Pore structure and chemical state of the surface of carbon adsorbents Communication 1. Selection of the comparative isotherm of adsorption of nitrogen vapors on the surface of carbon adsorbents

Волощук, А. М.; Dubinin, M. M.; Moskovskaya, T. A.; Ivakhnyuk, G. K.; Fedorov, N. F.

doi:10.1007/bf00957410

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…It seems that thermally graphitized soot with a surface presenting structural and energetic homogeneities is the best choice among sootlike adsorbents. The generalized standard adsorption isotherms for C 6 H 6 and N 2 on graphitized soots have been elaborated in Isirikian and Kiselev and Voloshchuk et al ., respectively, and used in our analysis. A linear comparative plot means high similarity of the adsorption isotherms for the studied soot and for the standard graphitized soot.…”

Section: Resultsmentioning

confidence: 99%

Microstructure and Water Adsorbability of Aircraft Combustor Soots and Kerosene Flame Soots: Toward an Aircraft-Generated Soot Laboratory Surrogate

Popovicheva¹,

Persiantseva²,

Kuznetsov³

et al. 2003

J. Phys. Chem. A

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The morphology, microstructure, surface area, porosity, and chemical composition of soot particles emitted from a gas-turbine combustor have been studied. Combustor soot particles appear to be chemically and structurally unstable and present microporosity and a strongly disordered graphitic structure. Discrepancies between the properties of combustor-generated soots arise from their postformation conditions, quenching environments, and sampling conditions. During long accumulation time, soot collected on the combustor walls experiences graphitization and oxidation. Upon long processing by hot exhaust gases, soot particles collected far from the combustor exit exhibit significant transformations (1) from paracrystalline to nodular amorphous microstructure and (2) from spherical particles to fused agglomerates following the increase in microporosity and oxygen content. Combustor-generated soot properties are compared to those of kerosene flame soot, which is produced in the laboratory and is proposed to be a surrogate of combustor soot for atmospheric studies. It is shown that the chemical composition, porosity, and extent of graphitization of combustor-generated and kerosene flame soots influence their electrical and hygroscopic properties. The characteristics of kerosene soot appear to be close to those of combustor soot but exhibit a number of specific feature variations such as graphitized nanostructure and ultramicroporosity, which influence its water adsorbability.

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Section: Resultsmentioning

confidence: 99%

Microstructure and Water Adsorbability of Aircraft Combustor Soots and Kerosene Flame Soots: Toward an Aircraft-Generated Soot Laboratory Surrogate

Popovicheva¹,

Persiantseva²,

Kuznetsov³

et al. 2003

J. Phys. Chem. A

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“…The specific surface of samples was determined using the Brunauer-Emmett-Teller (BET) method [10]. The surface of mesopores was evaluated using comparative methods: t-plot and micropore (MP) analysis methods [10][11][12]. The samples of TiO 2 /Al 2 O 3 belong to mesoporous adsorbents containing a small amount of micropores and representing aerogels.…”

Section: Methodsmentioning

confidence: 99%

“…The samples of TiO 2 /Al 2 O 3 belong to mesoporous adsorbents containing a small amount of micropores and representing aerogels. From the slope of the initial segment of a comparative MP plot, the total specific surface was determined, and from the comparative plot in the region of polymolecular adsorption the surface of mesopores was found according to the MP method [12]. From the t-plot method [10] the relations between the volume and surface of micro-and mesopores were determined ( Table 2).…”

Section: Methodsmentioning

confidence: 99%

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Structural transformation of TiO2/Al2O3 nanowires into nanotubes caused by high-temperature hydrogen treatment

et al. 2016

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It has been shown that the high-temperature hydrogen treatment of aluminum oxide nanowires coated with a monolayer of titanium oxide causes them to curl into nanotubes as a result of self-organization. The physicochemical properties of the nanotubes of a composite aluminum oxide aerogel coated with titanium oxide have been studied using X-ray phase analysis (XRD) and transmission electron microscopy (TEM). As a result of TiO 2 /Al 2 O 3 nanofibrous aerogel treatment with hydrogen, a conversion of amorphous aluminum oxide fibers into tubes of nanocrystalline η-Al 2 O 3 occurs, but in this case the titanium dioxide monolayer does not form a separate phase. A study of the porous structure by the low-temperature adsorption of nitrogen vapors has shown that the aerogels of TiO 2 /Al 2 O 3 nanotubes have a developed mesoporous structure with a small amount of micropores and a specific surface of more than 300 m 2 /g. An increase in the temperature of hydrogen treatment first leads to the growth of an increase in the specific surface to 348 m 2 /g at 923 K, and then to a gradual decrease to 145 m 2 /g at 1123 K. In this case, the diameter of mesopores corresponding to a maximum on a curve of the pore size distribution decreases from 35 nm for a freshly prepared sample to 25 nm at 923 K and to 20 nm at 1123 K. The most homogeneous pores of a 25 nm diameter have the samples activated at 923 K. As a result of the high-temperature hydrogen treatment of the samples, the number of primary adsorption centers of water vapor adsorption decreases about two times. The resulting samples of TiO 2 /Al 2 O 3 aerogels are close in structure to the initial aluminum oxide, whose wires just form nanotubes having a surface coated with titanium dioxide. As a result of the interaction between molecules of titanium dioxide adsorbed on the surface of aluminum oxide tubes, a substantial densification of the composite structure occurs.

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Rumpled graphite basal plane as a model heterogeneous carbon surface

Бакаев

1995

The Journal of Chemical Physics

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A new model is suggested for the heterogeneous surfaces of nongraphitized carbon adsorbents. It may be called the rumpled graphite basal plane (RGBP). The atomic structure of RGBP can be obtained by squeezing a graphite basal plane in a molecular dynamics computer simulation under a random distribution of initial atomic velocities. The empirical Tersoff potential describes the carbon–carbon interactions. The degree of squeezing is chosen to reproduce the main features of the x-ray interference function of nongraphitized carbon blacks. Grand canonical ensemble Monte Carlo simulation of the isotherms of adsorption of N2 on RGBP reproduce experimental isotherms on these carbon blacks reasonably well, especially in the BET region of relative pressures.

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Pore structure and chemical state of the surface of carbon adsorbents Communication 1. Selection of the comparative isotherm of adsorption of nitrogen vapors on the surface of carbon adsorbents

Cited by 6 publications

References 7 publications

Microstructure and Water Adsorbability of Aircraft Combustor Soots and Kerosene Flame Soots: Toward an Aircraft-Generated Soot Laboratory Surrogate

Microstructure and Water Adsorbability of Aircraft Combustor Soots and Kerosene Flame Soots: Toward an Aircraft-Generated Soot Laboratory Surrogate

Structural transformation of TiO2/Al2O3 nanowires into nanotubes caused by high-temperature hydrogen treatment

Rumpled graphite basal plane as a model heterogeneous carbon surface

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