新型纳米金属氧化物制备及吸附和降解染料性能研究

发布时间：2018-01-23 01:32

  本文关键词： 金属氧化物 纳米复合材料 吸附 光催化 高级氧化技术 污水处理 有机染料　出处：《吉林大学》2015年博士论文　论文类型：学位论文

【摘要】：随着全球经济和现代化工业的迅速发展，水体污染问题日益突出，已经成为当今世界的一大难题。水体污染物尤其是染料废水的排放对人类和生态环境的危害是及其巨大的。因此，有效地处理染料废水对于保护人类和生态环境，以实现可持续发展的意义重大。 为了去除废水中的染料污染物，一些物理，化学，生物方法,例如，吸附，离子交换，化学催化氧化，生物降解，光催化氧化，纳米过滤等方法已被广泛研究。本文所采用的吸附法，光催化氧化法和化学催化氧化法是处理染料废水行之有效的方法。然而这三种污水处理方法也存在着一些问题，例如：吸附量小、不易回收、光利用率低、稳定性差等。 因此，本文在大量现有文献的基础上，，制备了几种新型纳米金属氧化物材料做为高效、环保的污水处理剂，在一定程度上可以有效的解决之前吸附剂和催化剂的一些弊端。并对制备材料的结构、形貌、生长机理、性能等方面进行系统的研究。本论文以实验研究为主，结合机理讨论，主要研究工作如下: （1）通过简单的水热法合成了CoFe2-xMxO4(M=Al3+,In3+和Cu2+)铁氧体纳米晶体，并对它们吸附刚果红（CR）的能力进行了比较。掺杂后的铁氧体仍为尖晶石结构，其矫顽力以及吸附能力得到显著增强。与纯钴铁氧体的磁学性质相比，我们推测Al3+占据了四面体空隙A位，In3+和Cu2+占据了八面体空隙B位。物理吸附是其主要的吸附性质。首次提出磁性材料的矫顽场比其表面积对其吸附能力有更重要的影响。为了解释矫顽场与吸附能力之间的关系，我们提出了水磁化机理。所制备的CoFe2-xMxO4铁氧体具有较强的磁性，可通过外加磁场进行磁分离，把污染物从水体中快速分离出来。在所有对比样品中，矫顽力最大（达2014.2Oe）的In3对CR具有最高的吸附能力（605.4mg g1）。 （2）结合简便的水热法和适度的超声制备了一系列的磁性可回收MnO2薄片包覆Fe3O4纳米复合材料。光催化研究表明这种MnO2/Fe3O4纳米复合材料在紫外-可见光的照射条件下对降解亚甲基蓝溶液表现出优秀的光催化效率和稳定性。磁性测试证明MnO2/Fe3O4纳米复合材料拥有铁磁性质，这就使得它在光催化反应后可以通过一个简单的外加磁场来实现回收再利用。它良好的耐酸性和可回收性使其成为潜在的具有重要应用前景的光催化剂。 （3）采用简单的一步水热法制备了Mn3O4/石墨烯纳米复合材料。这种复合材料具有尺寸分布窄、分散性好的特点。我们仔细研究了它在异质催化过硫酸氢盐（PMS）去降解一种偶氮染料（橙黄II）方面的应用。相对于单独的Mn3O4纳米颗粒或者石墨烯纳米片而言，Mn3O4/石墨烯纳米复合材料由于之间存在协同效应使之具有更高的催化活性。在250ml浓度为30mg L1的橙黄II溶液中，加入Mn3O4/石墨烯纳米复合材料（0.05g L1）和PMS（15g L1），90min可100%降解橙黄II染料。另外，我们分析了Mn3O4/石墨烯纳米复合材料/PMS体系降解橙黄II染料的机理。同时，利用电感耦合等离子体质谱分析得出锰离子的析出量是很低的。通过稳定性试验，在四次连续循环后，这种复合材料仍然表现出良好的稳定性。
[Abstract]:With the rapid development of the global economy and modern industry, water pollution problems have become increasingly prominent, has become a big problem in the world today. Water pollutants especially dye wastewater emissions harmful to human and ecological environment is huge. Therefore, effective treatment of dye wastewater for the protection of human and ecological environment, to achieve sustainable development of great significance.
In order to dye pollutants, the removal of some physical, chemical and biological methods, such as adsorption, ion exchange, chemical oxidation, biological degradation, photocatalytic oxidation, nano filtering methods have been widely studied. The adsorption method used in this paper, photocatalytic oxidation and chemical oxidation method is effective in treating dye however, these three kinds of wastewater. Wastewater treatment methods also exist some problems, such as adsorption capacity, easy recovery, low light utilization rate, poor stability and so on.
Therefore, based on a large number of existing literature on the preparation of several new nano metal oxide materials as efficient, environment-friendly sewage treatment agent, can effectively solve the drawbacks of adsorbent and catalyst in a certain extent. And the structure of the material on the morphology, growth mechanism, performance and other aspects system research. In this paper, experimental research, the binding mechanism is discussed, the main research work is as follows:
(1) CoFe2-xMxO4 was synthesized by a simple hydrothermal method (M=Al3+, In3+ and Cu2+) ferrites nanocrystals, and the adsorption of Congo red (CR) ability were compared. The doped ferrite is spinel structure, the coercivity and the adsorption capacity was significantly enhanced. Compared with the the magnetic properties of cobalt ferrite, we speculate that Al3+ occupy the tetrahedral A, In3+ and Cu2+ accounted for eight of the surface of body clearance B. Physical adsorption is the main adsorption properties of magnetic materials. First proposed the coercive field than the surface area of the adsorption capacity of the more important influence to the relationship. Interpretation of the coercive field and adsorption capacity, we put forward the mechanism of water magnetization. CoFe2-xMxO4 ferrite prepared with strong magnetic, magnetic separation can be carried out by the external magnetic field, the contaminant separated quickly from the water. In all contrast sample, the coercivity of the The In3 of large (up to 2014.2Oe) has the highest adsorption capacity for CR (605.4mg G1).
(2) a series of magnetic Recyclable sheet MnO2 coated Fe3O4 nano composite materials were prepared by ultrasonic hydrothermal method is simple and modest. The research of photocatalytic show that the radiation condition of this MnO2/Fe3O4 nano composite material in ultraviolet visible light degradation of methylene blue solution showed excellent photocatalytic efficiency and stability. The test has proved the ferromagnetic magnetic properties of MnO2/Fe3O4 nano composite material, which makes it through a simple magnetic field to achieve the recycling in the photocatalytic reaction. Its good acid resistance and Recyclable of the photocatalyst has important potential application prospect.
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本文编号：1456307