纳米晶粒TiO2多孔微球的制备及其光催化性能的研究进展

介绍了纳米晶粒TiO2多孔微球的主要制备方法、主要参量及表征、光催化性能研究进展，指出了纳米晶粒TiO2多孔微球制备过程的技术关键与基本参量的功能。针对目前存在的问题，提出了今后的主要研究方向，并展望了纳米晶粒TiO2多孔微球在水处理领域的应用前景。     

纳米二氧化钛处理含砷废水的研究

研究了无机纳米材料二氧化钛对含砷废水的处理效果.实验主要从纳米二氧化钛的溶液pH值、不同投加量、实验温度、吸附搅拌时间、静置时间等方面对除砷效率进行了研究,并通过模拟水样和实际水样的对比,分析了纳米二氧化钛处理含砷废水的实际可行性.     

土壤颗粒对纳米TiO_2悬浮稳定性作用机制的实验研究

在不含表面活性剂和含有表面活性剂两种条件下,研究了土壤颗粒对纳米TiO2(nTiO2)悬浮稳定性的影响.结果表明,土壤颗粒降低了nTiO2在水相中的悬浮稳定性.当体系中不含表面活性剂时,nTiO2在土壤大颗粒上的沉积是导致nTiO2脱稳沉淀的主要原因.在含有表面活性剂的溶液中,土壤颗粒降低nTiO2悬浮稳定性的作用变得更加明显了.一方面,表面活性剂加速了土壤颗粒本身的沉降从而增强了nTiO2在其中的沉降,另一方面,表面活性剂在土壤上的强烈吸附促进了表面活性剂-nTiO2在土壤上的沉积.扫描电镜显示,nTiO2不仅吸附在土壤大颗粒上,还会吸附在土壤小颗粒表面.3种表面活性剂中,十六烷基三甲基溴化铵(CTAB)悬浮的nTiO2与土壤颗粒共沉淀现象最明显.除了土壤对CTAB的吸附作用之外,XDLVO/DLVO能量计算显示CTAB体系中土壤颗粒与nTiO2之间存在显著第二极小值,表明nTiO2能够在第二极小值位置与土壤颗粒结合,从而与土壤颗粒一起快速沉淀.     

Feasibility of metabolic parameter estimation in pharmacokinetic models of carbon tetrachloride exposure in rats1

Carbon tetrachloride (CCl₄) is a toxic chemical that was once used in degreasers and detergents, and some remnants of the chemical may be present in the water supply. Physiologically-based pharmacokinetic (PBPK) modeling can assist in understanding resulting internal doses of CCl₄ after exposure, but the pharmacokinetic parameters describing the metabolism of CCl₄ are not well characterized. The goal of this study was to provide insights into how to more accurately estimate these values in rats using PBPK modeling and data from previous studies. Three different PBPK models were constructed to describe CCl₄ exposure in rats via inhalation, oral ingestion, and venous injection. Each of these models was compared to data, and sensitivity analysis was performed for each model to determine whether the available data could be used to accurately determine the metabolic parameters of interest. These parameter sensitivities were so low that optimization to the available data yielded physiologically unrealistic results. Model sensitivities were analyzed for different doses and routes of exposure in order to find experimental conditions that would allow for greater identifiability of the metabolic parameters. Data were simulated from these models at optimal conditions with varying levels of noise from a normal distribution. Optimizations were then performed to confirm that the original values could be obtained. The experiments developed are left as suggestions for investigators who wish to further pursue estimating these metabolic parameters.     

Preparation and performance of photocatalytic regenerationable activated carbon prepared via sol-gel TiO2

Preparation of photocatalytic regenerationable activated carbon （AC） is the key step for the practical application of in situ regeneration of exhausted AC. A novel photocatalytic regenerationable AC was prepared by sol-gel TiO2 in this work. The adsorption and regeneration performance of TiO2/AC were evaluated using phenol as model compound. Scanning electron microscope （SEM） and nitrogen （77 K） adsorption isotherm were used to determine the surface area, pore structure and the distribution of TiO2. The results showed that with the increase of TiO2 loading, adsorption capacity of TiO2/AC decreased and the regeneration efficiency increased. The photocatalytic regenerationable AC with suitable TiO2 loading （2 wt%） exhibited suitable adsorption capacity and regeneration efficiency. TiO2 located mainly in the entrance of macro-pore of carbon. The prepared TiO2/AC exhibited similar surface structure and pore structure with material carbon.     

