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1.
The transport of Dy(Ⅲ) through a dispersion supported liquid membrane (DSLM) consisting of polyvinylidene fluoride mem-brane (PVDF) as the liquid membrane support and dispersion solution including HC1 solution as the stripping solution and 2-ethyl hexyl phosphonic aeid-mono-2-ethyl hexyl ester (PC-88A) dissolved in kerosene as the membrane solution, was studied. The effects of pH value, initial concentration of Dy(Ⅲ) and different ionic strength in the feed phase, volume ratio of membrane solution and stripping solution, con-centration of HC1 solution, concentration of carder, different stripping agents in the dispersion phase on transport of Dy(Ⅲ) were also inves-tigated, respectively. As a result, when the concentration of HCI solution was 4.0 mol/L, concentration of PC-88A was 0.10 mol/L, and vol-ume ratio of membrane solution and stripping solution was 40:20 in the dispersion phase, and pH value was 5.0 in the feed phase, the trans-port effect of Dy(Ⅲ) was the best. Ionic strength had no obvious effect on transport of Dy(Ⅲ). Under the optimum condition studied, when initial concentration of Dy(Ⅲ) was 0.8×10-4 mol/L, the transport rate of Dy(Ⅲ) was up to 96.2% during the transport time of 95 min. The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry. The diffusion coefficient of Dy(Ⅲ) in the membrane and the thickness of diffusion layer between feed phase and membrane phase were obtained and the values were 1.99×10-7 m2/s and 15.97 μm, respectively. The results were in good agreement with experimental results.  相似文献   

2.
The conventional rare earth solvent extraction equipments have many problems such as long mixing time, low processing capacity, large factory area occupation, high energy consumption and so on. In order to solve the problems, many types of equipments were brought out. In this work, studies were carried out on the La(III) extraction process with 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (EHEHPA) by membrane dispersion micro-extractor. Equilibrium studies showed that the initial aqueous pH value 4.15 with the saponification rate 40%was the optimal operation condition. The effects of membrane dispersion micro-extractor operational conditions such as dispersion mode, bulk flow rate and organic phase flow rate on the extraction efficiency were studied. The results showed that when the organic solution was the dispersed phase, the extraction efficiency was higher than that of others. Increasing bulk flow ratio could enhance the extraction efficiency greatly. When the ratio of organic phase flow rate to that of aque-ous phase was 80:80, the extraction efficiency was over 95%. The effect of stripping phase acidity on the La(III) recovery was studied. The results showed that when the stripping phase pH was 2.0, organic phase flow rate to stripping phase flow rate was 20:80;the re-covery efficiency of La(III) can reach 82%.  相似文献   

3.
The research on electroluminescence based on europium(III) complexes has come to an important phase. This article reviewed the progresses in photoluminescence and electroluminescence of Eu(III) complexes in recent years from the views of the design of Eu(III) complexes and optimization of device structures, and discussed some important factors influencing electroluminescence performance. The problems existing in the practical application such as the volatility and thermal stability of Eu(III) complexes in this area were discussed, and the possible corresponding solutions were briefly prospected.  相似文献   

4.
The thermokinetics of liquid-liquid reaction of dysprosium nitrate with histidine were studied using a microcalorimeter. On the basis of experimental and calculated results, threethermodynamic parameters (the activation enthalpy, the activation entropy and the activation free enegy),the rate constant, three kinetic parameters (the activation energy, the pre-exponential constant and the reaction order) wereobtained. On the basis of thermodynamics and kinetics, the for marion reaction of the complex was discussed.  相似文献   

5.
The eutectoid decomposition reaction that occurred in RECo5 phases ( RE=Dy and Gd ) at low temperature was discussed and confirmed by X-ray powder diffraction (XRD), differential thermal analysis, and scanning electron microscopy. The decomposition temperature of the GdCo5 and DyCo5 were identified as 805.8 and 900℃, respectively. The GdCo5 and DyCo5 phases could not be found in the isothermal section of Gd-Dy-Co ternary system at 800 K. Reasons for the absence of the RE2Co7 phase in the XRD patterns were discussed in detail.  相似文献   

