核壳型TiO2／HAP纳米复合光催化剂的制备与表征

采用非均相沉淀的方法，首次在纳米TiO2的表面诱导沉积一层羟基磷灰石（HAP）。通过X射线衍射（XRD）和傅立叶红外光谱（FT-IR）对制备的样品进行结构和成分分析；用原子力显微镜（AFM）、扫描电子显微镜（SEM）和电子能谱仪（EDS）对样品包覆进行表征；采用甲基橙的光催化降解反应和大肠杆菌吸附率测定对所制光催化剂的光催化活性和吸附特性进行了评价；并与纯的纳米TiO2进行比较分析，文中还初步探讨了TiO2／HAP纳米复合材料的包覆机理．结果表明，TiO2／HAP为核壳结构，且包覆均匀，羟基磷灰石包覆层的厚度为8nm。所制备的样品具有良好的光催化活性和对细菌良好的吸附性能。这种核壳型TiO2／HAP纳米复合材料可用作环境净化和杀菌材料．     

旅客机环境控制系统优化研究

为了选择经济高效的旅客机环境控制系统，对现役各种旅客机采用的环境控制系统方案进行了优化设计和比较，分别建立了二轮简单式低压除水系统、三轮升压式高压除水系统和四轮升压式高压除水系统（又称冷凝循环制冷系统）的优化设计数学模型，以起飞燃油质量代偿损失为目标函数，采用广义乘子法结合单纯形加速法求解，优化结果可作为设计研究旅客机环境控制系统的理论依据。     

纳米二氧化钛的光催化性能研究

采用TiOSO4常温水解法制备纳米二氧化钛，以甲基橙溶液做光催化降解实验，考察各种因素对光催化降解效果的影响。结果表明：加入表面活性剂方式制备的纳米TiO2具有更大的比表面积,光催化降解效果明显；甲基橙溶液的初始浓度越低,光催化降解效果越好；锐钛晶型96．5％、金红石晶型3．5％(质量比)的混晶型纳米TiO2具有更高的光催化活性；进行过多次光催化实验的纳米TiO2经再生后仍然可保持较高的光催化活性。     

纳米TiO2稀土元素掺杂改性光催化还原CO2制甲醇研究

讨论采用改良的溶胶-凝胶法，以钛酸丁酯为前驱体，以冰醋酸为鳌合剂，通过水解缩聚作用制备纳米TiO2，掺杂稀土金属进行改性，进行CO2光催化还原制甲醇研究；利用X射线衍射（XRD）、高分辨透射电镜（HRTEM）、BET比表面积、光致发光光谱（PL）技术来分析制得的光催化材料结构、吸光性能、化学吸附等特性，期待能弄清楚纳米TiO2结构与催化效果之间的关系，从而确定主导CO2光催化还原反应效率的因素。     

石墨烯负载小尺寸氧化锌纳米颗粒及其光催化性能研究

利用共沉淀法实现石墨烯纳米片均匀负载粒径为5nm的氧化锌颗粒,并研究了石墨烯／氧化锌纳米衍生体的光催化性能,结果表明,合成的石墨烯／氧化锌纳米衍生体比纯氧化锌纳米颗粒对甲基橙有机染料具有更好的光催化活性。当石墨烯在衍生体中的含量为0．51wt．％时,获得的衍生体具有最强的光催化活性,在90rain内能全部降解溶液中的甲基橙。光催化活性的提高主要贡献于石墨烯良好的电子输运性能,能有效阻止氧化锌纳米颗粒中光生电子和空穴对之间的复合。     

可见光响应型ZnO基纳米复合光催化材料的研究进展

本文综述了ZnO基纳米复合光催化材料的基本结构与性能、光催化效果及其作用机理;系统概述了可见光响应型ZnO基纳米复合光催化材料在有机物污染物降解、光催化制氢和抗菌等方面的应用,并对其进一步研究提出了思路和建议。相信随着基础研究与应用实践的不断深入,ZnO基纳米复合光催化材料最终会在高效催化剂、环境净化、太阳能转换等方面得到长久发展与广泛应用。     

