【作者】 王道军；

【导师】 何建平；

【作者基本信息】 南京航空航天大学 ， 应用化学， 2010， 硕士

【摘要】 传统吸附剂活性炭的结构中微孔(孔径<2 nm)占有很大比例,重金属离子不易进入孔道中,其吸附能力有限。因此,本文制备了高孔容、大孔径的有序介孔碳,并进行胺化修饰,以期得到高吸附量和高选择性的新型吸附材料。以可溶性酚醛树脂为前驱体、F127为模板剂、正硅酸乙酯(TEOS)为硅源,三组分共组装法制备介孔碳-氧化硅复合材料,去除硅模板,得到有序介孔碳。研究了其对重金属离子Cr(VI)的吸附行为,探讨了吸附时间、吸附质浓度、温度等对吸附的影响,并与活性炭进行对比。实验发现,在60 min内吸附基本达到平衡,符合准二级速率方程。用Langmuir和Freundlich等温吸附方程可以较好地描述吸附行为。介孔碳对Cr(VI)吸附率随pH值增加而显著降低,在pH>6时,吸附率较低,饱和吸附量明显大于活性炭,可达225.23 mg/g,而活性炭为72.31 mg/g。通过原子转移自由基聚合合成两亲嵌段共聚物PEO-b-PS,以其为大分子模板剂,酚醛树脂为碳源,有机-有机自组装制备大孔径介孔碳。使用适量的模板剂可以获得高度有序结构的介孔碳LC(0.25),其孔径分布在20-25 nm,比表面积和孔容分别可达553 m2/g、0.74 cm3/g。与微波一次碳对比研究Cr(VI)吸附过程发现,适量的模板剂所得介孔碳对Cr(VI)的饱和吸附量明显大于微波一次碳,其值达189.39 mg/g,显示了较好的吸附性能。对有序介孔碳表面进行胺基修饰可以实现对Cu(II)的选择性吸附。实验发现,随着表面修饰剂乙二胺用量的增加,介孔碳表现了较强的选择性吸附Cu(II)的能力,同时对Cr(VI)则显示出较弱的吸附能力。介孔碳表面修饰后所表现出的这种选择性吸附能力,将有助于去除含Cr(VI)溶液中的铜离子杂质。更多还原

【Abstract】 As a traditional sorbent, actived carbon has much micropore(pore size<2 nm) in its structure, heavy metal ions can’t access easily, thus its adsorption capacity is limited. Therefore, ordered mesoporous carbon was tried to prepare with higher pore volume and larger pore size. Furthermore, the surface of ordered mesoporous carbon was modified using amino groups in order to obtain new-type adsorption materials with higher adsorption capacity and higher selectivity.Ordered mesoporous carbon was synthesized by first using soluble phenolic resins as carbon precursor, F127 as template-directing agent, and TEOS as silicon source based on three-constituent assembly method, and then removing silicon. The investigation was to study the adsorption behavior of ordered mesoporous carbon to heavy metal ion of Cr(VI), and the effect of adsorption time, the adsorbate concentration and temperature on its adsorption behavior. This experiment was undertaken employing actived carbon as a comparison. It was found that the adsorption basically reached equilibrium in sixty minutes, consistent with the pseudo-second rate equation. Langmuir and Freundlich isothermal absorption can describe the adsorption behavior. Experimental evidences showed that, the adsorbability of ordered mesoporous carbon to Cr(VI) was decreased dramatically as pH increasing, and with pH>6, the adsorbability was lower, and the saturated adsorptive capacity was significantly higher than activated carbon, that of 225.23 mg/g.The amphiphilic diblock copolymer PEO-b-PS was synthesized by the copolymerization of atom transfer free radicals. Ordered mesoporous carbon with large pore size was synthesized using PEO-b-PS as macromolecular templating agent, phenolic resins as carbon source based on organic-organic self-assembly. Mesoporous carbon LC(0.25) with highly ordered structure can be obtained with appropriate templating agent, wherein, the pore size centered at 20-25 nm, the specific surface area and pore volume reached 553 m2/g and 0.74 cm3/g, respectively. Compared with microwave-synthesized carbon, ordered mesoporous carbon with appropriate templating agent, showed a significantly higher adsorption capacity of Cr(VI), with the value of 189.39 mg/g, indicating an excellent adsorption behavior.The selective adsorption of Cu(II) can be achieved by modifying the surface of ordered mesoporous carbon using amino groups. As increasing the surface-modification agent ethylenediamine, mesoporous carbon exhibited a better selective adsorption of Cu(II), and a worse selective adsorption of Cr(VI). Such a selective adsorption behavior, showed after surface modification of mesoporous carbon, can contribute to removing the copper ion impurity in Cr(VI)-containing solution.更多还原