Adsorption in micropores

Dubinin, M. M.

doi:10.1016/0021-9797(67)90195-6

Cited by 416 publications

(133 citation statements)

References 6 publications

Supporting

Mentioning

123

Contrasting

Unclassified

Order By: Relevance

“…The fundamentals of the adsorption model and of the characteristic curve of adsorption can be taken from Polányi [19] and Dubinin [21]. The energy balances for the adsorbate and the adsorbent are given in equations (6) and (7).…”

Section: Modeling Sectionmentioning

confidence: 99%

Influence of different adsorbates on the efficiency of thermochemical energy storage

Kohler

Müller

2017

Energy Science & Engineering

View full text Add to dashboard Cite

Thermal energy storage can be divided in three main categories: the storage of sensible heat, latent heat, and thermochemical heat [1]. Thermochemical heat storage is divided into storage by adsorption and storage by reaction [2]. In this work, the focus lies on the thermochemical adsorptive heat storage, which follows the mechanism shown in Scheme 1, where two components A (adsorbent) and B (adsorbate) either interact physically or react chemically [3]. The interaction or reaction of the surface A and the adsorbate B to the adsorbed species AB is exothermic and therefore releases heat which can be utilized. If energy in form of heat has to be stored, the endothermic reverse process of AB to A and B is performed.All examined adsorption systems in this work follow the mechanism of physisorption only. The energy is stored through the enthalpy of adsorption, which results from attractive forces between the adsorbate and the adsorbent (plus contributions from interactions between molecules of the adsorbate). Under the assumption of an adiabatic adsorbent fixed bed, the only loss in the process is the sensible heat, which is needed to heat the adsorbent in the adsorption and desorption process. This loss is mainly effected by the isobaric heat capacity of the adsorbent. The operation of an adsorptive energy storage system is shown in Scheme 2. If energy, in this case heat, is needed, a gas stream which is saturated with the adsorbate flows through the adsorber (A). The adsorption of the adsorbate releases heat, which heats the gas stream. AbstractThe main influencing parameter on the efficiency of adsorptive thermochemical energy storage is the efficiency of the desorption process, which is influenced by the process conditions, for example, desorption time and desorption temperature, and the working pair (adsorbent-adsorbate). Due to constrained process requirements, for example, hours of sun shine and low desorption temperatures available from a flat plate solar collector (333-373 K), the only possibility to increase the efficiency is to change the working pair. The reference working pair water-zeolite 13X needs high desorption temperatures of 500 K and high heat inputs per mass adsorbent (1080 kJ kg −1 ) in the desorption process to reach the maximum efficiency of 79 % and maximum energy density of 844 kJ kg −1 . Therefore, the goal is to reach efficiencies in the same range as the maximum efficiency of water-zeolite 13X for desorption temperatures lower than 500 K with the usage of different adsorbates. Four systems of alcohol as adsorbate on activated carbon are compared with the reference working pair. The usage of alcohols on activated carbon allows for highly efficient adsorptive storage even at low desorption temperatures between 360 and 450 K. The maximum efficiency is shifted to higher desorption temperatures with increasing carbon chain length of the alcohol. At low desorption temperatures, the energy density and efficiency of methanol, ethanol, and propanol are higher than the energy density of the refer...

show abstract

Section: Modeling Sectionmentioning

confidence: 99%

Influence of different adsorbates on the efficiency of thermochemical energy storage

Kohler

Müller

2017

Energy Science & Engineering

View full text Add to dashboard Cite

show abstract

“…The micropore filling theory was first proposed by Dubinin to study vapor adsorption in microporous solids (Dubinin, 1967). This theory assumes that the adsorbate fills the adsorption space via the mechanism of volume filling, and hence it does not form discrete monolayers in micropores (Dubinin and Astakhov, 1971).…”

