改性PVDF中空纤维液膜富集Er~(3+)的研究

为改善聚偏氟乙烯(PVDF)液膜稳定性并获得较高Er~(3+)萃取率,采用0.5%LiCl共混改性膜自制膜萃取器,研究了LiCl改性PVDF中空纤维膜对稀土离子Er~(3+)的富集。结果表明,Er~(3+)的萃取率随着载体HEHEHP浓度、反萃剂盐酸浓度和两相流速的增加先增大后减小,随着料液相初始H~+浓度增加而降低。研究获得Er~(3+)的最佳萃取工艺为:料液相初始H~+浓度为0.065 mol/L,反萃剂盐酸浓度为3.0 mol/L,载体HEHEHP浓度为0.25 mol/L,两相流速为10 mL/min。在此条件下,进一步考查了不同LiCl含量改性中空纤维膜富集Er~(3+)的效率。     

A fluorescent probe based on a spiropyran for sensitive detection of Ce~(3+) ion

A spiropyran-based probe was developed.It serves as a fluorescence turn-on probe for selective detection of Ce~(3+) in both ethanol and aqueous(water/ethanol,1:9 or 9:1,v/v) media.Ce~(3+) can induce photochromism of the probe though the probe exhibits negligible photochromic property by itself.The probe is sensitive to Ce~(3+) and the detection limit reaches 1.7 μmol/L.It exhibits a high selectivity for Ce~(3+)ion over other common metal cations including Li~+,Na~+,Ag~+,Sr~(2+),Ni~(2+),Co~(2+),Hg~(2+),Zn~(2+),Cr~(3+),Al~(3+),Fe~(3+) and Bi~(3+) and lanthanide ions Nd~(3+),Yb~(3+) and La~(3+).The probe may be used for quantitative determination of the concentration of Ce~(3+) ion in a range of 1-10 μmol/L and for application to environmental water samples.Sensing mechanism of the probe towards Ce~(3+) ion is proposed.     

杯[8]芳烃磷酸酯萃取分离镧铈混合离子的研究

合成了对叔丁基杯[8]芳烃磷酸酯(简记为TPA),通过红外光谱和核磁共振谱表征了TPA的结构,研究了TPA对镧铈混合离子的萃取分离条件,初步探讨了TPA萃取La~(3+)、Ce~(4+)的分离机理。在水相pH=6.5、O/A相比1∶1、萃取时间150 min、萃取剂浓度3.0×10~(-3) mol/L下,TPA对La~(3+)、Ce~(4+)的萃取分离效率最高,Ce~(4+)/La~(3+)分离因子为6.74,略优于传统萃取剂P507-磺化煤油,且无需对镧铈混合离子溶液进行皂化处理,无氨氮废水产生。TPA在镧铈混合离子溶液中对Ce~(4+)有较好的选择性,若利用多级离心萃取分馏,有望实现La~(3+)、Ce~(4+)的高效、无氨氮污染萃取分离。     

Trace detection of Ce3+ by adsorption strip voltammetry at a carbon paste electrode modified with ion imprinted polymers

To develop a convenient method for sensitive and selective determination of Ce3+ in aqueous phase with complicated matrices, a carbon paste electrode(CPE) modified with ion imprinted polymers(IIPs) were fabricated. The polymers were prepared by precipitation polymerization using Ce3+ as template, allyl phenoxyacetate(APA) as monomer, ethylene glycol dimethacrylate(EGDMA) as crosslinker and azobisisobutyronitrile(AIBN) as initiator under the molar ratio of Ce3+, APA and EGDMA as 1:4:40, respectively. Ce~(3+) was detected directly by differential pulse adsorptive stripping voltammetry(DPASV) and its oxidation peak appears at about 0.93 V. All parameters affecting the sensor's response are optimized and a calibration curve is plotted at a linear range of 1.0 × 10~(-6)-1.0 x 10~(-5) mol/L and 1.0×10~(-5)-2.0 × 10~(-4)mol/L with the detection limit of 1.5 × 10~(-7) mol/L. All other rare earth ions have no interference with the determination of Ce~(3+) even at a concentration 500 times higher than that of Ce~(3+).This sensor was successfully applied to determination of Ce~(3+) in two catalyst sample solutions with RSD≤3.3%(n = 5)and recoveries in the range of 99.2%-106.5% at our optimal conditions.     

