黄铜矿在含铁酸性介质中氧化过程的电化学研究

以天然黄铜矿为研究对象,运用开路电位,循环伏安曲线,Tafel极化曲线和交流阻抗(EIS)等电化学手段,对在硫酸介质中三价铁离子对黄铜矿的氧化过程的电化学行为进行了研究.结果表明,黄铜矿在酸性介质中的氧化可能通过两步反应完成,第一步中电极表面形成了一层主要成分是含硫中间产物的钝化膜,第二步则是黄铜矿主体的氧化.Fe3+离子有助于黄铁矿的直接氧化,在黄铜矿的溶解过程中起到了重要作用.极化曲线测量的结果显示随着溶液中Fe3+离子浓度的增加,黄铜矿的极化电流也在增加,黄铜矿也更容易进入钝化阶段.同时,交流阻抗对Fe3+离子浓度改变的响应也很敏感.     

Effect of denitrifying bacteria on the electrochemical reaction of activated carbon fiber in electrochemical biofilm system

An electrochemical-activated denitrifying biofilm system consisting of activated carbon fiber electrodes immobilized with denitrifying bacteria film as cathode was studied. A revised model for an electrochemical-activated denitrifying biofilm was developed and validated by electrochemical analysis of cathodal polarization curves and nitrate consumption rate. The cathodal polarization curve and nitrate consumption rate were introduced to verify the rate of electrochemical reaction and the activity of denitrifying bacteria, respectively. It was shown that the denitrification process effectively strengthened the electrochemical reaction while the electron also intensified denitrification activity. Electron was transferred between electrochemical process and biological process not only by hydrogen molecule but also by new produced active hydrogen atom. Additionally, a parameter of apparent exchange current density was deprived from the cathodal polarization curve with high overpotential, and a new bio-effect current density was defined through statistical analysis, which was linearly dependent to the activity of denitrification bacteria. Activated carbon fiber (ACF) electrode was also found to be more suitable to the electrochemical denitrifying system compared with graphite and platinum. Translated from Environmental Pollution & Control, 2005, 27(7): 501–504 [译自: 环境污染与防治]     

A simple fluorescence anisotropy assay for detection of bisphenol A using fluorescently labeled aptamer

Bisphenol A (BPA) is one of the environmental endocrine disruptors (EDCs), and BPA contamination in environment can cause high risks to human health. Rapid determination of BPA on sites is in high demand in environmental analysis. Taking advantage of aptamers as affinity ligands and fluorescence anisotropy (FA) analysis, we developed a simple and rapid FA assay for BPA by employing a single tetramethylrhodamine (TMR) labeled short 35-mer DNA aptamer against BPA. The assay is based on the BPA-binding induced conformation change of TMR-labeled aptamer and alteration of interaction between TMR and guanine bases, resulting in change of FA signals. We screened the FA change of aptamer probes having TMR label on a specific site of the aptamer upon BPA addition. The aptamer with a TMR label on the 22nd T base showed large FA-decreasing response to BPA and maintained good binding affinity to BPA. By using this TMR-labeled aptamer, we achieved FA detection of BPA with a detection limit of 0.5 μmol/L under the optimized conditions. This assay was selective towards BPA and enabled the detection of BPA spiked in tap water sample, showing the potential applications on water samples.     

纳米金修饰分子印迹聚合膜电极检测双酚A

以纳米金修饰玻碳电极为基础电极,以双酚A为模板分子,以邻氨基苯硫酚为聚合单体,采用循环伏安法电聚合制备分子印迹聚合膜,利用循环伏安和交流阻抗法研究电极的电化学特性。结果表明,双酚A在修饰电极表面的反应是一个受吸附控制的等电子、质子转移的不可逆反应。采用差分脉冲伏安法检测双酚A,线性范围为5. 0×10~(-6)mol/L～4. 0×10~(-4)mol/L,检出限为2. 3×10~(-7)mol/L。将该电极用于自来水和牛奶样品的测定,结果均为未检出,加标回收率分别为93. 5%和95. 4%,3次测定结果的RSD分别为4. 0%和5. 7%。     

pH值变化对B30铜镍合金腐蚀电化学行为的影响

采用电化学阻抗谱、动电位极化曲线等电化学测试方法,研究了NaCl（质量分数为3．5％）溶液中pH值变化对B30铜镍合金腐蚀电化学行为的影响。结果表明：随着溶液pH值升高,B30材料的腐蚀行为由均匀腐蚀变为点蚀;材料阻抗值和瞬时腐蚀速率提高,极化电流密度降低;材料发生点蚀的倾向增大。     