6.
The Eu(III) separation in supported dispersion liquid membrane (SDLM),with polyvinylidene fluoride membrane (PVDF) as the support and dispersion solution containing HNO3 solution as the stripping solution and Di(2-ethylhexyl) phosphoric acid (D2EHPA) dis-solved in kerosene as the membrane solution,was studied.The effects of pH value,initial concentration of Eu(III) and different ionic strengths in the feed phase,volume ratio of membrane solution and stripping solution,concentration of HNO3 solution,concentration of carrier,different stripping agents in the dispersion phase on the separation of Eu(III) were also investigated,respectively.As a result,the optimum separation conditions of Eu(III) were obtained as the concentration of HNO3 solution was 4.00 mol/L,concentration of D2EHPA was 0.160 mol/L,and volume ratio of membrane solution to stripping solution was 30:30 in the dispersion phase,and pH value was 5.00 in the feed phase.Ionic strength had no obvious effect on the separation of Eu(III).Under the optimum conditions studied,when initial concentration of Eu(III) was 1.00×10–4 mol/L,the separation rate of Eu(III) was up to 94.2% during the separation period of 35 min.The kinetic equation was developed in terms of the law of mass diffusion and the theory of interface chemistry.The results were in good agreement with the literature data.  相似文献   

7.
A novel rare earth complex Eu(TTA)2(N-HPA)Phen (TTA = thenoyltrifluoroacetone, N-HPA = N-phenylanthranilic acid, and phen = 1,10-phenathroline ), which contains three different ligands, was synthesized. The Eu complex was blended with poly N-vinylcarbazole (PVK) in different weight ratios and spin coated into films. The luminescence properties of films were investigated and energy transfer between PVK and the complex was discussed. Multilayer structural devices consisting of ITO/PVK: Eu (TTA)2 (N-HPA) phen/BCP/Alq3/Al were fabricated with PVK : Eu (TTA)2(N-HPA) as light-emitting layer. Increasing the concentration of Eu in the PVK thin film would inhibit the emission of PVK to different degrees. Finally, the pure red luminescence of europium( Ⅲ ) was observed when the doping weight ratio was approximately 1 : 5, which indicated an effective energy transfer from PVK to rare earth complex.  相似文献   

8.
The complex of [Tb(2-IBA)3(H2O)2]n (2-IBA=2-iodobenzoate)was prepared by solvent method from TbCl3·6H2O and 2-iodobenzoic acid. The crystal structure was determined with X-ray single-crystal diffraction. The X-ray diffraction analysis indicated that the title complex crystallized in triclinic crystal system and Pī space group. The Tb3+ ion was coordinated by six oxygen atoms from five 2-IBA ligands and two oxygen atoms from two water molecules, giving a distorted square-antiprism polyhedral geometry. The carboxyl groups were bonded to the Tb3+ ions with bidentate-bridging and bidentate-chelating coordination modes. The adjacent Tb3+ ions were linked by two bidentate-bridging 2-IBA ligands, forming 1-D chain structure. The fluorescence spectrum of the complex showed four main peaks at 489, 543, 587, and 618 nm, corresponding to 5D47FJ (J=6?3) transition emissions of the Tb3+ ion, respectively.  相似文献   

9.
本文研究了用MOC100TD新萃取剂在氯化钠水溶液中萃取La(Ⅲ)与Ce(Ⅲ)。结果表明:分相时间很快,使用正辛烷为稀释剂比用煤油效果好;在低pH值下,对Ce(Ⅲ)的萃取能力大于对La(Ⅲ)的萃取能力,因此,有可能使La(Ⅲ)与Ce(Ⅲ)得到萃取分离。确定了萃取时生成的萃合物为MeR3。求取出La的logK(ex)=-16.03±0.4,Ce的logK(ex)=-15.94±0.4。可认为MOCT100TD是比Lix70、Kdex100、SME529萃取La(Ⅲ)、Ce(Ⅲ)更有效的萃取剂。  相似文献   

