| Summary: | 碩士 === 中原大學 === 化學研究所 === 106 === In this study, a new type of low-temperature catalyst was synthesized. Palladium metal was embedded onto the surface of graphene to prepare a Palladium/Graphene (Pd/G) catalyst. Degradation of dibenzo-p-dioxin (DD), 2-chlorodibenzo-p-dioxin (2CDD), Dibenzofuran (DBF) and 4-Bromodiphenyl ether (4-BDPE) in organic solvents was achieved by using this Pd/G catalyst with the presence of hydrogen gas. The optimal rate of degradation was studied by UV/VIS spectrometry.
The experimental results show that by 20 mg of Pd/G catalyst is optimal for the degradation of DD, 2CDD, and 4-BDPE at 115 °C and 20 bar of hydrogen pressure for 1 hour. Whereas for DBF, 20 mg of Pd/G catalyst at 95 °C and 20 bar of hydrogen pressure for 30 minutes is the optimal conditions. The degradation efficiencies are higher than 99 % in all cases.
The effect of different solvents was also studied and analyzed by GC-MS. DD has great degradation efficiency by using hexane as the reaction solvent. However, 2CDD and DBF have the same degradation products by using hexane or methanol. 4-BDPE will degrade into small molecules by using mixed solvent or methanol.
Various templates for embedding the palladium metal was also studied by replacing graphene with carbon nanofiber to prepare a palladium/carbon nanofiber composite catalyst (Pd/CNF). The experimental results show that Pd/CNF has similar degradation capability to DD, 2CDD, DBF, and 4-BDPE as compared to Pd/G.
Simulated real sample study was done by spiking 2CDD into lard and performing degradation of the 2CDD in situ. The results show that 2CDD can be fully degraded by the Pd/G catalyst.
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