Accumulation and Fractionation of Rare Earth Elements in a Soil-Wheat System

Time series bioaccumulation of rare earth elements （REEs） in field-grown wheat with and without a dressing of extraneous REE fertilizer at different growth stages and fractionation of REEs during their transport in a soil-wheat system were determined. Time-dependent accumulation of extraneous REEs was found in different parts of wheat. An upward transport of extraneous REEs from roots to shoots under a soil dressing and a downward transport from leaves to roots with a foliar dressing were also observed. Moreover, fractionation of REEs occurred in the soil-wheat system. Compared to the host soil a positive Eu anomaly in the stems and grains as well as heavy REE enrichment in the grains were found. The ability of the different wheat organs to fractionate Eu from the REE series was ranked in the order of sterns 〉 grains 〉 leaves 〉 roots.

Distribution of rare earth elements of granitic regolith under the influence of climate

The distribution and anomalies of rare earth elements(REEs) of granitic regolith were studied in Inner Mongolia and Hainan Island, China. One profile showed slight REE enrichment of an upper layer and no obvious light REE/heavy REE(LREE/HREE) fractionation(La_N/Yb_N of 0.9). The second profile was significantly enriched in REEs and enriched in LREEs in the upper portion(La_N/Yb_N>1.8). Eu, Ce, and Gd anomalies of the two profiles are different. Slightly negative Eu, Ce, and Gd anomalies in NMG-3-1 indicate slow dissolution of primary minerals and little secondary products; in contrast, a positive Eu anomaly in HN-2 suggests the vegetation cycle may contribute to soil. The Ce anomaly of HN-2 reflects oxidation of Ce and coprecipitation by Fe-and Mn-oxides and organic matter. Correlation between Ce and Gd anomalies in HN-2 suggests Ce and Gd are both influenced by redoxreduction.

Eu(Ibu)_(3)phen配合物的合成表征及发光性

以药物布洛芬为第一配体,稀土离子Eu(Ⅲ)为中心离子,采用溶剂法合成了Eu^(3+)、布洛芬(Ibu)和邻菲罗啉(phen)的稀土-布洛芬药物配合物Eu(Ibu)3phen,采用元素分析、紫外光谱、红外光谱对配合物进行了初步结构表征,并研究了配合物的荧光性能.结果表明,该合成方法简单,Eu(Ibu)_(3)phen产率较高,配合物Eu(Ibu)_(3)phen的荧光发射光谱在612 nm出现Eu离子强特征荧光发射峰.该配合物有较好的发光性能,可作为安全环保的荧光材料.

STUDY ON THE SEPARATION AND EXTRACTION MECHANISM OF RARE EARTH ELEMENTS BY MEANS OF REVERSED-PHASE PAPER CHROMATOGRAPHY

Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep- aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with a solution of monomyristyl phosphoric acid (MPA) in chloroform.Mineral acids are used as developers. The effect of concentration of acids and/or salts upon R_f has been investigated.According to the re- sults of R_f values for a given rare earth element in various acids,the order of extraction ability is HCl>HNO_3>H_2SO_4.A tetrad effect is clearly observed.for the R_f value of rare earth elements.The effects of other parameters on the R_f value,such as the quantities of extractant retained by the paper and the temperature are also examined.Based on the determination of the molar ratio of MPA to rare earth elements and the number of H^+ ions released in extraction reaction,a reasonable mechanism is proposed.The mutual separation of heavy rare earth elements will be better than that of the light rare earth group because of the larger separation coefficient of the former.A mixture of Ho-Er-Tm-Lu is successfully separated by the present method.

