铋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：2018-04-15 01:16

本文选题：可见光催化剂 + Sn掺杂的BiOCl　；参考：《河南师范大学》2017年硕士论文

【摘要】：光催化氧化技术是简便高效去除废水中有机物的一种技术,在处理难降解污染物方面有极大的潜力。然而,光催化技术存在一些问题,如量子效率低,对太阳光中可见光区利用率差等,严重制约着光催化技术在实际废水处理方面的应用。因此,开发可以高效利用可见光的光催化剂是国内外水处理领域的重要课题。本研究采用液相沉淀法、水热法,并通过掺杂和负载石墨烯的手段制备出具有高效可见光活性的Sn-Bi OCl、Sn/BiOCl/RGO和Bi_2Sn_2O_7/RGO光催化剂;通过X射线衍射(XRD)、紫外可见漫反射光谱(DRS)、透射电子显微镜(HRTEM)、荧光光谱(PL)、比表面积(BET)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)等技术对光催化剂的晶型、微观形貌、物理吸附性能、化学结构、光学性质、能带结构等方面进行表征分析;通过在自然太阳光或模拟可见光下降解目标污染物孔雀石绿(MG)、罗丹明B(Rh B)、甲基橙(MO)、橙黄-IV(OG4)、亚甲基蓝(MB)或者龙胆紫(GV)等模拟废水,来评价光催化剂的活性。本研究为以后铋系光催化剂的开发和铋系光催化剂在处理有机废水方面的应用提供了理论基础。主要研究内容和结论如下:(1)锡掺杂的氯氧化铋可见光催化剂的制备、表征及其性能的研究:通过调节pH来合成不同性能的光催化剂,重点探讨了合成过程中pH对于光催化剂微观结构以及性能的影响。实验结果表明,p H对该光催化剂的微观结构以及性质有很大的影响,pH=6时制备的Sn-BiOCl催化剂(BS-6)由纳米薄片堆积而成,其比表面积最大(83.4402 m2/g);采用降解染料废水来评价其光催化活性,BS-6展现出最好的光催化活性,进一步确定最佳投加量以及最优浓度分别为0.5 g/L和35 mg/L,另外,通过循环实验证明BS-6具有较好的稳定性和循环性。(2)锡掺杂的氯氧化铋/石墨烯复合可见光催化剂的制备、表征及其性能的研究:通过负载石墨烯的方法来提高Sn-BiOCl光催化剂的活性,实验结果证明,石墨烯负载量对复合光催化剂的微观结构和性能均有重要影响,当RGO负载量为0.25 wt%,得到的催化剂(BG-0.25)活性最高。当污染物初始浓度为80 mg/L,催化剂投加量为0.5 g/L时,光照8 h情况下,RhB的降解率高达99%。电镜可以观察到,Sn-BiOCl被超声打碎,且均匀的分布在石墨烯片层中。(3)锡酸铋/石墨烯复合可见光催化剂的制备、表征及其性能的研究:通过水热法成功制备出了Bi_2Sn_2O_7光催化剂(BSO)和Bi_2Sn_2O_7/RGO复合光催化剂。研究了石墨烯负载量对制备的锡酸铋光催化剂的影响,并得出当石墨烯负载量为20 wt%时,制备出的光催化剂(BG-20)具有最优活性,比纯锡酸铋的降解效率高出85%。并研究了BG-20对亚甲基蓝和龙胆紫模拟染料废水的降解效果,结果证明,BG-20能够有效地去除水中的亚甲基蓝和龙胆紫,模拟可见光照射120分钟后,两者的降解率分别达到99%和91%。另外,对制备的BSO和BG-20进行了表征,XRD证明石墨烯负载没有改变原有光催化剂的晶型,但使光催化剂的结晶度变弱,从SEM和TEM可以看到有锡酸铋颗粒附着在石墨烯片层上,UV-vis证明石墨烯的负载使锡酸铋的禁带宽度窄化(2.3 e V),另外,XPS和拉曼光谱相互佐证了石墨烯的存在,并且证明了石墨烯被成功还原。
[Abstract]:Photocatalytic oxidation technology is a simple and efficient technique for removal of organic matter in wastewater, have great potential in treatment of hard degradation of pollutants. However, the photocatalytic technology has some problems, such as low quantum efficiency in the visible region of the sun light, the utilization rate of the poor, seriously restricting the application of Photocatalytic technology in practice wastewater treatment. Therefore, development of efficient use of photocatalyst under visible light is an important research topic in the field of water treatment at home and abroad. This study adopts liquid phase precipitation method, hydrothermal method, system and means by doping and loading of graphene prepared by a high visible light activity of Sn-Bi OCl, Sn/BiOCl/RGO and Bi_2Sn_2O_7/RGO catalysts by X; X-ray diffraction (XRD), UV Vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (HRTEM), fluorescence spectroscopy (PL), specific surface area (BET), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (F T-IR), X ray photoelectron spectroscopy (XPS) techniques such as crystal, light catalyst morphology, physical adsorption, chemical structure, optical properties, band structure and other aspects of characterization analysis; in the natural sun light or visible light degradation simulation of target pollutants of malachite green (MG), Luo Danming B (Rh B), methyl orange (MO), orange -IV (OG4), methylene blue (MB) or Long Danzi (GV) simulation wastewater