含氮、硫中孔洞碳材的合成、鑑定及重金屬吸附行為研究

Synthesis and characterization of nanoporous carbon materials with N and S heteroatoms and their selective adsorption of heavy metals

林鴻名(Hong-Ming Lin)

指導教授 ： 鄭吉豐

中原大學/理學院/化學研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400968

摘要

本論文製備具有高表面積之規則排列中孔洞碳材，並以中孔洞碳材當作載體，透過表面改質方式將含N和S雙功能複合之螯合物導入中孔洞碳材並對於重金屬吸附能力及選擇性進行探討。首先將先製備具有高表面積之中孔洞碳材當作載體，並以硝酸進行表面改質，將含氧官能基導入中孔洞碳材，然後利用SOCl2將碳材表面含氧官能基醯氯化，將多胺類以及含硫化合物藉由表面改質方式導入中孔洞碳材，最後進行重金屬吸附能力及選擇性的探討。結果顯示在重金屬Hg2+最高吸附量能力方面，多胺類表面改質中孔洞碳材對Hg2+有一定吸附能力，此時在多胺類中孔洞碳材改質接上含硫官能基便可再提升對Hg2+有吸附能力而最高吸附量可高達796.8 mg/g，在1 ppm低濃度Hg2+吸附後，殘餘[Hg2+]僅0.04 ppb，遠低於WHO飲用水最大可接受的汞濃度1ppb，Kd高達2000000。中孔洞碳材經過表面改質後對於重金屬Hg2+吸附具有顯著的吸附能力和獨特的選擇性。此外，為了探討pH值對於重金屬Hg2+吸附的影響，嘗試改變pH值範圍1.5-6，表面改質中孔洞碳材至少要達到pH 4才能完全顯現出重金屬Hg2+的吸附能力，因此，pH值在重金屬Hg2+的吸附應用上扮演著舉足輕重的角色。最後本論文嘗試將實驗數據以Langmuir和Freundlich兩種等溫吸附方程式和三種動力學模式Pseudo first-order rate equation、Pseudo second-order rate equation及intraparticle diffusion equation進行曲線模擬，探討Hg2+在改質後中孔洞碳材吸附平衡及動力學行為。

關鍵字

重金屬吸附 ； 中孔洞碳材

並列摘要

Ordered mesoporous carbon (OMC) material was synthesized and functionalized with different kinds of multi-amine, 2-aminothiolphenol, methylisothiocyanate (MITC), and mercaptoacetic acid (TGA) for the adsorption of Hg(II). The modified ordered mesoporous carbon material was identified structural by X-ray diffraction, N2 adsorption–desorption
isotherm, scanning electron microscopy and Fourier transform infrared spectroscopy. The effects of solution different metals, pH, initial Hg(II) concentration, contact time, and temperatures effect were studied.
The results showed that through modification of mesoporous carbon materials the adsorption capacity gave a significant and unique selectivity for heavy metal Hg(II) adsorption. In addition, correlation between pH and adsorption was investigated by treating the modified mesoporous carbon materials with varying the pH values from 1.5-6. Acidity in solution plays an important role on Hg(II) adsorption due to the competition of H+ with Hg(II) on adsorption sites and the optimum adsorption condition of modified mesoporous carbon is pH > 4.
Given the results on different ligands, NS bifunctional composite functional (OMC-6N-TGA) gave the highest absorption of 796.8mg/g which can be attributed to the number of nitrogen and sulfur available that can be attracted to heavy metal Hg(II). It can be deduced that the maximum adsorption capacity of the mesoporous carbon materials would be determined by the number of available nitrogen and sulfur.
Furthermore, Langmuir and Freundlich isotherm adsorption were performed. These results shows that Hg(II) isotherm adsorption on NS-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 Hg(II) adsorption kinetics of NS-OMC.

並列關鍵字

selective adsorption of heavy metals ； nanoporous carbon

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