石墨烯基碳纳米材料对类金属和抗生素吸附特性研究

发布时间：2018-02-10 03:04

本文关键词： 氧化石墨烯改性吸附类金属砷四环素　出处：《苏州科技学院》2015年硕士论文　论文类型：学位论文

【摘要】：目前地下水中类金属以及抗生素环境污染问题越来越严重。针对水体环境的恶化，对于水中这些污染物的去除已经迫在眉睫。对水中类金属及抗生素的去除常规处理技术有：生物法、化学氧化法和吸附法。其中，吸附法由于具备低成本、易操作、易再生、不易发生二次污染等优势，被广泛应用。而吸附剂性能是评判吸附效果的重要指标。氧化石墨烯作为一种新型吸附剂由于具有独特的孔隙结构、较大的比表面积、丰富的含氧官能团以及能与污染物产生多种相互作用的特性，对水中许多无机和有机污染物具有优异的吸附能力。论文根据氧化石墨烯表面的物理化学性质，通过固相活化和磁性修饰等化学方法，获得一系列新型改性氧化石墨烯吸附剂。论文系统研究了改性氧化石墨烯的物理、化学性质等与污染物吸附特性之间的内在关系，并结合多种表征手段，从微观上探讨了改性氧化石墨烯与单一污染物及多种污染物共存的吸附机理。论文主要研究内容与结果如下：（1）通过简单化学一步法制备出高含铁量的磁性氧化石墨烯（MGO），并对水体中的类金属砷进行了吸附研究。通过高倍透射电镜扫描（HRTEM）、X射线衍射分析（XRD）、拉曼光谱分析（Raman）、热分析（TGA-DTA）、X射线光电子能谱分析（XPS）、磁性分析、X射线吸收近边结构（XANES）等手段表征后得知：MGO具有褶皱的石墨片层结构，铁颗粒均匀分布在MGO表面上并以α-Fe2O3和Fe3O4形态存在，且铁含量高达51%。此外，根据μ-XAFS图谱可以从宏观和微观上看到As(V)的分布与铁的分布是紧密相连的，铁在整个吸附过程起到极其重要的作用。（2）研究了磁性氧化石墨烯对水体中三价砷As(III)和五价砷As(V)的吸附性能。结果表明：在pH=8的条件下，MGO对三价砷As(III)的最大吸附容量高达54.18mg/g；在pH=5的条件下，MGO对五价砷As(V)的吸附性能最大高达26.76mg/g；二者吸附等温线符合Freundlich模型，动力学符合二级动力学，pH、离子强度、共存离子对MGO吸附As(III)和As(V)存在影响。此外，还发现MGO具备解吸附的能力，具有再次被利用的潜力。（3）通过KOH活化的方法制备出活化氧化石墨烯（KOH-GO），并在此基础上，探讨了活化的KOH-GO与未活化的氧化石墨烯(GO)与对水中四环素的吸附性能，并对吸附等温模型、吸附动力学模型、pH、离子强度以及在阴阳离子共存条件下的吸附性能进行了研究。结果表明：根据对固液比、动力学和等温线拟合的分析，可知通过KOH活化的氧化石墨烯对四环素的吸附性能要优于未活化的氧化石墨烯。KOH-GO材料对四环素的吸附等温线符合Langmuir模型。GO和KOH-GO对四环素的最大吸附容量分别为269.36mg/g和525.64mg/g；GO和KOH-GO对四环素的动力学吸附符合二级动力学模型；pH、离子强度对KOH-GO吸附四环素的存在影响；在阴阳离子存在条件下，阴阳离子均对KOH-GO的吸附产生抑制作用，，同时，阴阳离子还能与复合污染物之间展开竞争，占据吸附孔位，从而降低KOH-GO对四环素的吸附能力。
[Abstract]:The groundwater in the metal and antibiotic pollution is increasingly serious. In view of the deterioration of water environment, for the removal of these pollutants is imminent. The removal of conventional processing technology of water metal and antibiotics: biological method, chemical oxidation and adsorption. The adsorption method with low cost, easy to operate. Easy regeneration, easy occurrence of two pollution and other advantages, is widely used. But the adsorbent performance is an important index of evaluation. The adsorption effect of graphene oxide as a new adsorbent because of its unique structure and pore structure, large surface area, abundant oxygen-containing functional groups and can produce various characteristics of the interaction with pollutants, has excellent adsorption capacity in many inorganic and organic pollutants.
According to the physical and chemical properties of the graphene oxide surface, through the activation and modification of magnetic solid phase chemical method, a series of new modified graphene oxide adsorbent. This thesis studies the physical modification of graphene oxide, chemical properties and the relationship between the pollutant adsorption characteristics, combined with a variety of characterization methods, discussion the adsorption mechanism of coexistence of graphene oxide and single pollutant and various pollutants from microcosmic.
The main contents and results of this paper are as follows:
(1) by a simple chemical step method to produce magnetic graphene oxide with high iron content (MGO), and the metal arsenic in water were studied.
Through high-resolution transmission electron microscope scanning (HRTEM), X ray diffraction (XRD), Raman spectroscopy (Raman), thermal analysis (TGA-DTA), X ray photoelectron spectroscopy (XPS), magnetic analysis, X ray absorption near edge structure (XANES) characterized that: graphite layer structure MGO has the folds of the iron particles uniformly on the surface of MGO and -Fe2O3 and Fe3O4 in alpha form, and the iron content is as high as 51%. in addition, according to the -XAFS of As can be seen from the macro and micro (V) distribution and iron are closely linked, to the extremely important role in the whole the adsorption process.
(2) on the magnetic properties of graphene oxide on the trivalent arsenic in water As (III) As (V) and pentavalent arsenic adsorption properties.
The results show that under the condition of pH=8 MGO As (III) on arsenic. The maximum adsorption capacity of up to 54.18mg/g; under the condition of pH=5 MGO As (V) on arsenic adsorption performance of up to 26.76mg/g; two Freundlich adsorption isotherm model, kinetics of two order kinetics, pH, ion the strength of adsorption of As ions on the coexistence of MGO (III) and As (V) effect. In addition, MGO was also found to have the ability of desorption, has the potential to be utilized again.
(3) by KOH activation of the prepared activated graphene oxide (KOH-GO), and on this basis, discussed the activation of KOH-GO and non activated graphene oxide (GO) and the adsorption of tetracycline in water, and the adsorption isotherm, adsorption kinetics model, pH, ionic strength and adsorption the performance under the condition of coexistence ions were studied.
The results showed that according to the analysis of solid-liquid ratio, kinetics and isotherm fitting, the adsorption properties of graphene oxide by KOH activation of tetracycline to the adsorption isotherms of graphene oxide.KOH-GO material is better than that without activation of tetracycline with Langmuir model.GO and KOH-GO maximum adsorption capacity of tetracycline were 269.36mg/g and 525.64mg/g; GO adsorption kinetics and KOH-GO of tetracycline with two levels of dynamic model; pH, KOH-GO has the effect of ionic strength on adsorption of tetracycline; in the presence of ions produced under the conditions, the adsorption of KOH-GO ions were inhibited at the same time, the competition among the ions can occupy and compound pollutants, adsorption holes, thereby reducing the adsorption capacity of KOH-GO tetracycline.

【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】：X523

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