Pore network modeling of a solid desiccant for dehumidification applications

Yu, Lili; Hsu, Wei‐Yen; Shamim, Jubair A.; Daiguji, Hirofumi

doi:10.1016/j.ijheatmasstransfer.2021.122456

Cited by 7 publications

(7 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The finite size of the lattice can be implemented using a universal scaling relation for bond percolation 57 or numerical simulations 58,59 . This model is readily applicable to a large set of porous materials, as has been shown also by the use of other groups [60][61][62] . Within the proposed model, a method to estimate the connectivity of micropores was developed 63 .…”

Section: Introduction and Theorymentioning

confidence: 78%

Development and application of an advanced percolation model for pore network characterization by physical adsorption

Söllner,

Neimark,

Thommes

2024

Preprint

View full text Add to dashboard Cite

Physical adsorption is one of the most widely used techniques to characterize porous materials because of being reliable and able to assess micro- and mesopores within one approach. However, challenges and open questions persist in characterizing disordered and hierarchically structured porous materials. This study introduces a pore network model aiming to enhance the textural characterization of nanoporous materials. Our model, based on percolation theory on a Bethe lattice, includes all mechanisms known to contribute to adsorption hysteresis in mesoporous pore networks during capillary condensation and evaporation. The model accounts for delayed and initiated condensation during adsorption as well as equilibrium evaporation, pore blocking and cavitation during desorption. Coupled with dedicated non-local-density functional theory (NLDFT) kernels, the proposed method provides a unified framework for modeling the entire experimental adsorption-desorption isotherm, including desorption hysteresis scans. Hence, this model unveils key pore network characteristics like the effective connectivity, but also has the potential to determine pore size distributions of mesoporous materials by taking quantitatively pore network effects into account. The applicability of the method is demonstrated on a selected set of nanoporous silica materials exhibiting distinct types of hysteresis loops (types H1, H2a, H1/H2a and H5), including ordered mesoporous silica networks, i.e, KIT-6 silica, hybrid SBA-15/MCM-41 silica with plugged pores, but also two disordered silica pore networks, i.e., a hierarchical meso-macroporous monolith and porous Vycor glass. For all materials, good correlation is found between calculated and experimental primary adsorption and desorption isotherms as well as desorption scans allowing for a determination of key pore network characteristics such as pore connectivity and pore size distributions as well as a parameter correlated with the impact of pore network disorder and corresponding effects on the adsorption behavior. The versatility and enriched textural insights provided by the proposed novel network model allows for a comprehensive characterization previously inaccessible, and hence will contribute to a further advancement in the textural characterization of novel nanoporous materials. It has the potential to provide important guidance for the design and selection of porous materials for optimising various applications, including separation processes (such as chromatography), heterogeneous catalysis, gas-and energy storage.

show abstract

Section: Introduction and Theorymentioning

confidence: 78%

Development and application of an advanced percolation model for pore network characterization by physical adsorption

Söllner,

Neimark,

Thommes

2024

Preprint

View full text Add to dashboard Cite

show abstract

“…This model is based on the Kelvin equation, and in this approach, the pore volume and diameter are derived by calculating the radius of curvature and thickness of the liquid-nitrogen film. This approach is the most commonly used theoretical model for calculating the diameter of cryogenic nitrogen adsorption pores . The BJH model can be expressed as follows: V ln = r n 2 false( r c n + normalΔ t n false) 2 ( Δ V n − Δ t n ∑ j = 1 n − 1 S j ) where V ln is the pore volume of layer n th; r n is the pore radius of layer nth ; r cn is the capillary radius within the nth pore; Δ V n is the desorption volume of the adsorbed nitrogen; Δ t n is the thickness of the n th adsorbed liquid nitrogen layer; S j is the sum of the average areas of the unfilled pores; the pores emptied during the n th desorption are not included.…”

Section: Results and Analysismentioning

confidence: 99%

Experimental Study on the Effects of High- and Low-Temperature Cyclic Impact on Pore and Fracture Distributions and Acoustic Emission Characteristics of Coal Measure Sandstone

