纳米二氧化钛负载改性天然高分子材料的研究

对丝瓜络及纳米二氧化钛进行接枝改性处理,再以戊二醛为中间反应物进行丝瓜络及纳米二氧化钛的交联反应从而在丝瓜络表面形成纳米二氧化钛薄膜,制备复合光催化剂。通过傅立叶变换红外光谱仪(FTIR)及扫描电子显微镜(SEM)对样品结构、形貌进行了分析表征,表明纳米二氧化钛通过KH550的连接负载到了丝瓜络表面;室温下,以甲基橙为底物在365nm波长的紫外光照射下进行光催化降解试验,结果表明,复合光催化剂对甲基橙的催化降解率达到32.21%,且重复性光降解试验表明其可持续光降解能力较好。     

纳米复合ZnO-TiO2晶体的制备及其光电催化性能研究

采用溶胶-凝胶法制备了纳米复合半导体ZnO-TiO2薄膜,并进行了结构和光电催化性能的测试.TiO2薄膜对五氯酚溶液的光电催化降解结果表明当输入正向偏压后,其光催化性能有较大提高.由于ZnO的掺入,半导体薄膜电极的光吸收能力增强;同时,Zn2+可能作为光生载流子的浅俘获中心,导致表面界面电荷转移加速,从而延长光生电子/空穴对的寿命并抑制其复合,有效地提高了TiO2薄膜光电催化活性.     

纳米复合ZnO-TiO2晶体的制备及其光电催化性能研究

采用溶胶一凝胶法制备了纳米复合半导体ZnO—TiO2薄膜，并进行了结构和光电催化性能的测试。TiO2薄膜对五氯酚溶液的光电催化降解结果表明：当输入正向偏压后，其光催化性能有较大提高。由于ZnO的掺入，半导体薄膜电极的光吸收能力增强；同时，Zn^2 可能作为光生载流子的浅俘获中心，导致表面界面电荷转移加速，从而延长光生电子／空穴对的寿命并抑制其复合，有效地提高了TiO2薄膜光电催化活性。     

CuO/ZnO复合光催化剂降解海水养殖废水中盐酸四环素

为降解海水养殖废水中盐酸四环素,采用沉淀法自制CuO/ZnO复合光催化剂。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外—可见漫反射(UV-Vis DRS)等表征手段对其进行表征,得到CuO/ZnO复合光催化剂的粒径、外貌特征以及光吸收范围。可见光照射下,考察了CuO/ZnO复合光催化剂投加量、煅烧温度、掺杂比(ZnO和CuO摩尔比)、过氧化氢浓度、反应时间以及盐酸四环素初始浓度6项因素对光催化降解海水养殖废水中盐酸四环素的影响。通过正交试验得到CuO/ZnO复合光催化剂降解盐酸四环素的优化反应条件为:海水养殖废水中含有的盐酸四环素初始质量浓度为0.025g/L,过氧化氢质量浓度为0.5g/L,掺杂比为10∶1,煅烧温度为550℃,CuO/ZnO复合光催化剂投加量为0.15g/L,可见光下反应3.5h。在此条件下海水养殖废水中盐酸四环素的平均去除率可达93.01%。     

一种新型铋基光催化剂的合成及其可见光催化性能

采用水热法合成铋基光催化剂Bi4VO8Br,通过X-射线粉末衍射、扫描电镜等手段对其进行表征.选择甲基橙为目标降解物来评价不同条件下合成的Bi4VO8Br在可见光下的光催化活性,发现pH 3、反应时间15 h、反应温度160℃为材料水热合成的最佳条件.考察了Bi4VO8Br在可见光及紫外光下对几种农药和增塑剂的光催化降解性能,显示了Bi4VO8Br对不易光解的含苯环有机物的可见光高活性.五氯酚的光催化过程影响因素优化结果表明,可见光和紫外光分别照射120 min和20 min,其降解率分别达到97％和99％,Bi4VO8Br表面上活性基团的捕获即空穴的氧化作用是主要反应原理.     