Characteristics of Rare Earth Elements of Zircons from Mesozoic Volcanic Rocks in Luanping Region, Hebei

Rare earth elements of the zircons from the Mesozoic volcanic rocks in Luanping region, Hebei, were analyzed the results reflect that the average values of δEu and （Lu/Gd）N are 0.49 and 21.8 respectively in the zircons from the top part of Tiaojishan Formation; but the average values of δEu and （Lu/Gd）N are 0.15, 0.06, 0.09 and 14.51, 15.66, 16.25 respectively in the zircons from the lower, and upper part of the Tuchengzi Formation and the bottom bed of the Zhangjiakou Formation. The results show that the characteristics of the zircons from the Tuchengzi Formation are coincident with those of the zircons from the Zhangjiakou Formation, but are different from those of the zircons from the Tiaojishan Formation, and imply that the Tuchengzi Formation has close relation with the Zhangjiakou Formation. Combining the results above with the former isotopic dating results of the volcanic rocks, the authors draw the conclusions as follows ： The Tuchengzi Formation not only has a long interval period with the Tiaojishan Formation, but also is very different from the Tiaojishan Formation in zircon geochemical characteristics. The Zhangjiakou Formation in time, but also is coincident with the Tuchengzi Formation not only is nearly continuous with the Zhangjiakou Formation in geochemistry of zircons. The resuhs imply that the Tuchengzi Formation and the Zhangjiakou Formation were formed in the same geological background, that is, there are not the boundary of the J3-K1 and the interface of the transition of tectonic framework between the Tuchengzi Formation and the Zhangjiakou Formation in the Luanping region. The research shows that the （Lu/Gd）N, δEu are two important parameters which are relatively stable in the analysis of zircons from Crust-source; but the values of ∑LREE of zircons from Crust-source change greatly, especially the abundance of La element, so some ratios of rare earth elements related with La （or ∑LREE） are not usable in determining the characteristics of zircons.

Study of the relationship between the content of the rare earth element Eu in rice plants and in Nilaparvata lugens （Hemiptera： Delphacidae）

The current study investigated changes in the content of the rare earth element Europium （Eu） in roots, shoots and leaves of rice plants and in Nilaparvata lugens Stal （Hemiptera： Delphacidae） using an Eu marker and hydroponic culture. The results showed that N. lugens infestation significantly reduced Eu content in roots, shoots and leaves of two rice varieties, Shenyou 1 and Xieyou 963. The Eu content in roots, shoots and leaves of the susceptible variety, Shenyou 1, was significantly higher than that in the resistant variety, Xieyou 963. The Eu content ofN. lugens fed on Shenyou 1 was significantly higher than of those fed on Xieyou 963. In addition, the Eu level was elevated at a higher density ofN. lugens infestation. Eu content in the bodies ofN. lugens was related to their weight and honeydew excretion, with a significant positive correlation. Thus, Eu content in the bodies ofN. lugens can be considered an index of the amount of phloem sap taken in by N. lugens because the amount of honeydew excretion is proportional to the amount of phloem sap consumed. The ratios of Eu content in N. lugens to that in roots, shoots and leaves of rice plants were elevated at a higher N. lugens infestation density. That ratio was maximal in leaves, was intermediate in shoots and was minimal in roots. There was no significant difference in ratios between the two plant varieties. An Eu marker may be useful in the screening of resistant varieties and in the study of the mechanisms of resistance.

Contents and distribution of rare earth elements in wheat seeds

Contents of 15 rare earth elements (REEs) in the seeds of 60 breeds of wheat have been analyzed by the inductively-coupled plasma mass spectrometry (ICP-MS). The distribution pattern of contents of REEs in wheat seeds has been observed and compared with that in soils. Comparison with literature data has also been made. The results show that the background of REEs in wheat seeds is 10 11-108 g -g-1, 3-4 levels lower than in soils. The distribution pattern is light REEs higher in contents and slight Eu-anomaly, similar to that in soils. The data obtained in this study can accurately represent the background content of REEs in wheat seeds.

