造纸黑液COD的催化降解

通过复合絮凝-化学氧化-光催化氧化-电降解相结合的方法对造纸黑液进行降解处理选择了PAC-PFS-CPAM复合絮凝剂的最佳配比:PAC:PFS:CPAM=5:2:3(体积比),以及过硫酸铵氧化剂的合理用量通过溶胶凝胶法制备二氧化钛薄膜来进行光催化氧化造纸黑液,所得到的水样再通过电降解,最终处理后的造纸废水COD指数从111 500mg·L~(-1)降到20mg·L~(-1),与饮用纯净水相当,使废水达到了高度净化     

Ce-SiO2-TiO2三元复合催化剂的制备及其光催化降解性能

采用溶胶-凝胶法制备了Ce-SiO2-TiO2三元复合纳米催化剂,用TG-DTA、FT-IR、XRD和UV-Vis等对样品的结构进行了表征,并以罗丹明B(RhB)作为探针反应,分别在紫外光和可见光照下评价了其光催化性能.与TiO2一元纳米催化剂和Ce-TiO2、SiO2-TiO2二元纳米催化剂进行对比,Ce-SiO2-TiO2三元复合纳米催化剂对罗丹明B溶液(5 mg/L)表现出更高的光催化降解性能,可见光下的降解率达到98.5%.     

絮凝-纳米二氧化钛光催化氧化法处理造纸废水

通过絮凝-纳米TiO2光催化氧化法对造纸废水进行了处理,并对其处理工艺进行了研究。讨论了在常温下,混凝过程中硫酸铝的投加量和废水pH值以及纳米光催化氧化过程中纳米TiO2投加量、H2O2投加量和光照时间等因素对造纸废水的COD去除率的影响,结果表明,造纸废水的COD去除率达到95%以上,色度去除率达到98%以上,pH值6.82,造纸废水的各项指标达到了排放标准。     

双微乳液法制备掺杂Fe~(3+)的纳米TiO_2及其光催化性能

为了研究双微乳液法在制备纳米级光催化剂的应用,以TiCl4和NH3.H2O为原料,采用十六烷基三甲基溴化铵-正丁醇-环己烷-水微乳体系制备Fe3+掺杂纳米TiO2,对粉末的晶体结构进行X射线衍射表征,并以其对p-甲酚的降解考察其光催化活性。结果表明,在较小的掺杂量时,Fe3+掺杂量的提高可以提高TiO2的光催化活性,进一步提高掺杂量将引起光催化活性的降低;掺杂Fe3+可导致纳米TiO2的粒径减小;Fe3+的半径较小以及Fe2O3的熔点较低均有利于TiO2从锐钛矿向金红石的相变;当Fe3+掺杂摩尔分数为0.06%,煅烧温度为550℃时,纳米TiO2的光催化活性最高,此时形成TiO2的锐钛矿和金红石相的混晶;乳液中含水量也会影响晶相的组成和粒径大小,随着含水量增加产物中出现了一定比例的金红石相。     

纳米TiO2微球的制备及光催化性能研究

以钛酸四丁酯为前驱体,在油酸和正己烷的混合溶剂中,采用溶剂热技术成功地合成了纳米TiO2微球.以X射线衍射(XRD)、透射电镜(TEM)等方法对产物进行了表征,并对其光催化降解甲基橙溶液的性能进行了研究.实验结果表明:纳米TiO2微球的平均尺寸约为60nm,其中含有粒径平均约4.5nm的超细粒子.此种结构趋向于高的比表面积,与P-25型光催化剂相比,两者对甲基橙溶液的脱色具有相近的光催化活性.     

Metal‐Free 2D/2D Phosphorene/g‐C3N4 Van der Waals Heterojunction for Highly Enhanced Visible‐Light Photocatalytic H2 Production