纳米TiO2-Ag复合光催化剂对涤棉混纺织物净化氨气性能的改善研究

本研究中采用沉积法制备了纳米TiO2-Ag复合光催化剂水分散液，然后应用浸轧方法将纳米TiO2-Ag复合光催化剂负载于涤棉混纺织物表面，制成了具有光催化特性的纳米TiO2-Ag负载涤棉混纺织物，并利用X射线衍射仪(XRD)和扫描电镜(SEM)等对其进行了表征。最后在自行设计的光催化反应器和小型环境舱系统中，研究了纳米TiO2-Ag负载涤棉混纺织物对模拟室内混凝土释放氨气的光催化净化性能，并与纳米TiO2负载的涤棉混纺织物和纯棉织物进行了比较。     

有机分子控制下TiO2纳米材料的制备及光催化性能研究

采用溶胶-凝胶技术，利用表面活性剂AOT控制TiO2的生长，在不同温度下进行热处理．制备出晶粒度为10～35m的TiO2粉。研究了AOT在制备高光催化活性纳米TiO2粉中的作用。在对甲基红／乙醇溶液的降解反应过程中，纳米TiO2粉光催化活性受其晶粒大小、结构和结晶程度的影响。晶粒越小，结晶程度越高，光催化能力越强；锐钛矿相的TiO2粉具有最高的光催化活性；同时含有锐钛矿相和金红石相的TiO2粉的光催化活性与二相比率有关。本TiO2粉循环使用性较好。     

信息快递

纳米光催化涂料研制成功 北京工业大学环境与能源工程学院与北京紫外光云科技有限公司新近研制成功的一种纳米光催化涂料,能有效分解氧化空气中的有害物质,且不会产生二次污染。 采用纳米二氧化钛进行光催化是一项正在蓬勃兴起的新型污染治理技术,它能直接利用包括太阳光在内的各种途径的紫外光,在室温下对各种有机的或无机制的污染物进行分解或氧化,达到从空气中清除这些污染物的效果。这项技术具有能耗低、易操作、除净度高等特点,尤其对一些特殊的污染     

纳米科技普遍性原理的探讨

在纳米科技研究中，我们有机会接触多个纳米科技领域的理论，它们都是针对纳米科技的某一领域的某个特殊问题提出，并且适用于该局部领域，例如：金属薄膜电导率尺寸效应理论：半导体表面纳米光催化理论；半导体超晶格物理：纳米结构增强原理；X射线反射多层膜原理；介观物理；纳米多层膜磁阻效应及其信息存储技术原理：纳米结构电磁工程原理；电磁波局域化理论；光子晶体和微腔技术理论。这类理论通常称之为纳米科技的特殊性原理。     

Revision of testing criteria for air cleaning unit of renovated APR-1000 and APR-1400 NPPS

Designing Air Cleaning Units (ACU) of an Engineered Safety Feature and normal atmosphere clean-up system at the renovated APR-1000 and APR-1400 NPP, and fuel cycle facilities in Korea, is required to meet the standards of ASME AG-1 (1997), ASME N509/N510 (1989) and KEPIC-MH (2001) to enhance the removal efficiency of aerosols and particulates from the effluents. The revised ACU testing criteria are allowed to use alternative challenge agents of the dioctyl phthalate and Refrigerant-11 for in situ testing of high efficiency particulate air filters and adsorption banks. The operability testing time of engineered safety feature (ESF) trains was changed from 10 h to 15 min. The activated carbon in adsorption banks should undergo laboratory tests at a temperature of 30 °C and relative humidity 95 %. The removal criteria of methyl iodide should be over 99.5 % for ESF and 99 % for normal systems. This paper provides the background of the changed criteria for designing and testing of the ACU system in nuclear facilities.     

