Gas-Adsorption Chromatography

Киселев, А. В.; Yashin, Ya. I.

doi:10.1007/978-1-4899-6503-5

Cited by 232 publications

(220 citation statements)

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“…Similarly, the value for the adsorption heat of benzene onto shungite (49-55 kJ/mol) was somewhat higher than that for hexane (45 kJ/mol), and much higher than the values obtained for adsorption onto graphitised carbon black (41-42 kJ/mol) (Kiselev and Yashin 1969). This difference between the energy values strongly indicates the contribution of specific interaction between benzene molecules and the active centres present on the carbon and silica constituents of the mineral to the total adsorption energy.…”

Section: Resultsmentioning

confidence: 93%

Adsorption Properties of the Natural Carbon–Mineral Sorbent Shungite

Бондаренко

Tarasevich

Polyakov

et al. 2008

Adsorption Science & Technology

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Physicochemical methods were used for a comprehensive study of the structural/sorption properties of the natural mineral shungite. It was shown that the composite structure of the mineral determines its main physicochemical characteristics. The isosteric heat of adsorption of water vapour was estimated by calorimetric methods as 70 kJ/mol. This value corresponds to the interaction of water molecules with the vicinal hydroxy groups of the silica constituent of shungite; adsorption heats with values in the range 40-45 kJ/mol are characteristic of the carbon constituent of the sorbent. The heat of adsorption of benzene onto shungite was higher than that for hexane adsorption onto the mineral, indicating that specific interaction occurs between the benzene molecules and the active centres which exist on both the carbon and silica constituents of the mineral. It was shown that the adsorption parameters of shungite with respect to organic compounds which dissociate in an anionic manner suggest that the mineral could be applied as a filtering material with a sorptive action for water cleansing.

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Section: Resultsmentioning

confidence: 93%

Adsorption Properties of the Natural Carbon–Mineral Sorbent Shungite

Бондаренко

Tarasevich

Polyakov

et al. 2008

Adsorption Science & Technology

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“…The Gutmann approach involves a simple four-parameter equation, with an acid and base term for each amphoteric polar probe according to Eq 6: For the determination of of pentan-2-ol and hexan-3-ol, it was assumed that the adsorption enthalpy was independent on temperature on the range studied. was then obtained from a plot of ln(V G /T) versus , according to Eq 7, derived from the ClausiusClapeyron equation , giving the differential isosteric heat of adsorption ∆H st , by plotting ln p versus 1/T, applied to chromatographic data at infinite dilution, which are necessarily isosteric (constant adsorbate coverage of zero) [25,26].…”

Section: Theory Of Igcmentioning

confidence: 99%

Lipase hydration state in the gas phase: Sorption isotherm measurements and inverse gas chromatography

Márton

Chaput

Pierre

et al. 2010

Biotechnology Journal

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Fax : +33 5 46 45 82 65Abbreviations: IGC, Inverse Gas Chromatography a W , water thermodynamic activity, CALB, Candida antarctica Lipase B, BET, Brunauer-Emmet-Teller. AbstractThe adsorption of water and substrate on immobilized Candida antarctica lipase B was studied by performing adsorption isotherm measurements and using Inverse Gas Chromatography (IGC). Water adsorption isotherm of the immobilized enzyme showed singular profile absorption incompatible with the BET model, probably due to the hydrophobic nature of the support, leading to very low interactions with water. IGC allowed determining the evolution with a W of both dispersive surface energies and acidity and basicity constants of immobilized enzyme. These results showed that water molecules progressively covered immobilized enzyme, when increasing a W , leading to a saturation of polar groups above a W 0.1 and full coverage of the surface above a W 0.25. IGC also enabled relevant experiments to be performed to investigate the behavior of substrates under a W that they will experience, in a competitive situation with water. Results indicated that substrates had to displace water molecules in order to adsorb on the enzyme from a W values between 0.1 to 0.2, depending on the substrate. As the conditions used for these adsorption studies resemble the ones of the continuous enzymatic solid/gas reactor, in which activity and selectivity of the lipase were extensively studied, it was possible to link adsorption results with particular effects of water on enzyme properties.

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“…Gas adsorption chromatography has been used in many instances to measure the thermodynamic functions of adsorption on various adsorbents [7]. Graphitized carbon black is a priviledged adsorbent for hydrocarbons as symmetrical peaks are observed.…”

Section: Ln (Vn/a) = Ln K H Rt + 2b2d Na + 2b12 Po J4/rt (12)mentioning

confidence: 99%

“…A general survey of the thermodynamics of HPLC has recently been published [5]. This work will be limited to the study of the infinite dilution chromatography since measurements at finite concentration permits the determination of equilibrium isotherm in both gas-liquid [6], gas-adsorption [7] and liquid-adsorption [8,9] systems.…”

Section: Introductionmentioning

confidence: 99%