稀土矿浮选中柠檬酸对铈离子活化方解石的影响研究

通过单矿物浮选试验、Zeta电位测试和红外光谱分析等方法,研究稀土矿浮选中柠檬酸CA对Ce~(3+)离子活化方解石的去活作用机理。试验研究结果表明,矿浆中Ce3+离子的浓度低于1×10~(-4)mol/L时对方解石浮选有活化作用,采用柠檬酸CA可达到去活目的。机理分析结果表明,柠檬酸CA能与方解石表面的Ce3+离子生成一种稳定的络合物,可降低方解石表面的Zeta电位,去除Ce~(3+)离子对方解石的活化作用。     

石墨烯-离子液体修饰玻碳电极同时测定矿石中铅和镉

将石墨烯(GR)滴涂在玻碳电极(GCE)上制备GR/GCE电极,采用循环伏安法将离子液体(1-辛基-3-甲基咪唑六氟磷酸盐)聚合在GR/GCE电极表面,制得新型OMIMPF_6/GR/GCE修饰电极。以0.1mol/L HAc-NaAc缓冲溶液(pH 4.5)为支持电解液,利用差分脉冲法研究了Pb~(2+)和Cd~(2+)在OMIMPF_6/GR/GCE电极上的电化学行为。结果表明,Pb~(2+)和Cd~(2+)在修饰电极上有较好的电化学行为,Pb~(2+)和Cd~(2+)的浓度分别在1.0×10~(-8)~4.2×10~(-5)mol/L和1.0×10~(-8)~6.0×10~(-5)mol/L范围内与峰电流呈良好的线性关系;Pb~(2+)和Cd~(2+)的检出限分别为1.0×10~(-9) mol/L和5.0×10~(-8)mol/L。实验方法用于矿石中铅和镉的测定,结果的相对标准偏差(RSD,n=6)为2.9%~4.4%;并与原子吸收光谱法对比,测定结果基本一致。     

YP_5O_(14):Ho~(3+)、Er~(3+)、Tm~(3+)晶体的发光性质

本文用水热法合成了YP_5O_(14):Ho~(3+)、Er~(3+)、Tm~(3+)晶体,最大线度为49mm。测定了晶体的紫外可见吸收,激发和荧光光谱。观察到Ho~(3+)离子的~3K_7,Er~(3+)离子的~4G_(11/2)和Tm~(3+)离子的~1D_2能级有强的叠加吸收。用380nm激发,Ho~(3+)离子的~5S_2和Er~(3+)离子的~4S_(3/2)能级绿色荧光(550nm)发射较强,可望是一种绿色发光材料。值得注意的是引入Tm~(3+)离子会强化绿色发射。本文还讨论了Ho~(3+)—Er~(3+)离子间的敏化及Tm~(3+)→Ho~(3+),Er~(3+)离子的能量转移。     

M_2YSbO_6:RE~(3+)的合成、组成、结构及发光性能的研究(M=Ba、Ca;RE~(3+)=Sm、Dy、Ho、Er、Tm)

本文首次较系统地研究了稀土离子Sm~(3+)、Dy~(3+)、Ho~(3+),Er~(3+)、Tm~(3+)在具有不同结构的M_2YSbO_6(M=Ba、Ca)中的发光性能。合理地确定了各种谱项及跃迁。发现稀土离子的发光强烈地依赖于复合氧化物的晶体结构及其掺杂浓度。浓度猝灭是由于稀土激活离子对之间交叉驰豫无辐射跃迁所致。从实验上,确定了某些稀土离子发光的最佳浓度。结果表明Ca_2YSbO_6对Sm~(3+)、Dy~(3+)、Ho~(3+)、Er~(3+)是一个有效的基质并对激活离子具有敏化作用。发现重稀土激活离子Dy~(3+)黄光发射强度和兰光发射强度之比R随Dy~(3+)浓度的增加发生规律性的变化。并解释了其原因。     

