An Electrochemical method for determination of the iodine adsorption number of carbon blacks
| Autor: | Zong-Sin Guo, 郭宗信 |
|---|---|
| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 Active carbon materials are widely used in various applications including as a pigment, an absorber for purifications and a reinforcing agent for rubber materials. A general method for characterizing the absorptive capacity of a carbon black is by determining its iodine adsorption number (IN). The IN is the amount of iodine that is absorbed by a defined amount of carbon black, which is related to the surface area and adsorption abilities of the carbon black samples. The measurement of IN is an important test within the carbon black industries, such as manufacturing of carbon blacks and various products into which the carbon black is incorporated. The determination of IN has become increasingly important in recent years as the increasing demand of quality control of carbon blacks for the various applications. The iodine adsorption number of carbon black is generally determined according to the standard volumetric method. The measurement is performed by mixing an accurately weighed sample of carbon black with a portion of standard iodine solution. The excess iodine is then titrated with standard sodium thiosulfate solution to obtain the amount of iodine adsorbed by the carbon black samples. However, the accuracy of the measurement is limited, because the titration endpoint is determined by eyes. Moreover, the titration method contains many time-consuming steps such as regularly preparation and check of the concentrations of sodium thiosulfate solution. In this work, the determination of IN of carbon blacks by electrochemical reduction methods was investigated. The electrochemical reduction of iodine was performed directly at a controlled-potential via setting the carbon black sample with iodine adsorption as a cathode of an electrochemical cell. The amount of iodine was obtained directly from the charge of iodine reduction. The results show that the IN calculated based on the electrochemical reduction of iodine is nearly equal to that obtained by the traditional titration methods, and the amount of iodine adsorbed on the carbon and that in the residue solution correlated well with the calculation of material balance for the iodine. The relative standard deviation is less tar 6 %. The electrochemical reduction of the iodine adsorbed on carbon blacks can be a practical method for determination of the IN. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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