CA-100萃取稀土及二价金属的热力学和动力学研究

该文系统研究了一种新型有机羧酸类萃取剂仲壬基苯氧基乙酸(CA-100)对稀土及其杂质的萃取热力学和动力学规律,并通过协同萃取、双溶剂萃取、加入络合剂等手段对CA-100萃取体系进行改善,为该萃取剂在工业上的应用打下基础,具体的研究内容如下:1.研究了CA-100对于稀土及Zn,Cd,Cu,Co,Ni,Mn,Mg等金属元素的萃取热力学规律,计算了金属间分离系数,获得了萃取平衡方程式,考察了反萃性能及稀释剂和甲庚醇的加入对萃取的影响.研究发现该萃取剂可用于Sc同其它稀土的分离及某些金属对的分离,在很多方面优于环烷酸体系.2.探讨了CA-100与—盐基磷(膦)酸类萃取剂对锌和镉的协同萃取,研究了协同萃取机理,确定了协萃配合物的组成.3.研究了在络合试剂的存在下CA-100萃取重稀土的行为及Y同重稀土的分离情况.4.用恒流层界面池研究了CA-100萃取Y,Yb,La的萃取动力学,考察了各因素对萃取速率的影响,获得了萃取速率方程,探讨了动力学机理.5.探讨了各种因素对CA-100界面活性的影响.6.在上述热力学和动力学研究基础上,进行了CA-100从混合稀土溶液中富集和纯化Sc的工艺模拟实验.

Separation of yttrium from heavy lanthanide by CA-100 using the complexing agent

The selective extraction of yttrium front heavy lanthanide by liquid-liquid extraction using CA-100 in the presence of the complexing agent, such as EDTA, DTPA, and HEDTA was investigated. The extraction of heavy lanthanide in the present of the complexing agent was Suppressed when compared to that of Y because of the masking effect, but the selective extraction of Y was enhanced. All complexing agents formed 1: 1 complex with rare earth elements (RE), and only free rare earth ions could take part in the extraction. The condition for separation was obtained by exploring the effects of the complexing agent concentration, the extractant concentration, pH and the equilibration time on the extraction of the heavy rare earth elements.

Selective separation of yttrium by CA-100 in the presence of a complexing agent

The selective separation of Y from yttrium solution containing small heavy rare earth (HRE) impurities (Ho, Er, Tm, Yb, Lu) by liquid-liquid extraction using CA-100 in the presence of a water-soluble complexing agent of ethylenediaminetetraacetic acid (EDTA) was experimentally studied at 298K. Experiments were carried Out in two feeds, Feed-I: [RE](f) = 4.94 x 10(-3) M, Y = 98.5%, HRE (Ho, Er, Tm, Yb, Lu) = 1.5%; Feed-II: [RE](f) = 4.94 x 10(-3) M, Y = 99.9%, HRE (Ho, Er, Tm, Yb, Lu) = 0.1%, as a function of equilibrium pH (pH(eq)), the concentration ratio of [EDTA]:[HRE impurities]. It was shown that the extraction of HRE in the presence of EDTA was suppressed when compared to that of Y because of the masking effect, while the selective extraction of Y was enhanced and the separation factors increased to maximum at appropriate condition for Feed-I: Y/Ho = 1.53, Y/Er = 3.09, Y/Tm = 5.61, Y/Yb = 12.04, Y/Lu = 27.51 at pH 4.37 and [EDTA]:[HRE impurities] = 4: 1, for Feed-II: Y/Ho = 1.32, Y/Er = 1.91, Y/Tm = 2.00, Y/Yb = 3.05, Y/Lu = 3.33 at pH 4.42 and [EDTA]: [HRE impurities] = 8:1. The separation and purification of Y by this method was discussed.