Study of Adsorption Properties and Enriching RE on Clay Minerals by Ouantum Chemical Calculation

The order of adsorbability of three kinds of clay minerals and their selectivity of adsorption tocommon cations and RE ions have been studied by quantum chemical calculation.They are as follows:montmorilionite>halloysite>kaolinite,RE~(3+)>Al~(3+)>Ca~(2+)>Mg~(2+)>K~+>NH_4~+>Na~+,Sc~(3+)>La~(3+)>Ce~(3+)>Pr~(3+)>Nd~(3+)>Sm~(3+)>Eu~(3+)>Gd~(3+)>Tb~(3+)>Dy~(3+)>Ho~(3+)>Y~(3+)>Er~(3+)>Tm~(3+)>Yb~(3+)>Lu~(3+).Based onthese orders,the facts that RE is preferentially adsorbed in weathered residual type of clay mineral and lightRE and heavy RE are enriched at the upper layer and at the lower layer respectively in ore body have beenexplained.     

稀土隔室配合物——(Ⅱ)稀土-N、N′-二(3—醛基水扬酸)二乙基三胺配合物的合成及表征

用稀土硝酸盐与N、N′-二(3—醛基水扬酸)二乙基三胺(H_4L)在甲醇介质中反应,合成了9种新的固态配合物RE(H_2L)NO_3·nH_2O,(RE~(3+)=Y~(3+)、Pr~(3+)、Sm~(3+)、Eu~(3+)、Gd~(3+)、Tb~(3+)、Dy~(3+)、Ho~(3+)、Er~(3+),n=0～4不等);用元素分析、红外、紫外及热分析鉴定了所有配合物,从而推测配合物中可能RE~(3+)在O_2O_2室,—COO~-单齿配位,NO_3~-双齿配位     

铽Ⅲ-均苯四甲酸-对苯二甲酸多核体系的荧光增强及其应用

研究表明,在铽Ⅲ-均苯四甲酸(PMA)-对苯二甲酸(TPA)体系中加入一定量三苯基氧化膦(TPPO)能使体系荧光强度增大约一个数量级,稀土离子La3+,Gd3+,Y3+与Tb3+-PMA-TPA-TPPO形成的多核发光体系,具有很强的发光效果,据此建立了测定稀土样品中痕量铽的新方法,并且优化了最佳反应条件。方法线性范围为8.0×10-9~2.0×10-6mol/L,检出限为6.0×10-11mol/L,用于人工合成稀土混合物样品的分析,结果满意。     

双冠醚PVC膜铷离子选择电极的研制

用冠醚类为中性载体制作铷离子选择电极的报道国外很少,国内尚未见有文献报道.本文以新合成的双[2′:3′,9′:10′-2苯并-16-冠-5)-6-基]-2,6-吡啶二甲酸酯为中性载体,制作碳棒涂膜式铷离子选择电极.电极对铷离子的线性响应范围为4.00×10~(-5)～1.00×10~(-1)mol/L;检出下限为2.45×10~(-5)mol/L;(?)应斜率为63.5mV;对Li~+,Na~+,K~+,Cs~+,NH_4~+,Mg~(2+),Ca~(2+),Ba~(2+)的选择性系数分别为4.9×10~     

还原-离子交换法制取高纯氧化铕

在本研究中,应用联用的还原-沉淀和还原-离子交换法,采用EDTA作洗脱剂,进行了Y~(3+)、Gd~(3+)和其他稀土离子与Eu~(3+)分离的研究。微量杂质,尤其是Gd_2O_3和Y_2O_3与Eu_2O_3难以分离。选择EDTA作离子交换过程的洗脱剂,是因为复杂化合物Eu~(2+)/EDTA和三价稀土离子/EDTA的稳定常数差别很大。     

Nd~(3+)/Yb~(3+) co-doped mid-infrared luminescence fluorobromide glass with energy transfer and zero-thermal-quenching IR emission

