| Summary: | 碩士 === 中原大學 === 化學研究所 === 102 === Ordered mesoporous carbon material with high surface area containing different kinds of multi-amine ligands was synthesized to enhance the adsorption capacity of heavy metal Cr (VI)from aqueous environment. Correlation between pH in solution and adsorption capacity was investigated. Results showed pH in solution plays an important role on Cr (VI) adsorption due to the variation of Cr (VI) species at different acidity and the optimum adsorption condition of modified mesoporous carbon is pH < 5. Given the results on different ligands, poly(ethyleneimine) ligand gave the highest absorption of 185 mg/g which can be attributed to the number of nitrogen available that can be attracted to heavy metal Cr (VI). It can be deduced that the adsorption capacity of the mesoporous carbon materials would be determined by the number of available nitrogen.
Furthermore, Langmuir and Freundlich isotherm adsorption were performed. These results shows that Cr(VI) isotherm adsorption on N-OMC is Freundlich type and the adsorption is heterogeneous. The adsorption kinetics was analyzed by three kinetic models, namely pseudo first-order, pseudo second-order and the intraparticle diffusion equations. Pseudo second-order kinetics was well fitted to the of Cr(VI) adsorption kinetics of N-OMC.
Bilateral silane-functionalized mesoporous silicas were also prepared in one pot reaction via the co-condensation of tetraethoxylsilane(TEOS) and bilateral amine silane with different ratio of X = silane/(silane + TEOS).
The anion-exchange liquid chromatography using above home-made stationary phase have higher separation efficiency with the number of theoretical plates about 27000 to 63000 compared with literature report.
Functionalized SBA-15 with bilateral aminewas also used for hexavalent chromium ion exchange. The exchange capacities of amine-SBA-15 for Cr (VI) were 157.5 mg/g. Its isotherm and kinetics of Cr(VI) adsorption were carefully studied.
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