改性氧化石墨烯复合材料的制备及对U（VI）的吸附性能研究

发布时间：2018-04-25 14:11

本文选题：氧化石墨烯 + U(VI)　；参考：《安徽建筑大学》2017年硕士论文

【摘要】：本论文以氧化石墨烯为原材料,制备出了三种吸附量高、便于分离、可重复利用的环境友好型吸附材料,并通过SEM、TEM、FTIR、XRD和Raman等手段对其微观形貌及性能进行了表征。同时,研究了溶液pH值大小、吸附时间、初始浓度、反应温度等因素对铀离子在吸附剂上吸附行为的影响,并对吸附机理进行了分析。(1)磁性氧化石墨烯复合材料(MGO)的制备及其对U(VI)的吸附性能研究:以石墨为原材料,采用Hummers法制备氧化石墨烯(GO),然后在其表面包覆Fe_3O_4磁性纳米粒子,从而合成磁性氧化石墨烯(MGO)复合材料。通过常见的表征手段对MGO的结构和性能进行表征并将其用于溶液中铀离子的去除。实验结果表明吸附后的材料很容易通过小磁铁分离出来,且Langmuir模型和准二级动力学速率模型可以很好地描述吸附过程。温度为298 K时,根据Langmuir等温式拟合出MGO复合材料对U(VI)的最大吸附能力为28.32 mg·g~(-1)。由温度相关的等温线计算出的热力学参数(ΔG,ΔS,ΔH)表明MGO对U(VI)的吸附是自发和吸热的过程。(2)氨基化磁性氧化石墨烯复合材料(AMGO)的制备及其对U(VI)的吸附性能研究:水热法合成氨基化磁性氧化石墨烯(AMGO),探讨U(VI)在AMGO上的吸附行为和机理研究。吸附过程可以在100分钟内达到吸附平衡,实验数据遵循准二级动力学速率模型。Langmuir模型比Freundlich模型可以更好地解释U(VI)的吸附等温线,且在298 K时AMGO对U(VI)的最大吸附能力是141.2 mg·g~(-1)。同时,吸附机理表明AMGO对U(VI)的吸附过程主要是通过螯合或离子交换来实现的。(3)零价铁-聚苯胺-石墨烯气凝胶三元复合材料的制备及其对U(VI)的吸附性能研究:零价铁-聚苯胺-石墨烯气凝胶(Fe-PANI-GA)复合材料被成功制备并应用于溶液中U(VI)的去除。批量实验表明:Fe-PANI-GA在pH=5.5下对U(VI)的最大吸附能力为350.47 mg·g~(-1)。准二级动力学速率模型和朗格缪尔等温模型可以很好地描述吸附过程和吸附等温线。此外,在XRD、FTIR和XPS结果的基础上研究Fe-PANI-GA对U(VI)的吸附机理,表明Fe-PANI-GA复合材料对U(VI)的吸附通过U(VI)的吸附和U(VI)的部分还原沉淀共同作用。
[Abstract]:In this paper, three kinds of environment-friendly adsorption materials with high adsorption capacity, easy separation and reusability were prepared by using graphene oxide as raw materials. The microcosmic morphology and properties of these materials were characterized by means of SEMTEM FTIR and Raman. At the same time, the effects of pH value, adsorption time, initial concentration and reaction temperature on the adsorption behavior of uranium on adsorbent were studied. The adsorption mechanism was analyzed. 1) the preparation of magnetic graphene oxide composite (MGO) and its adsorption properties to UVI: graphene oxide was prepared by Hummers method, and then coated with Fe_3O_4 magnetic nanoparticles on its surface. Thus, the magnetic graphene oxide (MGO) composite was synthesized. The structure and properties of MGO were characterized by common methods and used to remove uranium ions in solution. The experimental results show that the adsorbed materials are easily separated by small magnets, and the Langmuir model and the quasi-second-order kinetic rate model can well describe the adsorption process. When the temperature is 298K, according to the Langmuir isothermal equation, the maximum adsorption capacity of MGO composite to Uttrium isotherm is 28.32 mg / g ~ (-1) 路g ~ (-1) 路L ~ (-1) 路L ~ (-1). The thermodynamic parameters (螖 G, 螖 S, 螖 H) calculated from the temperature dependent isotherms show that the adsorption of MGO on UVI is spontaneous and endothermic. The adsorption behavior and mechanism of aminated magnetic graphene oxide (AMGOO) on AMGO were investigated. The adsorption process can reach the adsorption equilibrium within 100 minutes. The experimental data follow the quasi-second-order kinetic rate model. Langmuir model can better explain the adsorption isotherm of AMGO than the Freundlich model, and the maximum adsorption capacity of AMGO to UVI is 141.2 mg / g ~ (-1) at 298K. At the same time, The adsorption mechanism shows that the adsorption process of AMGO on UVI is mainly realized by chelation or ion exchange. The preparation and adsorption properties of zero-valent iron-Polyaniline-graphene aerogel ternary composites are studied. Polyaniline-graphene aerogel Fe-PANI-GAA composites were successfully prepared and applied to the removal of UVI in solution. The results of batch experiments show that the maximum adsorption capacity of pH=5.5 for pH=5.5 is 350.47 mg / g ~ (-1) ~ (-1) 路g ~ (-1) 路mol ~ (-1) 路mol ~ (-1) 路L ~ (-1). The quasi-second-order kinetic rate model and Langmuir isothermal model can well describe the adsorption process and adsorption isotherm. In addition, based on the results of Fe-PANI-GA FTIR and XPS, the adsorption mechanism of Fe-PANI-GA on UVI is studied. It is shown that the adsorption of UVI by Fe-PANI-GA composite is through the adsorption of UVI) and the partial reduction precipitation of UVI).
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;O647.3

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