纳米银对水中三价砷的催化氧化研究

纳米银由于具有优良的杀菌性能,越来越多地用到饮用水消毒等领域.其作为杀菌剂主要针对饮用水中细菌超标以及水处理膜组件中存在的膜污染（菌污染）等问题.然而,由于AgNPs具有良好的光催化活性,可能会影响水处理系统中共存无机砷[As（Ⅲ）和As（V）]的形态转化.本研究采用液相色谱-电感耦合等离子质谱联用技术（HPLC-ICP/MS）测定As（Ⅲ）和As（V）,系统考察了水相中AgNPs对As（Ⅲ）和As（V）的吸附性能,体系pH值、NOM及共存离子（以Ca²⁺为例）等环境因素以及AgNPs的粒径和包覆剂等对As（Ⅲ）形态变化的影响.结果表明,AgNPs对As（Ⅲ）不存在物理吸附,但对As（Ⅲ）的氧化具有明显的催化作用.体系pH大于7.0时,AgNPs开始呈现对As（Ⅲ）氧化的显著催化作用,NOM、Ca²⁺、光照等环境因素均在一定程度上促进As（Ⅲ）的形态转化.此外,该过程与AgNPs本身的性质密切相关,粒径越小其催化性越好,PVP/CTS包覆AgNPs对As（Ⅲ）的催化氧化反应速率常数（k＝15.82×10^－2 h^－1）为柠檬酸包覆AgNPs的2倍.最后,在实际环境水样中验证了AgNPs对As（Ⅲ）的催化氧化.以上研究结果表明,水处理系统中的AgNPs在杀菌抑菌的同时,还能够促使As（Ⅲ）向低毒As（V）的转化,为As污染的去除提供了新的思路.     

络合剂作用下光催化氧化纳米铁氧化物的生成及机理

进行了空气氧化Fe(OH)₂悬浮液, 络合剂(乙二胺、草酸、柠檬酸)作用下光催化氧化制备FeOOH的研究. 结果表明: 在室光下, 一定量乙二胺、草酸、柠檬酸的加入有利于纯γ-FeOOH的生成; 且随光强的增强, γ-FeOOH的晶化性降低. 机理分析表明: 可见光存在下, 络合剂的加入, 不仅使中间物绿锈GR(II)结晶度变差, 溶解加快; 而且络合剂与Fe^2＋形成的配合物可吸收部分可见光, 生成强氧化型的自由基, 使反应初期Fe^2＋快速氧化为Fe^3＋, 快的氧化速度利于生成低晶化度的γ-FeOOH.     

针铁矿对焦磷酸根的吸附特征及吸附机制

为深入了解自然水体中焦磷酸盐的迁移转化行为,以表生环境中广泛存在的稳定矿物-针铁矿为研究对象,系统研究了其对焦磷酸根的吸附过程,探索了不同实验条件下(pH值、电解质、时间、温度)针铁矿对焦磷酸根吸附的影响。 结果表明,溶液pH值从6.27升至10.99时,总磷吸附量从3.00 mg/g降低至0.75 mg/g;电解质浓度越低越有利于针铁矿对焦磷酸根的吸附;吸附剂对焦磷酸根的吸附量在最初1 h内增长较快,随后渐渐达到吸附平衡;溶液温度的升高对吸附量提高具有增强作用。 用动力学和热力学模型对吸附过程进行拟合,发现准二级动力学和Langmuir模型具有更好的适用性。 结合材料吸附焦磷酸根前后的表征,推导出针铁矿对焦磷酸根的吸附机制可能是以表面配合和物理吸附为主导。     