Synergistic extraction of zinc(II) with mixtures of CA-100 and cyanex 272

The extraction of zinc(II) from an aqueous chloride medium has been studied using mixtures of sec-nonylphenoxy acetic acid (CA-100) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272). The results demonstrate that zinc ion is extracted into heptane as ZnA(2).2HA with CA-100, ZnL2.2HL with Cyanex 272, and ZnA(2)L(2)H(2) with synergistic mixture. The equilibrium constants of the these species have been calculated and extraction mechanisms have been proposed. Thermodynamic parameters of the extraction process were determined by the temperature coefficient of extractability. The synergistic system enhances the extraction efficiency of zinc(II) and also improves the selectivity between zinc(II) and cadmium(II).

Kinetics and mechanism of Y(III) extraction with CA-100 using a constant interfacial cell with laminar flow

The Yttrium(III) extraction kinetics and mechanism with secnonylphonoxy acetic acid (CA-100) were investigated by a constant interfacial cell with laminar flow. The studies of interfacial tension and solubility of extractant and effects of the stirring rate, temperature, specific interfacial area and species concentration on the extraction rate showed that the extraction regime was dependent on the extraction conditions and the most probable reaction zone was at the liquid-liquid interface. The rate equation of extracting yttrium by CA-100 in heptane was Rf = k[Y3+]((a))[H(2)A(2)]((o))(0.88)[H+]((a))(-1.08).

Cyanex302及CA-12萃取稀土动力学的研究

随着萃取技术的不断发展，人们日益要求更加深入的了解萃取过程的机制及其动力学特性。以便有效地控制和强化萃取过程，提高萃取效率，或者利用萃取动力学的差异来实现某些分离嘴过程。尽管许多萃取过程进行得很快，但是人们也发现不少的金属鳌合物萃取体系，其萃取过程相当缓慢。因而这类体系的萃取机制和萃取动力学问题已日益引人注目。除此而外，在设计，放大或改进萃取设备时，研究和掌握有关萃取过程的动力学规律也有十分重要意义。在本文中主要对稀土萃取动力学进行了研究，得到主要结果如下：1．研究了硫代有机磷酸Cyan.ex302萃取饵的动力学。通过测定各种萃取条件对萃取速率的影响，获得了萃取速率方程，并讨论了萃取的控制过程。实验发现萃取剂中的杂质对萃取具有较大的加速作用，这对工业生产具有一定的实际意义。2.用两相滴定法测定了两种新合成的J梭酸萃取剂CA-12和CA-100的某些重要的物理常数。这将有助于深入研究它们的萃取性质及机理。3．用层流恒界面池研究了CA-12萃取La, Gd,Er, Yb和Y的动力学。考察了各种因素对萃取速率的影响，获得了它们的萃取速率方程，实验发现了它们的萃取控速步骤并推测了其萃取机理。4．研究了HEHEHP对CA-12萃取Yb和Y的动力学的影响。实验发现在CA一12中加入少量的HEHEHP后，萃取活化能显著降低，萃取速率明显加快。由于加入HEHEHP后，萃取Yb的活化能的降低要比萃取Y的活化能降低的程度大'，所以使Yb和Y的萃取分离因素加大。5．用两相滴定法研究了HEHEHP萃取铭的机理，CA-12萃取稀土及其相关离子的机理。并计算了它们相应的平衡常数。

Human lens lipids differ markedly from those of commonly used experimental animals

Electrospray ionisation tandem mass spectrometry has allowed the unambiguous identification and quantification of individual lens phospholipids in human and six animal models. Using this approach ca. 100 unique phospholipids have been characterised. Parallel analysis of the same lens extracts by a novel direct-insertion electron-ionization technique found the cholesterol content of human lenses to be significantly higher (ca. 6 times) than lenses from the other animals. The most abundant phospholipids in all the lenses examined were choline-containing phospholipids. In rat, mouse, sheep, cow, pig and chicken, these were present largely as phosphatidylcholines, in contrast 66% of the total phospholipid in Homo sapiens was sphingomyelin, with the most abundant being dihydrosphingomyelins, in particular SM(d18:0/16:0) and SM(d18:0/24:1). The abundant glycerophospholipids within human lenses were found to be predominantly phosphatidylethanolamines and phosphatidylserines with surprisingly high concentrations of ether-linked alkyl chains identified in both classes. This study is the first to identify the phospholipid class (head-group) and assign the constituent fatty acid(s) for each lipid molecule and to quantify individual lens phospholipids using internal standards. These data clearly indicate marked differences in the membrane lipid composition of the human lens compared to commonly used animal models and thus predict a significant variation in the membrane properties of human lens fibre cells compared to those of other animals. © 2008 Elsevier B.V. All rights reserved.

