纳米氧化锌光催化涂料降解甲醛的研究

采用水热法制备纳米Zn O(氧化锌),并利用扫描电镜(SEM)、X-射线衍射(XRD)法等对其结构进行了表征。将自制的纳米Zn O引入光催化涂料中,并以暗箱内甲醛降解率为评价指标,着重探讨了纳米Zn O负载量、温度和湿度等对光催化涂料甲醛降解率的影响。研究结果表明:当紫外(UV)灯照射150 min、暗箱温度为25℃、暗箱中相对湿度为50%和纳米Zn O负载量为6 g时,光催化涂料的甲醛降解率88%。     

纳米氧化锌光催化降解甲基橙的研究

以硝酸锌、聚乙烯吡咯烷酮为原料,反应温度为80℃,反应时间为8 h,通过加热煅烧制备出纳米氧化锌粉体,煅烧温度500℃可制备纳米级的ZnO粉末,平均粒径为32 nm;水溶液中甲基橙在ZnO光照催化下,能迅速分解。以甲基橙为脱色对象,讨论了催化剂用量、光照时间及pH值对光催化降解甲基橙性能的影响。     

纳米ZnO的形貌对光催化降解焦炭废水效果的研究

制备了片状多孔、花状、球状、棒状和菱形的纳米ZnO粒子,采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)进行表征,并研究了片状多孔、花状、球状、棒状和菱形的纳米ZnO颗粒对焦炭废水的降解以及其不同形貌对光催化处理焦炭废水效果的影响。结果表明,不同形貌纳米ZnO的光催化降解焦炭废水能力大小顺序为:片状多孔>花状>球状>棒状>菱形,当片状多孔纳米ZnO的加入量为焦炭废水质量的2%,降解时间为0.5 h,其吸附性能与催化效果达到最佳。     

纳米ZnO的形貌对光催化降解焦炭废水效果的研究

制备了片状多孔、花状、球状、棒状和菱形的纳米ZnO粒子,采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)进行表征,并研究了片状多孔、花状、球状、棒状和菱形的纳米ZnO颗粒对焦炭废水的降解以及其不同形貌对光催化处理焦炭废水效果的影响。结果表明,不同形貌纳米ZnO的光催化降解焦炭废水能力大小顺序为:片状多孔>花状>球状>棒状>菱形,当片状多孔纳米ZnO的加入量为焦炭废水质量的2%,降解时间为0.5 h,其吸附性能与催化效果达到最佳。     

多种光源下氮掺杂TiO_2光催化降解染料废水的研究

以尿素为氮源,采用溶胶-凝胶法制备了氮掺杂纳米TiO2粉末,以甲基橙溶液为模拟染料废水,分别在可见光、模拟太阳光和紫外光条件下,研究了氮掺杂纳米TiO2光催化降解染料废水的性能。结果表明:氮掺杂可以提高TiO2的可见光催化活性;氮含量和煅烧温度对氮掺杂TiO2光催化活性影响较大,n(N)∶n(Ti)为10%且经500℃煅烧的氮掺杂TiO2在可见光和模拟太阳光下均具有最佳的光催化活性;然而在紫外光下,氮掺杂TiO2的光催化活性低于未掺杂的TiO2样品。     

棒状纳米ZnO的制备及其光催化性能研究

采用溶胶-凝胶法,以醋酸锌、草酸为主要原料,乙二胺为添加剂制得棒状结构的纳米ZnO,通过XRD和TEM对产物的结构和形貌进行了表征,并以有机染料亚甲基蓝溶液为光催化反应模型降解物,考察了样品的光催化活性。结果表明,ZnO纳米棒为纤锌矿结构的六方相ZnO,对亚甲基蓝溶液具有良好的光催化活性,且乙二胺的添加量对产物的形貌和光催化活性具有显著影响。     

Preparation and photocatalytic kinetics of nano-ZnO powders by precipitation stripping process

Ultra-fine zinc oxalate powders were prepared through a precipitation stripping method with bis(2-ethylhexyl) phosphate (HDEHP) diluted by tetrachloride carbon as the extractant, and oxalic acid ethanol aqueous solution as the re-extractant and precipitator. Zinc oxide powders were obtained by decomposing zinc oxalate powders at 450°C. The prepared zinc oxide powders were characterized by transmission electron microscope (TEM), Scanning electron microscope (SEM), Thermogravimetric analysis (TG), X-ray diffraction (XRD) and Fourier transmission infrared (FT-IR) spectrum. The photocatalytic performance of methylene blue by zinc oxide was studied based on the Langmuir model and Photo-Layer model. The results show that some zinc oxide powders were micro-multipore materials with hexagonal crystal. The particle size was around 32 nm. The photocatalytic process was the control step in the chemical reaction. The photo catalytic process followed pseudo-first order kinetics and •OH concentration inside the photo-layer in different reaction condition were calculated according to the Photo-Layer model.     