燃煤电厂煤及其燃烧副产物中砷形态分析

燃煤电厂煤中砷（As）的形态在燃烧过程中不可避免地会发生转化。煤及其副产物中砷的形态与人体健康和环境安全密切相关，亟待鉴别。然而目前针对煤燃烧相关产物中砷形态的前处理手段和分析方法尚缺乏。本研究采用高效液相色谱-氢化物发生-原子荧光光谱法（HPLC-HG-AFS）成功测定了电厂煤、粉煤灰和石膏中砷的形态，优化了仪器参数、提取试剂和前处理方法（超声和微波辅助）。优化后，无机砷的分离时间缩短至7 min，As（Ⅲ）和As（V）的检出限分别为1.8 ng/g和4.6 ng/g。砷形态的高效提取剂为1.0 mol/L 磷酸和0.1 mol/L 抗坏血酸的混合溶液。微波辅助（2000 W、80 ℃、40 min）和超声辅助（40 kHz、20 ℃、40 min）分别是煤/粉煤灰和石膏样品中砷形态的最佳提取方法。在微波和超声波辅助提取条件下，As（Ⅲ）/As（V）的回收率分别为95.8%/104.5%和90.6%/89.7%。样品分析结果表明，煤中砷主要以As（V）形式存在，As（Ⅲ）所占比例很小，而在粉煤灰和石膏中只观察到As（V）。该研究揭示了As（Ⅲ）向As（V）的转化是气态砷捕获的关键，可以为控制电厂砷排放提供科学依据。     

从可溶性单源分子前驱体采用溶胶凝胶法制备ZnO/TiO2 纳米复合物

合成了单源分子前驱体Cl2TiZn（dmae）4 （dmae为2-二甲基乙醇胺）,并以乙醇为溶剂,加入等摩尔量的水对其进行可控水解得ZnO/TiO2纳米复合凝胶,经pH=9沉淀,在200、400和600℃烧结得到不同的产物T200、T400、T600. XRD分析表明未烧结产物为无定形粉末并随着烧结温度升高晶型改善. ZnO呈纤锌矿结构（六方晶系）,TiO2呈板钛矿型结构（正交）. BET分析和扫描电镜表明颗粒的大小随着烧结温度的提高而增加. 红外光谱证明Zn-O和Ti-O的特有的振动频率,OH基团烧结后的产物中被去掉. 所有的样品都显示良好的光催化活性, 且T600活性最高.     

Adsorption of arsenate on lanthanum-impregnated activated alumina: In situ ATR-FTIR and two-dimensional correlation analysis study

Lanthanum modified materials have been widely used for the removal of hazardous anions.In this study,in situ ATR-FTIR and two-dimensional correlation analysis were employed to investigate the adsorption mechanism of arsenate（As（V）） on lanthanum-impregnated activated alumina（LAA）.Our results showed that electrostatic interaction attracted As（V） anions to the LAA surface,and then As（V） could form monodentate configuration on the LAA surface at pH 5-9.The result of 2D-COS showed that two coexistent adsorbed As（V） species,H₂AsO₄^- and HAsO₄^2-,were adsorbed on the LAA surface without specific sequence at different pH conditions,indicating a negligible role of the incorporated protons of As（V） on the adsorption affinity to LAA surface.The results of this study reveal insights into LAA surface complexes on the molecular scale and provide theoretical support to new metal oxides design for efficient arsenic removal.     

纳米零价铁对水中砷和硒去除的比较研究

采用纳米零价铁去除水中的砷和硒,考察了不同溶解氧、纳米零价铁投加量、接触时间以及溶液初始pH值等条件下纳米零价铁去除水中砷和硒的效果,并比较了反应前后固体的形貌、组成、溶液pH值及反应机制.结果表明,纳米零价铁可广泛用于去除水中的砷/硒污染,去除效果顺序依次为Se（IV）> As（Ⅲ）> Se（VI）> As（V）;水中溶解氧（DO）对As（Ⅲ）和Se（IV）的去除没有显著的影响,而高浓度的DO对As（V）和Se（VI）的去除产生了一定的抑制作用;增加纳米零价铁投加量可促进砷和硒的去除;溶液初始pH值对纳米零价铁去除As（Ⅲ）,As（V）和Se（VI）的影响较大,而对Se（IV）的去除几乎没有影响;反应后固体的形貌、组成及溶液pH值存在差异.纳米零价铁与砷、硒反应机理的不同造成了去除效果及反应后固液两相的差异.     

