三维石墨烯负载纳米零价铁对水体污染物的吸附降解研究

发布时间：2018-05-05 12:37

  本文选题：3DGA + 3DGA-nZVI　； 参考：《电子科技大学》2017年硕士论文

【摘要】：石墨烯是近年来比较受欢迎的吸附材料,可是吸附完污染物后较难从水中收集和分离,以至于容易造成二次污染。而三维结构的石墨烯(3DGA)疏松多孔,导致其比表面积更大,优势更显著。纳米零价铁(nZVI)也是一种比较受热捧的吸附材料,但是容易发生团聚和被氧化的状况。本文结合这两者的优势,弥补各自的不足,在探究出3DGA的制备方法并对其性能进行表征后,又对三维石墨烯-纳米零价铁(3DGA-nZVI)复合材料的制备、表征以及复合物对甲基橙和三氯乙烯(TCE)的吸附性能进行研究和分析。吸附实验考察不同吸附条件的影响,并且分别用吸附动力学模型和等温吸附模型来描述整个的吸附过程。全文通过对本实验的分析总结,得到如下结论:先通过经过氧化还原法和冷冻干燥得到3DGA,再进行电镜扫描(SEM)、傅里叶红外光谱(FT-IR)、拉曼(Raman)、X射线(XRD)和BET比表面积的测试,证明了原材料氧化石墨烯(GO)中的含氧官能团大多数被去除,新制得的是有较大比表面积和较强的吸附能力并且材料内部是多孔的三维结构的特殊材料。实验制得的3DGA比表面积达到65.34 m2/g,孔径分布为3.939 nm,并且它具有很好的亲油疏水的特性。再通过调节醇水比、PVP浓度以及液相还原法制备最佳的3DGA-n ZVI复合材料,对其做了SEM、FT-IR、Raman、XRD表征,可知复合材料的纯净度较高,类似粉末状小颗粒物依然具有三维结构,而纳米零价铁也成功地负载在了3DGA上面,使其具有很好的磁性。然后在3DGA-nZVI复合材料对甲基橙的吸附实验中,得出结论大概在135min即可到达平衡吸附,吸附最佳pH为2,在100mL浓度为10mg/L的甲基橙废液中,投放0.07g 3DGA-nZVI复合材料即可达到89%以上的去除率,在25℃进行吸附效果会更好。而且其吸附过程切合准一级动力学吸附和弗伦德里希吸附等温模型。最后在3DGA-nZVI复合材料吸附TCE的实验中,可以看出吸附最佳pH值为8,最快反应30min即可达到较好的平衡状态,在25mL 10mg/L的TCE溶液中,投放0.015g的材料既可以到达91%以上的去除率,并且在温度25℃是最有利于吸附降解反应的进行的。同时该吸附过程符合二级动力学吸附和弗伦德里希吸附等温模型。
[Abstract]:Graphene is a popular adsorption material in recent years, but it is difficult to collect and separate from water after adsorbing pollutants, so it is easy to cause secondary pollution. The three-dimensional structure of graphene 3DGA is porous, resulting in a larger specific surface area and a more significant advantage. Nanocrystalline zero-valent iron (NZVI) is also a popular adsorption material, but it is easy to reunite and be oxidized. In this paper, the advantages of these two methods are combined to make up for their shortcomings. After exploring the preparation method of 3DGA and characterizing its properties, the preparation of 3D graphene nano-zero valence iron oxide 3DGA-nZVI composite is studied. Characterization and adsorption of methyl orange and TCE-trichloroethylene were studied and analyzed. The effects of different adsorption conditions on adsorption were investigated and the adsorption process was described by adsorption kinetic model and isothermal adsorption model respectively. The results are as follows: first, 3DGA was obtained by redox method and freeze-drying, then the specific surface area of BET was measured by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman Raman Ramanine X-ray diffraction (XRD) and BET. It is proved that most of the oxygen-containing functional groups in the raw materials of graphene oxide (GOO) have been removed. The new materials have a large specific surface area and a strong adsorption capacity and the material interior is a porous three-dimensional structure of the special material. The specific surface area of 3DGA is 65.34 m2 / g, the pore size distribution is 3.939 nm, and it has a good hydrophobic property. The optimal 3DGA-n ZVI composite was prepared by adjusting the concentration of alcohol to water and the liquid phase reduction method. The results showed that the purity of the composite was high, and the similar powder particles still had three dimensional structure. Nanocrystalline zero-valent iron is also successfully loaded on 3DGA, which makes it magnetic. Then, in the experiment of adsorption of methyl orange by 3DGA-nZVI composite, it is concluded that equilibrium adsorption can be achieved in 135min, and the optimum pH is 2. In the waste liquid of methyl orange with 100mL concentration of 10mg/L, 0.07g 3DGA-nZVI composite can get more than 89% removal rate. It is better to adsorb at 25 鈩，

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