Preparation and photocatalytic kinetics of nano-ZnO powders by precipitation stripping process

Ultra-fine zinc oxalate powders were prepared through a precipitation stripping method with bis(2-ethylhexyl) phosphate (HDEHP) diluted by tetrachloride carbon as the extractant, and oxalic acid ethanol aqueous solution as the re-extractant and precipitator. Zinc oxide powders were obtained by decomposing zinc oxalate powders at 450uC. The prepared zinc oxide powders were characterized by transmission electron microscope (TEM), Scanning electron microscope (SEM), Thermogravimetric analysis (TG), X-ray diffraction (XRD) and Fourier transmission infrared (FT-IR) spectrum. The photocatalytic performance of methylene blue by zinc oxide was studied based on the Langmuir model and Photo-Layer model. The results show that some zinc oxide powders were micro-multipore materials with hexagonal crystal. The particle size was around 32 nm. The photocatalytic process was the control step in the chemical reaction. The photo catalytic process followed pseudo-first order kinetics and •OH concentration inside the photo-layer in different reaction condition were calculated according to the Photo-Layer model. __________ Translated from Transactions of Beijing Institute of Technology, 2007, 27(7): 641–645 [译自: 北京理工大学学报]     

微波辅助制备纳米ZnO及其光催化降解染料的性能

以硝酸锌、氢氧化钠为原料,聚乙二醇400(PEG 400)为溶剂,采用微波加热共沉淀法制备纳米ZnO,并采用X射线衍射、场发射电镜及紫外-可见漫反射对样品进行表征;考察纳米ZnO对结晶紫(CV)及刚果红(CR)的光催化降解性能,以λ=365nm的紫外光为光源,考察了催化剂投加量、染液浓度、pH值以及催化时间对催化效率的影响。实验结果表明,在较少的投加量下,纳米ZnO对50mg/L的CV和CR染液的降解率可分别达到98.8%和97.4%,pH值对两种染料的光催化效果影响不大。CR及CV染液的光催化降解均符合一级动 力学。     

纳米ZnO光催化处理养殖废水中盐酸四环素污染的研究

用硝酸锌与氢氧化钠反应,制备纳米ZnO光催化剂,用于养殖废水中盐酸四环素污染的光催化处理。在紫外光照射下,讨论了ZnO煅烧温度、煅烧时间、投加量、H_2O_2质量浓度、反应时间以及盐酸四环素初始浓度等对光催化处理效果的影响。XRD、SEM的表征结果显示,纳米ZnO光催化剂的平均粒径为34. 14 nm,纳米ZnO光催化处理养殖废水中盐酸四环素污染的优化条件为:紫外光下盐酸四环素浓度0. 01 g/L,纳米ZnO于350℃煅烧0. 5 h,投加量0. 3 g/L,H_2O_2质量浓度0. 4 g/L,反应4 h。优化条件下,养殖废水中盐酸四环素的平均去除率可达91. 12%,有较好的稳定性和重复利用性。     

木质素及模型化合物光催化降解用催化剂研究进展

为总结木质素光降解催化剂的研究状况,从金属氧化物、金属硫化物、金属复合物、有机金属配合物等光催化剂方面,综述了木质素及模型化合物光降解催化剂的研究与应用情况,展望了光降解催化剂未来发展趋势,即随着光催化降解机理研究的不断完善,将会开发出更多类型的高效、低价和高选择性的木质素及模型化合物光降解催化剂,并在规模化应用上实现突破。     

氮掺杂对TiO_2催化剂吸附性能及光催化性能的影响

以低浓度碱溶剂热法制备钛酸纳米纤维,利用二次水热法掺杂氮元素制得N-Ti O2催化剂;采用X射线衍射和扫描电子显微镜对制备的催化剂进行表征。以亚甲基蓝溶液模拟有机废水,考察氮掺杂量对催化剂吸附性能和光催化性能的影响,揭示吸附性和光催化性能的内在联系。结果表明,掺杂氮元素未改变Ti O2的晶型,但能改变Ti O2晶体尺寸,对其形貌有一定影响,同时显著提高N-Ti O2催化剂的吸附性能和催化活性。氮掺杂量越高,晶粒尺寸越小,比表面积越大,吸附和光催化性能越好。在n(N)∶n(Ti)=1∶1时,Ti O2光催化活性和吸附性能最佳。     

沉淀法制备纳米ZnO及光催化甲基橙脱色研究

以Zn(NO3)2·6H2O为锌源,(NH4)2CO3和NH3·H2O混合碱为沉淀剂,通过并流沉淀法制备出纳米ZnO粉体,采用XRD和SEM对其进行了表征。以甲基橙为脱色对象,紫外灯(最大吸收波长254nm)为光源,研究了催化剂用量、甲基橙初始浓度、pH值及外加氧化剂(H2O2)对光催化性能的影响。     

Azo-dye Orange II degradation by heterogeneous Fenton-like reaction using carbon-Fe catalysts

