除镍化学镀镍废液制成复合肥对玉米肥效的研究

盆栽试验施用2种由磷，氮含量较高的化学镀镍废液沉淀除镍之浓缩液制成的复合肥，结果表明；施用浓缩液复合肥后，玉米幼苗生长正常，肥效与对照的“过磷酸钙”复合肥无显著差异；与不施肥相比，可显著提高玉米幼苗地上部干质量和土壤的N、P、K含量，表明浓缩液复合肥对玉米生长有明显的效果。     

雷州半岛农业土壤与作物镍含量及其潜在健康风险

在雷州半岛采集了106个农业土壤表层样品和43个农作物样品(包括蔬菜、水果、甘蔗和稻谷),分析了土壤和农作物可食部分镍的含量,研究镍的分布特征和富集能力,评价其健康风险。结果表明,雷州半岛土壤中镍平均含量为49.81mg·kg-1,超过国家土壤二级标准(GB15618-1995)的样品占25.47%,徐闻、雷州等地超标较严重。蔬菜和稻谷镍含量分别介于0.083￣0.733mg·kg-1和0.360￣1.09mg·kg-1,不同程度超过食品卫生建议标准,而水果类(含甘蔗)镍含量较低。不同种类农作物可食部分对镍元素的富集均存在着差异,其中蔬菜类的芥菜、小白菜镍的富集能力较强,青瓜、生菜、花菜、油麦菜等蔬菜品种和菠萝、香蕉、橙子、甘蔗等水果类镍的富集能力则较低,菠萝和甘蔗镍的富集系数仅为0.0013和0.0005,较适合在雷州半岛镍含量较高的玄武岩风化土种植;稻谷镍的富集系数介于0.0056￣0.0259,6个样品差异较大,可能与不同样点间土壤pH值不同或复合污染有关。依据USEPA推荐的RfD值和广东省居民平均食物消费结构进行计算,雷州半岛蔬菜、稻谷和水果(含甘蔗)三大类作物可食部分通过土壤-植物-人体途径年平均摄入量为174.4mg·人~(-1)·a~(-1),若考虑其他的摄入途径,雷州半岛农产品中的镍对人体潜在一定的健康风险。     

金属泡沫镍负载纳米TiO2光催化降解甲醛和VOCs

采用溶胶-凝胶法制备了3种掺杂金属离子的纳米TiO₂光催化剂,并将其负载于泡沫镍板上,以室内空气典型污染物甲醛和VOCs为模型反应物,研究了对甲醛和VOCs气体的光催化作用并讨论了La³⁺的最佳掺杂比例以及环境因素对光催化效率的影响.结果表明:该TiO₂催化剂具有良好的锐钛矿型结构;负载掺La 1.5%TiO₂的泡沫镍板90min对甲醛和VOCs的降解率分别为94%和87%,远高于未掺:83%和72%,掺Fe     

我国小麦镍的污染调查及健康风险评估

为了解我国小麦主产区小麦镍的污染情况及暴露风险,本研究收集北方冬麦区、南方冬麦区和春麦区小麦样品3 444份,采用石墨炉原子吸收光谱法检测镍含量,分析小麦镍污染水平及分布特征;基于全麦籽粒镍含量的分布,采用蒙特卡洛法估算我国成人和儿童小麦镍的暴露剂量水平,采用美国环境保护署(USEPA)的暴露剂量-反应外推模型,评价小麦镍的暴露健康风险。结果表明,我国3个小麦主产区小麦镍平均含量为0.225 mg·kg^-1,南方冬麦区小麦镍污染水平显著高于其他2个产区,最高值达4.779 mg·kg^-1。 膳食暴露评估结果显示,我国成人和儿童小麦镍的单位体重日均暴露量(ADD)分别为6.31×10^-4和8.32×10^-4 mg·kg^-1·d^-1;与不同国际组织推荐的参考摄入剂量(RfD)相比,成人和儿童ADD值超过RfD值的人群概率范围分别为0~0.23%和0.02%~0.49%。风险评估结果显示,小麦镍暴露不会对我国大部分居民产生明显的健康影响,但少数高暴露人群可能潜存健康隐患。本研究结果为我国小麦重金属污染安全监管、标准制定和风险评价提供了科学依据。     

Live and death of streptomyces in soil—what happens to the biomass?

The formation of soil organic matter (SOM) has been proposed to depend on fragmentation of biomass after cell death. However, this is hard to mimic in laboratory experiments showing the process directly. We used heavy metal contamination in order to provide an environment in which one Streptomyces strain, the heavy metal resistant S. mirabilis P16B‐1, could survive while the sensitive strain S. lividans TK24 was expected to die and disintegrate; the necromass fragments would then contribute to SOM formation. Both strains were grown for 30 d in sterile mesocosms containing either highly metal‐contaminated soil from a former uranium‐mining site in Ronneburg, Germany, or control soil from a municipal park, Jena, Germany. The fate and morphology of living and dead bacterial biomass (necromass) was observed using scanning electron microscopy. Attachment of soil particles to the intact mycelium as well as decay of dead biomass was observed. Dead bacterial biomass was identified in form of patchy fragments while the superordinate filamentous structure of the hyphae was still visible and obviously stabilized in soil. The fate of cytosolic compounds was followed using the example of a nickel‐containing superoxide dismutase (NiSOD) which was found to be released after death of cells grown in liquid soil‐extract medium. Activity of the enzyme was proven for concentrated media supernatant by a gel‐based qualitative activity assay. This indicates that NiSOD remains active in soil after cell death. Hence, bacterial cell death results in the release of cytosolic compounds, e.g., intact proteins, as well as the formation of residual cell‐envelope fragments contributing to SOM formation.     

