| Summary: | 碩士 === 國立中正大學 === 化學工程所 === 94 === Adsorption method was used to decrease volatile organic compounds (VOCs) and odors fraction emitted from waste-plastic recycle process. The VOC saturated adsorbent was then regenerated by wet air oxidation (WAO). During the wet air oxidation, Pt clusters on the carbon support were aggregated to bigger particles leading to a catalyst deactivation. In order to regenerate the sintered catalysts, oxychlorination technique was used to redisperse the aggregated Pt clusters. Active carbon (GAC830) and bamboo carbon were used as adsorbents in this study and GC-Mass was used to characterize the species evolved from waste-plastic recycle process. The results indicated that pentane, isopentane, and acetaldehyde are the main species evolved from nylon recycle process, paraffins and olefins from polyethylene, methanol, acetaldehyde, acetic acid from polyethylene terephthalate, and isopentane, styrene, and xylene from emulsified polystyrene. Model gas, air containing toluene, and methanol (polar) and air containing hexane and cyclohexane (non-polar) air were used to test the adsorption capacity and the results indicated that GAC-830 is superior to bamboo carbon; 0.13 g polar and 0.17 g non-polar species, respectively, for GAC-830 and 0.10 and 0.12 g, respectively, for bamboo carbon. As to the catalyst regeneration, after wet-air oxidation, the deactivated Pt/C catalysts was regenerated by oxychlorination and the results indicated that the activity can only be recovered partially because of the limitation of carbon combustion commenced at 400 °C. By EXAFS、XRD and XANES, the redispersion mechanism was proposed as the spreading of Pt clusters on carbon support because of the formation of PtClx species during the redispersion process. The high affinity between PtClx and carbon surface retards the growth of Pt clusters toward 3-dimensionsl during hydrogen reduction step.
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