Section: Micropore Filling Theorymentioning

confidence: 99%

“…Organic-rich shale has a broad pore size distribution with a significant proportion of micropores (< 2 nm), mesopores (2-50 nm), and macropores (> 50 nm) according to the pore size classification of the International Union of Pure and Applied Chemistry (IUPAC) (Sing et al, 1985). However, the mechanisms of gas adsorption are different in micropores and mesopores (Dubinin, 1967;Findnegg, 1983;Li et al, 2017). In micropores, gas molecules are adsorbed in the form of pore filling (Dubinin, 1967), which is caused by the overlapping of the adsorption potential from both sides of the pore wall surfaces (Mosher et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…However, the mechanisms of gas adsorption are different in micropores and mesopores (Dubinin, 1967;Findnegg, 1983;Li et al, 2017). In micropores, gas molecules are adsorbed in the form of pore filling (Dubinin, 1967), which is caused by the overlapping of the adsorption potential from both sides of the pore wall surfaces (Mosher et al, 2013). On the other hand, in mesopores, gas molecules are adsorbed as a single layer on the pore wall surfaces (Do and Do, 2003).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of methane adsorption mechanism on Longmaxi shale by combining the micropore filling and monolayer coverage theories

Zhou

Yang

Wang

et al. 2018

Adv. Geo-Energy Res.

View full text Add to dashboard Cite

Abstract:Understanding the methane adsorption mechanism is critical for studying shale gas storage and transport in shale nanopores. In this work, we conducted low-pressure nitrogen adsorption (LPNA), scanning electron microscopy (SEM), and high-pressure methane adsorption experiments on seven shale samples from the Longmaxi formation in Sichuan basin. LPNA and SEM results show that pores in the shale samples are mainly nanometersized and have a broad size distribution. We have also shown that methane should be not only adsorbed in micropores (< 2 nm) but also in mesopores (2-50 nm) by two hypotheses. Therefore, we established a novel DA-LF model by combining the micropore filling and monolayer coverage theories to describe the methane adsorption process in shale. This new model can fit the high-pressure isotherms quite well, and the fitting error of this new model is slightly smaller than the commonly used D-A and L-F models. The absolute adsorption isotherms and the capacities for micropores and mesopores can be calculated using this new model separately, showing that 77% to 97% of methane molecules are adsorbed in micropores. In addition, we conclude that the methane adsorption mechanism in shale is: the majority of methane molecules are filled in micropores, and the remainder are monolayer-adsorbed in mesopores. It is anticipated that our results provide a more accurate explanation of the shale gas adsorption mechanism in shale formations.

show abstract

“…These results were explained in terms of substitution for some adsorbed water as well as adsorption of ethanol into the micropores. The following DA equation was known to correlate with the adsorption data of organic solvents on activated carbon (Dubinin, 1960(Dubinin, , 1967 , calculated for binary adsorption; ---, calculated for pure adsorption; values (q*,) of water-ethyl acetate system (Miyauchi et al, 1995b). triacetin added in the process of molding the filter. The value of qe for the binary vapor was less than that for the pure one.…”

Section: Adsorption Isothermsmentioning

confidence: 99%

A New Ethanol Adsorption Treatment to Decrease Flavor and Water Migration during Storage of a Tobacco Product.

Miyauchi

Miyake

Nakanishi

et al. 1995

FSTI

View full text Add to dashboard Cite

A new "Ethanol Adsorption Treatment" (EAT) for a filter has been presented to depress the migration of volatile flavor and water in a box of a tobacco product during storage and marketing. The EAT is performed by applying the binary vapor of water and ethanol to the filter tip before connecting it with a tobacco column. During the EAT, ethanol was adsorbed physically on the filter as an additive agent, and thus the water content within the filter tip was controlled to a desirable level at which the water does not migrate. Then during storage, the presence of ethanol vapor depressed the flavor migration mainly by decreasing the amounts of flavors adsorbed on the activated carbon within the filter tip. The EAT was confirmed to be effective for decreasing both the water and flavor migration simultaneously.

show abstract

Adsorption in micropores

Cited by 416 publications

References 6 publications

Influence of different adsorbates on the efficiency of thermochemical energy storage

Influence of different adsorbates on the efficiency of thermochemical energy storage

Investigation of methane adsorption mechanism on Longmaxi shale by combining the micropore filling and monolayer coverage theories

A New Ethanol Adsorption Treatment to Decrease Flavor and Water Migration during Storage of a Tobacco Product.

Contact Info

Product

Resources

About