Copper complexation by tannic acid in aqueous solution

The speciation of titrated copper in a dissolved tannic acid (TA) solution with an initial concentration of 4 mmol organic carbon (OC)/l was investigated in a nine-step titration experiment (Cu/OC molar ratio = 0.0030–0.0567). We differentiated between soluble and insoluble Cu species by 0.45 μm filtration. Measurements with a copper ion selective electrode (ISE) and diffusive gradients in thin films (DGT) were conducted to quantify unbound Cu(II) cations (‘free’ Cu) and labile soluble Cu complexes. For the DGT measurements, we used an APA hydrogel and a Chelex 100 chelating resin (Na form). Insoluble organic Cu complexes (>0.45 μm) was the dominant Cu species for Cu/OC = 0.0030–0.0567 with a maximum fraction of 0.96 of total Cu. At Cu/OC > 0.0100, Cu-catalysed degradation of aggregate structures resulted in a strong increase of free Cu and (labile) soluble Cu complexes with a maximum fraction of 0.28 and 0.32 of total Cu, respectively. Labile (i.e. DGT-detectable) soluble Cu complexes had a relatively high averaged diffusion coefficient (D) in the APA hydrogel (3.50 × 10⁻⁶– 5.58 × 10⁻⁶ cm² s⁻¹).     

PVA-SbQ固定叶绿体及其生物传感器在检测除草剂中的应用

聚乙烯－苯乙烯吡啶（PVA－SbQ）是一种新的光敏聚合物，在紫外光诱导下形成大分子网状结构，电镜照片显示PVA－SbQ固定的新鲜菠菜叶绿体－20℃贮存6mo后，内，外膜结构完整，类囊体膜排列整齐，还原DPIP的能力保留50％，将叶绿体膜固定在铂电极上，制成生物传感器，在含0．035H2O2的50mmol L^-1,pH7.4Tris-HCl缓冲液中，25℃条件下用示差脉冲伏安法检测除草剂，在0－1.0 μg/L浓度范围，百草枯，敌草隆，扑草净和阿特闰津具有较好的线性关系。图6参29     

Pt/Mg-Ce-O catalyst for NO/H<Subscript>2</Subscript>/O<Subscript>2</Subscript> lean de-No<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> reaction

The NO/H₂/O₂ reaction was studied under oxidizing conditions in the 100-400 °C range over 0.1 wt% Pt supported on various metal oxides such as MgO, CeO₂, SiO₂, La₂O₃, CaO, Y₂O₃ and TiO₂. The Pt/MgO and Pt/CeO₂ catalysts showed good catalytic behaviours. Here, we find that the Pt/Mg-Ce-O catalyst, prepared from MgO and CeO₂ by the sol-gel method, is a very active and selective catalyst towards N₂ formation in the whole 100–400 °C range. This catalyst appears to be the most active, selective and stable one ever reported in the literature for the NO/H₂/O₂ reaction, even in the presence of 5%v H₂O or 20 ppmv of SO₂ in the feed stream.Selected article from the Regional Symposium on Chemistry and Environment, Krusevac, Serbia, June 2003, organised by Dr. Branimir Jovancicevic.     

高浓度苯酚在石墨电极上电解特性的研究

研制了数据在线采集记录系统对高浓度苯酚在石墨电极上电解过程的循环伏安行为进行了研究。采用连续循环伏安法考察了体系电解的特点,并考察了支持电解质、扫描速率、苯酚的浓度对反应体系的影响。结果表明:峰电流密度与扫描速率的平方根及苯酚浓度呈线性递增关系,支持电解质的添加量在苯酚电解过程存在最佳值,多次扫描过程中峰电流密度有下降趋势。实验推断电解效率下降是由于电极表面被聚合物污染导致,这一现象对电解处理有机物种的系统控制过程具有重要意义。     

化学修饰电极在环境微量及痕量有机物分析中的应用

根据实验研究及国内外文献,从伏安及电位溶出分析,流动注射/液相色谱电化学检测,化学修饰电极生物传感器及化学修饰电极预富集—石墨炉原子吸收法联用等方面,重点综述了化学修饰电极在环境微量及痕量有机物分析中的应用。     

活性炭纤维电极法处理草浆造纸黑液的应用研究

用活性炭纤维（ＡＣＦ）电极法和酸析、凝聚处理加电极组合方法，对造纸黑液进行处理。结果表明，电极法处理黑液，ＣＯＤｃｒ、色度去除率分别达６４．２５％和９４％；“酸化＋电解（４５ｍｉｎ）＋Ｆｅｎｔｏｎ试剂”的综合治理方法效果较好，ＣＯＤｃｒ、色度去除率分别达９４．２％和９９．６％，出水近乎清澈透明。     

离子选择电极法与离子色谱法测量低浓度氟化物比较

用离子选择电极法、离子色谱法两种方法对氟化物国家标准样品进行测量,通过比较发现两种方法测量国家标样低浓度样品时有显著差异.     