负载型TiO_2纳米管对水体中萘普生光催化作用

为了解决水体中光催化剂的分离和回收问题,对纳米TiO_2的固载化及其应用进行了研究。首先以纳米TiO_2为原料,采用水热合成法制备TiO_2纳米管;再以聚氨酯膜片为载体制备负载型TiO_2纳米管(PU/TiO_2)。对负载材料进行FT-IR和SEM表征,表征结果表明:TiO_2纳米管能很好地接枝在PU薄膜表面;然后在空气曝气、p H=5、T=26℃的条件下,进行光催化降解萘普生的实验。实验结果表明:制备的负载材料对水体中的萘普生有较强的吸附作用,在300 W紫外光的照射下,5 min内能使10.00 mg/L的萘普生降解完全;紫外光照与光催化剂对萘普生的降解具有协同效应;光催化反应近似符合一级模型。综合表明,负载型TiO_2纳米管是一种具有潜在应用前景的光催化剂。     

环境污染与防治 网络版论文摘要

水相、泥相中混合及单一菌株对菲的微生物降解；复合纳米SnO2／ZnO光催化降解对甲酚溶液的研究；Pt／TiO2薄膜光催化降解甲基橙的性能研究；两种水生园林植物对小流域富营养化水体的净化作用；废钯-炭催化剂回收钯的工艺中试研究     

Fe(Ⅲ)-富马酸盐体系光降解黄连素

紫外光(UV)照射下,利用Fe(Ⅲ)-富马酸盐体系对黄连素(berberine)的降解反应进行研究。探讨Fe(Ⅲ)、富马酸盐(fumarate)和黄连素的初始浓度及溶液pH值对黄连素降解率的影响,并对黄连素的降解过程进行了动力学分析和机理分析。结果表明,在紫外光照射下,Fe(Ⅲ)-富马酸盐体系对黄连素有较好的降解效果。当Fe(Ⅲ)和富马酸钠初始浓度分别为25μmol/L和250μmol/L,溶液pH值为3.0时,紫外光照75 min后黄连素降解率接近91%。在pH 2.0~6.0范围内,pH值越大黄连素的降解率越低;Fe(Ⅲ)和富马酸盐初始浓度的增大能促进黄连素的降解;而随着黄连素初始浓度的增大,其降解率逐渐降低。动力学分析表明,黄连素光降解过程符合一级动力学。利用异丙醇和硫脲猝灭法证明Fe(Ⅲ)-富马酸盐体系在光反应过程中产生了羟基自由基和超氧负离子自由基。通过紫外光谱、红外光谱、TOC检测和GC-MS分析表明,在紫外光照射下黄连素在Fe(Ⅲ)-富马酸盐体系中结构被破坏,降解为小分子物质。     

Fe_3O_4@SiO_2/TiO_2核壳结构纳米颗粒降解TNT溶液

针对TNT炸药废水具有成分复杂、排放量大、有毒等特点,立足于炸药废水在排放前的降解处理,研究开发一种基于核壳结构Fe3O4@SiO2/TiO2纳米颗粒的高效、可控回收、无二次污染且成本低的光催化降解方法。利用高温碳还原法和溶胶凝胶法制备了具有核壳结构的Fe3O4@SiO2/TiO2纳米颗粒。XRD分析表明,内核Fe3O4呈现磁铁矿特征,表面覆盖的纳米TiO2为锐钛矿型。磁滞回线测试结果显示,复合颗粒的饱和磁化强度为46.5 emu/g,N2吸附-解吸分析结果表明,该颗粒具有典型的介孔结构。使用Fe3O4@SiO2/TiO2纳米颗粒在紫外光下对含TNT废水进行降解,降解率达到81.9%,且颗粒的回收率达到88.4%,为实现高效、可控回收、无二次污染光催化-吸附降解TNT奠定了基础。     

络合凝胶法合成Al掺杂纳米ZnO及其光催化性能

氧化锌(ZnO)纳米粉体是一种重要的可用来降解有机污染物的光催化剂。然而，纯的ZnO仅仅能够吸收紫外光和部分可见光，不能够充分利用太阳光。采用了一种络合凝胶法来合成掺杂Al的ZnO纳米粉体。所制备出来的纳米颗粒尺寸在20～50 nm之间，它不仅对波长范围在200～400 rm之间的紫外光有很强的吸收，而且对波长范围在4...     

