Gas permeation through porous glass membranes

Markovic, A.; Stoltenberg, Daniel; Enke, Dirk; Schlünder, Ernst‐Ulrich; Seidel‐Morgenstern, A.

doi:10.1016/j.memsci.2009.02.030

Cited by 24 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This effect may also be related to pore shape nonideality because it is highly unlikely that pores created by leaching out a precipitated phase will be cylindrical as assumed in the theory. In support of these arguments, it may be noted that a decrease in the nominal pore diameter to about 1.4 nm reduced the permeability by 30−200 times, as is evident from data in a companion publication by Markovic et al Such a large decrease in this pore size range could not be explained by a cylindrical pore model and suggests structural irregularities and/or pore mouth effects. More detailed studies and characterizations of the structure are needed to confirm this.…”

Section: Resultsmentioning

confidence: 85%

Modeling Pure Gas Permeation in Nanoporous Materials and Membranes

Bhatia

2010

Langmuir

View full text Add to dashboard Cite

The low-pressure transport of simple fluids in nanopores and in disordered nanoporous networks is analyzed, using a recent oscillator model theory from the author's laboratory, considering the trajectories of molecules moving in the potential energy field of the fluid-pore wall interaction. The scaling behavior of the single-pore theory is discussed, and it is shown that the Knudsen model provides an upper bound to the diffusivity scaled with the pore radius. The single-pore theory is shown to apply well to ordered materials and successfully interprets recent literature data on the variation of permeability with diffusant molecular size for a DDR zeolite membrane. A peak in permeability is seen at a pore-size-dependent molecular size because of the opposing effects of equilibrium and transport. Application to disordered pore networks is also presented on the basis of a hybrid correlated random walk effective medium theory imbedding the oscillator model at the single-pore level, and a rigorous expression for the tortuosity is derived from the theory. A rich variety of behavior is predicted for the tortuosity, which can increase or decrease with increasing extent of pore size nonuniformity as well as with changes in temperature because the diffusing species preferentially flows through more conducting pores. Weakly adsorbing gases such as helium are seen to have a higher tortuosity than more strongly adsorbing ones. The predicted values of tortuosity are shown to be in line with those obtained from the interpretation of recent experimental mesoporous membrane transport data and are in the range of 5-10 whereas those extracted using the Knudsen model are unrealistically high, in the range of 10-20.

show abstract

Section: Resultsmentioning

confidence: 85%

Modeling Pure Gas Permeation in Nanoporous Materials and Membranes

Bhatia

2010

Langmuir

View full text Add to dashboard Cite

show abstract

“…Membranes prepared using this method usually exhibit higher permeance in contrast to those prepared with the chemical vapour deposition methods. Inorganic membrane may be classified based on their pore size as macrospores (>500 Å), mi-cropores (20 Å) and mesopores (20 -500 Å) [8]. Gas transport in inorganic membranes may be explained using various mechanism of transport through the pore.…”

Section: Introductionmentioning

confidence: 99%

Advanced Catalytic Membrane Characterisation and Gas Permeation Properties for Enhanced Ethyl Lactate Conversion

Okon¹,

Shehu²,

Orakwe³

et al. 2017

MSCE

View full text Add to dashboard Cite

In this work, membrane evaluation, gas permeation properties and characterisation have been presented. A silica composite membrane was prepared, characterized and used for the permeation tests with four carrier gases to determine the most suitable carrier gas for enhancing the analysis of esterification product with gas chromatograph. The carrier gases used for the permeation tests were carbon dioxide (CO 2 ), argon (Ar), helium (He) and nitrogen (N 2 ). The permeation analysis was carried out between the gauge pressure range of 0.10 -1.00 bar and temperature of 60˚C. The gas flow rate was found to increase with respect to gauge pressure. The order of the gas flow rate with respect to the gauge pressure was Ar > CO 2 > He > N 2 . The surface morphology and elemental composition of the membrane were analysed using scanning electron microscopy coupled with energy dispersive analysis of x-ray (the Zeiss EVO LS10). The SEM results exhibited a defect-free surface while the EDAX results identified different elements on the spectra including titanium (Ti), silicon (Si) and oxygen (O). Liquid nitrogen adsorption method (Quantachrome 2013 model) was used for the surface area and pore size distribution analysis. The Brunauer-Emmette-Teller (BET) surface area results of the 5 th and 6 th dip-coated membranes were 1.497 and 0.253 m 2 /g respectively, while the Barrette-Joyner-Halender (BJH) curves gave a pore size of 4.184 and 4.180 nm respectively for the 5 th and 6 th dip-coated membranes indicating a mesoporous structure. The BET curve exhibited a type IV isotherm. The BJH curve of the 6 th dip-coated membrane showed a significant reduction in flow rate after the modification process. The membrane recorded a permeance in the range of 6

show abstract

“…Despite having no confirmed molecular basis, there are several investigations introducing an Arrhenius‐type activation factor to incorporate the potential barrier in the Knudsen formulation even for the least adsorbing gases (see Ref . and references there in).…”

Section: Introductionmentioning

confidence: 99%

Pore network simulation for diffusion through a porous membrane: A comparison between Knudsen and Oscillator models

2013

View full text Add to dashboard Cite

Low density permeations of some gases (He, H2, N2, CH4, CO2 and CF4) through micro‐ and mesocarboneous pores were investigated using Knudsen and Oscillator models. Lennard‐Jones model in single layer pores was used to simulate the gas–solid interactions in the Oscillator model. The effects of the pore radius as well as the molecular size and the temperature on the pore diffusivity and the activation energy were studied. The Monte Carlo simulation was then performed to calculate the permeability of these gases in three‐dimensional cubic networks of different connectivities (2.5–6) and different pore size distributions (ra = 2.74 and 6.95 nm). It was shown that for networks with larger pores there is a minor difference between the two models, while a large discrepancy exists in networks with fine pores. Both models tend to have the same permeability as the coordination number decreases. To investigate the accuracy of the models, the simulation results were compared with the experimental selectivities of some pure gases in two different membranes extracted from the literature. It was shown that the Oscillator model can better predict the experimental data in the membranes of smaller pores (i.e. ra = 2.74 nm). However, both models were comparable in membranes of larger pores (ra = 6.95 nm). The capability of the models to predict the activation energy of the diffusion was also studied.

show abstract

Gas permeation through porous glass membranes

Cited by 24 publications

References 17 publications

Modeling Pure Gas Permeation in Nanoporous Materials and Membranes

Modeling Pure Gas Permeation in Nanoporous Materials and Membranes

Advanced Catalytic Membrane Characterisation and Gas Permeation Properties for Enhanced Ethyl Lactate Conversion

Pore network simulation for diffusion through a porous membrane: A comparison between Knudsen and Oscillator models

Contact Info

Product

Resources

About