Hydro‐Assisted Self‐Regenerating Brominated N‐Alkylated Thiophene Diketopyrrolopyrrole Dye Nanofibers—A Sustainable Synthesis Route for Renewable Air Filter Materials

With rising global concerns over the alarming levels of particulate pollution, a sustainable air quality management is the need of the hour. Air filtration research has gained momentum in recent years. However, the research perspective is still blinkered toward formulating new fiber systems for the energy‐intensive electrospinning process to fabricate high quality factor air filters. A holistic approach on sustainable air filtration models is still lacking. The air filter model presented in this work uses a simple process involving water‐induced self‐organization and self‐regeneration of nanofibers, and an easy recycling route after the filter life that not only facilitates reuse of the microfibrous scaffold holding the nanofibers but also allows renewal of nanofibers. Three generations of air filters are fabricated and tested, all having high particulate matter (PM)‐adsorbing tendency, high filtration efficiency (>95%), and high Young's modulus (≈5 GPa). The renewable air filters offer a sustainable alternative to the present cost‐intensive electrospun air filters.     

Photocatalytic degradation of gaseous 1-propanol using an annular reactor: kinetic modelling and pathways

Photocatalytic oxidation of airborne contaminants appears to be a promising process for remediation of air polluted by Volatile Organic Compounds (VOCs). In the present work, the photocatalytic oxidation of gaseous 1-propanol has been investigated by using an annular photoreactor. The annular photocatalytic reactor was modelled by a cascade of heightened elementary continuously stirred tank reactors. The influence of several kinetic parameters such as pollutant concentration, incident light irradiance, contact time and humidity content has been studied. The photocatalytic degradation by-products of 1-propanol has been identified in the gas-phase by GC/MS. Propionaldehyde and acetaldehyde were found to be the main gaseous intermediates. Propionaldehyde and acetaldehyde have been taken into account in a "two-site model" to evaluate the possible competition of adsorption between 1-propanol and its by-products of degradation. A mechanistic pathway is then proposed for the photocatalytic degradation of 1-propanol.     

Catalytic properties of carbon materials for wet oxidation of aniline

A mesoporous carbon xerogel with a significant amount of oxygen functional groups and a commercial activated carbon, were tested in the catalytic wet air oxidation of aniline at 200 degrees C and 6.9 bar of oxygen partial pressure. Both carbon materials showed high activity in aniline and total organic carbon removal, a clear increase in the removal efficiency relatively to non-catalytic wet air oxidation being observed. The best results in terms of aniline removal were obtained with carbon xerogel, an almost complete aniline conversion after 1h oxidation with high selectivity to non-organic compounds being achieved. The materials were characterized by thermogravimetric analysis, temperature programmed desorption, N(2) adsorption and scanning electron microscopy, in order to relate their performances to the chemical and textural characteristics. It was concluded that the removal efficiency, attributed to both adsorption and catalytic activity, is related to the mesoporous character of the materials and to the presence of specific oxygen containing functional groups at their surface. The effect of catalytic activity was found to be more important in the removal of aniline than the effect of adsorption at the materials surface. The results obtained indicate that mesoporous carbon xerogels are promising catalysts for CWAO processes.     

PARTICULATE CONCENTRATION IN AUTOMOBILE PASSENGER COMPARTMENTS

An experimental study of the dust concentration in automobile passenger compartments was conducted to understand how driving conditions and a vehicle's ventilation system can affect cabin air quality. The results of this study are essential for designing appropriate cabin air filters and developing proper test procedures.

The particle size distribution of atmospheric contaminants entering the vehicle's passenger compartment through air registers and in the occupants' breathing zone was measured using an optical particle counter. The concentration and size distribution of aerosol in the cabin was found to be dependent on traffic conditions, road surface, environmental conditions (e.g., weather) and ventilation mode. In all cases over 90% of the particles were smaller than 1 µm. The vehicle's HVAC system (evaporator core) reduces the concentration of aerosol entering the car interior, especially larger particles. Commercial vehicle ventilation filters decrease particle concentrations in a driver's breathing zone for all particle sizes. However, the reduction in the submicron particle range is not sufficient to substantially improve air quality in the passenger cabin.     

活性炭负载TiO2光催化材料的研究

活性炭(AC)及活性炭纤维(ACF)作为光催化剂载体具有较高的比表面积和较强的吸附性能,可以有效提高负载型光催化剂TiO2/AC和TiO2/ACF对有机污染物的光催化降解效率.首先介绍了TiO2光催化剂的结构特性以及各种掺杂改性方法,对负载型TiO2/AC及TiO2/ACF光催化剂的各种制备方法进行了详细评述.在此基础上,讨论了影响有机污染物光催化降解性能的重要因素,指出了负载型TiO2光催化材料研究中有待解决的问题和发展方向.     

