基于不同还原剂制备石墨烯气凝胶的研究

发布时间：2019-05-10 13:15

【摘要】：单层石墨烯是目前已知最轻最薄的材料,它的理论比表面积、热导率、杨氏模量、抗拉强度等性能优异,是一种应用潜力非常广泛的一种碳材料。由溶胶过程得到的石墨烯气凝胶又称为石墨烯海绵,继承了石墨烯和气凝胶高比表面积、高孔隙率和高电导率等优点,同样引起了学术界的极大关注和研究。本论文的具体研究内容如下:首先,通过改良的Hummers法,以天然鳞片石墨为原料制备氧化石墨烯。通过扫描电镜、红外分析、拉曼分析、电导率测试以及BET比表面积分析、X射线衍射分析等手段进行分析与表征。其次,以氧化石墨烯为原料,通过添加还原剂并进行水热反应,经冷冻干燥后,制备了还原氧化石墨烯气凝胶。研究了水热反应时间、水热温度以及氧化石墨烯浓度的优化条件。以抗坏血酸、硫酸亚铁、氨硼烷/硫酸亚铁为还原剂,分别研究了不同还原剂对气凝胶的影响。通过扫描电镜、接触角测试、BET比表面积分析以及拉曼对石墨烯气凝胶的结构进行表征与分析,寻求制备气凝胶的最优条件。并且测试了不同还原剂气凝胶对汽油、氯仿、甲醇、甲苯、DMF的吸附能力。结果表明以抗坏血酸作为还原剂制备得到的石墨烯气凝胶对不同有机溶剂/油料基本均具有良好的吸收效果,而另外以硫酸亚铁以及氨硼烷/硫酸亚铁作还原剂制备得到的石墨烯气凝胶对于有机溶剂/油料的吸附效果明显弱于前者。最后,利用紫外光谱研究了石墨烯气凝胶对各种染料的吸附能力,包括罗丹明B和橙黄G。定量表征了石墨烯气凝胶对于染料的吸附过程,将石墨烯气凝胶对于染料的吸附过程分别进行热力学以及动力学的拟合。结果表明,吸附过程的热力学满足Langmuir单分子吸附热力学模型,而动力学满足伪二级动力学模型。经过计算,以硫酸亚铁/氨硼烷协同还原制备得到的石墨烯气凝胶对于染料的吸附效果最佳,在环境治理方面将会发挥出巨大的应用潜力。
[Abstract]:The single-layer graphene is the most light and thinnest material currently known, and has excellent theoretical specific surface area, thermal conductivity, Young's modulus, tensile strength and the like, and is a kind of carbon material with very wide application potential. The graphene aerogel obtained from the sol process is also called a graphene sponge, and the advantages of high specific surface area, high porosity and high electric conductivity of the graphene and the aerogel are inherited, and the great attention and the research of the academic community are also caused. The specific research contents of this thesis are as follows: First, the graphene oxide is prepared by the modified Hummers method with natural flake graphite as the raw material. By means of scanning electron microscope, infrared analysis, Raman analysis, conductivity test, BET specific surface area analysis, X-ray diffraction analysis and so on, the analysis and characterization are carried out. Secondly, taking the graphene oxide as a raw material, adding a reducing agent and performing hydrothermal reaction, and after the freeze-drying, a reduction oxidized graphene aerogel is prepared. The conditions of hydrothermal reaction time, hydrothermal temperature and the concentration of graphene oxide were studied. The effect of different reducing agents on aerogels was studied by using ascorbic acid, ferrous sulfate, ammonia borane/ ferrous sulfate as reducing agent. The structure of the graphene aerogel was characterized and analyzed by scanning electron microscope, contact angle test, BET specific surface area analysis and Raman, and the optimal conditions for preparing aerogels were obtained. And the adsorption capacity of different reducing agent aerogel on the gasoline, the chloroform, the methanol, the toluene and the DMF is tested. The results show that the graphene aerogel prepared by using ascorbic acid as a reducing agent has good absorption effect on different organic solvents/ oil materials, And the graphene aerogel prepared by using the ferrous sulfate and the ammonia borane/ ferrous sulfate as a reducing agent is obviously weak in the adsorption effect of the organic solvent/ oil. finally, the adsorption capacity of the graphene aerogel on various dyes, including rhodamine B and orange yellow G, is studied by using the ultraviolet spectrum, and the adsorption process of the graphene aerogel on the dye is quantitatively characterized, The adsorption process of the graphene aerogel for the dye is respectively subjected to thermodynamics and kinetic fitting. The results show that the thermodynamics of the adsorption process can satisfy the Langmuir single-molecule adsorption thermodynamic model, and the dynamics meet the pseudo-secondary dynamic model. The results show that the graphene aerogel prepared by the co-reduction of the ferrous sulfate and the ammonia borane has the best adsorption effect on the dye, and has great application potential in the aspect of environmental governance.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TQ427.26

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