冠醚—离子液体负载碳纳米管对铀的去除性能研究
发布时间：2018-11-25 07:00
【摘要】：离子液体,新一代最具有发展潜力的溶剂,其优良的特性已经吸引了各行各业专业人士的研究兴趣。以离子液体替代有毒、易燃、易挥发的有机物用于高放废液的处理的研究方兴未艾。本文选用了1-丁基-3-甲基咪唑六氟磷酸盐(C4mimPF6)、1-己基-3-甲基咪唑六氟磷酸盐(C6mimPF6)及1-丁基-3-甲基咪唑双三氟甲烷磺酰亚胺盐(C4mimNTf2)三种离子液体。首先将离子液体作为溶剂,将所选的二环己基-18-冠醚-6(DCH18C6)溶解,得到冠醚-离子液体体系。然后用冠醚-离子液体体系对水相中的铀酰离子进行萃取研究,最后将冠醚-离子液体体系用物理负载法负载到碳纳米管上制成吸附材料,进一步用未负载以及负载化的碳纳米管对水相中的铀的吸附效果及规律做一系列研究,主要研究结果如下:以二环己基-18-冠醚-6为萃取剂,以所选的三种离子液体为溶剂的冠醚-离子液体萃取体系对水相中铀酰离子(UO22+)的萃取实验。实验结果表明:UO22+在1-丁基-3-甲基咪唑双三氟磺酰亚胺盐([C4min]NTf2)体系的去除效率明显高于六氟磷酸盐类(PF6-)离子液体。在水相中当硝酸浓度在3mol/L左右时萃取效率最高,体系的萃取效率随着萃取剂浓度的增加而变大,共存离子的加入会降低体系的萃取效率,但是当加入的是硝酸根离子时,萃取率会相应增大。根据实验结果以及萃取后离子液体相的红外图谱分析可以判断此萃取体系主要为阳离子交换过程。通过物理负载法得到的冠醚-离子液体体系负载型碳纳米管对铀的吸附实验结果表明:当pH为5到6之间时,三种吸附材料的吸附容量达到最大,随着铀初始浓度的增加,相应的吸附容量也增大。当吸附时间超过60分钟后,吸附基本达到平衡,随着温度的不断上升,吸附材料的吸附容量都相应的提高,说明本实验用的吸附材料对铀的吸附过程属于吸热过程,温度的升高有助于其对铀更好的吸附。同时我们还对未进行负载的碳纳米管进行了对比试验,可以发现经过负载后的碳纳米管吸附容量明显高于未负载的碳纳米管。将吸附实验的结果进行动力学和热力学拟合,结果表明四种吸附材料对铀的吸附动力学符合准二级动力学模型,而吸附热力学符合Langmuir模型假设。说明吸附过程为化学吸附,吸附主要发生在吸附剂表面。
[Abstract]:Ionic liquids, the most promising solvent of the new generation, have attracted the research interest of all kinds of professionals. The use of ionic liquids to replace toxic, flammable and volatile organic compounds for the treatment of high-level waste liquid is in the ascendant. Three ionic liquids, 1 Ding Ji 3 methyl imidazole hexafluorophosphate (C4mimPF6), 1 hexyl 3 methyl imidazolium hexafluorophosphate (C6mimPF6) and 1 Ding Ji 3 methyl imidazole bisfluoromethane sulfonimide salt (C4mimNTf2), were selected. Firstly, the ionic liquid was used as solvent to dissolve the selected dicyclohexyl-18-crown-6 (DCH18C6) to form the crown ether-ionic liquid system. Then the uranyl ions in water phase were extracted by crown-ether-ionic liquid system. Finally, the crown ether-ionic liquid system was loaded on carbon nanotubes by physical loading method to make adsorption material. A series of studies were carried out on the adsorption efficiency and regularity of unloaded and loaded carbon nanotubes for uranium in water phase. The main results are as follows: using dicyclohexyl-18-crown ether-6 as extractant, The extraction experiment of uranyl ion (UO22) in aqueous phase by Crown Ether Ionic liquid extraction system with three ionic liquids as solvent. The results showed that the removal efficiency of UO22 in [C4min] NTf2 system was significantly higher than that in hexafluorophosphate (PF6-) ionic liquids. When the concentration of nitric acid is about 3mol/L in aqueous phase, the extraction efficiency is the highest, and the extraction efficiency of the system increases with the increase of the concentration of extractant. The extraction efficiency of the system decreases with the addition of coexisting ions, but when the nitrate ion is added, the extraction efficiency of the system increases with the increase of the concentration of the extractant. The extraction rate will increase accordingly. According to the experimental results and the infrared spectrum analysis of the ionic liquid phase after extraction, it can be concluded that the extraction system is mainly a cationic exchange process. The experimental results of adsorption of uranium by crown ether-ionic liquid supported carbon nanotubes obtained by physical loading method show that when pH is between 5 and 6, the adsorption capacity of the three kinds of adsorption materials reaches the maximum, and with the increase of the initial concentration of uranium, the adsorption capacity of the three adsorbed materials reaches the maximum. The corresponding adsorption capacity is also increased. When the adsorption time is more than 60 minutes, the adsorption reaches equilibrium basically, and the adsorption capacity of the adsorbed material increases with the increase of temperature, which indicates that the adsorption of uranium by the adsorption materials in this experiment is an endothermic process. The higher the temperature is, the better the adsorption of uranium is. At the same time, the adsorption capacity of unloaded CNTs is obviously higher than that of unloaded CNTs. The results of adsorption experiments were fitted with kinetics and thermodynamics. The results showed that the adsorption kinetics of uranium by four kinds of adsorption materials was in accordance with the quasi-second-order kinetic model, while the adsorption thermodynamics was in accordance with the hypothesis of Langmuir model. It shows that the adsorption process is chemisorption, and the adsorption occurs mainly on the surface of adsorbent.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O647.33;TL941.1