Ag/ZnO hollow sphere composites: reusable photocatalyst for photocatalytic degradation of 17α-ethinylestradiol

Characterizations of Ag/ZnO hollow sphere by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectra, and UV–vis absorption spectra have been made after its synthesis. The results showed that the composite was hollow structure with diameters of about 1–4 μm. The samples synthesized were tested and identified as silver doped ZnO, which have extended and boosted the spectral absorption. The photocatalytic activity of Ag/ZnO hollow spheres was assessed using 17α-ethinylestradiol aqueous solution under UV irradiation. It has been observed that the 17α-ethinylestradiol absorption efficiency and degradation rate is higher for Ag/ZnO hollow spheres. As reusable photocatalysts, Ag/ZnO hollow spheres which could be easily separated from a suspension will facilitate their application in wastewater treatment with enhanced photostability.     

Solar photocatalytic decolorization of methylene blue in water

In this study, a photocatalytic decolorization system equipped with immobilized TiO2 and illuminated by solar light was used to remove the color of wastewater. To examine the decoloring efficiency of this system, photocatalytic decolorization of an organic dye such as methylene blue was studied as an example. The effects of light source, pH, as well as the initial concentration of dye were also investigated. It was observed that the solution of methylene blue could be almost completely decolorized by the solar light/TiO2 film process while there was about 50% color remaining with solar irradiation only. In addition, it was found that the decoloring efficiency of solution was higher with solar light irradiation than with artificial UV light irradiation, even though the artificial UV light source supplied higher UV intensity at 254 nm. The color removal rate of methylene blue with solar light irradiation was almost twice that of artificial UV light irradiation. This phenomena was mainly attributed to that some visible light range of solar light was useful for exciting the methylene blue molecules adsorbed on TiO2 film, leading to a photosensitization process undergoing and decoloring efficiency promoted. This solar-assisted photocatalytic device showed potential application for decoloring organic dyes in wastewater.     

Enhancement of photocatalytic activity of sprayed nitrogen-containing ZnO powders by coupling with metal oxides during the acetaldehyde decomposition

Colored N-containing MOx-ZnO (M = W, V) composite powders with high surface area were synthesized by spray pyrolysis. The nitrogen content was controlled from 600 to 3000 ppm by changing the powder ingredients and the spray pyrolysis temperature. Ultraviolet-visible spectra indicated that the N-containing MOx-ZnO powders absorbed not only ultraviolet light like pure ZnO powder, but also some visible-light. Acetaldehyde decomposition was used as a probe reaction to evaluate the photocatalysis of these MOx-ZnO powders. The photocatalytic activity of the N-containing ZnO powder was pronouncedly enhanced by the WO3 or V2O5 addition under both UV and visible-light irradiation. This enhancement was ascribed to the MOx acting as a sink for photogenerated electrons in the UV case, and to a synergistic effect of N-doping and MOx-ZnO coupling in the case of visible-light.     

Fe^3＋掺杂TiO2/凹凸棒复合材料的光催化性能

采用酸催化的溶胶-凝胶法制备了一系列Fe^3＋掺杂TiO2/凹凸棒（Fe^3＋-TiO2/ATP）复合光催化剂材料。在可见光条件下,以亚甲基蓝（MB）溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe^3＋掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计（L25（53））优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood（L-H）动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe^3＋掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10^-3min^-1,反应4 h后MB的降解率（Dt）可达75.88%,相同实验条件下与P25（1.51×10^-3min^-1）相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。敏世雄王芳魏立强王永生冯雷佟永纯韩玉琦     

Photocatalytic degradation of Orange G dye under solar light using nanocrystalline semiconductor metal oxide

Introduction

The photocatalytic degradation of Orange G (OG) dye has been investigated using synthesised nanocrystalline ZnO as a photocatalyst and sunlight as the irradiation source. The formation of ZnO prepared from its precursor was confirmed through FT-IR and powder X-ray diffraction analyses.