Wang,

Kang,

Kang

et al. 2024

Energy Fuels

View full text Add to dashboard Cite

Sandstone is a common type of rock found in coal measure reservoirs, and its pore and fracture distributions are key factors influencing the comining of coal and gas. To improve the structure of coal measure reservoirs and enhance interlayer compatibility, a method for high-and low-temperature cyclic impact on sandstone was developed in this study, and the effects of high-temperature (+200 °C) and low-temperature (−196 °C) cyclic impacts (number of cycles: 0, 1, 5, 10, and 15) on the pore and fracture distribution characteristics of sandstone were investigated. Ultrasonic testing, low-temperature nitrogen adsorption tests, micro-CT scanning, uniaxial compression tests, and acoustic emission (AE) tests were employed to analyze and characterize the distribution patterns of the pores and fractures in sandstone under different impact conditions. With the increase in the number of high-and low-temperature cyclic impacts, the peak pore and fracture diameters and porosities of the sandstone samples were found to increase logarithmically, whereas the P-wave velocity, uniaxial compressive strength, and AE b value decreased logarithmically. After the fifth high-and low-temperature cyclic impact, the relative decay rate of the P-wave velocity and the increase in the porosity of the sandstone samples reached maximum, which were 20.86% and 20.98%, respectively. The application of highand low-temperature cyclic impact could promote the development of pore fractures and the emergence of secondary fractures in sandstone, forming a pore network. The cyclic thermal impact helped improve the pore fracture distribution and increase the number of transport channels for coal gas molecules, thus enhancing the permeability and interlayer compatibility of sandstone and creating the necessary conditions for the colayering and comining of coal and gas.

show abstract

“…e porosity characteristics are entirely determined by nitrogen sorption [82]. e adsorbed gas amount gives a complete description of the porosity state and even the overall structure [82][83][84][85][86]. Quantachrome NOVA 2000e series volumetric gas adsorption instrument, which is a USA automated gas adsorption system using nitrogen as the adsorptive, is used for the BET-specific surface area and PSD measurement.…”

Section: Adsorption Measurement and Porosity Investigationmentioning

confidence: 99%

“…Experience setting conditions are as follows: (i) adsorption isotherms are obtained at 77 K and at P/P0∼0.95 (relative pressure); (ii) the SA and PSD measurements require the removal of adsorbed nitrogen and oxygen. is is carried out under reduced pressure (vacuum) at 100 °C for 10 h. e desorption isotherms section, assuming a cylindrical pores model, is the basis of the application of the BJH method to define the PSD [82][83][84][85][86][87][88][89][90][91].…”

Section: Adsorption Measurement and Porosity Investigationmentioning

confidence: 99%

Impact of Uniaxial Mechanical Perturbation on Structural Properties and Smectite Porosity Features: Ion Exchanger Efficiency and Adsorption Performance Fate

Oueslati

Mejri

Amara

2022

Advances in Civil Engineering

View full text Add to dashboard Cite

The use of montmorillonite in the context of engineered barriers makes it possible to minimize the spread of heavy metals from industrial and even radioactive waste. An evaluation of the performance of the mechanisms controlling the clay-environment interaction and predicting the dynamics/configuration of the interlayer space (IS) is required. This work focuses on a quantitative identification of the structural changes and porosity alteration in the case of heavy metal-exchanged montmorillonite samples (Co2+ and Cd2+ cations) undergoing mechanical stresses (uniaxial oedometric test (loading/unloading)). Relationships between mechanical stress strength, intrinsic structural response, ion exchanger efficiency, and adsorption performance fate are investigated. This goal is achieved through the correlation of in situ quantitative X-ray diffraction (XRD) analysis (under an extremely controlled atmosphere reached by varying relative humidity rate %rh) and porosity investigation (assured by combining outcomes from BET (Brunauer–Emmett–Teller) and BJH- (Barrett, Joyner, and Halenda-) PSD (pore size distribution) analysis). Obtained results show an upsurge in the structural heterogeneities accompanying the theoretical increase in the mixed layer structure (MLS) number and developing an unconventional hydration behaviour after stress relaxation regardless of exchangeable cation nature. Experimental XRD patterns are reproduced using MLS, which suggests the coexistence of more than one “crystallite” specie and more than one exchangeable cation indicating a complex cation exchange capacity (CEC) saturation. For extremely low %rh value, a new homogeneous dehydrated state trend is observed in the case of the Co2+ cation. Porosity analysis shows mesopore volume growth for the stressed sample and confirms crystallite exfoliation layer trends, results of the layer cohesion damage, and subsequent constraint strength fluctuations.

show abstract

Pore network modeling of a solid desiccant for dehumidification applications

Cited by 7 publications

References 40 publications

Development and application of an advanced percolation model for pore network characterization by physical adsorption

Development and application of an advanced percolation model for pore network characterization by physical adsorption

Experimental Study on the Effects of High- and Low-Temperature Cyclic Impact on Pore and Fracture Distributions and Acoustic Emission Characteristics of Coal Measure Sandstone

Impact of Uniaxial Mechanical Perturbation on Structural Properties and Smectite Porosity Features: Ion Exchanger Efficiency and Adsorption Performance Fate

Contact Info

Product

Resources

About