用原子吸收光谱对痕量铬作价态分析

本文详细研究了鱼腥藻对Ｃｒ＾３＋和Ｃｒ＾６＋离子的选择吸附条件，发现Ｃｒ＾３＋的最佳吸附ＰＨ值为４－５；Ｃｒ＾６＋的最佳ＰＨ为７左右，一定量柠檬酸能抑制Ｃｕ＾２＋，Ｐｂ＾２＋及Ｃｄ＾２＋对Ｃｒ＾６＋的吸附干扰。建立了痕量铬的不同价态原子吸收分析方法；对金属离子与藻之间的吸附机理作了初步探讨。     

钙钛矿型SrFeO3-λ对部分染料的光催化活性

本文用柠檬酸法合成钙钛矿型ＳｒＦｅＯ３－λ,并用水溶性染料在ＳｒＦｅＯ３－λ悬浮体系中进行光催化降解实验。实验发现了在ＳｒＦｅＯ３－λ化合物中,由于Ｆｅ＾３＋、Ｆｅ＾４＋、Ｆｅ＾５＋离子的共存使ＳｒＦｅＯ３－λ具有优异的光催化染料降解活性。     

FeO4^2—与ClO^—共存体系的氧化还原滴定分析法

在重铬酸钾容量法测Ｆｅ＾２＋和硫酸亚铁铵容量法测Ｃｒ（Ⅳ）的基础上,提出ＦｅＯ４＾２－与ＣｌＯ＾－共存体系的氧化还原滴定分析法。该方法实用、可靠、对样品分析,结果令人满意。     

La1-xCaxCrO3连接材料的研制

用溶胶－凝胶法制备了单相性和均匀性好的Ｌａ１－ｘＣａｘＣｒＯ３系列材料,Ｘ射线衍射分析表明,当０≤ｘ≤０．５时样品具有畸变的正交钙钛矿结构。ＸＰＳ测定确定了样品中存在Ｃｒ离子从Ｃｒ＾３＋变到Ｃｒ＾６＋的变价现象,随着ｘ的增加样品中Ｃｒ＾６＋的含量增加。     

笼形聚偕氨肟树脂的研究：酸处理树脂的吸附性能

笼形聚偕氨肟树脂（ＣＡＯ）经盐酸处理垢，伯胺基转变成胺盐。酸处理笼形聚偕氨肟树脂（ＡＣＡＯ）对Ｍｇ＾２＋，Ｃａ＾２＋，Ｂａ＾２＋，Ｍｎ＾２＋，Ｃｏ＾２＋，Ｎｉ＾２＋离子不吸附；对Ｚｎ＾２＋，Ｃｄ＾２＋，Ｃｕ＾２＋，Ｐｂ＾２＋离子的吸附效率在２０％以下，但对Ｈｇ＾２＋离子的吸附效率则高达７１．２％；对一些金属络阴离子的吸附效率顺序是Ｆｅ（ＣＮ）＾２－６＞Ｃｒ２Ｏ＾２－７＞ＭｏＯ＾２－４＞ＰｔＣｌ＾２     

La^3＋和Ca^2＋对金电极上谷胱甘肽单分子膜离子闸门的影响

谷胱甘肽能自组装吸附到金电极上形成单分子膜。该膜能阻止Ｆｅ（ＣＮ）６离子在金电极上还原，起离子闸门的作用。当溶液中加入Ｌａ＾３＋或Ｃａ＾２＋时，了穿透膜的能力得到改善。本课题应用循环伏安法和计时库仑法，在ＰＨ５．６的溶液中研究了Ｌａ＾３＋的调控能力，与Ｃａ＾２＋比较，发现在改变谷胱甘肽单分子膜的结构和Ｆｅ（ＣＮ）６离子的扩散系数方面，Ｌａ＾３＋具有更强的能力。     

新催化动力学光度法测定痕量铝

根据ＡＩ＾３对ＫＢｒＯ３氧化Ｂａｎｇ花青褪色的催化行为,建立了测定痕量铝的催化动力学动力学分析方法。本法线性范围为０～１６０ｎｇ．ｍＬ＾－１,检出限为１．０ｎｇ．ｍＬ＾－１。除Ｃｕ＾２＋、Ｆｅ＾３＋、Ｃｒ（Ⅵ）外,其余离子均不影响测定。Ｆｅ＾３＋和Ｃｕ＾２＋、Ｃｒ（Ⅵ）的干扰可分别有效消除。测定了人发、茶叶和不中的,加标回收率为９８．４％～１０２％,ＲＳＤ为１．３％～２．１％（ｎ＝６）。     

