功能化三维石墨烯材料的制备及吸附性能研究

发布时间：2018-03-10 18:54

本文选题：氧化石墨烯海绵　切入点：改性氧化石墨烯海绵　出处：《南京信息工程大学》2017年硕士论文　论文类型：学位论文

【摘要】：石墨烯是由碳原子组成的单层片状结构的一种新材料,严格来说是目前我们发现的最薄的二维材料。它的许多独特和优异的性质已受到人们的特别关注,如它的导电性强,机械强度高,灵敏度好和稳定性高等,并且由于其高的比表面积,而被视为一种很有前途的吸附剂,已在重金属离子,染料和油的去除有了高性能领域的研究。然而,由于石墨烯容易发生团聚,会大大降低比表面积的接触,且无法从水中很好的分离和收集。因此,一个有序的,多孔的石墨烯组装材料将成为环境吸附材料的最佳选择。由于它们较高的比表面积,化学稳定性,低成本和发达的三维网状结构,在离子吸附和染料的去除等领域被作为最有前景的吸附剂。本文中,氧化石墨烯通过冷冻干燥法技术制备出三维结构的氧化石墨烯海绵材料(GOS)。将氧化石墨烯溶液与N-羟甲基丙烯酰胺(N-MAM)和六氟异丙醇(HFIP)做改性反应实验制备改性氧化石墨烯海绵材料(MAHP-GO)。以水合肼为还原剂,用水热法还原改性氧化石墨烯制备出功能化的改性石墨烯海绵材料(MAHP-GS)。将制备出的三种新型材料对亚甲基蓝(MB)进行吸附实验,研究不同的吸附材料对亚甲基蓝吸附行为的影响,实验结论如下:1、常温下,利用改性hummers法及冷冻干燥技术制备出的三维氧化石墨烯海绵对亚甲基蓝(MB)的吸附时间在200min左右达到吸附平衡,当亚甲基蓝的浓度为80mg/L时,最大吸附量为361.28mg/g。氧化石墨烯海绵对亚甲基蓝的吸附属于准二级动力学模型,吸附等温线符合Langmuir模型。2、利用N-羟甲基丙烯酰胺和六氟异丙醇对氧化石墨烯进行了功能化的改性实验制备出改性氧化石墨烯海绵,增强其在水中的稳定性。改性氧化石墨烯海绵(MAHP-GO)对亚甲基蓝的最大吸附浓度为80mg/L,最大吸附量347.16mg/g,330min左右达到吸附平衡。Langmuir等温吸附模型适合描述其吸附过程,吸附过程为准二级动力学模型。3、以水合肼为还原剂,采用水热还原的方法和冷冻干燥技术将改性氧化石墨烯还原,制备改性石墨烯海绵(MAHP-GS)材料,并用来做对亚甲基蓝染料的吸附实验。研究发现吸附达到平衡的时间大约在260min,MB的最大浓度为60mg/L时得到最大的吸附量131.195mg/g。吸附过程符合准二级动力学和Langmuir等温模型。4、分别对上述三种吸附材料进行了 XRD、SEM、红外和BET表征。结果表明不同孔结构和不同含量的含氧官能团对亚甲基蓝的吸附行为有着重要影响,吸附材料吸附能力的大小主要靠大量含氧官能团的协同作用和交联的三维多孔网状孔径结构。
[Abstract]:Graphene is a new material with monolayer flake structure composed of carbon atoms, which is strictly the thinnest two-dimensional material we have found at present. Many unique and excellent properties of graphene have been paid special attention to, such as its strong conductivity. Because of its high specific surface area, it is regarded as a promising adsorbent and has been studied in the field of heavy metal ion, dye and oil removal. Because graphene is easy to agglomerate, it greatly reduces the specific surface area of contact, and is not well separated and collected from water. Porous graphene assembly materials will be the best choice for environmental adsorption materials due to their high specific surface area, chemical stability, low cost and developed three-dimensional network structure. It is used as the most promising adsorbent in the fields of ion adsorption and dye removal. Graphene oxide sponges with three dimensional structure were prepared by freeze-drying technique. The modified oxidation of graphene oxide solution with N-MAM (N-MAM) and HFIP (hexafluoroisopropanol) was studied. Graphene sponge material MAHP-GO.Using hydrazine hydrate as reductant, The functional modified graphene sponge (MAHP-GSN) was prepared by hydrothermal reduction modification of graphene oxide. The adsorption of methylene blue (MBB) by three new materials was studied to study the effect of different adsorption materials on the adsorption behavior of methylene blue. The experimental results are as follows: at room temperature, the adsorption time of the three-dimensional graphene oxide sponge prepared by modified hummers method and freeze-drying technique for methylene blue is about 200 minutes. When the concentration of methylene blue is 80 mg / L, The maximum adsorption capacity is 361.28 mg / g. The adsorption of methylene blue by graphene oxide sponge belongs to the quasi-second-order kinetic model. The adsorption isotherm accords with the Langmuir model. The modified graphene oxide sponge was prepared by functionalization of graphene oxide with N-hydroxymethylacrylamide and hexafluoroisopropyl alcohol. The maximum concentration of methylene blue adsorbed by modified graphene oxide sponge MAHP-GO) is 80 mg / L, and the maximum adsorption capacity is 347.16 mg / g / g ~ 330min. The adsorption equilibrium. Langmuir isothermal adsorption model is suitable for describing the adsorption process of methylene blue. Using hydrazine hydrate as reducing agent, modified graphene oxide was reduced by hydrothermal reduction and freeze-drying technique to prepare modified graphene sponge MAHP-GSS material. It was found that the maximum adsorption capacity of methylene blue dye was 131.195 mg / g when the maximum concentration of 60mg / L was about 260 min ~ (MB). The adsorption process was in accordance with the quasi-second-order kinetics and Langmuir isothermal model .4. The three kinds of adsorption materials were characterized by XRD-SEM, IR and BET. The results showed that the adsorption behavior of methylene blue was significantly affected by different pore structure and different content of oxygen functional groups. The adsorption capacity of the adsorbents mainly depends on the synergistic action of a large number of oxygen functional groups and the cross-linked three-dimensional porous reticular pore structure.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;O647.3;X703

【相似文献】