改性氧化石墨烯吸附染料的性能研究

发布时间：2018-12-11 13:16

【摘要】：目前水体污染问题变得越来越严峻,染料废水因具有难降解、化学结构复杂、色度高等特点,使其处理困难。吸附法因操作简单、处理效果好,成为处理染料废水的主要方法。石墨烯基类改性材料作为一种新型吸附剂,已在染料废水处理领域得到广泛应用。论文通过氢氧化钾(KOH)高温固相活化刻蚀氧化石墨烯(GO)的方法,获得新的吸附材料-活化氧化石墨烯(GOKOH),以提高GO的比表面积。采用物理化学表征手段,包括X射线衍射仪(XRD)、傅里叶红外光谱(FTIR)、比表面积测定仪(BET)、Zeta电位仪、扫描电镜(SEM)等表征方法对活化前后的GO进行表征,分析活化前后形貌、结构的变化。将活化前后的GO用于对甲基橙(MO)和橙黄IV吸附,并研究吸附性能及机理。本实验研究的主要内容和结果如下:(1)GOKOH表面的含氧官能团有所减少,比表面积增加到672.475 m2/g,孔隙率增加,表面负电荷减少,这些变化都有助于MO及橙黄IV的吸附。(2)合成GOKOH时,固体氧化石墨和KOH的质量比为1:4时,GOKOH去除染料MO和橙黄IV的效果最佳;无论是GO还是GOKOH对于MO和橙黄IV的吸附效果都是在酸性条件下优于碱性条件下。(3)MO和橙黄IV在GO及GOKOH上面的吸附结果表明,GOKOH吸附MO和橙黄IV的吸附容量分别为500.13 mg/g与524.09 mg/g,远远高于氧化石墨只经过简单的超声分散得到的GO的吸附容量(113.98 mg/g和119.08 mg/g)。(4)实验数据采用了吸附动力学进行了拟合,结果表明准二级动力学能够较好的描述染料MO和橙黄IV在GO和GOKOH的吸附,且吸附过程均由多个阶段组成。(5)运用了吸附等温线模型中的Langmuir模型和Freundilich模型对吸附数据进行了线性拟合,Langmuir模型能够较好阐述GO和GOKOH吸附MO与橙黄IV的整个吸附行为,MO和橙黄IV在GO上吸附采用Langmuir模型拟合出来的最大吸附容量分别是125.00 mg/g与137.56 mg/g,在GOKOH上的最大吸附容量分别是632.91 mg/g和606.061 mg/g,且两种染料在GO和GOKOH上的吸附主要由单层吸附控制。(6)GOKOH吸附完MO后,还对GOKOH本身进行了循环多次再生利用,再生利用四次后对MO的吸附容量高达为第一次的55.1%,因此GOKOH作为一种新型材料,可以广泛应用于染料废水处理工艺中。
[Abstract]:At present, the problem of water pollution becomes more and more serious. Dye wastewater is difficult to treat because of its characteristics of difficult degradation, complex chemical structure and high chroma. Adsorption method is the main method for dye wastewater treatment because of its simple operation and good treatment effect. As a new adsorbent, graphene modified materials have been widely used in dye wastewater treatment. In order to improve the specific surface area of graphene oxide (GO), a new adsorption material, activated graphene oxide (GOKOH), was obtained by high temperature solid phase activation of potassium hydroxide (KOH) to etch graphene oxide (GO). The GO before and after activation was characterized by means of physicochemical characterization, including X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), specific surface area measurement (BET), Zeta) potentiometer, scanning electron microscope (SEM), etc. The changes of morphology and structure before and after activation were analyzed. GO before and after activation was used to adsorb methyl orange (MO) and orange yellow IV, and the adsorption properties and mechanism were studied. The main contents and results of this experiment are as follows: (1) the oxygen functional groups on GOKOH surface decrease, the specific surface area increases to 672.475 m2 / g, the porosity increases and the surface negative charge decreases. These changes are helpful to the adsorption of MO and orange IV. (2) when the mass ratio of solid graphite oxide and KOH is 1:4, the removal of MO and orange IV by GOKOH is the best; Both GO and GOKOH have better adsorption effects on MO and orange IV than on alkaline conditions. (3) the adsorption results of MO and orange IV on GO and GOKOH show that: 1. The adsorption capacities of MO and orange IV by GOKOH were 500.13 mg/g and 524.09 mg/g, respectively. The adsorption capacity of GO (113.98 mg/g and 119.08 mg/g). (4) obtained by ultrasonic dispersion is much higher than that of graphite oxide. The adsorption kinetics is used to fit the experimental data. The results show that the quasi-second-order kinetics can well describe the adsorption of dye MO and orange IV on GO and GOKOH. The adsorption process is composed of several stages. (5) the adsorption data are fitted linearly by using the Langmuir model and Freundilich model in the adsorption isotherm model. The Langmuir model can better explain the whole adsorption behavior of GO and GOKOH adsorption MO and orange IV. The maximum adsorption capacities of MO and orange IV on GO by Langmuir model are 632.91 mg/g and 606.061 mg/g, respectively, which are 125.00 mg/g and 137.56 mg/g, on GOKOH, respectively. The adsorption of the two dyes on GO and GOKOH was mainly controlled by monolayer adsorption. (6) after the MO was adsorbed by GOKOH, the GOKOH itself was reused for several times, and the adsorption capacity of MO was up to 55.1% of that of the first one. Therefore, as a new material, GOKOH can be widely used in dye wastewater treatment process.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X788;O647.3

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