合并带流动注射分光光度法研究硫羟乳酸掩蔽性能

本文运用合并带流动注射分析技术，建立了以Ｙｂ＾３＋ＸＯ显色体系为参考体系研究硫羟乳酸掩蔽性能的方法，在ｐＨ５．６硫羟乳酸能掩蔽Ｓｎ＾４＋，Ｂｉ＾３＋，Ｔｌ＾３＋，Ｈｇ＾２＋，Ｃｕ＾２＋，Ｃｒ＾３＋和Ｃｄ＾２＋测定Ｙｂ＾３＋的线性范围为１．３６×１０＾－６～２．７２×１０＾－５ｍｏｌ／Ｌ，采样频率可达１２０次／ｈ。     

碘量法测定冶金物料中铁

系统地研究了Ｆｅ＾３＋与Ｉ＾－定量反应的条件，共存离子的干扰及消除方法，在ＨＣｌ和ＫＩ存在下，Ｆｅ＾３＋与Ｉ＾－定量反应，Ｃｕ＾２＋，ＡｓＯ４＾３－，ＶＯ２＾＋，等定量干扰，使用ＮａＦ或Ｈ３ＰＯ４制备参比液可抵消干扰。可不经分离直接测定大部分冶金物料中的高含量铁。     

PTFE—乙醚柱反相萃取层析连续分离和测定镓（Ⅲ）铟（Ⅲ）的研究

研究了在抗坏血酸存在下的６ｍｏｌ／Ｌ ＨＢｒ介质作流动相，以ＰＴＦＥ（聚四氟乙烯）负载的乙醚作固定相，反相萃取层析使微量Ｇａ（Ⅲ），Ｉｎ（Ⅲ）与Ｆｅ＾３＋、Ｔｌ＾３＋、Ｍｏ＾６＋、Ａｕ＾３＋、Ｔｉ＾４＋、Ｂｉ＾３＋、Ａｌ＾３＋、Ｍｇ＾２＋、Ｃａ＾２＋、Ｎｉ＾２＋、Ｃｏ＾２＋、Ｃｄ＾２＋、Ｚｎ＾２＋、Ｐｂ＾２＋、Ｃｕ＾２＋等多种离子分离。留于柱上的铟、镓分别用ＨＣｌ（４ｍｏｌ／Ｌ）－Ｈ２Ｏ２（３％）     

Ag改性提高TiO_2对Cr(VI)的光催化还原活性机理

在消除了质子缺乏、光生电子-空穴复合对Cr6 光催化还原负效应影响下,比较了TiO2和Ag/TiO2(Ag质量分数1.0％)光催化还原活性.结果表明,相同条件下Ag/TiO2表现出比TiO2更高的催化活性.EPR分析表明,对于Ag/TiO2,UV照射后Ag表面有活性物种O2生成,在TiO2上有活性中心表相Ti3 生成.光生电子通过表相Ti3 向Cr6 传递电子是cr6 光催化还原的速度控制步骤.较多的表相Ti3 参与还原反应是Ag/TiO2表现出较高催化活性的主要原因,担载Ag上积聚光生电子的较强流动性对反应也起到一定促进作用.     

Ag改性提高TiO2对Cr(VI)的光催化还原活性机理

在消除了质子缺乏、光生电子-空穴复合对Cr6＋光催化还原负效应影响下，比较了TiO2和Ag/TiO2（Ag质量分数 1.0％）光催化还原活性.结果表明，相同条件下Ag/TiO2表现出比TiO2更高的催化活性. EPR分析表明，对于Ag/TiO2，UV照射后Ag表面有活性物种生成，在TiO2上有活性中心表相Ti3＋生成.光生电子通过表相Ti3＋向Cr6＋传递电子是Cr6＋光催化还原的速度控制步骤.较多的表相Ti3＋参与还原反应是Ag/TiO2表现出较高催化活性的主要原因，担载Ag上积聚光生电子的较强流动性对反应也起到一定促进作用.     

