145. The formation of surface oxide by carbons during oxidation by atomic oxygen at different temperatures

✍ Scribed by H Marsh; T.E O'Hair

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 135 KB
• Volume: 6
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(68)90448-x

✦ Synopsis

Carbons were prepared from carbonized polyvinylidene chloride (850°C) by activation with CO, at 830°C to 85 per cent burn-off. Characterization of these carbons was made from gas phase adsorption data using nitrogen (77°K) and carbon dioxide (195" and 273°K) as adsorbates in conjunction with the Dubinin theory of pore filling. Iodine was adsorbed by the carbons from aqueous I,/KI solution to cover a wide range of concentration ratio of I-/II. The correct isotherm to represent iodine adsorption uses the concentration of free iodine in solution and not total iodine concentration. Control of iodine concentration must therefore be exercised. Adsorption of iodine is very similar to adsorption of nitrogen (77°K) or carbon dioxide (195°K) with the iodine filling reversibIy both the micropores and transitional porosity. Unrealistic surhace areas of over 3000 m"g-r can be predicted from the iodine isotherms. Using rrnI, no adsorption of Ior Il-could be detected at high coverage, 144. The degassing products of a high surface area graphite as measured by a partial pressure mass spectrometer.