Nd~(3+)/Yb~(3+) co-doped fluorobromide glass samples were prepared by melt quenching.The mid-infrared(MIR) luminescence of the Nd~(3+)/Yb~(3+) co-doped fluorobromide glass was investigated by Br-doping reduces the phonon state density of the matrix.The 3.9 μm MIR luminescence of the samples excited at 793 and 980 nm pump excitation was investigated in detail.There is an effective mutual energy transfer process between Nd~(3+) and Yb~(3+).It is proved under 793 nm excitation that the luminescence of Nd~(3+)at 3.9 μm is reduced by effective energy transfer from,Nd~(3+):~2 H_(11/2)→Yb~(3+):~2 F_(5/2),At the same time,it is proved that the effective energy transfer from Yb~(3+):~2 F_(5/2)→Nd~(3+):2 H_(11/2) under the excitation of 980 nm enhances the luminescence of Nd~(3+) at 3.9 μm.In addition,it is found that the samples still have good infrared(IR) luminescent properties when the temperature changes.The emission cross-sectional area and the absorption cross-sectional area are σ_(em)(3.87 × 10~(-20) cm~2) and σ_(abs)(4.25×10~(-20) cm~2).The fluorescence decay characteristics of the sample at 3.9 μm at the ~2 H_(11/2) level were investigated and the fluorescence lifetime was calculated.The gain performance of the sample was calculated and analyzed,which can reach 4.25 × 10~(-20) cm~2.Those results prove that Nd~(3+)/Yb~(3+)co-doped fluorobromide glass is the potential mid-infrared laser gain material.     

Er3+/Yb3+/Li+/Zn2+: Gd2(MoO4)3 upconverting nanophosphors in optical thermometry

Er~(3+)-Yb~(3+)-Li~+:Gd_2(MoO_4)_3 and Er~(3+)-Yb~(3+)-Zn~(2+):Gd_2(MoO_4)_3 nanophosphors, synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse reflectance, photoluminescence, photometric and decay time analysis. The enhancement of about～28, ～149 and ～351 times in the green upconversion emission band is observed for the optimized Er~(3+)-Yb~(3+),Er~(3+)-Yb~(3+)-Li~+ and Er~(3+)-Yb~(3+)-Zn~(2+):Gd_2(MoO_4)_3 nanophosphors in comparison to the singly Er~(3+) doped nanophosphors. The electric dipole-dipole interaction is found to be responsible for the concentration quenching. The temperature dependent behaviour of the two green thermally coupled levels of the Er~(3+) ions based on the fluorescence intensity ratio technique was studied. The maximum sensor sensitivity ～38.7 × 10~(-3) K~(-1) at 473 K for optimized Er~(3+)-Yb~(3+)-Zn~(2+) codoped Gd_2(MoO_4)_3 nanophosphors is reported with maximum population redistribution ability～88% among the ~2H_(11/2) and ~4S_(3/2) levels.     

激光晶体YAG:Er中的浓度效应

本文讨论了激光晶体YAG:Er中Er~(3+)浓度效应所引起的晶体结构畸变,Er~(3+)离子高激发态(~4S_(3/2),~4F_(9/2)和~2H_(11/2)能级)的发光与浓度猝灭,~4I_(11/2)→I_(13/2)自饱和跃迁和激光波长红移的变化规律。     

Energy transfer and cross-relaxation induced multicolor upconversion emissions in Er~(3+)/Tm~(3+)/Yb~(3+) doped double perovskite La_2ZnTiO_6 phosphors

Investigation on the bright and stable upconversion(UC) phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er~(3+),Tm~(3+)and Yb~(3+) concentrations in Er~(3+)singly,Er~(3+)-Tm~(3+)-Yb~(3+)co-and tri-doped double perovskite La_2 ZnTiO_6(LZT) phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at "first biological windo w" is collected in Tm~(3+)-Yb~(3+)co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels(~2 H_(11/2)/~4S_(3/2)) of Er~(3+) ions were analyzed from 298 to 573 K of LZT:0.15 Er~(3+)/0.10 Yb~(3+)phosphor,demonstrating that the maximal sensitivity value is about56×10-4 K~(1-) at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.     