利用磷脂脂肪酸生物标记分析猪舍基质垫层微生物亚群落的分化

采用磷脂脂肪酸（PLFA）生物标记法,分析不同使用时间猪舍基质垫层微生物群落结构的动态变化及其亚群落的分化.结果表明,不同使用时间猪舍基质垫层中的微生物脂肪酸生物标记分布差异显著,一些微生物的脂肪酸生物标记在不同使用时间不同层次的基质垫层中均有分布,为完全分布,而另外一些微生物的脂肪酸生物标记只在特定层次分布,为不完全分布.此外,不同微生物的脂肪酸生物标记在不同使用时间不同层次的基质垫层中的分布量也不同,如生物标记i17:0 3OH仅分布于使用时间为1个月的基质垫层的第1、2、3层中,而在使用时间为1个月的基质垫层的第4层以及使用时间为6、24个月的基质垫层的各层分布量均极低.对猪舍基质垫层中的微生物亚群落分化的研究结果表明,当马氏距离为56.62时,可将不同使用时间的猪舍基质垫层微生物分为3个亚群落：初始亚群落、过渡亚群落和稳定亚群落.对各亚群落的特征分析表明,当欧氏距离为12.70时,可将初始亚群落（垫层使用时间为1个月）的脂肪酸生物标记继续分化为2类群;当欧氏距离为71.10时,可将过渡亚群落（垫层使用时间为6个月）的脂肪酸生物标记分化为2个类群;当欧氏距离为22.22时,可将稳定亚群落（垫层使用时间为24个月）的脂肪酸生物标记分为3个类群.     

牺牲阳极的阴极保护电位的测定与比较

采取连续实车监测的方法,对安装不同材料牺牲阳极的两栖车辆的车体电位进行了采集.通过数据整理和分析得出,五元和六元牺牲阳极保护方案都不能够为车辆提供足够的保护电位,但是五元要比六元牺牲阳极的极化速度慢.与五元牺牲阳极相比较,六元牺牲阳极更适合应用于干湿交替特点的两栖车辆.     

掺硼金刚石薄膜电极在水处理中应用的研究进展

掺硼金刚石(BDD)薄膜电极作为一种新型的电极材料,在水溶液中电解时具有较宽的电位窗口,在浓酸浓碱中具有很好的耐腐蚀性,其表面不易吸附污染物,与它的同素异构体电极及其他普通电极相比,具有更好的化学、物理性能,从而表现出潜在的功能,近年来被科研人员用于废水处理,并取得了很好的处理效果,对近期BDD薄膜电极的制备、在污水处理中的应用及其进展进行了总结与讨论.     

Determination of estrogenic activity by LYES-assay (yeast estrogen screen-assay assisted by enzymatic digestion with lyticase)

In order to enhance the sensitivity and the speed of the yeast estrogen screen (YES)-assay, which has been established in many laboratories for the determination of estrogenic activity of compounds and environmental samples, the LYES-assay, a modified version of the YES-assay including a digestion step with the enzyme lyticase, was developed. With the LYES-assay the estrogenic activities of natural (17β-estradiol E2 and estrone), synthetic (17-ethinylestradiol EE2) and pharmaceutical estrogens (diethylstilbestrol DES) as well as xenoestrogens (4-nonylphenol NP and five parabens) were determined and compared with the results obtained by other in vitro-assays namely the conventional YES-assay, the E-Screen-assay (MCF-7 breast tumor cell proliferation) and a receptor binding-assay (RB) with human estrogen receptors hER- and hER-β. In the case of E2 the LYES-assay had a significantly lower limit of quantification (LOQ) than the conventional YES-assay and even two orders of magnitude lower than the RB-assay. Compared to the E-Screen-assay the LOQ of the LYES-assay was almost one order of magnitude higher. The time required to perform the LYES-assay was as little as seven hours compared to three to five days for the conventional YES-assay. Thus, the LYES-assay is a very good alternative to existing estrogenic in vitro-assays, since it has a good sensitivity, is cheap and much faster than the other assays.     

含取代苯胺类化合物工业废水的电解处理研究

在酸性条件下投加ＮａＣｌ对含取代基团的苯胺类废水，进行了电解和过滤循环的处理。对含氯苯胺、硝基苯胺、甲苯胺等１２种废水进行处理试验，结果表明，在实验条件下电解１．０～２．０ｈ后，含１０００ｍｇ／Ｌ左右的苯胺类废水的出水ＣＯＤｃｒ＜２５０ｍｇ／Ｌ，芳胺含量＜３ｍｇ／Ｌ。采用质谱法分析了部分芳胺的电解固体产物，并对反应机理进行了探讨。