新型双掺杂红色荧光粉Ba_(2)MgGe_(2)O_(7):xBi^(3+),yEu^(3+)的制备及性能研究

通过高温固相法制备出Ba_(2)MgGe_(2)O_(7)固体荧光粉,采用实验研究方法进行分析测定,其中包括对所得BMGO荧光粉进行荧光光谱分析,了解掺杂离子不同含量下各个样品的光学性能,分析解释BMGO荧光粉通过掺杂Bi^(3+)、Eu^(3+)后,样品发射光谱强度大大提高,呈现稀土铕离子的特征峰,具有荧光效应的显著特点;分析系列荧光粉的粉末X射线衍射光谱,探究掺杂新离子后,BMGO的晶态物质的物相分析,晶态物质组成元素是否有结构差异;CIE色度图和荧光光谱显示,样品含量为Ba_(2)MgGe_(2)O_(7):0.01%Bi^(3+),4%Eu^(3+)荧光强度最高,色纯度接近正红色。

Direct microwave leaching conditions of rare earth elements in fluorescent wastes

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.Moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

Fluorescence Properties of Eu^(3+)/Gd^(3+)/Citric Acid Mixed Complexes Doping in Silicon Rubber Matrix

Series of doped rare earth compiexes-EuxGd(1-x) (CA)3·nH2O (CA = citric acid) were synthesized. Some characterizations were taken for these complexes. The experimental results shows that the doped rare earth complexes have the best fluorescence property when the ratio of Eu and Gd is from 0.7 to 0.3. Silicon rubber-based composites were prepared by mechanical blending the EuxGd(1-x) (CA)3·nH2O and silicon rubber. Then, the fluorescent property of the composites was studied. It is found that the fluorescence intensity of the composites increase linearly with the contents of the rare earth complexes increasing.

Study on Fluorescence Properties of Eu(Ⅲ) Cryptates

The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was studied by phosphorescence spectrum. The fluorescent properties of Eu(Ⅲ) cryptates in MeOH solution show that the cryptand (H 3L F) can sensitize the Eu(Ⅲ) ion to luminescence and the introduction of the Zn(Ⅱ) ion into the mononuclear Eu(Ⅲ) cryptate resulted in blue shift of three ligand centered bands, increase of molar absorption coefficient and increase of the luminescence intensity of Eu(Ⅲ).

Spectroscopic Characterization of Eu-Enoxacin-Phen Complexes and Determination of ATP by Fluorescence Quenching

The complex of Eu 3+ and Enoxacin(ENX) and Phen was synthesized. Its compositions is Eu(ENX)_3(phen)Cl_3·2H_2O. Its fluorescence spectra were studied. The results show that the strong fluorescence emitting of 592 and 616 nm for Eu 3+ in the Eu(ENX)_3(phen)Cl_3·2H_2O complex is related to the transitions 5D_0-7F_1 and 5D_0-7F_2 respectively. A sensitive method for the determination of adenosine triphosphate(ATP) by fluorescence quenching is proposed. The method is based on the ability of ATP to inhibit the formation of a strong fluorescent complex of Eu(ENX)_3(phen)Cl_3·2H_2O. In conditions of pH 6.7 in HAc-NaAc buffer and λ_ ex=340 nm and λ_ em=616 nm, the linear range of the determination is 0.4～ 10 μg·ml -1 and the detection limit is 0.034 μg·ml -1 for ATP. The method was applied to determine ATP in adenosine disodium triphosphate injection samples with relative standard deviation of 212% and recovery of 94.8%～1037%.

Preparation and Fluorescence Properties of Polymethyl Methacrylate Resin Incorporated with Sodium Tris (Pyridine Dicarboxylato) Europate

Based on the strong fluorescence and the highly thermal stability of sodium tris (pyridine dicarboxylato) europate (Na 3Eu(DPA) 3), polymethyl methacrylate (PMMA) composite material incorporated with the complex, PMMA: Na 3Eu(DPA) 3, was prepared at 250 ℃. The fluorescence behavior of PMMA: Na 3Eu(DPA) 3 material was examined. The results show that the composite material keeps the luminescent characteristics of the Eu 3+ chelate after PMMA is incorporated with Na 3Eu(DPA) 3, and strong orange-red emission of the composite was observed. The fluorescence intensity of the composite material increases with the increase of the weight ratio of Na 3Eu(DPA) 3 to PMMA, but the relationship is not linear.