光活性二氧化钛膜的制备方法

近二十年来发展起来的光催化技术可利用太阳光能对水体中的多种有机污染物进行降解．这符合可持续发展的长远需要,具有诱人的发展前景。光催化技术利用可再生的清洁资源,氧化能力强．适用于广谱有机物,能使难被一般氧化剂氧化、又难生物降解的污染物降解．是当前太阳能利用及水污染控制方面开辟的前沿领域．在治理环境污染方面具有明显的发展优势。本文以溶胶-凝胶法、金属有机化学气相淀积、煅烧沉淀法等多种方法制备光活性二氧化钛膜。     

介孔纳米TiO2的超声化学法合成及其表征

采用超声化学法制备介孔TiO2，并采用XRD，TEM，FT-IR等方法对样品进行了表征．结果表明，在超声波作用下，液相体系中能够一步合成锐钛矿相TiO2；添加有机模板剂并控制实验条件，则能直接合成具有介孔结构的锐钛矿相TiO2．超声化学法能更好地控制粒子的形貌和尺寸，所制备的TiO2晶型完整，孔径均匀，分散性好．     

超细TiO2粒子的超滤分离及回用特性

针对TiO2超细粒子的超滤分离特性进行了试验研究,探讨了操作压力、膜面流速、TiO2投量、pH、电解质等参数条件对膜通量的影响规律及作用机理,证实了浓差极化及滤饼层阻力是影响通量变化的主导因素,在此基础上确定了适宜的超滤工艺条件及膜清洗方式.以甲基橙为降解基质分别测试了经混凝与超滤分离后的TiO2光催化活性,结果表明,超滤不仅可实现TiO2粒子与水的彻底分离,且分离后TiO2催化活性与初次使用相当.研究表明超滤用于悬浮光催化体系的固液分离及催化剂再用是可行的.     

四氯化碳的生产与应用及其淘汰策略

四氯化碳是一种消耗臭氧层物质,其生产和消费都面临着严峻的淘汰形势.简要叙述了四氯化碳的生产技术,以四氯化碳为原料生产大宗化学品和精细化学品的转化技术,四氯化碳作为化工助剂在我国的应用情况以及相应的淘汰方法和技术进展.     

Model reactor for photocatalytic degradation of persistent chemicals in ponds and waste water

A laboratory scale flow-through model reactor for the degradation of persistent chemicals using titanium dioxide (TiO₂) as photocatalyst immobilized on glass beads is presented. In the test system with a volume of 18 L contaminated water is pumped to the upper part of the floating reactor and flows over the coated beads which are exposed to UV-radiation. The degradation of two dyes of different persistance was investigated. Primary degradation of methylene blue did not fit a first order kinetic due to coincident adsorption onto the photocatalyst and direct photolysis, resulting in a half-life of 6 h. A filtrate of a green algae suspension accelerated the colour removal. In contrast, reactive red 2 was degraded only by photocatalysis; neither adsorption nor direct photolysis led to a colour removal. The course of primary degradation followed a first order kinetic with a half-life of 18 h and a rate constant of 0.04 h⁻¹. Analysis of the degradation products indicated mineralization by detection of NO₂⁻ and NO₃⁻, accompanied by a decrease of pH and an increase of conductivity. A successful adaptation of the model reactor (scale 1:10) to dimensions required for surface waters and waste water treatment plants would be a costefficient and environmentally sustainable application of photocatalysis for the treatment of industrially polluted water and could be of relevance for third world contries, particularly those favoured by high solar radiation.