单扫描示波极谱法测定金

河南师大周漱萍教授等提出:在pH3的KCl-甲酸-甲酸钠溶液中金和茜素紫在-0.79伏有还原峰。峰高与金浓度有线性关系。用0.1mol/L KCl-0.04 mol/l甲酸-甲酸钠,茜素紫为5.0×10~(-6)mol/l的底液时、测定金的范围为1.0×10~(-7)—5×10~(-6)mol/l;茜素紫为2.5×10~(-5)mol/l时、测金范围为2.5×10~(-6)—1.0×10~(-5)mol/l。大量Zn、Mg、Mn~(2+)、Co、Cu、Ni、Al、Ag、Cd不干扰。40倍Te~(4+)、Ge~(4+),20倍In,8倍Pb等也不干扰。大量碱、碱土金属、常见阴离子不干扰。氧化性阴离子NO_2~(-1)、BrO_3~(-1),     

Enhanced afterglow performance of CaAl_2O_4:Eu~(2+),Nd~(3+) phosphors by co-doping Gd~(3+)

In order to effectively improve the afterglow properties of CaAl_2 O_4:Eu~(2+),Nd~(3+) phosphors,a series of Ca_(0.982-x)Al_2 O_4:0.012 Eu~(2+),0.006 Nd~(3+),xGd~(3+)(x=0,0.012,0.024,0.036,0.048,0.060 mol) phosphors were prepared by a high-temperature solid-phase approach.Crystalline composition and microstructure were characterized by XRD,TEM,HRTEM,and XPS,luminescence properties were systematically analyzed by fluorescence spectra,afterglow decay curves and TL glow curve.Results show that all of Ca_(0.982-x)Al_2 O_4:0.012 Eu~(2+),0.006 Nd~(3+),xGd~(3+)phosphors belong to monoclinic CaAl_2 O_4,without other cystalline phase.The blue emission at 442 nm is observed,which is assigned to the 4 f~65 d→4 f~7 transition of Eu~(2+) ions.Doping with appropriate amount of Gd~(3+) ions(x=0.036 mol) significantly improves the afterglow properties of phosphors,but the excessive doping of Gd~(3+) induces the fluorescent quenching.The doping of moderate Gd3+changes the traps states,the trap depth varies from 0.598 to 0.644 eV and the trap concentration is also greatly improved,thus significantly improving afterglow performance.     

Er~(3+)/Yb~(3+)掺杂NaY(MoO_4)_2荧光粉的制备及其上转换发光性能研究

采用高温固相法合成了一系列Er~(3+)单掺和Er~(3+)/Yb~(3+)共掺NaY(MoO_4)_2荧光粉样品。通过X射线衍射仪、扫描电子显微镜、激光粒度仪和荧光光谱仪分别对样品的相纯度、微观形貌、粒径分布和上转换发光性能进行了表征。在980 nm激光激发下,Er~(3+)单掺和Er~(3+)/Yb~(3+)共掺样品的发射光谱中均能观测到中心波长位于536 nm、560 nm的上转换绿光发射和位于660 nm的红光发射,分别归因于Er~(3+)的~2H~(11/2)→~4I_(15/2)、~4S_(3/2)→~4I_(15/2)和~4F_(9/2)→4I_(15/2)能级跃迁。在Er~(3+)单掺体系中共掺Yb~(3+),可以轻松实现由上转换绿光到红光的转变。NaY_(1-x-y)(MoO_4)_2∶x Er~(3+),y Yb~(3+)样品中最优的Er~(3+)/Yb~(3+)掺杂浓度和最佳的烧结温度为x=0.04、y=0.5、T=850℃。基于泵浦依赖和能级图,在Er~(3+)单掺和Er~(3+)/Yb~(3+)共掺体系上转换发光过程中所涉及的能量转移机制被详细讨论。