 adsorption capacity of these materials. The modification of alkali-activated materials was carried out by acid leaching using 0.1 M HCl and then using 3 M HCl. The properties of these materials were determined using N2 physisorption, Hg porosimetry, XRF, XRD, DRIFT, TGA and strength measurements. The results showed that the addition of blast furnace slag significantly increased the cutting-edge strength of the obtained materials and affected the textural properties, especially in leached samples. The presence of blast furnace slag generated a higher proportion of mesopores, which are attributed to the presence of the calcium silicate hydrate (C–S–H) phase and are easily removed by leaching, as shown by the XRF results. The obtained data showed an improvement in properties and extension of the potential applicability of these materials in the chemical industry, especially for catalytic and adsorption applications.

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“…The main advantage of the PAL method is its ability to characterize local free volumes (including both open and closed pores) in subnanometer-level materials. [25][26][27] The PAL method is particularly effective in the formation of positronium (Ps). Two conditions should be satisfied for Ps to be formed in solids, the first one being geometric diameter of free-volume pore captured Ps (more than 1.941 Å) and the second being sufficiently low electron density preventing direct positron-electron annihilation.…”

Section: Introductionmentioning

confidence: 99%

Extended Positron–Positronium Trapping Defects in the MgAl₂O₄ Spinel Ceramics

Klym

Hadzaman

Vilá

et al. 2022

Physica Status Solidi (b)

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Extended free‐volume positron trapping defects (positron trapping channel) and nanopores (positronium decaying channel) in the initial and modified MgAl2O4 ceramics sintered at 1200, 1300, and 1400 °C are investigated using positron annihilation lifetime spectroscopy within four‐component fitting procedure. It is established that the number and size of extended defects near grain boundaries (described by the second component) decrease with increasing sintering temperature of ceramics, which correlates with the content of additional phases in the materials. The agglomeration of nanopores occurs in the initial ceramics (described by the third component) and the decrease of number and size of nanopores in the modified ceramics. The corresponding processes of the evolution of nanopores described by the fourth component are reflected mainly in their reduction, except for ceramics sintered at 1400 °C. Such changes are associated with the evolution of porous structure and increased contact area between the grains of ceramics.

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Advanced textural characterization of biogenic silica by nitrogen physisorption, positron annihilation lifetime spectroscopy and hyperpolarized 129Xe NMR spectroscopy

Cited by 8 publications

References 45 publications

Spectroscopic insight into post-synthetic surface modification of porous glass beads as a silica model system

Spectroscopic insight into post-synthetic surface modification of porous glass beads as a silica model system

Influence of the Addition of Blast Furnace Slag to Alkali-Activated Mixtures Based on Natural Zeolites

Extended Positron–Positronium Trapping Defects in the MgAl₂O₄ Spinel Ceramics

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Advanced textural characterization of biogenic silica by nitrogen physisorption, positron annihilation lifetime spectroscopy and hyperpolarized 129Xe NMR spectroscopy

Cited by 8 publications

References 45 publications

Spectroscopic insight into post-synthetic surface modification of porous glass beads as a silica model system

Spectroscopic insight into post-synthetic surface modification of porous glass beads as a silica model system

Influence of the Addition of Blast Furnace Slag to Alkali-Activated Mixtures Based on Natural Zeolites

Extended Positron–Positronium Trapping Defects in the MgAl2O4 Spinel Ceramics

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Product

Resources

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Extended Positron–Positronium Trapping Defects in the MgAl₂O₄ Spinel Ceramics