TS-1/H2O2碱溶液中低温氧化愈创木酚制备马来酸（英）

可再生生物质资源的开发与利用能够缓解化石燃料产生的温室气体对环境的负面影响.在生物质燃料制备过程中联产高附加值化学品能大幅提高生物质炼制的经济性.愈创木酚是常见的木质纤维素快速热解产物.本文研究了低温液相氧化愈创木酚制备马来酸,并重点考察了催化剂添加量、pH值、反应时间和反应温度等反应条件的影响.研究发现,在钛硅沸石-过氧化氢碱溶液氧化反应体系中（80℃,pH=13.3）,20₃0mol%的愈创木酚可以选择性转化为马来酸.同时初步探讨了愈创木酚氧化开环转化为马来酸的反应机理.     

PbO2将Mn2＋氧化成几价

研究了在酸性介质中，Ｍｎ~（２＋）被ＰｂＯ_２氧化的产物，氧化产物的物种与反应条件──酸浓度、温度、ＰｂＯ_２用量的关系。实验结果表明：酸浓度较高时（ＣＨ_２ＳＯ_４≥６ｍｏｌ·Ｌ（－１）），有利于Ｍｎ~（３＋）的生成与稳定；酸浓度较低时，有利于ＭｎＯ_４~－的生成；在酸浓度居中时，也有可能得到Ｍｎ（Ⅳ）。氧化剂用量的增加，温度的提高有利于ＭｎＯ_４~－的生成。     

氧化还原刻蚀铜表面对二氧化碳电催化还原性能的研究

大规模化石燃料的使用排放了大量的二氧化碳（CO₂）,导致环境中二氧化碳的含量急剧增加. 为了降低大气中二氧化碳的含量,以电催化的方法将二氧化碳转化为有用的化工原料和燃料是解决能源和环境问题的重要途径. 本文主要利用氧化还原刻蚀法,在铜表面形成复合纳米结构,用于二氧化碳的电催化还原反应研究. 首先,作者通过一定浓度的三氯化铁（FeCl₃）溶液与铜片的氧化还原反应,在刻蚀铜表面时形成具有立方体结构的氯化亚铜纳米材料,用于二氧化碳的电催化还原反应. 为了研究反应时间对催化性能的影响,作者通过改变反应时间（1、2、3和4 h）合成了不同结构的铜基催化剂. 研究发现,在反应3 h后,Cu-3h催化剂对二氧化碳的电催化还原具有较小的起始电压（-0.3 V vs. RHE）和较大的电流密度值,表现出了较强的还原能力. 经检测,所得到主要还原产物为一氧化碳（CO）和甲烷（CH₄）. 在-0.6 V时,二氧化碳催化还原的法拉第效率可达到60%,表明以氧化还原法刻蚀铜表面具有较好的改善二氧化碳电催化还原的能力.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

钒与糖代谢及糖尿病

微量元素钒作为生物体内必需元素，经证实有很重要的生理学功能，与机体糖代谢有十分密切的关系，且能降低糖尿病动物模型的高血糖，极有可能被开发为治疗糖尿病的药物。     

Ferrocene and ferrocenium modified clays and their styrene and EVA composites

In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer.     

Synthesis and Optical and Redox Properties of Symmetric and Asymmetric BODIPYs

Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission.     

Synthesis of Tyrosol and Hydroxytyrosol Glycofuranosides and Their Biochemical and Biological Activities in Cell-Free and Cellular Assays

Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection.     

Conformations and steric and stacking interactions of trisubstituted ureas and thioureas with alkyl and phenyl groups

The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R₂UPh type and -thioureas of the R₂TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments.