The Ionic Strength Dependence of Rare Earth and Yttrium Fluoride Complexation at 25°C

Formation constants for the complexation of yttrium and rare earth elements(YREE) by fluoride ions have been measured at 25°C. The ionic strength ()dependence of YREE formation constants in perchlorate solution for ionicstrengths between 0 and 6 molar can be expressed aslog_F1 (M, ) =log_F1 ^o (M) –3.066 ^0.5/(1 + 1.769 ^0.5)+ 0.1645 where log_F1 ^o(M) represents MF²⁺formation constants at zero ionic strength.The log_F1 ^o(M) results obtained inthis work are: Y(4.46), La(3.62), Ce(3.86),Pr(3.84), Nd(3.82), Sm(4.15), Eu(4.27), Gd(4.24), Tb(4.37), Dy(4.39), Ho(4.28),Er(4.27), Tm(4.29), Yb(4.39), and Lu(4.25). The relative magnitudes of YREEformation constants are independent of ionic strength. The pattern oflog_F1(M,),formation constants obtained in this work [relative magnitudes oflog_F1 ^o (M)],exhibits a shallow minimum between Dy and Yb. In contrast to the smoothpattern of stability constants expected if fluoride were to interact with bare ions(with monotonically decreasing crystal radii between La and Lu), theinteractionof F^– with YREEs, which have extensive hydration spheres[M(H₂O)_8–9 ³⁺] resultsin a relatively complex pattern of lanthanide stability constants. The fluoridecomplexation behavior of yttrium differs distinctly from the behavior of any rareearth. Although the crystal radius of Y3;pl is approximately equalto that of Ho³⁺,differences in the covalence/ionicity of Y³⁺ relative to therare earths leads to aYF²⁺ stability constant that exceeds that of any rare earthelement (REE).     

ICP-MS同时测定植物性食品中稀土元素的方法研究

建立了植物性食品中16种稀土杂质(Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu)元素的电感耦合等离子体质谱(ICP-MS)的分析方法.考察了基体效应及质谱干扰,应用In内标,有效地补偿基体效应所引起的测量偏差,建立修正公式校正质谱干扰.对照分析了参考标准物质.对所测定元素,校正曲线的相关系数为＞0.9990,方法的检出限低于2.2 pg/g(Sc为95pg/g),回收率为92%～106%,RSD优于3.2%(n=7).     

Adsorption of fluoride from aqueous solution by acid treated spent bleaching earth

Acid treated spent bleaching earth was studied to assess its capacity for the adsorption of fluoride from aqueous solutions. Adsorption isotherms have been modeled by Langmuir and Freundlich equations and isotherm constants for both isotherms were calculated. The effect of the adsorbent concentration on the adsorption was studied. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH-value and a better understanding of the adsorption mechanism. It has been found that maximum adsorption of fluoride from aqueous solutions takes place at pH-value of 3.5. Second-order equation was used to describe the adsorption rate of fluoride and adsorption rate constant was calculated. Intraparticle and mass transfer coefficients were calculated. The influence of addition of the anions on the adsorption of fluoride was also studied to simulate industrial waste waters and the addition of anions decreased the adsorption of fluoride on the acid treated spent bleaching earth (SBE).     

两性离子交换纤维柱富集-电感耦合等离子体原子发射光谱法测定水样中稀土元素

提出了两性离子交换纤维柱吸附富集镧、钕、铕、钆、铒和镱,1.5mol·L~(-1)硝酸溶液作洗脱剂,电感耦合等离子体原子发射光谱法测定水样中上述痕量稀土元素含量的方法。在优化的试验条件下,两性离子交换纤维柱对镧、钕、铕、钆、铒和镱的吸附容量分别为7.32,7.61,8.04,7.95,9.12,8.49 mg·g~(-1);镧、钕、铕、钆、铒和镱的检出限(3S/N)分别为0.032,0.068,0.033,0.053,0.045,0.019μg(-1)。方法用于水样中镧、钕、铕、钆、铒和镱含量的测定,回收率在90.0%～101.0%之间,相对标准偏差(n=5)在1.7%～5.4%之间。     

超级微波消解-电感耦合等离子体发射光谱(ICP-OES)法测稀土废料中15种稀土元素

稀土废料已成为战略性物质且不可再生,针对其回收利用已成为一个重要的发展方向,开发稀土废料中稀土元素的快速准确定量的方法至关重要。超级微波消解法解决了湿法消解法的元素损失、易引入污染的问题。本研究采用超级微波消解法采用硝酸-盐酸-过氧化氢及硝酸-盐酸-过氧化氢-氟硼酸消解体系和使用湿法消解法采用硝酸-盐酸-过氧化氢消解体系进行条件实验,利用电感耦合等离子体发射光谱法进行分析,通过比较消解效果、检出限、精密度及加标回收率,确定使用超级微波消解法采用硝酸-盐酸-过氧化氢-氟硼酸(4.5mLHCl-1.5mLHNO3-0.5mL H2O2-4mL HBF4)消解体系,并优化了消解条件。实验结果表明,使用超级微波消解法采用硝酸-盐酸-过氧化氢-氟硼酸消解体系可以较好的完成对稀土废料的处理,15种元素的检出限为0.120~6.62 mg/kg,15种元素测定结果相对标准偏差（RSD,n=7）均小于1.7%,加标回收率在97.4%~102%之间,方法准确度及精密度均可以满足多种元素分析测试要求,该方法可以实现稀土废料中稀土元素的准确测定。     

Stability constant for the lanthanide fluoride complexes in aqueous solution at 25°C

Stability constants for the mono- and difluoride complexes of fourteen lanthanides in aqueous solution 25°C and an ionic strenght of 0.5 M have been measured using the newly developed Orion expandable and digital ion analyzer and their fluoride specific ion electrode. A simplified potentiometric procedure was employed to measure the stability constant for the monofluoride complex and this value was used to compute analytically the stability constant for the difluoride complex in separate experiments. In the case of heavy lanthanides a linear regression method was also used to compute simultaneously the stability constant for both complexes. The stability constant for the monofluoride complexes may be arranged into four groups that shows the tetrad effect with maxima at Pr, Sm, Dy and Er. There is a gradual but unsystematic increase in the stability constant for the monofluoride complex with atomic number of the lanthanides.     

茶叶中稀土元素的萃取分离-ICP-AES法测定

采用1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮(PMBP)苯溶液萃取分离-ICP-AES法同时测定茶叶中15种稀土元素,消除了基体的干扰,并对样品前处理方法、萃取分离条件进行了考查.方法回收率为: 92.3%～112%,相对标准偏差＜2.5%.在最佳工作条件下,测定了茶叶标准物质(GBW07605)中稀土元素,结果与标准值吻合.     

化学-X-射线荧光光谱法测定地质样品中的痕量稀土元素

本文采用对氯偶氮氯膦(CPA—PCL)为螯合剂,VS-Ⅱ型强碱性阴离子交换纤维为载体,以先吸着后螯合方式对稀土元素与基体元素进行分离与富集,并经酸溶制备成溶液,采用溶液进样法直接由X射线荧光光谱法(XRFS)测定15个稀土元素。该法具有简便、整合剂用量少、基体效应小的特点,精密度、准确度及检测限均能满足地质样品分析要求,取得满意结果。     

电感耦合等离子体发射光谱测定稀土铝合金中稀土和非稀土元素

本工作用 ICP-AES 法测定稀土-6063变形铝合金中 La、Ce、Pr、Nd、Sm、Gd、Fe、Mg、Ti、Zn,Cu 和 Mn,本方法不用化学分离,可一次同时测定这些元素,并做了 ICP光源参数、基体量变化、酸度(HCl)变化、稀土总量变化、共存元素 Fe 和 Mg 量的变化对被测元素的影响。本方法速度快、准确度高(除 Cu 稍差)。回收率91.0～110.0%,相对标准偏差±1.4～8.0%。     

铁及稀土元素在DOWEX 1-X8阴离子交换树脂上分配系数的测定及其应用于原子发射光谱法测定钢中稀土元素含量

对铁和稀土元素在DOWEX 1-X8阴离子交换树脂上于不同浓度的盐酸和硝酸介质中的分配系数(K_d)进行了研究,试验结果表明:在6～9 mol·L~(-1)盐酸介质中Fe~(3+)的K_d10~3,即强吸附于DOWEX 1-X8阴离子交换树脂,而稀土元素在DOWEX 1-X8阴离子交换树脂的K_d≤10,即不吸附于树脂;而在浓度低于2 mol·L~(-1)的硝酸介质中,Fe~(3+)的K_d6.4,即不吸附于树脂上,故选用1.6 mol·L~(-1)硝酸溶液将吸附于柱上的Fe~(3+)洗脱下来。在此基础上提出了一种阴离子交换树脂分离电感耦合等离子体原子发射光谱法测定洁净钢中微量稀土元素含量的方法。该方法用于测定产于日本及韩国的洁净钢样品,测得回收率在87.7%～118.3%之间,相对标准偏差(n=6)小于23%。     

Determination of rare earth elements in USGS rock standards by isotope dilution mass spectrometry and comparison with neutron activation and inductively coupled plasma atomic emission spectrometry

Rare earth element (REE) concentrations in United States Geological Survey (USGS) rock standards AGV-1, GSP-1, G-2 and PCC-1 were determined by isotope dilution mass spectrometry (IDMS), neutron activation and inductively coupled argon plasma atomic emission spectrometric techniques. The procedure involved acid digestion of samples in PTFE pressure bombs and group separation of REEs by an ion-exchange method. For IDMS an additional separation step using α-hydroxyisobutyric acid as an eluent was used in a cation-exchange column to split the REEs into subgroups. Comparison of the results with literature values showed that the IDMS values are the most precise and accurate. However, the precisions and the accuracies of the other techniques are acceptable.     