10.
Eu( Ⅲ ) can be utilized as an indirect electrochemical probe to investigate the interaction of bio-molecules such as DOPA and Dopamine with Ca( Ⅱ ) in vitro. The interaction of DOPA and Dopamine with Eu( Ⅲ )-Eu( Ⅱ ) redox pair was investigated by electrochemical techniques. Both the neurotransmitters are structurally related and undergo interaction with Eu (Ⅲ ). Eu ( Ⅲ ) coordinates with DOPA and Dopamine through five-member chelate tings via carboxylic oxygen and amino nitrogen. The electrode kinetic parameters viz, transfer coefficient (αna), diffusion coefficient (D), forward heterogeneous rate constant ( k^0 fh) were evaluated for Eu( Ⅲ )-DOPA/Eu( Ⅲ )-Dopamine. The results obtained were used to investigate the nature of interaction of Eu (Ⅲ) with muhi-donor biomolecules. The possible mechanism was also proposed.  相似文献   

11.
The photoluminescence of Dy^3 doped and Dy^3 , Ce3 codoped in Ba3La(BO3)3 were studied. The dependence of the charge-to-radius ratio (z/r) for RE^3 (RE=La,Ce), the Ce^3 , Dy^3 content on the emission intensity and the yellow to blue intensity ratio (Y/B) of Dy^3 were investigated too. The results obtained indicate that Ce^3 can sensitize the luminescence of Dy^3 .The optimum concentration of Dy^3 in Ba3La(BO3)3 is XDy=0.06. According to the dependence of the concentration of Dy^3 in Ba3La(BO3)3 under the excitation of 350 nm, it is confirmed that the mechanism of concentration selfquenching of Dy^3 4F9/2→6H15/2, ^6H13/2 transition is electric dipole-quadrupole interaction.  相似文献   

12.
The divalent state of Ln(Ⅲ) ions has attracted much interest because of their ability to serve isomorphously in many biological sys-tem of divalent Ca(II) ion. Therefore, present paper deals with the study of divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium. In present study, cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions. The cy-clic voltammetric technique showed two-step reduction process at cathode for both Ln(Ⅲ) ions under specified experimental conditions and chronopotentiometric method also showed two different transition times (). Looking to the shape of cyclic voltammogram we calculated het-erogeneous forward rate constant (K0fh, cm/s) and diffusion coefficient (D, cm2/s) for both ions, which suggested that sweep rate had great ef-fect on the shape of cyclic voltammogram of Eu(Ⅲ) and Nd(Ⅲ) ions. The result of chronopotentiometry also suggested that stable divalent states of Eu(Ⅲ) and Nd(III) ions existed with chronopotentiogram with two distinct transition times. The diffusion coefficients (D, cm2/s) were calculated from Sand equation. The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.  相似文献   

13.
利用Mn(Ⅲ)作氧化剂氧化一些有机物具有很高的选择性。Mn(Ⅲ)通常是由Mn(Ⅱ)阳极氧化制备,也可以通过焙烧二氧化锰矿得到。文章探讨了Mn(Ⅲ)氧化甲醇制甲醛的可行性,目的在于寻找利用软锰矿的新途径,并分析了反应的可能产物,确定出反应的最佳条件。结果表明,甲醇相对过量,甲醇与Mn(Ⅲ)的浓度比大于10∶1,在9mol/L的H2SO4溶液中,90℃以上温度有利于Mn(Ⅲ)氧化甲醇转变成甲醛。  相似文献   