Development of new photocatalytic water splitting into H2 and O2 using two different semiconductor photocatalysts and a shuttle redox mediator IO3-/I-

A new type of photocatalytic reaction that splits water into H2 and O2 was designed using a two-step photoexcitation system composed of an iodate/iodide (IO3-/I-) shuttle redox mediator and two different photocatalysts, one for H2 evolution and the other for O2 evolution. Photocatalytic oxidation of water to O2 and reduction of IO3- to I- selectively proceeded with good efficiencies over TiO2-rutile and Pt-WO3 photocatalysts under UV and visible light irradiations, respectively. The O2 evolution selectively proceeded even in the presence of a considerable amount of I- in the solutions, although the oxidation of water is thermodynamically less favorable than oxidation of I-. Both the adsorption property of IO3- anions and the oxidation property of the photocatalysts are doubtless responsible for the selective oxidation of water. On the other hand, photocatalytic reduction of water to H2 and oxidation of I- to IO3- proceeded over Pt-TiO2-anatase and Pt-SrTiO3:Cr/Ta (codoped with Cr and Ta) photocatalysts under UV and visible light, respectively. The combination of two different photocatalysts results in a stoichiometric evolution of H2 and O2 via the redox cycle of IO3- and I-. The photocatalytic water splitting under visible light irradiation (lambda > 420 nm) was demonstrated by using the Pt-SrTiO3:Cr/Ta, Pt-WO3, and IO3-/I- shuttle redox mediator.     

Enhanced photocatalytic reduction of Cr(VI) by manganese-doped anatase titanium dioxide

Nano-TiO₂ is frequently used as an optimal photocatalyst, since it is nontoxic, low cost, and environmentally friendly, especially for its photocatalytic oxidation action. However, its photocatalytic reducing action has not been widely researched. In this study, TiO₂ doped with different concentrations of manganese was prepared by the sol–gel method and characterized using different techniques to analyze the surface structure, phase composition, and surface elements of the different materials. To investigate the photocatalytic activity, Mn–TiO₂ was used for photocatalytic reduction of Cr(VI). Moreover, various organic pollutants were added to determine whether they enhanced the photocatalytic reduction of Cr(VI). The experiments indicated that the presence of Mn in TiO₂ could enhance its photocatalytic reduction action, especially at 0.02 % molar ratio. Manganese ions doped in TiO₂ behaved as electron accumulation sites. In addition, pH value, and photocatalyst dosage were investigated to analyze their effects on the photocatalytic reduction action. The results show that lower pH value improved the efficiency of photocatalytic reduction; there were no significant changes in the photocatalytic reduction rate with dosage above 1.0 g/L. In the presence of different electron donors (organic pollutants as hole scavengers), the photocatalytic reduction of Cr(VI) was generally improved. In short, manganese-doped TiO₂ exhibited improved photocatalytic reduction activity, especially in cooperation with various organics.     

Photophysical and photocatalytic properties of SrTiO3 doped with Cr cations on different sites

Usually, SrTiO3 monodoped with Cr cations at the Ti4+ site hardly shows visible light photocatalytic activity. Revealing the origin of this issue is important for us to find an alternative approach to make SrTiO3 active under visible light irradiation. In this paper, two Cr-doped SrTiO3-(Sr0.95Cr0.05)TiO3 and Sr(Ti0.95Cr0.05)O3-were synthesized by a conventional solid-state reaction method, and their photophysical and photocatalytic properties were studied comparatively. It was found that both (Sr0.95Cr0.05)TiO3 and Sr(Ti0.95Cr0.05)O3 showed considerable absorption to visible light. However, their photocatalytic activities for H2 evolution from aqueous methanol solution under visible light irradiation were significantly different: the H2 evolution rate over (Sr0.95Cr0.05)TiO3 (approximately 21 micromol/h) was more than 100 times that over Sr(Ti0.95Cr0.05)O3 (approximately 0.2 micromol/h). X-ray photoelectron spectroscopy analysis results revealed that the Cr cations doped at the Sr2+ site were all trivalent state (Cr3+), while those doped at the Ti4+ site were mixed valent states (Cr3+ and Cr6+). The different photocatalytic activities of H2 evolution are supposed to closely relate to the different valent states of Cr doped at different sites (Sr2+ or Ti4+) in SrTiO3. Possible electronic structures of (Sr0.95Cr0.05)TiO3 and Sr(Ti0.95Cr0.05)O3 were proposed in relation to their photophysical and photocatalytic properties.     

