- 學位論文
含三、四級胺R( dabco)SBA-15奈米孔洞材料的合成、鑑定及鉻(VI)吸附行為研究
Synthesis, characterization and chromium (VI) adsorption behavior of SBA-15 nanoporous materials tethered with R(dabco) containing tertiary and quaternary amines
摘要
以共縮合法合成具有三、四級胺共存的R( dabco)SBA-15奈米孔洞材料來做六價鉻的離子吸附，吸附一分鐘，吸附量為69 %至79 % Cr(VI)平衡吸附量(qe)，約在30分鐘內就達到吸附平衡，如此快速的吸附行為是文獻上少見的，主要由於吸附材具有利於擴散及輸送的大奈米孔洞及高表面積，親水性等優點。在不同pH值的條件下，在pH值等於3時吸附量最大，1 kg的吸附材可以吸附147.0 g的Cr(VI)或328 g鉻酸根離子，證明此材料具有優秀吸附六價鉻的能力。 最後本論文嘗試將實驗數據以linear Langmuir、linear Freundlich兩種等溫吸附方程式和三種動力學模式pseudo first-order rate equation、peudo second-order rate equation及intraparticle diffusion equation進行曲線擬合，探討單邊四級胺矽烷的吸附平衡及動力學行為，結果顯示linear Langmuir 單層吸附吻合熱力學吸附行為；動力學吸附模式研究中，以 Pseudo second-order rate equation 吸附模式描述遠優於使用 Pseudo first-order rate equation 和 Intraparticle diffusion equation 動力學模式。
並列摘要
R(dabco) silane containing tertiary and quaternary amines was prepared. R(dabco) silane-functionalized mesoporous silicas were prepared in one pot reaction via the co-condensation of tetraethoxylsilane (TEOS) and R(dabco) silane with different ratios of X = silane/(silane + TEOS). Functionalized SBA-15 was used for hexavalent chromium ion exchange. The exchange capacities of amine-SBA-15 for Cr (VI) were 147.0 mg/g. Its isotherm and kinetics of Cr(VI) adsorption were carefully studied. Furthermore, linear Langmuir and linear Freundlich isotherm adsorption were performed. These results shows that Cr(VI) isotherm adsorption on R(dabco)-SBA-15 is linear Langmuir type and the momolayer adsorption. 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 on R(dabco)-SBA-15.