14.
研究了以多孔聚偏氟乙烯为支撑体,N,N-二(1-甲基庚基)乙酰胺为膜载体,煤油为膜溶剂的支撑液膜体系中Mo(Ⅵ)的传输行为;考察了料液相pH、载体浓度、Mo(Ⅵ)浓度、反应温度、离子强度等因素对Mo(Ⅵ)传输的影响.结果表明,Mo(Ⅵ)支撑液膜体系传输的最佳传质条件为料液相pH为3.5~4.0,载体浓度为25%~30%,水相离子强度为0.3~0.6,反应温度为288~308K,迁移时间为90min时,Mo(Ⅵ)的迁移率可达99%以上.在最佳迁移条件下,可以实现W(Ⅵ)与Mo(Ⅵ)的有效分离.  相似文献   

15.
Magnetic Entropy Change of (Gd_(1-x)RE_x)_5Si_4(RE=Dy, Ho) Alloys  相似文献   

16.
17.
High resolution1Hmagicanglespinning(MAS)NMRspectroscopyisincreasinglybeingusedasause fultechniqueforinvestigatingthemetabolicstateof variousintacttissuesintheareasofdrugtoxicity[1,2]anddiseasediagnosis[3,4].Biologicaltissuesaresemi solidheterogeneouscomplexcontainingspecieswitha widerangeofmolecularweightssuchasproteins,lip ids,andlow molecularweightmetabolites[5].1HNMR spectraoftissuesufferfrommajorline broadeningcon tributionswhenacquiredbyconventionalsolution state NMRspectroscopybecau…  相似文献   

18.
本文对高含量As(Ⅲ、V)的萃取分离方法进行了研究。指出,在≥10.5mol/LHCl介质中用苯萃取,可使50mgAs(Ⅲ)定量分离(其萃取率达99.5%),共存的As(V)等不干扰。同时证明,向萃As(Ⅲ)后的液相中加过量的TiCl_3溶液,可使50mgAs(V)还原至As(Ⅲ),继用苯萃取分离,经水反萃取之后,均以碘量法完成测定。方法简便、快速,干扰少,对As(Ⅲ、V)的价态分析、具有广阔的应用前景。  相似文献   

19.
Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad- sorbent, La(IlI)-loaded bentonite/chitosan beads (La-BCB) was prepared for defluoridation from aqueous solution. The effects of various parameters such as dosage of La(III), pH, temperature, contact time, initial fluoride concentration and presence of co-existing anions were investigated to examine the defluoridation behavior. The maximum defluoridation capacity of La-BCB was 2.87 mg/g at pH 5, 30 ℃. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and Fourier transform infrared spectros- copy (FTIR) were employed to analyze the characteristics of La-BCB. The equilibrium fluoride adsorption data fitted well with both Langmuir and Freundlich isotherm models. The RL value revealed that the defluoridation process using La-BCB was favorable. The adsorption kinetics followed pseudo-second order kinetic as well as particle and intraparticle diffusion models. The presence of car- bonate and bicarbonate reduced defluoridation capacity of La-BCB while sulphate, nitrate and chloride showed slight effect. The ex- hausted La-BCB was regenerated using sodium hydroxide with only 17% loss. The reasonable defluoridation mechanism could be interpreted as adsorption and ion exchange.  相似文献   

20.
The pH dependent sorption of rare earth ions (La(Ⅲ), Ce(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Y(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), Gd(Ⅲ), Tb(Ⅲ), Dy(Ⅲ), Ho(Ⅲ), Er(Ⅲ), Lu(Ⅲ), and Yb(Ⅲ)) from HAC-NaAC buffer solution at 298 K by D152 resin containing -COOH function groups were presented. The sorption behaviors of D152 resin for Sm(Ⅲ) were discussed as an example. The effects of operational conditions such as pH, temperature, and contact time were studied. The statically saturated sorption capacity was 510 mg/g resin at pH 6.70 in HAc-NaAc medium at 298 K. The sorption behaviors obeyed the Freundlich isotherm. The capacity value for column study was obtained by graphical integration as 495 mg/g resin. Thomas model was applied to experimental data to predict the breakthrough curve and to determine the characteristic parameters of the column useful for process design.  相似文献   

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