本文编号：2355197
[Abstract]:Ionic liquids, the most promising solvent of the new generation, have attracted the research interest of all kinds of professionals. The use of ionic liquids to replace toxic, flammable and volatile organic compounds for the treatment of high-level waste liquid is in the ascendant. Three ionic liquids, 1 Ding Ji 3 methyl imidazole hexafluorophosphate (C4mimPF6), 1 hexyl 3 methyl imidazolium hexafluorophosphate (C6mimPF6) and 1 Ding Ji 3 methyl imidazole bisfluoromethane sulfonimide salt (C4mimNTf2), were selected. Firstly, the ionic liquid was used as solvent to dissolve the selected dicyclohexyl-18-crown-6 (DCH18C6) to form the crown ether-ionic liquid system. Then the uranyl ions in water phase were extracted by crown-ether-ionic liquid system. Finally, the crown ether-ionic liquid system was loaded on carbon nanotubes by physical loading method to make adsorption material. A series of studies were carried out on the adsorption efficiency and regularity of unloaded and loaded carbon nanotubes for uranium in water phase. The main results are as follows: using dicyclohexyl-18-crown ether-6 as extractant, The extraction experiment of uranyl ion (UO22) in aqueous phase by Crown Ether Ionic liquid extraction system with three ionic liquids as solvent. The results showed that the removal efficiency of UO22 in [C4min] NTf2 system was significantly higher than that in hexafluorophosphate (PF6-) ionic liquids. When the concentration of nitric acid is about 3mol/L in aqueous phase, the extraction efficiency is the highest, and the extraction efficiency of the system increases with the increase of the concentration of extractant. The extraction efficiency of the system decreases with the addition of coexisting ions, but when the nitrate ion is added, the extraction efficiency of the system increases with the increase of the concentration of the extractant. The extraction rate will increase accordingly. According to the experimental results and the infrared spectrum analysis of the ionic liquid phase after extraction, it can be concluded that the extraction system is mainly a cationic exchange process. The experimental results of adsorption of uranium by crown ether-ionic liquid supported carbon nanotubes obtained by physical loading method show that when pH is between 5 and 6, the adsorption capacity of the three kinds of adsorption materials reaches the maximum, and with the increase of the initial concentration of uranium, the adsorption capacity of the three adsorbed materials reaches the maximum. The corresponding adsorption capacity is also increased. When the adsorption time is more than 60 minutes, the adsorption reaches equilibrium basically, and the adsorption capacity of the adsorbed material increases with the increase of temperature, which indicates that the adsorption of uranium by the adsorption materials in this experiment is an endothermic process. The higher the temperature is, the better the adsorption of uranium is. At the same time, the adsorption capacity of unloaded CNTs is obviously higher than that of unloaded CNTs. The results of adsorption experiments were fitted with kinetics and thermodynamics. The results showed that the adsorption kinetics of uranium by four kinds of adsorption materials was in accordance with the quasi-second-order kinetic model, while the adsorption thermodynamics was in accordance with the hypothesis of Langmuir model. It shows that the adsorption process is chemisorption, and the adsorption occurs mainly on the surface of adsorbent.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O647.33;TL941.1
【参考文献】
相关期刊论文 前10条
1 宋均轲;王静;高波;;放射性废水处理技术研究进展[J];能源环境保护;2013年02期
2 袁立永;石伟群;蓝建慧;柴之芳;;离子液体在核燃料后处理中的应用[J];科学通报;2012年08期
3 郑慧;;重金属废水的处理技术现状和发展趋势[J];广东化工;2009年10期
4 林莹;高柏;李元锋;;核工业低浓度含铀废水处理技术进展[J];山东化工;2009年03期
5 王水云;谢水波;李仕友;张永亮;张纯;;啤酒酵母菌吸附废水中铀的研究进展[J];铀矿冶;2008年02期
6 张学礼;王尔奇;;环境中铀污染的植物修复[J];铀矿冶;2008年01期
7 张金带;李友良;简晓飞;;我国铀资源勘查状况及发展前景[J];中国工程科学;2008年01期
8 杨庆;侯立安;王佑君;;中低水平放射性废水处理技术研究进展[J];环境科学与管理;2007年09期
9 褚泰伟;秦丽;刘新起;王祥云;;离子液体用于溶剂萃取铀酰离子的初步研究[J];核化学与放射化学;2007年03期
10 魏广芝;徐乐昌;;低浓度含铀废水的处理技术及其研究进展[J];铀矿冶;2007年02期
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