Materials and methods

Surface morphology was characterised by scanning electron microscope and transmission electron microscope analysis. Band gap energy of synthesised nanocrystalline ZnO was calculated using diffuse reflectance spectroscopy (DRS). Different experimental parameters such as effects of pH, dye concentrations and mass of catalyst were standardised in order to achieve complete degradation of the dye molecules under solar light irradiation.

Results

The kinetics of oxidation of OG was also studied. The complete degradation of OG was evident after 90 min of irradiation at an initial pH of 6.86. The degradation of OG was confirmed by UV?CVisible spectrophotometer, high-pressure liquid chromatography, ESI-Mass and chemical oxygen demand analyses.

Conclusion

The adsorption of dye onto catalytic surface was analysed employing model equations such as Langmuir and Freundlich isotherms, and it was found that the Langmuir isotherm model best fitted the adsorption data. The solar photodegradation of OG followed pseudo-first-order kinetics. HPLC and ESI-Mass analyses of the degraded samples suggested that the dye molecules were readily degraded under solar irradiation with nanocrystalline ZnO.     

Photostabilizers for azadirachtin-A (a neem-based pesticide)

Photostability of azadirachtin-A (a neem based pesticide) has been studied without and with adding stabilizers such as ter. butyl-p-cresol, 8-hydroxy quinoline and ter. butyl hydroquinone as thin film on glass surface and on leaf surface under sunlight and UV light. Half-life of azadirachtin has been found to be 48 min and 3.98 days as thin film under UV light and sunlight and 2.47 days on leaf surface, respectively. 8-Hydroxy quinoline and ter. butyl hydroquinone have been found effective in controlling degradation of azadirachtin under both sunlight and UV light with half-life of 44.42 and 35.90 days under sunlight, and 55.80 and 48.50 h under UV light, respectively. Whereas ter. butyl-p-cresol has been found effective A only under sunlight. Significant decreases in antifeedant and insect growth regulatory activity against third instar larvae of Spodopterra litura has been observed with azadirachtin when exposed to sunlight and UV light. However, by the addition of above stabilizers, the biological activity of azadirachtin-A has been retained even after 24 h of irradiation under UV light and up to 30 days of exposure to sunlight.     

Degradation of ampicillin antibiotic in aqueous solution by ZnO/polyaniline nanocomposite as photocatalyst under sunlight irradiation

PURPOSE AND METHOD: ZnO/polyaniline nanocomposite in core-shell structure was prepared by the synthesis and adsorption of polyaniline chains on the structure of ZnO nanoparticles. Fourier transform infrared and ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction patterns, field emission scanning electron microscopy, and transmission electron microscopy were used to characterize the composition and structure of the nanocomposite. The nanocomposite was used as an active photocatalyst for photodegradation and removal of ampicillin in aqueous solution. RESULTS: UV-Vis spectroscopy studies showed that ZnO/polyaniline nanocomposite absorbs visible light irradiation as well as ultraviolet spectrum, and therefore, it can be photoactivated under visible and ultraviolet lights. The photocatalytic activity of ZnO/polyaniline nanocomposite in degradation of ampicillin molecules in aqueous solution under natural sunlight irradiation was evaluated and compared with that of ZnO nanoparticles and pristine polyaniline. The ZnO/polyaniline core-shell nanocomposite exhibited higher photocatalytic activity compared to ZnO nanoparticles and pristine polyaniline. The effect of operating conditions (pH, ZnO/polyaniline nanocomposite dosage, and ampicillin concentration) in the photocatalytic degradation of ampicillin using ZnO/polyaniline nanocomposite was investigated. The optimum conditions for maximum efficiency of ampicillin degradation under 120 min sunlight irradiation were found as 10 mg L(-1) dosage of ZnO/polyaniline nanocomposite, ampicillin concentration of 4.5 mg L(-1), and solution pH?=?5. Under optimum operating conditions, degradation efficiency was reached to 41% after 120 min of exposure to the sunlight irradiation.     

