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111. Ion exchange properties of gel-filtrated nitro-humic acid
ABSTRACTS
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results were interpreted in terms of an oxygen transfer mechanism involving oxidation and reduction of a copper-cupric oxide system. 108. Oxidation of graphite powder in carbon dioxide oxygen and air K. Seibold (Lonza Ltd., Sins, Switzerland). Oxidation of graphitized coke and anthracite in COZ is only to a small degree chemically controlled even as a fine powder. Reaction rates are increased upon addition of inert gas. The oxidation of powder in oxygen proceeds purely chemical while the reaction rate in air is diffusion controlled. 109. Change in properties and structure of carbon fibers during oxidation J. B. Donnet, H. Dauksch and E. Papirer (Centre o!eRecherches SW la Physico-Chemie des Surfaces Solides 24,682OO M&house, France). AC(H.T.T. = llOO°C) and AG(H.T.T. = 2500°C) carbon fibers, both formed from an acrylic precursor, have been treated with nitric acid and graphite oxide forming reagents. AC fibres are rapidly attacked by nitric acid whilst AG fibers resist the oxidation. Graphite oxide can be formed on the surface or in the bulk of AG fibers. Under the same conditions, AC fibers only give small amounts of degradation products. 110. High resolution electron micrography of oxidized and dellagrated carbon fibers and powders J. B. Donnet, A. Voet, P. Ehrburger, E. Papirer (Centre de Recherches SW la Physico-Chemie o!esSurfaces Solides, 68200 Mu/house, France) and P. A. Marsh (J. M. Huber Corporation, Borger, Texas). In carbon fibers produced from polyacronitrile carbonized at temperatures below 1 lOO”C, extensive graphitized areas were observed in oxidized specimen. By oxidation of graphitic carbons by agents promoting laminar intercalation, superficial graphitic oxide layer planes were produced. Upon deflagration, the graphitic oxide is not only decomposed, but the remaining carbon planes are also disturbed, creating a turbostratic carbon structure above the normal graphitic layer planes in graphitized carbon fibers and carbon blacks. 111. Ion exchange properties of gel-filtrated nitro-hmnic acid M. Nakagawa, S. Arita, T. Miki, H. Honda (National Industrial Research Institute of Kyushu, Tosu-Kyushu, Japan), Y. Nakayama, Y. Hosono and M. Saeki (Japan Metal and Chemicals Co. Ltd., Chuou-ku, Tokyo, Japan). Heavy metal ion exchange properties for gel-filtrated humic acid fractions prepared by nitric acid oxidation of Japanese coal have been studied in relation to their molecular weight. Their adsorption ability were more remarkable in the lower molecular weight fractions. 112. Microscopic study of the oxidation process at 0°C of several graphites J. D. Lopez-Gonzalez, A. Martin-Rodriguez and R. Rodriguez-Reinoso (Faculty of Sciences, University of Granada, +a&). The process of oxidation at 0°C of a natural graphite and an artificially prepared graphite has been studied by the different techniques of optical microscopy. The results have been compared with the process of oxidation, under the same conditions, of a highly oriented pyrolytic graphite. 113. The CO/CO2 ratio and surface complex formation for oxygen and steam reactions with carbon J. Dollimore and J. Bailey (The University of Salford, Salford 5, Laws., U.K.), B. H. Harrison and S. S. Barton, (The Royal Military College, Kingston, Ontario, Canada). The formation of surface oxygen complex is related to the structural changes during steam burn-off for an activated carbon. A region of constant CO/CO, behaviour and structural similarity is identified, along with the characteristics left by the steam activation process. 114. Isotherms of metal chloride vapors on graphite* J. G. Hooley (Department of Chemistry, University of British Columbia, Vancouver 8, Canada). The two temperature sealed tube method has been used to determine the isotherms on graphite of 9 metal chloride vapors at temperatures for which the saturation pressure is 1 atm. A conjectural theory is presented for threshold pressure and the existence of stages. *Supported by National Research Council of Canada. 115. Vapor pressure and hysteresis in the graphite-bromine system T. Sasa and Y. Takahashi (Department of Nuclear Engineering, University of Tokyo, Tokyo, Japan). Vapor pressure of graphite-bromine lamellar compound is measured with varying composition. Decomposi-