Multifunction ZnO/carbon hybrid nanofiber mats for organic dyes treatment via photocatalysis with enhanced solar-driven evaporation

ZnO-based photocatalytic materials have received widespread attention due to their usefulness than other photocatalytic materials in organic dye wastewater treatment. However, its photocatalytic efficiency and surface stability limit further applicability. This paper uses a one-step carbonization method to prepare multifunctional ZnO/carbon hybrid nanofiber mats. The carbonization creates a π-conjugated carbonaceous structure of the mats, which prolongs the electron recovery time of ZnO nanoparticles to yield improved photocatalytic efficiency. Further, the carbonization reduces the fiber diameter of the carbon hybrid nanofiber mats, which quadruples the specific surface area to yield enhanced adsorption and photocatalytic performance. At the same time, the prepared nanofiber mats can increase the evaporation rate of water under solar irradiation to a level of 1.46 kg·m⁻²·h⁻¹ with an efficiency of 91.9%. Thus, the nanofiber mats allow the facile incorporation of photocatalysts to clean contaminated water through adsorption, photodegradation, and interfacial heat-assisted distillation mechanisms.     

Photocatalytic degradation of gaseous toluene over ZnAl2O4 prepared by different methods: a comparative study

The development of a "green" treatment process for typical indoor pollutants such as toluene is greatly desirable. In this study, ZnAl(2)O(4) nanoparticles were prepared via three different routes, i.e., solvothermal, citrate precursor and hydrothermal methods. Their structural properties were systematically investigated by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), energy-dispersive X-ray spectra (EDX), Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance spectroscopy (DRS), and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic performances of the ZnAl(2)O(4) samples and nanostructured TiO(2) samples were comparatively studied by the degradation of gaseous toluene under UV lamp irradiation in in situ FTIR reactor. The results indicated that the sample synthesized by facile solvothermal method exhibited about 90% photocatalytic efficiency of toluene. The toluene was mineralized into carbon dioxide and water as the major species. The photocatalytic oxidation of gaseous pollutant over UV-illuminated ZnAl(2)O(4) is a promising technique for air purification.     

COMPARISONS OF MECHANICAL MELT-BLOWN FILTERS AND ELECTROSTATICALLY ENHANCED SPLIT-FIBER FILTERS FOR CABIN AIR FILTRATION APPLICATIONS

In this paper, compared are filtration characteristics of two different filters made from uncharged melt-blown media and electrostatically charged split-fiber media. The split-fiber filters have stronger electrostatic charges in the media than the melt-blown filter, which in turn enhances the initial fractional efficiency. The compared parameters are fractional efficiencies, dust holding capacities, incremental fractional efficiencies, and pressure drop. The advantages and disadvantages of these filters for cabin air filtration applications are discussed based on the experimental results obtained using SAE-fine dust and sodium chloride test aerosol. The optimization process of the filter selection is also discussed.     

Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon composites

A photocatalyst comprising nano-sized TiO(2) particles on granular activated carbon (GAC) was prepared by a sol-dipping-gel process. The TiO(2)/GAC composite was characterized by scanning electron microscopy (SEM), X-ray diffractiometry (XRD) and nitrogen sorptometry, and its photocatalytic activity was studied through the degradation of humic acid (HA) in a quartz glass reactor. The factors influencing photocatalysis were investigated and the GAC was found to be an ideal substrate for nano-sized TiO(2) immobilization. A 99.5% removal efficiency for HA from solution was achieved at an initial concentration of 15 mg/L in a period of 3h. It was found that degradation of HA on the TiO(2)/GAC composite was facilitated by the synergistic relationship between surface adsorption characteristics and photocatalytic potential. The fitting of experimental results with the Langmuir-Hinshelwood (L-H) model showed that the reaction rate constant and the adsorption constant values were 0.1124 mg/(L min) and 0.3402 L/mg. The latter is 1.7 times of the calculated value by fitting the adsorption equilibrium data into the Langmuir equation.