新型铋、锌系可见光催化剂的制备及降解有机废水性能研究

发布时间：2017-12-27 09:25

本文关键词：新型铋、锌系可见光催化剂的制备及降解有机废水性能研究　出处：《河南师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：光催化氧化技术是一种去除水体中难降解有机污染物的有效手段,具有极大的开发与应用前景。当今,光催化氧化技术仍存在量子效率低,可见光利用效率差等缺陷,严重制约着该技术的工业化应用和发展。因此,研究开发性能优异的可见光催化剂,是国内外水处理领域的重要前沿课题。基于锌、铋系半导体材料具有良好的可见光催化活性,还原氧化石墨烯(RGO)具有优异的吸附性能和高透光性。本研究采用水热法、化学水解法,并通过优化煅烧温度、表面活性剂含量及RGO负载修饰手段制备具有高效可见光催化活性的新型锌、铋系光催化剂Bi VO4、Bi OF/Bi2O3/RGO和Zn O;利用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、N2吸附、傅里叶变换红外光谱(FT-IR)、紫外可见漫反射光谱(UV-vis DR)、光致发光光谱(PL)、循环伏安法(CV)等手段对其光催化剂的结晶、形态、吸附性能、能带结构、化学结构、光化学性质和电子转移特性进行表征;通过对目标污染物罗丹明B(Rh B)、橙黄-IV(OG-IV)或甲硝唑(MNZ)模拟废水在可见光或自然太阳光照射下的降解率,评价新型光催化剂的光催化活性,从而为新型锌、铋系可见光催化剂的制备和在难降解有机废水处理中的应用提供理论依据。主要研究结论如下:(1)水热法制备棒状Bi VO4光催化剂及其自然太阳光催化性能研究:以Bi(NO3)3·5H2O和NH4VO3为原料,采用水热法制备出新型Bi VO4光催化剂。实验结果表明:煅烧温度对Bi VO4光催化剂的性质及光催化活性均有重要影响,300°C煅烧条件下制备得到的催化剂(Bi V-3)活性最优;通过表征发现,Bi V-3具有均一的棒状结构,属于单斜白钨矿型,可见光吸收限达到540 nm,禁带宽度为2.44 e V,比表面积为3.4652m2/g;在自然太阳光下,以Rh B和OG-IV作为模拟废水进行光催化化活性研究,结果显示:在进水浓度分别为10 mg/L和7.5 mg/L,催化剂投加量分别为1.0 g/L和0.5 g/L条件下,两者的降解率分别达到99%和75%;与未煅烧的相比,Rh B和OG-IV的降解率分别提升了45%和49%;且Bi V-3对Rh B和OG-IV的降解规律均符合一级动力学模型,其相应的反应速率常数分别为0.852 h-1和0.142 h-1;Bi V-3具有良好的循环性和稳定性。(2)水解法制备Bi OF/Bi2O3/RGO光催化剂及其自然太阳光催化性能研究:以Bi(NO3)3·5H2O和Na F为原料,采用水解法制备出了Bi OF/Bi2O3纳米光催化剂,通过水浴还原法将Bi OF/Bi2O3用RGO负载修饰,制备出性能优异的Bi OF/Bi2O3/RGO复合光催化剂。研究结果表明:煅烧温度对Bi OF/Bi2O3光催化剂具有显著影响,在300°C煅烧温度下,得到的光催化剂(BF-3)活性最高;石墨烯负载量对复合光催化剂的活性具有重要影响,当负载量为1wt%时,样品(BG-1)的光催化活性最高;在自然太阳光下,以Rh B为模拟废水进行光催化活性测试,结果显示:在进水浓度为15 mg/L,复合光催化剂BG-1的投加量为0.5 g/L条件下,Rh B降解率高达99%;与未负载BF-3光催化剂相比,BG-1样品的催化活性提高了48%;并且发现该催化剂具有良好的稳定性和循环性。(3)水热法制备Zn O光催化剂中不同表面活性剂含量对光催化活性的影响:以Zn(CH3COO)2·2H2O和Na WO4·2H2O为原料,采用水热法制备出Zn O光催化剂,并通过十二烷基苯磺酸钠(SDBS)表面活性剂对Zn O光催化剂进行修饰。研究结果显示:当SDBS添加量为0.75 g时,制备的光催化剂(ZO-0.75)活性最优;经过表征发现SDBS的存在,改变了催化剂的形态、禁带宽度等性质,修饰后的ZO-0.75为纳米棒状结构,禁带宽度为3.17e V;通过羟基自由基捕获实验验证出该催化剂的主要活性成分为·OH;在模拟可见光下,ZO-0.75光催化剂对甲硝唑的降解率达72%,比未修饰的Zn O活性高出56%。
[Abstract]:Photocatalytic oxidation technology is an effective means to remove the refractory organic pollutants in water, and has great prospects for development and application. Nowadays, photocatalytic oxidation still has some defects, such as low quantum efficiency and poor utilization of visible light, which seriously restrict the industrial application and development of this technology. Therefore, the research and development of excellent photocatalyst of visible light is an important frontier subject in the field of water treatment at home and abroad. Zinc and bismuth based semiconductors have good photocatalytic activity, and the reduction of graphene oxide (RGO) has excellent adsorption properties and high light transmittance. This study using the hydrothermal method and chemical hydrolysis method, and by optimizing the calcination temperature, surfactant content and RGO load model, modified zinc preparation methods with high visible light photocatalytic activity of bismuth based photocatalyst Bi VO4, Bi OF/Bi2O3/RGO and Zn O; using X ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), N2 adsorption, Fu Liye transform infrared spectroscopy (FT-IR), UV Vis diffuse reflectance spectroscopy (UV-vis DR), photoluminescence spectroscopy (PL), cyclic voltammetry (CV) and other means of crystallization, on the photocatalytic agent morphology, adsorption properties, energy band the structure, chemical structure, photochemical properties and electron transfer properties were characterized by B; the target pollutants Luo Danming (Rh B), orange -IV (OG-IV) or metronidazole (MNZ) simulated wastewater under visible light or natural sun light irradiation degradation rate, the evaluation model of light The photocatalytic activity of the catalyst provides a theoretical basis for the preparation of new zinc and bismuth visible light catalysts and the application of the photocatalyst in the treatment of refractory organic wastewater. The main conclusions are as follows: (1) hydrothermal synthesis of rod like Bi VO4 photocatalyst and its natural solar photocatalytic performance: Bi (NO3) 3. 5H2O and NH4VO3 are used as raw materials, and new Bi VO4 photocatalyst is prepared by hydrothermal method. The experimental results show that the calcination temperature has on the Bi VO4 photocatalyst properties and photocatalytic activity of the important effect of catalyst prepared by 300 DEG C under calcination conditions (Bi V-3) activity was optimal; characterized by Bi V-3 found that the rod like structure with uniform, which belongs to the monoclinic, visible light absorption limit reached 540 nm. The band gap is 2.44 e V, the specific surface area of 3.4652m2/g; in the natural sunlight, with Rh B and OG-IV as simulated wastewater was studied. The results showed that the photocatalytic activity of the influent concentration were 10 mg/L and 7.5 mg/L, catalyst dosage were 1 g/L and 0.5 g/L, both the degradation rate reached 99% and 75% respectively; compared with the method, the degradation of Rh B and OG-IV respectively increased by 45% and 49%; and Bi V-3 of Rh B and OG-IV degradation were accorded with the first-order kinetics model, the corresponding reaction rate constants were 0.852 H-1 And 0.142 H-1; Bi V-3 has good circulatory and stability. (2) the preparation of Bi OF/Bi2O3/RGO photocatalyst and its photocatalytic properties of natural sun hydrolysis method: Bi (NO3) 3 - 5H2O Na and F as raw materials, was prepared by hydrolysis of Bi OF/Bi2O3 nano photocatalyst, Bi OF/Bi2O3 with RGO modified by water bath load reduction method, the preparation of Bi OF/Bi2O3/RGO composite photocatalyst excellent performance. The results showed that the calcination temperature has significant effect on Bi OF/Bi2O3 photocatalyst in the calcination temperature of 300 DEG C, the obtained Photocatalyst (BF-3) was the highest; has an important influence on graphene load on the activity of composite photocatalyst, when the load is 1wt%, the sample (BG-1) the highest photocatalytic activity; in natural sunlight, photocatalytic activity test, using Rh B as the simulation results show that: in the wastewater influent concentration was 15 mg/L, the composite photocatalyst dosage of BG-1 is 0.5 g/L, Rh degradation rate of B was 99%; compared with non immobilized BF-3 catalyst, the catalytic activity of BG-1 were increased 48%; and found that the catalyst has good stability and cycle. (3) prepared by hydrothermal method Zn O photocatalyst with different surfactant content on photocatalytic activity: Zn (CH3COO) 2 - 2H2O Na and WO4 2H2O as raw material, prepared by hydrothermal method Zn O photocatalyst, and by twelve sulfonate (SDBS) surfactants modified Zn O photocatalyst. The results showed that when the amount of SDBS is 0.75 g, the prepared Photocatalyst (ZO-0.75) characterized by optimal activity; found that the presence of SDBS, change the morphology of the catalysts and the band gap properties of modified ZO-0.75 nano rod structure, the band gap is 3.17e V; through hydroxyl radical capture experiments the main active component of the catalyst is OH; in the simulation under visible light, ZO-0.75 photocatalytic degradation of metronidazole rate reached 72%, 56% higher than the unmodified Zn O activity.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ426;X703

【共引文献】