稀土在天然植物铁芒萁体内结合形式的光谱学研究

利用ICP-MS研究了江西赣州沙河稀土矿区天然植物铁芒萁体内稀土元素的分布规律,发现叶片和叶绿素中Ce含量最高,分别占其稀土总量的79.43%和66.71%。铁芒萁叶片光系统（Ⅱ）（PSⅡ）荧光发射峰较普通植物紫移15-25nm,且峰强是PSⅠ的6.79倍,表明PSⅡ活性提高。由于铁芒萁叶绿素中稀土叶绿素含量较低（约占叶绿素总量的0.1%）,测定的UV-Vis和FTIR光谱特征与标样叶绿素a相似,未能反映出稀土的配位信息。而利用EXAFS则表征出在铁芒萁叶绿素中Ce为八配位,Ce-N键长为0.252nm,推测Ce是与两个卟啉环配位的,为一双层结构。     

光谱复杂的稀土基体中稀土杂质ICP光谱测定的一些问题

ICP激发光源以其独特的功能使ICP/AES技术在稀土分析中的应用日益广泛,在一定程度上取代了经典的直流电弧光谱法,但应指出,由于常规雾化器的低雾化效率(≤5％)和试样的高倍稀释,ICP/AES技术的实际检测能力的改善并不明显,本文用ICP光谱法测定了     

Dissolution of copper oxide by the ethanolamine and ammonium fluoride in aqueous solution

Dissolution properties of copper oxide in aqueous solutions containing ethanolamine and/or ammonium fluoride have been evaluated at various pH ranges. The dissolution rate was strongly affected by the pH of the solution. The solution of ammonium fluoride showed good properties for the dissolution of copper oxide in the range of acidic conditions, whereas the solution containing ethanolamine showed a dissolution property within the basic condition. A mixture solution of ethanolamine and ammonium fluoride displayed enhanced dissolution property of copper oxide at acidic and basic conditions only. An expected synergy effect on the dissolution rate and selectivity could not be produced through a mixture of ethanolamine and ammonium fluoride in an aqueous solution. Copyright © 2011 John Wiley & Sons, Ltd.     

Rare earth elements determined in Antarctic ice by inductively coupled plasma--time of flight, quadrupole and sector field-mass spectrometry: An inter-comparison study

Inductively coupled plasma mass spectrometry (ICP-MS) is a suitable tool for multi-element analysis at low concentration levels. Rare earth element (REE) determinations in standard reference materials and small volumes of molten ice core samples from Antarctica have been performed with an ICP-time of flight-MS (ICP-TOF-MS) system. Recovery rates for REE in e.g. SPS-SW1 amounted to ∼103%, and the relative standard deviations were 3.4% for replicate analysis at REE concentrations in the lower ng L⁻¹ range. Analyses of REE concentrations in Antarctic ice core samples showed that the ICP-TOF-MS technique meets the demands of restricted sample mass. The data obtained are in good agreement with ICP-Quadrupole-MS (ICP-Q-MS) and ICP-Sector Field-MS (ICP-SF-MS) results. The ICP-TOF-MS system determines accurately and precisely REE concentrations exceeding 5 ng L⁻¹ while between 0.5 and 5 ng L⁻¹ accuracy and precision are element dependent.     

电感耦合等离子体质谱测定中草药中痕量稀土元素的研究

本文报道了微波消解／ICP－MS测定中草药中痕量稀土元素的新方法。在优化实验条件下，方法的检出限为0.71-15.2pg/mL，相对标准偏差为0.80%-3.3%，加标回收率为87.4%-106%。该法具有操作简便、快速、灵敏度高、准确度好和多元素同时测定等优点。     

Solubilizing sodium fluoride in acetonitrile: synthesis, molecular structure, and complexation behavior of bis(organostannyl)methyl-substituted crown ethers

The synthesis of the crown-ether-substituted bis(organostannyl)methanes Ph(3)SnCH(2)Sn(Ph(2))-CH(2)-[16]crown-5 (1) and Ph(2)ISnCH(2)Sn(I)(Ph)-CH(2)-[16]crown-5 (2) is reported. Both compounds have been characterized by elemental analyses, (1)H, (13)C, (19)F, and (119)Sn NMR spectroscopy, and in the case of compound 2 also by electrospray ionization mass spectrometry. Single-crystal X-ray diffraction analysis revealed for the aqua complex 2.H(2)O trigonal-bipyramidal-configured tin atoms with intramolecular Sn(1)-O(1) and Sn(2)-O(1W) distances of 2.555(2) and 2.440(3) A, respectively. The water molecule is trapped in a sandwich-like fashion between the crown ether oxygen atoms O(2) and O(4) and the Sn(2) atom. NMR spectroscopy unambiguously proved the ability of compound 2 in acetonitrile to overcome the high lattice energy of sodium fluoride and to complex the latter under charge separation.     

弱酸阳离子交换纤维柱富集-电感耦合等离子体原子发射光谱法测定水样中的稀土

提出了聚丙烯基弱酸性阳离子交换纤维柱富集痕量稀土元素,1.0 mol/L HCl溶液作为洗脱剂,电感耦合等离子体原子发射光谱法测定水样中稀土元素的方法。在优化的试验条件下,弱酸性阳离子交换纤维对La、Nd、Eu、Gd、Er和Yb的吸附容量分别为86.5,98.2,98.7,99.2,84.9,91.5 mg/g;La、...