In this work, the degradation and mineralization of the non-biodegradable azo dye Orange II (OII) was studied, making use of a heterogeneous Fenton-like oxidation process. For that, hydrogen peroxide activation was achieved by means of two different carbon-based catalysts, which have been impregnated with 7 wt% of iron. The carbon supports employed are quite different, one of them being an activated carbon prepared from agricultural by-products (olive stone), while the other one is a carbon aerogel, prepared by carbonization of an organic resorcinol–formaldehyde polymer. The solids have been characterized using several techniques, namely N₂ and CO₂ adsorption at −196 and 0 °C, respectively, mercury porosimetry, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). Then, the catalyst's performance in the Fenton-like oxidation of OII was compared, and the effects of the most relevant operating conditions (pH, catalyst concentration, H₂O₂ concentration and temperature) analyzed for the most promising one (the carbon aerogel based catalyst). In this catalyst, characterization data point for a very good iron dispersion on the carbon surface. This sample showed very good catalytic performances, with mineralization degrees as high as 90%. However, iron leaching from the support is also considerable leading to a progressive deactivation in consecutive reaction cycles.     

Ti基CO2光催化还原及其影响因素研究进展

综述了Ti基CO2光催化还原的研究进展,简要介绍了近年来用于光催化还原CO2的Ti基催化剂,包括纯TiO2催化剂、金属掺杂TiO2催化剂、非金属掺杂TiO2催化剂、共掺杂TiO2催化剂、Ti基纳米复合催化剂、有机光敏化剂修饰TiO2催化剂及其它TiO2催化剂等,比较了各类TiO2基催化剂光催化活性,介绍了其相应的反应机理及优缺点,讨论了光照时间、反应温度、CO2分压力、H2O和CO2摩尔比、光反应器等因素对光催化活性的影响。通过综合运用多种改性措施,开发高效Ti基催化剂并优化反应系统以提高光催化反应活性及光利用率将会成为CO2光催化还原领域重点研究内容与发展趋势,最后展望了利用该技术光催化还原工业烟气,尤其是富氧燃烧烟气的潜在应用前景与挑战。     

纳米二氧化钛光催化降解水中有机污染物的研究

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Optimizing photocatalytic degradation of phenol by TiO2/GAC using response surface methodology

TiO₂ deposited on granular activated carbon (TiO₂/GAC) was used for photocatalytic degradation of phenol. The effects of photocatalyst loading, initial substrate concentration and addition of an oxidizing agent as H₂O₂ were investigated using a one-factor-at-a-time experiment. Central composite design, an experimental design for response surface methodology (RSM), was used for the modelling and optimization of the phenol degradation. Analysis of variance (ANOVA) indicated that the proposed quadratic model was in agreement with the experimental case with R² and R _adj ² correlation coefficients of 0.9760 and 0.9544, respectively. Accordingly, the optimum conditions for phenol degradation were a photocatalyst loading of two layers, initial phenol concentration of 34.44 mg L^?1 and H₂O₂ concentration of 326.90 mg L^?1. The TiO₂/GAC was used for five cycles with phenol degradation efficiency still higher than 90%. Finally, the phenol that remained adsorbed on GAC was able to migrate to TiO₂ and then photocatalytically be degraded.     

UV-TiO2-Fenton光催化降解敌百虫农药废水的研究

研究了UV-TiO2-Fenton体系光催化降解敌百虫农药.结果表明:UV-TiO2-Fenton有极强的氧化性,能有效地降解敌百虫农药.当敌百虫农药浓度为0.1 mmol/L,反应液起始pH为3.25,通空气量为2 L/min,TiO2质量浓度为2 g/L,Fe3 用量为0.10mmol/L,H2O2用量为2 mmol/L,光照时间为2 h时,敌百虫农药有机磷的降解率为92.50%,同时发现Cl-、SO42-和H2PO4-等无机阴离子对敌百虫农药的光催化降解产生抑制作用.还探讨了起始pH、无机阴离子,以及电子接受体Fe3 等对光催化降解敌百虫农药的影响.     

光催化降解活性染料K-GL的动力学及其盐效应

以分散态纳米TiO2为光催化剂,在鼓泡流化床光催化反应器中对活性翠兰K-GL染料溶液进行光催化降解实验研究。通过改变光催化剂投入量、染料溶液的初始浓度和Na2SO4与NaCl的掺加,探讨了影响光催化降解K-GL的因素,运用Langrmuir-Hinshelwood动力学方程对染料降解动力学规律进行了研究。结果表明,TiO2光催化降解活性翠兰K-GL的反应遵循准一级反应动力学方程,且表观反应速率表常数随活性翠兰溶液初始浓度的升高而降低;反应的催化剂最佳投入量为0.122g/L;光催化体系中的Na2SO4对于染料K-GL的降解表现出明显的促进作用,在较低浓度下,Na2SO4的最佳添加量为0.104mol/g,且随着其浓度的升高,表观反应速率常数随之增大;而掺加不同浓度的NaCl对光催化降解K-GL有抑止作用。     

不同催化剂光催化降解分散蓝56染料的效果

分析了锐钛晶型TiO2和锰矿光催化降解分散蓝56染料的效果。结果表明,锰矿对分散蓝56染料的降解效果与锐钛晶型TiO2对分散蓝56染料的降解效果相近。