PH玻璃电极对比观测及误差研究

经过对PH玻璃电极对比观测实验，总结其在日常观测中衰减变化规律，以及PH电极失效前所具有的特征；讨论了对现有PH观测数据进行修正的方法，并编著相关修正程序；分析日常存在的测量误差，提出提高观测精度的措施。     

电极材料对电解法处理循环式准好氧垃圾填埋场渗滤液效果的影响研究

分别用3种不同材料电极（不锈钢、Ti／Pt和Ti／RuO2-IrO2）作阳极、石墨电极作阴极在同一条件下分别对循环式准好氧填埋垃圾场渗滤液进行电解处理对比研究。研究结果表明，随着电解时间的变化，渗滤液中的COD、BOD5、BOD5／COD、重金属离子浓度、色度和pH值均会发生改变。当电解时间为10—20min时，用上述3种电极作阳极电解均会出现渗滤液COD、BOD5、BOD5／COD增大的现象；当电解时间为30—40min时，用Ti／RuO2-IrO2或Ti／Pt电极作阳极电解均可使渗滤液的色度降为0；当电解时间为120min时，分别用3种电极作阳极电解都可使渗滤液中的COD、BOD5和重金属得到有效的去除，其中用Ti／RuO2-IrO2电极作阳极电解对COD、BOD5的去除效果最好：用Ti／Pt电极作阳极电解对Pb^2＋的去除效果最好。     

Significance of platinum group metals emitted from automobile exhaust gas converters for the biosphere

Intention, Goal, Scope, Background  Following the introduction of automobile catalytic converters the platinum group metals (PGM) platinum (Pt), palladium (Pd) and rhodium (Rh) gain on increasing interest in environmental research as these metals are emitted with exhaust fumes into the environment. Consequently, elevated PGM levels were found in different environmental matrices uch as road dusts, soils along heavily frequented roads, sediments of urban rivers etc. Accordingly, the effects of increasing PGM emissions on the biosphere are controversially discussed. Objective  This paper summarizes the present knowledge on the biological availability of PGM to plants and animals. As biological availability is one of the most decisive factors determining the toxicologi-cal potential of xenobiotics, this information is very important to evaluate the possible threat of the noble metals to ecosystems. Results and Discussion  The availability of soluble as well as particle bound PGM to terrestrial plants was demonstrated in several studies. Experimental investigations revealed uptake of Pt, Pd and Rh also by aquatic plants. Additionally, the biological availability of the noble metals for animals has been verified in experimental studies using soluble metal salts, catalytic converter model substances, sediments of urban rivers, road dust or tunnel dust as metal sources. These studies refer mainly to aquatic animals. Beside of free living organisms, in particular worms parasitizing fish demonstrated a high potential to accumulate PGM. This could be of great interest in respect of biomonitoring purposes. Generally, for plants as well as for animals Pd turns out to be the best available metal among the PGM. Compared to other heavy metals, the biological availability of PGM from road dust to zebra mussels(Dreissena polymorpha) ranged between that of Cd and Pb. Conclusion  Especially chronic effects of PGM on the biosphere can not be excluded due to (1) their cumulative increase in the environment, (2) their unexpected high biological availability and bioaccumulation and (3) their unknown toxicological and ecotoxicological potential. However, it appears that acute effects on ecosystems due to anthropogenic PGM emission are not likely. Recommendation and Outlook  Research on environmental PGM contamination of the biosphere, especially the fauna, and on long-term toxiciry of low PGM concentrations is highly appreciated. These studies require very sensitive analytical techniques to determine PGM even in low sample amounts. Research has to be done in particular on reliable determination of (ultra) trace levels of Pd and Rh as the lack of data on these two metals is mainly due to analytical problems.