and to evaluate the photocatalytic activity. The research for the future development and bismuth bismuth photocatalyst photocatalyst in the treatment provides a theoretical basis for the application of organic wastewater the main research contents and conclusions are as follows: (1) bismuth tin doped visible light catalyst preparation, characterization and properties of photocatalysts by regulating pH synthesis of different performance, focusing on the synthesis process of pH photocatalyst for microstructure and property. Ring. The experimental results show that P has a great effect on the microstructure of H photocatalyst and the properties of pH=6 Sn-BiOCl catalysts prepared by nanosheets (BS-6) accumulation, the largest surface area (83.4402 m2/g); the degradation of dye wastewater to evaluate the photocatalytic activity of BS-6 light show the best catalytic activity, further to determine the best dosage and the optimal concentrations were 0.5 g/L and 35 mg/L, in addition, through the experiments proved that BS-6 has better stability and cycle. (2) bismuth oxychloride / tin doped graphene composite visible light catalyst preparation, characterization and performance: to improve the photocatalytic activity of Sn-BiOCl by the method of load of graphene, the experimental results show that the graphene load of composite photocatalyst on the microstructure and properties have an important effect, when the loading amount of RGO is 0.25 wt%, the catalyst (BG-0 .25) the highest activity. When the initial concentration was 80 mg/L, adding 0.5 g/L light catalyst, 8 h, RhB degradation rate of 99%. can be observed by Sn-BiOCl electron microscope, ultrasonic broken, and evenly distributed in the graphene layer. (3) tin bismuth / graphene composite visible light catalyst preparation, characterization and performance: success by hydrothermal method to fabricate Bi_2Sn_2O_7 Photocatalyst (BSO) and Bi_2Sn_2O_7/RGO composite photocatalyst. The effects of loading on graphene tin bismuth photocatalyst prepared, and when the loading of graphene 20 wt%, light catalyst prepared (BG-20) has the best activity, the degradation efficiency than pure tin bismuth higher 85%. and studied the degradation effect of methylene blue and Long Danzi, BG-20 simulated dye wastewater results show that BG-20 can effectively remove methylene blue and Long Danzi Simulation, visible light irradiation for 120 minutes, the degradation rate reached 99% and 91%. in addition, on the preparation of BSO and BG-20 were characterized by XRD, prove that crystal graphene load does not change the original light catalyst, but the crystallization degree of photocatalyst is weak, from SEM and TEM can see a tin bismuth particles attached to graphene layers, UV-vis shows that the load of graphene to bandgap bismuth stannate narrow width (2.3 e V), in addition, XPS and Raman spectroscopy are evidence of graphene, and prove that the graphene was successfully restored.

【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;O643.36

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