Fe~(3+)掺杂TiO_2/凹凸棒复合材料的光催化性能

采用酸催化的溶胶-凝胶法制备了一系列Fe3+掺杂TiO2/凹凸棒(Fe3+-TiO2/ATP)复合光催化剂材料。在可见光条件下,以亚甲基蓝(MB)溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe3+掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计(L25(53))优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood(L-H)动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe3+掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10-3min-1,反应4 h后MB的降解率(Dt)可达75.88%,相同实验条件下与P25(1.51×10-3min-1)相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。     

Transition metal-modified zinc oxides for UV and visible light photocatalysis

In order to use photocatalysis with solar light, finding more active and especially visible light active photocatalysts is a very important challenge. Also, studies of these photocatalysts should employ a standardized test procedure so that their results can be accurately compared and evaluated with one another. A systematic study of transition metal-modified zinc oxide was conducted to determine whether they are suitable as visible light photocatalysts. The photocatalytic activity of ZnO modified with eight different transition metals (Cu, Co, Fe, Mn, Ni, Ru, Ti, Zr) in three different concentrations (0.01, 0.1, and 1?at.%) was investigated under irradiation with UV as well as with visible light. The employed activity test is the gas-phase degradation of acetaldehyde as described by the ISO standard 22197-2. The results suggest that the UV activity can be improved with almost any modification element and that there exists an optimal modification ratio at about 0.1?at.%. Additionally, Mn- and Ru-modified ZnO display visible light activity. Especially the Ru-modified ZnO is highly active and surpasses the visible light activity of all studied titania standards. These findings suggest that modified zinc oxides may be a viable alternative to titanium dioxide-based catalysts for visible light photocatalysis. Eventually, possible underlying mechanisms are proposed and discussed.     

Comparison of azo dye degradation efficiency using UV/single semiconductor and UV/coupled semiconductor systems

This study examined degradation of azo dyes using photocatalytic oxidation (UV/semiconductor). The model substrates employed in this work were Procion Red MX-5B and Amaranth, while the photocatalysts were TiO2, ZnO, and SnO2. UV-Vis spectrum analysis demonstrated that the band gap energies of TiO2, ZnO, and SnO2 were 3.17, 2.92, and 4.13 eV, respectively. The band gap energy of SnO2 is insufficient to initiate photocatalytic reaction after UV irradiation (365 nm). The reaction rate constants fit a first-order reaction model and the reaction rate constant of Procion Red MX-5B for TiO2+SnO2 (0.31 h-1) is larger than that of TiO2 (0.24 h-1) and SnO2 at pH 10. The difference between the conduction bands of SnO2 and TiO2 enables the former to act as a sink for the photogenerated electrons. Most of the reaction rate constants had higher values at pH 10 than pH 7, and thus the OH attack could be assumed to represent the main reaction in this investigation. The quantities of sulfate and chloride ions released are below stoichiometry during the degradation. Owing to the sulfonate groups of Amaranth exceeding Procion Red MX-5B, Amaranth had larger electrostatic attraction than Procion Red MX-5B with the surface of ZnO, and also had higher adsorption percentage than Procion Red MX-5B on the surface of ZnO. The trend of adsorption is consistent with the reaction rate constant at pH 7, namely Amaranth>Procion Red MX-5B. The sulfate dissociation rate constant of Amaranth in UV/ZnO at pH 7 (0.49 h-1) approaches the overall rate constant (0.53 h-1); therefore, the first step involved in Amaranth can be suggested to the cleavage of the bonds of the C-S in Amaranth, causing sulfate ion formation.