Effects of zinc stress on growth and antioxidant enzyme responses of Kandelia obovata seedlings

This study evaluated the tolerance and accumulation potential in the mangrove Kandelia obovata under moderate and high levels of external Zn. A greenhouse experiment was conducted to investigate the effects of a range of external Zn concentrations (0–400 mg L^?1) on the growth of this species by counting the lateral root number and measuring the root length, leaf area, and total dry biomass. We also determined the Zn accumulation in plant tissues. K. obovata survived with external Zn concentrations of up to 400 mg L^?1, although the excess metal resulted in a biomass reduction of 34%. A significant increase in antioxidant enzyme activities occurred in roots of plants under high-level Zn stress, suggesting that K. obovata seedlings could tolerate up to 200 mg L^?1 zinc treatment.     

土施和喷施锌肥对镉低积累油菜吸收镉的影响

采用盆栽试验,研究了土施和喷施不同用量Zn SO4对镉(Cd)低积累油菜生长、Cd吸收及微量元素含量的影响,并通过分析Cd在油菜体内的累积分配规律及土壤Cd有效性变化来揭示其作用机理.结果表明,土施锌(Zn)肥可以显著提高Cd低积累油菜的地上部生物量,最大可使其比对照处理增加71.4%;而喷施Zn肥对Cd低积累油菜地上部生物量没有显著影响.土施和喷施Zn肥都可显著降低Cd低积累油菜的地上部Cd含量,最大降幅为41.4%;在Zn肥用量相差8~10倍的情况下,二者降低油菜地上部Cd含量的效果无显著差异.土施Zn肥可使Cd低积累油菜地上部Cu和Fe含量显著升高,而喷施Zn肥对其没有显著影响,土施和喷施Zn肥都使Cd低积累油菜地上部Mn含量显著降低.土施Zn肥可显著提高土壤有效态Zn含量,但对土壤有效Cd含量没有显著影响;土施和喷施Zn肥可以显著降低油菜根部Cd净吸收量和Cd转运系数,油菜地上部Cd含量与根部Cd净吸收量呈显著的正相关关系(p0.01),而与Cd转运系数无显著的相关性,这表明施用Zn肥降低油菜地上部Cd含量主要是由于抑制根部Cd吸收引起的.总之,喷施Zn肥是调控Cd低积累油菜安全生产的较好措施.     

Interaction between Cu2+ and different types of surface-modified nanoscale zero-valent iron during their transport in porous media

This study investigated the interaction between Cu²⁺ and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu²⁺ uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu²⁺. The uptake of Cu²⁺ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu²⁺, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu²⁺. The presence of Cu²⁺ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu²⁺ caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu²⁺ complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu²⁺ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu²⁺ may be contributing to this straining effect.     

A 1-dodecanethiol-based phase transfer protocol for the highly efficient extraction of noble metal ions from aqueous phase

A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques,including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichloromethane with an efficiency of 96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.     

重离子辐照1200V碳化硅二极管漏电退化的缺陷分析

目的研究1200 V碳化硅二极管重离子辐照诱生缺陷对漏电流退化的影响。方法以SiC结势垒肖特基二极管(Junction Barrier Schottky Diode,JBSD)为样品,采用能量为208 MeV,LET=37.3 MeV·cm^2/mg的锗离子进行辐照试验,利用半导体器件分析仪对重离子辐照前后1200 V SiC二极管的电学特性进行测试,利用深能级瞬态谱仪(Deep Level Transient Spectrum,DLTS)进行缺陷分析。结果辐照后,二极管的正向IV特性和CV特性未发生明显变化,反向IV特性退化。DLTS测试结果显示,E0.4能级和Z1/Z2能级基本未发生变化,EH能级有展宽的现象。测试电压VM=-8 V,填充脉冲电压VF=-1 V条件下测得的EH能级浓度比VF=-4 V条件下测得的高。结论分析认为,EH能级的缺陷复杂,推测是两个或多个缺陷能级的叠加(EH4、EH5、EH6、EH7等),此处缺陷的复杂程度与漏电流的退化成正相关,且这些缺陷的所在位置接近SiC外延层的表面。     

冬季中国东海大气气溶胶中水溶性离子的组成与来源分析

运用离子色谱对2009年冬季中国东海大气气溶胶中水溶性离子Cl-、NO3-、SO42-、CH3SO3-（MSA）、Na＋、K＋、NH 4＋、Mg2＋、Ca2＋进行了测定,同时由SPSS（statistical package for social sciences）软件进行相关性分析探讨其来源.分析结果表明,气溶胶中二...     

δ-MnO_2对ZnO和TiO_2光催化降解萘酚蓝黑活性影响

以萘酚蓝黑为模型污染物,采用动力学方法研究了δ-MnO2颗粒杂质对亚微米级商品TiO2(C)、ZnO(C)和纳米级自制TiO2(N)、ZnO(N)光催化作用的影响,并通过紫外-可见漫反射光谱(UV-vis DRS)和荧光光致发光光谱(PL)对试样进行了表征。结果表明,δ-MnO2能导致2种TiO2严重失活,而对2种ZnO的光催化活性影响很小。δ-MnO2导致TiO2光催化剂失活的主要原因为:能提高TiO2的带隙能,以及作为深能级杂质促进光生电子与空穴之间的复合。     

Adsorption of zinc on manganite (γ-MnOOH):particle concentration effect and adsorption reversibility

The adsorption and desorption processes of Zn(Ⅱ) on γ-MnOOH as a function of particle concentrations (Cp) were studied. An obvious Cp effect was observed in this adsorption system. The degree of adsorption hysteresis increased greatly with the increasing of Cp, indicating that the extent of the real metastable-equilibrium states deviating from the ideal equilibrium state was enhanced with the increasing of Cp. The Cp-reversibility relationship confirmed the metastable-equilibrium adsorption (MEA) inequality (Pan, 1998a), which was the core formulation of the MEA theory. Because the MEA inequality was based on the basic hypothesis of MEA theory that adsorption density Г is not a state variable, the Cp-reversibility relationship gave indirect evidence to the basic hypothesis of MEA theory.     

“十四运”期间西安PM2.5中水溶性无机离子污染特征

为探究中国第十四届运动会(简称“十四运”)期间西安大气PM_2.5中水溶性无机离子浓度水平及来源,利用高分辨率MARGA ADI 2080离子在线分析仪对西安“十四运”前、“十四运”期间和“十四运”后水溶性无机离子进行实时观测,分析了不同时段水溶性无机离子组分污染特征、pH变化及污染来源。结果表明,“十四运”前、“十四运”期间和“十四运”后PM_2.5质量浓度分别为13.4、11.9、32.6μg/m³,SNA(NO^-₃、SO₄^2-和NH⁺₄三者统称)质量浓度分别为5.8、5.4、13.3μg/m³,占总水溶性无机离子的91.6%～93.6%。“十四运”前和“十四运”期间NO^-₃与SO₄^2-质量浓度比分别为0.7和0.9,表明移动源的比例增加,主要受交通管控的影响。“十四运”后NO     

无机离子交换材料对废水中铯的吸附研究

用水热合成法合成钛硅酸钠无机离子交换材料,考察了它对Cs的吸附效果。探讨了体系pH值、温度、吸附时间等因素对吸附的影响。实验表明,所合成的钛硅酸钠对Cs的吸附能力较强,在30℃,1mol／L的H^ 环境下对Cs的吸附分配比为6066,饱和吸附量可达1．7420mmol／g。钛硅酸钠吸附Cs的稳定性实验表明,钛硅酸钠的解吸分配比很小,吸附稳定性很好。