双核中性镍的合成及其催化乙烯聚合

经希夫碱缩合反应,制得水杨醛亚胺配体(3),其Na盐与trans-NiClPh(PPh3)2合成了新型中性镍配合物4{[o-(3-Cyclopentenyl)-(5-Me)C6H2--oC(H)=N-2,6-(i-Pr)2C6H2]2CH2}[Ni(Ph3P)(Ph)]2.经Ni(COD)2活化,配合物4的最高活性达12.12×105gPE/(molNi.h),所得聚合物黏均相对分子质量在1.93×104~9.49×104之间.研究了不同聚合条件对催化性能的影响.配合物4可以作为单组分催化剂催化乙烯聚合,活性高达1.49×105gPE/(molNi.h),所得聚乙稀相对分子质量及其分布分别达到了5.27×104和3.34.     

杨木单板表面化学镀镍的工艺条件对镀层性能的影响

研究了杨木单板表面化学镀镍过程中pH值和温度变化对镀层的电磁屏蔽性能和表面导电性能影响。用扫描电镜和能谱分析了镀层结构和含磷量。结果表明,pH值和温度升高,电磁屏蔽性能和表面导电性提高,但达到一定值后,电磁屏蔽性能和表面导电性又有所下降。杨木单板经表面化学镀镍后,表面完全被金属镍覆盖,金属感增强,并且镀层中磷含量较低,镀层为晶体结构。     

黑土施镍对大豆幼苗生长的影响及镍中毒研究

为分析镍对大豆幼苗生长的影响及毒害作用,以黑土作为供试土壤,采用盆栽方法,研究了不同施镍水平下大豆幼苗的生长情况,并对大豆幼苗镍中毒临界值及中毒程度进行分析。结果表明:随着施镍量的增加,大豆植株鲜重、干重均呈先增加后降低的趋势。通过对土壤有效镍与大豆植株干重、土壤有效镍与植株含镍量进行拟合,推导出大豆幼苗生长状态最佳时的土壤有效镍含量为10.88 mg/kg,植株含镍量为26.46 mg/kg;中毒临界值(即某一施镍水平下的植株干物质累积量与不施镍处理相同)土壤有效镍为21.25 mg/kg,植株含镍量38.80 mg/kg;奢侈吸收区间黑土有效镍含量为10.88~21.25 mg/kg。以某一施镍水平下的干重占空白干重的90%~100%为轻度中毒分界点,得出大豆幼苗处于轻度中毒状态时的土壤有效镍含量为21.25~44.76mg/kg,此时植株镍含量为38.80~68.14mg/kg;促使大豆植株出现中度中毒时(干重为空白的80%~90%)的土壤有效镍含量为44.76~69.62mg/kg,此时植株镍含量为68.14~95.48 mg/kg;当土壤有效镍含量>69.62 mg/kg时,大豆植株则处于高度中毒状态(干重为空白的80%以下),此时植株含镍量>95.48 mg/kg。     

新型高选择性水杨酸根离子电极的研究

[目的]采用紫外可见光谱技术研究电极响应机理。[方法]首次研制基于二苯甲酮缩氨基硫脲合镍(Ⅱ)金属配合物[Ni(Ⅱ)-BBKT]为中性载体的电位型阴离子选择性电极。[结果]该电极对水杨酸根(Sal-)具有优良的电位响应性能和选择性,在磷酸盐缓冲体系(pH 5.0)中电极电位呈现近能斯特响应,线性响应范围为5.9×10-5～1.0×10-1mo l/L,斜率为-55.9 mV/dec(25℃),检测下限为8.2×10-5mol/L,其选择性次序为Sal->ClO4->SCN->I->NO2>Br->NO3->Cl->SO32-。[结论]该离子选择性电极具有设备简单,操作方便,测量的范围宽广,灵敏度高等优点,在医学和环境监测中具有一定的应用前景。     

Growth effects in tropical nickel‐agromining ‘metal crops' in response to nutrient dosing

Agromining is an emerging technology that utilizes selected ‘metal crops' (= hyperaccumulator plants) to extract valuable target metals from unconventional resources for profit from mineralised soils. Growth characteristics, shoot metal concentrations, and agrominable locations are important considerations in economic agromining. Globally, the greatest potential for nickel (Ni) agromining exists in the tropics. However, the agronomic systems of tropical ‘metal crops' have not been previously tested. Furthermore, it is currently unknown whether nutrient dosing of prospective tropical agromining Ni ‘metal crops’ could possibly cause a shoot Ni‐dilution effect which may ultimately limit economically viable Ni yields. We undertook a pioneering study on Ni uptake and growth responses to nutrient dosing in two promising tropical ‘metal crops' (Phyllanthus rufuschaneyi and Rinorea cf. bengalensis). The experiment consisted of a large randomised block growth trial in large pots over 12 months in Sabah (Malaysia). At 3‐month intervals, the plants were exposed to soluble treatments that altered available concentrations of nitrogen (N), phosphorus (P), and potassium (K). We found strong positive growth responses to N and P additions in P. rufuschaneyi, whereas K additions had negative growth effects. In R. cf. bengalensis, all treatments had positive growth effects. The increases in biomass in response to nutrient dosing did not significantly reduce shoot Ni concentrations in both species, with the exception of N addition in P. rufuschaneyi. This study reveals that Ni uptake and growth responses to nutrient dosing are species‐dependent, primarily influenced by the ecophysiology of the species. Inorganic fertilization could possibly be an important component of the management of local ‘metal crops' to be used in viable commercial agromining in the tropics, but this needs to be tested in the field with different formulations of N, P, and K.