The generation of green hydrogen (H₂) energy using sunlight is of great significance to solve the worldwide energy and environmental issues. Particularly, photocatalytic H₂ production is a highly promising strategy for solar‐to‐H₂ conversion. Recently, various heterostructured photocatalysts with high efficiency and good stability have been fabricated. Among them, 2D/2D van der Waals (VDW) heterojunctions have received tremendous attention, since this architecture can promote the interfacial charge separation and transfer and provide massive reactive centers. On the other hand, currently, most photocatalysts are composed of metal elements with high cost, limited reserves, and hazardous environmental impact. Hence, the development of metal‐free photocatalysts is desirable. Here, a novel 2D/2D VDW heterostructure of metal‐free phosphorene/graphitic carbon nitride (g‐C₃N₄) is fabricated. The phosphorene/g‐C₃N₄ nanocomposite shows an enhanced visible‐light photocatalytic H₂ production activity of 571 µmol h^?1 g^?1 in 18 v% lactic acid aqueous solution. This improved performance arises from the intimate electronic coupling at the 2D/2D interface, corroborated by the advanced characterizations techniques, e.g., synchrotron‐based X‐ray absorption near‐edge structure, and theoretical calculations. This work not only reports a new metal‐free phosphorene/g‐C₃N₄ photocatalyst but also sheds lights on the design and fabrication of 2D/2D VDW heterojunction for applications in catalysis, electronics, and optoelectronics.     

新型光电催化反应器处理腈纶废水的可行性

研制了一种新型的光电催化反应器,并对干法腈纶废水和外排腈纶废水进行了处理研究,考察了阳极偏压、pH值和H2O2投加量对处理效果的影响。结果表明,在最佳阳极偏压条件下COD去除率提高15％,B／C值显著提高,酸性条件和H2O2可以明显提高处理效果,结合光电催化技术提出了一套处理腈纶废水的工艺方案。     

掺杂锡的纳米二氧化钛光催化降解苯酚的研究

以钛酸丁酯为原料,用溶胶-凝胶(So l-gel)法制备了掺杂锡离子的纳米T iO 2粉末。采用透射电子显微镜和X光衍射仪对粉体的粒径、物相、形貌和热稳定性进行了表征。通过粉体对苯酚的降解情况对其光催化活性进行了测试,结果表明5%Sn4 -T iO 2具有良好的光催化氧化性能。     

掺杂铁的纳米二氧化钛光催化降解邻硝基苯酚的研究

以钛酸丁酯为原料,用溶胶-凝胶(So l-gel)法制备了掺杂铁的纳米T iO2粉末。采用X光衍射仪对粉体的物相进行了表征。样品经500℃焙烧2h后,0.02%(摩尔分数)Fe3 -T iO2纳米粉末为单一的锐钛型结构。通过粉体对邻硝基苯酚的降解情况对其光催化活性进行了测试,结果表明与纯T iO2相比,Fe3 -T iO2的光催化活性有较大提高,当Fe3 的掺入量为摩尔比0.02%时催化活性最高。以高压汞灯为光源,邻硝基苯酚的初始浓度为50m g.L-1、催化剂0.02%(摩尔分数)-T iO2投加量为1.0g.-L 1时,邻硝基苯酚的光催化降解效果最好。     

Two-Dimensional Titanium Dioxide–Surfactant Photoactive Supramolecular Networks: Synthesis,Properties, and Applications for the Conversion of Light Energy

The desire to harness solar energy to address current global environmental problems led us to investigate two-dimensional (2D) core–shell hybrid photocatalysts in the form of a 2D-TiO₂–surfactant, mainly composed of fatty acids. The bulk products, prepared by two slightly different methods, consist of stacked host–guest hybrid sheets held together by van der Waals forces between alkyl carboxylate moieties, favoring the synergistic conjugation of the photophysical properties of the core and the hydrophobicity of the self-assembled surfactant monolayer of the shell. X-ray diffraction and the vibrational characteristics of the products revealed the influence of synthesis strategies on two types of supramolecular aggregates that differ in the core chemical structure, guest conformers of alkyl surfactant tails and type, and the bilayer and monolayer of the structure of nanocomposites. The singular ability of the TiO₂ core to anchor carboxylate leads to commensurate hybrids, in contrast to both layered clay and layered double-hydroxide-based ion exchangers which have been previously reported, making them potentially interesting for modeling the role of fatty acids and lipids in bio-systems. The optical properties and photocatalytic activity of the products, mainly in composites with smaller bandgap semiconductors, are qualitatively similar to those of nanostructured TiO₂ but improve their photoresponse due to bandgap shifts and the extreme aspect-ratio characteristics of two-dimensional TiO₂ confinement. These results could be seen as a proof-of-concept of the potential of these materials to create custom-designed 2D-TiO₂–surfactant supramolecular photocatalysts.