苯在TiO2上的气相光催化氧化反应历程

 以超细TiO2为催化剂,在内循环光反应装置中考察了苯的气相光催化氧化反应．苯的初始质量浓度为50mg／m3时,在0．1g催化剂和0．013m2的光照面积下,460min后苯几乎全部分解完毕;光照面积增大1倍时,反应时间缩短为240min．常温下苯在TiO2表面不易吸附,但反应中间产物有较强的吸附性,能吸附在催化剂表面从而引起催化剂失活．经红外检测可知,反应的中间产物是个六元环醇,据此推测了苯的气相光催化可能的反应历程．通过实验结果并参考有关文献的结论,证明苯的气相光催化氧化在不同的反应条件下遵循不同的反应历程．     

以尿素为氮源制备氮改性二氧化钛及其改性机理

以钛酸丁酯为前驱体,以尿素为氮源,采用改进溶胶-凝胶法制备了不同N含量的改性TiO2光催化剂(N-TiO2).以重铬酸钾为目标污染物,以甲酸为空穴捕获剂,评价了可见光下该催化剂的催化还原活性.结果表明,N-TiO2催化剂活性明显高于未改性催化剂,当催化剂中N/Ti摩尔比为10%、焙烧温度为400℃时,其光催化还原活性最...     

Photocatalytic reactivity of surface platinized TiO2: substrate specificity and the effect of Pt oxidation state

Surface platinized TiO(2) (Pt/TiO(2)) has been frequently studied, but its photocatalytic reactivities reported in the literature are not consistent in some cases. To understand the discrepancies, the effects of Pt speciation on TiO(2) on the photocatalytic degradation (PCD) of a few chlorinated organic compounds (trichloroethylene (TCE), perchloroethylene (PCE), dichloroacetate, etc.) were investigated with several Pt/TiO(2) samples that were prepared differently. The oxidation state of Pt deposits was analyzed by X-ray photoelectron spectroscopy and was found to be the most important factor in determining the initial PCD rates of chlorinated organic compounds. TiO(2) with oxidized Pt species (Pt(ox)/TiO(2)) was less reactive than TiO(2) with metallic Pt (Pt(0)/TiO(2)) for all substrates tested. In particular, Pt(ox)/TiO(2) strongly inhibited the PCD of TCE and PCE whereas it was more reactive than pure TiO(2) for the PCD of other compounds. The photocurrents obtained with the Pt(ox)/TiO(2) electrode were lower than those with the Pt(0)/TiO(2) electrode, which was ascribed to the role of Pt(ox) species as a recombination center. It is proposed that TCE adsorbed on Pt(ox) chemically mediates the charge recombination through the redox cycle of TCE. The Pt effects in photocatalysis are highly substrate-specific and depend on the Pt-substrate interaction as well as the properties of Pt deposits.     

掺杂纳米TiO2光催化性能的研究

利用浸渍法分别制备了Cr、Mn、Fe、Co、Ni、Cu六种过渡金属离子掺杂改性的二氧化钛光催化剂，以乙酸水溶液的光催化氧化反应和二氧化碳还原反应为探针,评价了掺杂催化剂的光催化性能.借助光电子能谱（XPS）、X射线衍射分析（XRD）等手段对掺杂催化剂进行了表征.研究结果表明，经过渡金属离子掺杂后，光催化性能均有不同程度的改善，改善程度按Cr、Co、Ni、Fe、Mn、Cu递增.掺杂后催化剂表面吸附氧的活泼性、金属离子的价态及得电子能力上的差异决定了不同离子掺杂纳米二氧化钛光催化性能的差异.     

Cr(Ⅵ)-氯代苯酚共存污染体系中的光反应与光催化反应研究

Cr(Ⅵ)-4CP(4-氯苯酚)共存污染体系中Cr(Ⅵ)离子的紫外光致还原主要是由于Cr(Ⅵ)与4CP光解产物之间的氧化还原反应而引起的。Cr(Ⅵ)离子还原受光强和体系酸度影响较大,还原速率呈零级反应。随体系pH值增大,Cr(Ⅵ)离子还原速率下降。中性条件下,光反应结束后有沉淀产物生成,这对于采用光化学方法消除环境污染提供了很有意义的结果。4CP存在对Cr(Ⅵ)离子在TiO₂表面的暗态吸附没有影响。Cr(Ⅵ)-4CP-TiO₂体系中Cr(Ⅵ)离子的紫外光致还原主要包括了两种反应:Cr(Ⅵ)与4CP之间的均相反应以及Cr(Ⅵ)离子在TiO₂表面的光催化还原反应。一定波长紫外光下,排除Cr(Ⅵ)-4CP-TiO₂体系中的均相反应,使得4CP对Cr(Ⅵ)离子光催化还原反应的促进作用得以证实。