Eu^(3+)配合物掺杂聚合物的制备与光谱性能研究

以噻吩甲酰三氟丙酮(2-thenoyltrifluoroacetone,TTFA),六氟乙酰丙酮(hexafluoro-acetylacetone,HFA)和甲基联苯甲酰(dibenzoylmethide,DBM)分别为配体合成了Eu3+的三种β-二酮类配合物Eu(TTFA)3、Eu(HFA)3和Eu(DBM)3,以及掺杂这三种配合物的聚合物(聚甲基丙烯酸甲酯,PMMA),并用分光光度计对它们的荧光光谱特性进行了分析研究.结果表明,三种配合物中Eu(TTFA)3荧光强度最强,并分析了其原因,发现能级匹配、配体取代基、配体结构对称性等均对配合物发光效率有重要的影响.通过比对,证明了TTFA是Eu3+发红色荧光的优良配体.进一步研究还发现,Eu(TTFA)3掺杂PMMA中稀土离子的荧光强度和荧光寿命均随掺杂浓度(质量分数为0.08~0.5)的增加而增大.

Y_2O_3:Eu纳米晶的硝基取代苯甲酸配合物固相热解制备和性能

以苯甲酸、邻硝基苯甲酸、间硝基苯甲酸、对硝基苯甲酸、3,5-二硝基苯甲酸等为配体制备了Y3+、Eu3+二元配合物,配合物中Y3+与Eu3+的摩尔比为9:1.利用这些配合物的爆炸式热分解特性通过固相热解反应制备了一系列Y2O3:Eu纳米晶.透射电镜观察,可以看出所得纳米晶呈球形,粒度介于40～60nm,X射线衍射分析表明实验所得纳米晶属立方晶系,粒径与电镜观察所得结果基本一致;Eu3+的引入并不影响Y2O3的晶相组成;配体类型对纳米晶的结构没有显著影响,不过相对于硝基取代苯甲酸配合物,苯甲酸配合物热解所得Y2O3∶Eu纳米晶团聚严重;退火温度显著影响纳米晶粒度,退火温度高,纳米晶粒度大,反之亦然.荧光光谱测定表明所有Y2O3∶Eu纳米晶具有相似的发光行为,其中以苯甲酸配合物分解所得Y2O3:Eu纳米晶发光性能最为优越.

吡啶-2,6-二甲酰胺衍生物Tb(Ⅲ)、Eu(Ⅲ)配合物的制备及荧光性能测试

从吡啶-2，6-二甲酸（L1）出发，合成了2种含有多个共轭体系和多齿的N^2，N^6-二（3-甲基吡啶）-2-取代吡啶-2，6-二甲酰胺（L2）配体和N^2，N^6-二对甲苯基吡啶-2，6-二甲酰胺（L2）配体；制备了化合物N^2，N^6-二（3-甲基吡啶）-2-取代吡啶-2，6-二甲酰胺（L2）与Tb（Ⅲ）和Eu（Ⅲ）的配合物，培养出了单晶。通过红外光谱、元素分析和X射线单晶衍射仪确定配合物的组成和结构。结果表明：在Tb（Ⅲ）配合物的稀溶液中，当溶液pH值为7时荧光强度最强，pH值大于或小于7荧光强度都逐渐减弱；当溶液pH为7时，N^2，N^6-二（3-甲基吡啶）-2-取代吡啶-2，6-二甲酰胺对Tb（Ⅲ）的荧光强度敏化远大于吡啶-2，6-二甲酸；N^2,N6-二（3-甲基吡啶）-2-取代吡啶-2，6-二甲酰胺和吡啶-2，6-二甲酸与Eu（Ⅲ）形成稀的配合物溶液的荧光强度随pH值的增加而增大（pH3～11）。