685
results were interpreted in terms of an oxygen transfer mechanism involving oxidation and reduction of a copper-cupric oxide system. 108. Oxidation of graphite powder in carbon dioxide oxygen and air K. Seibold (Lonza Ltd., Sins, Switzerland). Oxidation of graphitized coke and anthracite in COZ is only to a small degree chemically controlled even as a fine powder. Reaction rates are increased upon addition of inert gas. The oxidation of powder in oxygen proceeds purely chemical while the reaction rate in air is diffusion controlled. 109. Change in properties and structure of carbon fibers during oxidation J. B. Donnet, H. Dauksch and E. Papirer (Centre o!eRecherches SW la Physico-Chemie des Surfaces Solides 24,682OO M&house, France). AC(H.T.T. = llOO°C) and AG(H.T.T. = 2500°C) carbon fibers, both formed from an acrylic precursor, have been treated with nitric acid and graphite oxide forming reagents. AC fibres are rapidly attacked by nitric acid whilst AG fibers resist the oxidation. Graphite oxide can be formed on the surface or in the bulk of AG fibers. Under the same conditions, AC fibers only give small amounts of degradation products. 110. High resolution electron micrography of oxidized and dellagrated carbon fibers and powders J. B. Donnet, A. Voet, P. Ehrburger, E. Papirer (Centre de Recherches SW la Physico-Chemie o!esSurfaces Solides, 68200 Mu/house, France) and P. A. Marsh (J. M. Huber Corporation, Borger, Texas). In carbon fibers produced from polyacronitrile carbonized at temperatures below 1 lOO”C, extensive graphitized areas were observed in oxidized specimen. By oxidation of graphitic carbons by agents promoting laminar intercalation, superficial graphitic oxide layer planes were produced. Upon deflagration, the graphitic oxide is not only decomposed, but the remaining carbon planes are also disturbed, creating a turbostratic carbon structure above the normal graphitic layer planes in graphitized carbon fibers and carbon blacks. 111. Ion exchange properties of gel-filtrated nitro-hmnic acid M. Nakagawa, S. Arita, T. Miki, H. Honda (National Industrial Research Institute of Kyushu, Tosu-Kyushu, Japan), Y. Nakayama, Y. Hosono and M. Saeki (Japan Metal and Chemicals Co. Ltd., Chuou-ku, Tokyo, Japan). Heavy metal ion exchange properties for gel-filtrated humic acid fractions prepared by nitric acid oxidation of Japanese coal have been studied in relation to their molecular weight. Their adsorption ability were more remarkable in the lower molecular weight fractions. 112. Microscopic study of the oxidation process at 0°C of several graphites J. D. Lopez-Gonzalez, A. Martin-Rodriguez and R. Rodriguez-Reinoso (Faculty of Sciences, University of Granada, +a&). The process of oxidation at 0°C of a natural graphite and an artificially prepared graphite has been studied by the different techniques of optical microscopy. The results have been compared with the process of oxidation, under the same conditions, of a highly oriented pyrolytic graphite. 113. The CO/CO2 ratio and surface complex formation for oxygen and steam reactions with carbon J. Dollimore and J. Bailey (The University of Salford, Salford 5, Laws., U.K.), B. H. Harrison and S. S. Barton, (The Royal Military College, Kingston, Ontario, Canada). The formation of surface oxygen complex is related to the structural changes during steam burn-off for an activated carbon. A region of constant CO/CO, behaviour and structural similarity is identified, along with the characteristics left by the steam activation process. 114. Isotherms of metal chloride vapors on graphite* J. G. Hooley (Department of Chemistry, University of British Columbia, Vancouver 8, Canada). The two temperature sealed tube method has been used to determine the isotherms on graphite of 9 metal chloride vapors at temperatures for which the saturation pressure is 1 atm. A conjectural theory is presented for threshold pressure and the existence of stages. *Supported by National Research Council of Canada. 115. Vapor pressure and hysteresis in the graphite-bromine system T. Sasa and Y. Takahashi (Department of Nuclear Engineering, University of Tokyo, Tokyo, Japan). Vapor pressure of graphite-bromine lamellar compound is measured with varying composition. Decomposi-