若干二维半导体催化剂在染料废水处理中的应用

发布时间：2018-04-05 21:16

本文选题：二维纳米片　切入点：静电组装　出处：《浙江理工大学》2017年硕士论文

【摘要】：随着城镇化和工业化的快速发展,能源匮乏和环境污染逐渐成为威胁人类可持续发展的两大难题。其中,工业染料废水是环境污染的一大主要来源,其来源非常广泛,包括纺织、塑料、造纸以及皮革工业。由染料所产生的毒性、诱变性和致癌性严重威胁了人类的健康,因此,寻找一种简单清洁的技术处理染料和工业废水中的污染物一直被认为是一个挑战。高级氧化技术,包括芬顿催化氧化和光催化等技术,具有无毒、反应速度快和氧化能力强等特点。其中,开发高性能的催化剂是高级氧化技术的关键。二维纳米材料由于其独特的物理化学性质,如大的比表面积及其薄的厚度,被广泛研究于光学、电子学、磁学以及光催化领域。本学位论文以二维纳米片为前驱体,研究其在无光以及可见光下对有机染料的催化性能。此外,利用XRD、FTIR、SEM、TEM、XPS、AFM、UV-vis等手段对材料进行表征,并通过降解Rh B等染料以及无色有机污染物来测试其催化性能、稳定性以及普适性。相关工作如下:1.通过一乙胺剥离质子化层状钛酸盐为带负电的二维钛酸盐纳米片(TNSs),在氢离子作用下絮凝得到一种非光驱动催化剂rs-TNSs。这种新颖的催化剂可以在过氧化氢的协同作用下无光条件下催化降解有机污染物,对不同浓度、不同p H条件、不同类型的染料均具有优异的催化性能。并且,该催化剂具有良好的稳定性和重复性。此外,我们基于XPS、UV-vis等表征技术提出了rs-TNSs可能的非光驱动降解有机污染物的机理。2.采用碱法剥离石墨相氮化碳获得表面带负电的二维氮化碳纳米片(CNNS)胶体材料。通过静电组装技术,采用Cd~(2+)离子絮凝带负电的氧化石墨烯(GO)和CNNS,并经后续还原和硫化处理获得三元CNNS/Cd S/r GO复合光催化剂。该复合催化剂具有优异的可见光吸收性能,梯度的能带结构,从而促进太阳光的吸收以及光生电荷的分离。光催化性能测试表明,该三元复合材料不仅具有优于单相、二元复合材料的光催化性能,而且优于纳米片的包裹作用。材料稳定性好,五次循环后性能几乎没有降低。该法为制备二维纳米片基的多元异质结提供了一种简便易操作的方法。3.通过带负电的二维CNNS、TNS和Cd~(2+)离子的静电组装,制备了纳米片基CNNS/Cd S/TNS三元复合光催化剂。高的可见光吸收与梯度的能带结构促进了光生电荷的高效产生和分离,相比于其他单相和两相复合物,三元催化剂在可见光下降解Rh B具有较高的催化性能。此外,三元复合催化剂还具有优越的重复性,5次循环之后降解效率仍能达到90%以上。
[Abstract]:With the rapid development of urbanization and industrialization, energy scarcity and environmental pollution have gradually become two major problems threatening the sustainable development of human beings.Among them, industrial dye wastewater is a major source of environmental pollution, including textile, plastic, paper and leather industries.The toxicity, mutagenicity and carcinogenicity of dyes pose a serious threat to human health. Therefore, it has been considered a challenge to find a simple and clean technology for the treatment of dyes and pollutants in industrial wastewater.Advanced oxidation technology, including Fenton catalytic oxidation and photocatalysis, has the advantages of nontoxic, fast reaction and strong oxidation ability.Among them, the development of high-performance catalyst is the key of advanced oxidation technology.Due to their unique physical and chemical properties, such as large specific surface area and thin thickness, two-dimensional nanomaterials have been widely studied in the fields of optics, electronics, magnetism and photocatalysis.In this dissertation, the catalytic properties of two dimensional nanochips for organic dyes were studied in the absence of light and visible light.In addition, the materials were characterized by means of XRDX FTIR, SEMTEMN, XPS, AFM and UV-vis, and their catalytic properties, stability and universality were tested by degradation of dyes such as Rh B and colorless organic pollutants.The related work is as follows: 1.A non-photo-driven catalyst, rs-TNSs, was obtained by stripping the protonated layered titanate into a 2-D titanate nanocrystalline with negative charge by using monoethylamine as a flocculating agent under the action of hydrogen ions.This novel catalyst can catalyze the degradation of organic pollutants without light under the synergistic action of hydrogen peroxide, and has excellent catalytic performance for different concentrations, pH conditions and different types of dyes.Moreover, the catalyst has good stability and repeatability.In addition, we proposed the possible mechanism of non-photocatalytic degradation of organic pollutants by rs-TNSs based on the characterization techniques such as XPS-UV-vis.Two dimensional carbon nitride nanocrystalline (CNNSs) colloidal materials with negative charge on the surface were obtained by alkali stripping of graphite phase carbon nitride.Cd~(2 was used to flocculate the negatively charged graphene oxide (GOO) and CNNS. the ternary CNNS/Cd Sr go composite photocatalyst was obtained by subsequent reduction and vulcanization.The composite catalyst has excellent visible light absorption and gradient band structure, which can promote the absorption of solar light and the separation of photogenerated charges.The photocatalytic performance test shows that the ternary composite not only has better photocatalytic performance than single-phase and binary composites, but also has better encapsulation effect than nanocrystalline composite.The stability of the material is good, and the properties of the material are almost unchanged after five cycles.This method provides a simple and easy to operate method for the preparation of multicomponent heterojunctions based on two dimensional nanochips.CNNS/Cd / S/TNS composite photocatalysts were prepared by electrostatic assembly of Cd~(2 and TNS ions with negative charge.The high visible light absorption and gradient band structure promote the efficient generation and separation of photogenerated charges. Compared with other single-phase and two-phase complexes, the ternary catalysts have higher catalytic performance in the degradation of RhB under visible light.In addition, the degradation efficiency of the ternary composite catalyst is over 90% after 5 cycles with excellent repeatability.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;O643.36

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