新型Eu^(3+)、Tb^(3+)掺杂配合物的合成与荧光性能研究

合成了稀土(Eu3+和Tb3+)与二苯甲酰甲烷(DBM)、2,2′-联吡啶(Dipy)的一系列稀土配合物EuxTb1-x(DBM)3Dipy。元素分析和红外分析确定了配合物的组成,荧光光谱研究了荧光性质。铽掺入配合物后,铽能极大地增强铕的特征荧光,铽对铕配合物的发光有协同作用。在该系列配合物中,不仅有机配体可以将吸收的能量传递给发光的铕离子使其发光,而且铽离子也可将其吸收的能量通过分子内能量传递给铕离子。

Eu掺杂YBa_(2-x)Eu_xCu_3O_(7-δ)超导体的X射线衍射研究

Eu掺杂(取代)导致Y系YBa2Cu3O7-δ(YBCO)超导材料临界电流密度增强,晶格应变被认 为是主要原因。本文研究了Eu掺杂YBa2-xEuxCu3O7-δ超导体的结构和应变,并从容忍因子讨论了 钙钛矿单元的结构稳定性和晶格畸变,以及结构与电输运的相互关系;当x<0．15时,样品中没有 杂相。我们发现Eu3+／Eu2+离子优先替代Ba位的Ba,对电输运几乎没有影响。研究还表明氧含量 对超导转变温度Tc几乎没有影响。进一步研究了所有正常态样品的自旋能隙打开温度与超导输 运及结构变化之间的关系。

TiO_2/Eu^(3+),Y^(3+)下转换薄膜的制备及其在染料敏化太阳能电池中的应用

采用溶胶-凝胶法制备了TiO2/Eu3+,Y3+下转换薄膜,将其应用到染料敏化太阳能电池中,利用其下转换特性将紫外光转换为可见光,提高了电池的可见光照强度.利用X射线衍射和荧光光谱对TiO2/Eu3+,Y3+粉体进行表征,利用荧光光谱和紫外-可见分光光度计对TiO2/Eu3+,Y3+下转换薄膜进行测试,荧光光谱显示,下转换薄膜受到396nm紫外光照射时可发射出535~620nm连续波长的可见光,具有下转换功能特性.与TiO2薄膜相比,二层下转换薄膜仍能保持较高的可见光透过率.当稀土元素总掺量为4%时,利用下转换特性使短路电流提高了21.5%,光电转换效率提高了14.1%.

碱土金属离子(Mg^(2+),Ca^(2+),Ba^(2+))掺杂对长余辉荧光粉SrAl_2O_4:Eu^(2+),Dy^(3+)发光性能的影响

采用高温固相法制备了碱土金属离子(Mg2+,Ca2+,Ba2+)掺杂的SrAl2O4∶Eu2+,Dy3+长余辉荧光粉。XRD谱分析表明,随着基质中掺入的碱土金属离子(Mg2+,Ca2+,Ba2+)浓度增加,基质晶格常数也随之发生变化。Mg2+,Ca2+和Ba2+3种碱土离子在SrAl2O4中的固溶范围分别为40%,15%和30%。光谱分析则表明在固溶范围内随着掺杂Mg2+,Ca2+和Ba2+浓度的增大,样品的发射峰值会在480~530 nm范围出现规律性移动。适当浓度的Mg2+,Ba2+掺杂会不同程度地提高样品的发光强度,而Ca2+的掺杂则会降低发光强度。但是碱土金属离子(Mg2+,Ca2+,Ba2+)的掺杂并不能延长SrAl2O4∶Eu2+,Dy3+荧光粉的余辉时间。