Measurements and Dubinin–Astakhov correlation of adsorption equilibria of toluene, acetone, n-hexane, n-decane and methanol solutes in supercritical carbon dioxide on activated carbon at temperature from 313 to 353 K and at pressure from 4.2 to 15.0 MPa

Ushiki, Ikuo; Ota, Masaki; Satō, Yoshiyuki; Inomata, Hiroshi

doi:10.1016/j.fluid.2013.01.014

Cited by 34 publications

(41 citation statements)

References 52 publications

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“…Most of them selected activated carbon as an adsorbent mainly because of its large adsorption capacity and high affinity to many organics. Our study also reported adsorption equilibria of VOCs on activated carbon in supercritical and pressurized CO 2 at temperatures from 313 to 353 K and pressures from 4.2 to 15.0 MPa [24,25].…”

Section: Introductionmentioning

confidence: 69%

“…As a result, the DA equation demonstrated satisfactory correlations of the adsorption equilibria on activated carbon within 6.5% of average relative deviation [25]. In addition, it was indicated that the DA parameters notably depended on adsorbates properties and CO 2 density [25]. Therefore, in the cases of mesoporous silica, the DA equation can be an effective model to provide quantitative understandings of the adsorption phenomena in the scCO 2 systems.…”

Section: Introductionmentioning

confidence: 80%

“…Additionally, in the cases of activated carbon as an adsorbent, our works [24,25] pointed out that the amount of adsorbed VOC strongly depended on CO 2 density that dramatically varies with temperature and pressure under scCO 2 conditions. Accordingly, in the cases of mesoporous silica, it must be important to investigate the adsorption equilibria over a wide range of CO 2 density condition.…”

Section: Introductionmentioning

confidence: 93%

“…Therefore, it is important to provide quantitative information about adsorption phenomena on silica with fitting parameters determined by appropriate models to the scCO 2 systems. In the cases of VOCs adsorption equilibria on activated carbon in scCO 2 [25], we adopted the Dubinin-Astakhov (DA) equation [40] (see also Eqs. (7)-(9)).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

VOCs (acetone, toluene, and n-hexane) adsorption equilibria on mesoporous silica (MCM-41) over a wide range of supercritical carbon dioxide conditions: Experimental and theoretical approach by the Dubinin–Astakhov equation

Ushiki

Ota

Satō

et al. 2015

Fluid Phase Equilibria

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Section: Introductionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

VOCs (acetone, toluene, and n-hexane) adsorption equilibria on mesoporous silica (MCM-41) over a wide range of supercritical carbon dioxide conditions: Experimental and theoretical approach by the Dubinin–Astakhov equation

Ushiki

Ota

Satō

et al. 2015

Fluid Phase Equilibria

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“…Based on the micropore filling theory and Polanyi adsorption potential theory, the Dubinin-Radushkevich (D-R) and Dubinin-Astakhov (D-A) equations have been developed to model Type I adsorption isotherms (Foo and Hameed, 2010;Pini et al, 2010;Ushiki et al, 2013;Hao et al, 2014). The two equations were considered to provide an appropriate description of the adsorption phenomena occurring in the adsorbent micropores.…”

Section: Micropore Filling Theorymentioning

confidence: 99%

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.

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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.

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Supercritical Fluid Extraction of Organics in Environmental Analysis

Benner

2015

Encyclopedia of Analytical Chemistry

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Supercritical fluids (SFs) possess several physical properties that make them attractive substitutes for conventional liquid solvents in analytical‐scale extractions. Molecular diffusivities of SFs are typically a factor of 10 greater (10 −4 cm 2 s −1 versus 10 −5 cm 2 s −1 ) and their viscosities are a factor of 10 lower (10 −4 N s m −2 versus 10 −3 N s m −2 ) than liquid solvents. These properties improve the rate of mass transfer of solutes from the matrix surface to the bulk extractions fluid – a transfer believed to be the rate‐limiting step of most extractions. Under optimized conditions, the improvements in mass transfer can enable a supercritical fluid extraction (SFE) to be completed in <1 h compared to ≥12 h for extractions involving conventional solvent techniques, while generating little solvent waste compared with traditional extraction methods. Significant limitations in the efficiency of SFE due to differences in sample composition (matrix effect) have been discussed in the past 15 years and have reduced its impact on environmental analysis. The ability of SFE with CO 2 to simulate (in minutes) long‐term leeching of pollutant species from soils and sediments, however, has enabled researchers to predict the efficacy of bioremediation and may be SFE's most important contribution to environmental analytical chemistry. This review discusses the progress made over the past nearly 30 years in SFE as an alternative technique to liquid solvent extractions of environmental samples for the subsequent measurement of organic constituents.

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Measurements and Dubinin–Astakhov correlation of adsorption equilibria of toluene, acetone, n-hexane, n-decane and methanol solutes in supercritical carbon dioxide on activated carbon at temperature from 313 to 353 K and at pressure from 4.2 to 15.0 MPa

Cited by 34 publications

References 52 publications

VOCs (acetone, toluene, and n-hexane) adsorption equilibria on mesoporous silica (MCM-41) over a wide range of supercritical carbon dioxide conditions: Experimental and theoretical approach by the Dubinin–Astakhov equation

VOCs (acetone, toluene, and n-hexane) adsorption equilibria on mesoporous silica (MCM-41) over a wide range of supercritical carbon dioxide conditions: Experimental and theoretical approach by the Dubinin–Astakhov equation

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

Supercritical Fluid Extraction of Organics in Environmental Analysis

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