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Two microporous carbons, derived from the same phenolic resin at 700 and 1000°C, were investigated by volumetric and gravimetric adsorption of CO 2 and N 2 at different temperatures. The combination with immersion calorimetry into liquids of different molecular sizes reveals the presence of constrictions near 0.4-0.45 nm leading into relatively large micropores. The size of the constrictions...
High pressure adsorption data of methane and hydrogen on four microporous carbons were obtained at supercritical temperatures. The data were analyzed on the basis of the Potential Theory using the Dubinin-Astakhov (D-A) equation. The method for estimating pseudo-vapor pressures proposed by Dubinin resulted in characteristic curves for methane but failed for the hydrogen data. A more general form...
Nitrogen-containing chars were prepared by low-temperature carbonization (460°C) of compounds containing pyrrolic, pyridinic, amino and cyano groups. The changes of precursor functionalities and transformation of nitrogen structures at 600 and 800°C were determined by X-ray photoelectron spectroscopy. From all precursors, at low-temperature carbonization, three types of nitrogen structure were obtained:...
Pyrolysis of used tires yields oil and pyrolytic carbon black (CB P ). The tire pyrolysis process can be performed either in vacuo or at atmospheric pressure. The CB P recovered in both processes are different from the commercial carbon blacks used in the tire fabrication. Different spectroscopic methods such as ESCA, SIMS, Auger-spectroscopy and XRD were used to characterize CB...
Based on the experimental results, and on the analysis of the chemistry of cyanide ion bonding, possible mechanisms of bonding of this pollutant were assumed and confirmed. Activated carbon cloth (ACC) was impregnated with metalorganic compounds consisting of the following cations: copper, silver, iron, magnesium and aluminum, and the following anions: acetate, oxalate, tartrate, stearate and citrate...
The deactivation of Cu-Cr impregnated carbon in the course of cyanogen chloride adsorption was examined. XPS study shows that the Cu(2+) and Cr(6+) content of a surface of fresh carbon is not significantly different from that of a used one. Consequently, it is assumed that deactivation results not only from changes that have taken place in these species but also from a blockage of active sites by...
The discharge capacity of ribbonlike carbon film with a disordered structure as an anode exceeds the theoretical capacity of graphite anode. In order to explain the phenomenon, a model for the interactions between disordered carbon and lithium in lithium ion rechargeable batteries has been proposed. The model is based on the assumptions that for the disordered carbon with a small crystallite size,...
A continuous powder coating process was used to produce flexible, preimpregnated towpreg from a heat-treated Mitsubishi AR mesophase pitch powder (AR-120) and three different carbon fibers: T300 PAN-based fiber, P55 pitch-based fiber, and an experimental high thermal conductivity pitch-based ribbon fiber. The towpreg was hot-pressed into unidirectional composites, carbonized at 1100°C, oxidized and...
Microtextural evolution in furan resin-derived carbon was investigated. The evolution was mainly studied from the viewpoint of the change in microtexture of surface and internal pores with heat-treatment and was characterized by observation with a scanning electron microscope, measurement of the BET surface area, X-ray diffraction and Raman spectroscopy. Microporous layers, about 60 μm thick, were...
Adsorption equilibria in slit pores are calculated using an analytic solution of the classical Ono-Kondo equation with modified boundary conditions. A new equation is developed for isotherms of gas adsorption on microporous adsorbents. This equation describes isotherms of Type I in the IUPAC classification scheme for temperatures below the critical point and also describes the unusual adsorption...
In this article the formation of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) on waste incinerator fly ash is described. Model experiments were performed by heating organic-C-free fly ash with organic model compounds. Both chlorobenzenes and phenol form PCDD and PCDF via condensation reactions. Phenol is 10-540 times as reactive as the chlorobenzenes. A second...
Iron benzoate and naphthoate were studied as catalyst precursors of an iron-catalyzed pyrolysis of a coal-tar pitch as a technical hydrocarbon mixture and of anthracene as an aromatic model compound. The results are compared with those obtained with ferrocene, which has been studied previously. Both iron compounds are decomposed by formation of iron clusters at a much lower temperature than ferrocene...
Commercially available carbon molecular sieve (CMS) materials, from a variety of sources, and molecular sieving carbons produced from the carbonization of coal have been studied. These materials have been assessed in terms of their kinetics of adsorption of oxygen and nitrogen. The diffusion kinetics of gases into the carbons have been analysed using Fickian and phenomenological models. The Arrhenius...
The thermal desorption process of phenol, m-aminophenol, p-cresol and p-nitrophenol from an activated carbon has been studied. For this purpose, the activated carbon-phenolic compound system was heated to 1100 K in a He flow following determination of weight loss and the evolution of light gases by a thermobalance and by mass spectrometry, respectively. Results showed that during the heat treatment,...
CO 2 decomposition to carbon was studied on α-Fe and Fe-Ni alloy formed by H 2 -reduction of magnetite and Ni(II)-bearing ferrite at 300°C. The metallic phases were transformed to ferrite phase by incorporating oxygen from CO 2 . The integrated amount of decomposed CO 2 reached 30 mmol CO 2 g -1 of Fe 3 O 4 by repeating the H ...
Deintercalation of CuCl 2 -intercalated graphite has been studied under two different conditions: during exposure to ambient air and to boiling water. The real-time X-ray powder diffraction method was used to follow the diffusion-controlled deintercalation reaction. The estimation of the phase composition at any time during the reaction enabled us to visualize the development of concentration...
Oriented carbon films with turbostratic structure were prepared from a commercially available polyimide film Novax, and X-ray diffraction (XRD) measurements including mosaic spread were made for the carbon films in reflection and transmission modes. The diffraction patterns for the oriented carbon films with turbostratic structure can be characterized by the 00l lines observed only in the reflection...
The effect of impurities on the anode carbon consumption in aluminium electrolysis was studied in a closed laboratory cell, which allowed the determination of the total carbon consumption (CC), the carbon gasification (CG) and the formation of carbon dust (CD). Addition of V 2 O 3 made CC, CG and CD all increase while LiCl addition caused CC and CG to increase, and CD to remain constant...
The results of this paper have shown that the ternary stage-2 CrO 3 -H 2 SO 4 -graphite intercalation compound is electrochemically formed on the subsequent intercalation of H 2 SO 4 into the host stage-5 CrO 3 -GIC/graphite matrix. In contrast to the binary H 2 SO 4 -GIC easily deintercalated upon cathodic reduction, stage-(4-6) CrO...
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