Stabilization of Phospholipid Coatings in Capillary Electrophoresis

The development of a simple method of coating a semi-permanent phospholipid layer onto a capillary for electrochromatography use was the focus of this study. The work involved finding good coating conditions, stabilizing the phospholipid coating, and examining the effect of adding divalent cations, cetyltrimethylammonium bromide, and polyethylene glycol (PEG)-lipids on the stability of the coating. Since a further purpose was to move toward more biological membrane coatings, the capillaries were also coated with cholesterol-containing liposomes and liposomes of red blood cell ghost lipids. Liposomes were prepared by extrusion, and large unilamellar vesicles with a diameter of about 100 nm were obtained. Zwitterionic phosphatidylcholine (PC) was used as a basic component, mainly 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC) but also eggPC and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Different amounts of sphingomyelin, bovine brain phosphatidylserine, and cholesterol were added to the PC. The stability of the coating in 40 mM N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid) (HEPES) solution at pH 7.4 was studied by measuring the electroosmotic flow and by separating neutral steroids, basic proteins, and low-molar-mass drugs. The presence of PC in the coating solution was found to be essential to achieving a coating. The stability of the coating was improved by the addition of negative phosphatidylserine, cholesterol, divalent cations, or PEGylated lipids, and by working in the gel-state region of the phospholipid. Study of the effect on the PC coating of divalent metal ions calcium, magnesium, and zinc showed a molar ratio of 1:3 PC/Ca2+ or PC/Mg2+ to give increased rigidity to the membrane and the best coating stability. The PEGylated lipids used in the study were sterically stabilized commercial lipids with covalently attached PEG chains. The vesicle size generally decreased when PEGylated lipids of higher molar mass were present in the vesicle. The predominance of discoidal micelles over liposomes increased PEG chain length and the average size of the vesicles thus decreased. In the capillary electrophoresis (CE) measurements a highly stable electroosmotic flow was achieved with 20% PEGylated lipid in the POPC coating dispersion, the best results being obtained for disteroyl PEG (3000) conjugates. The results suggest that smaller particles (discoidal micelles) result in tighter packing and better shielding of silanol groups on the silica wall. The effect of temperature on the coating stability was investigated by using DPPC liposomes at temperatures above (45 C) and below (25 C) the main phase transition temperature. Better results were obtained with DPPC in the more rigid gel state than in the fluid state: the electroosmotic flow was heavily suppressed and the PC coating was stabilized. Also dispersions of DPPC with 0−30 mol% of cholesterol and sphingomyelin in different ratios, which more closely resemble natural membranes, resulted in stable coatings. Finally, the CE measurements revealed that a stable coating is formed when capillaries are coated with liposomes of red blood cell ghost lipids.

An improved-performance liquid-feed solid-polymer-electrolyte direct methanol fuel cell operating at near-ambient conditions

Results on the performance of a 25 cm(2) liquid-feed solid-polymer-electrolyte direct methanol fuel cell (SPE-DMFC), operating under near-ambient conditions, are reported. The SPE-DMFC can yield a maximum power density of c. 200 mW cm(-2) at 90 C while operating with 1 M aqueous methanol and oxygen under ambient pressure. While operating the SPE-DMFC under similar conditions with air, a maximum power density of ca. 100 mW cm(-2) is achieved. Analysis of the electrode reaction kinetics parameters on the methanol electrode suggests that the reaction mechanism for methanol oxidation remains invariant with temperature. Durability data on the SPE-DMFC at an operational current density of 100 mA cm(-2) have also been obtained.

Flavio Josefo e o paradigma de circularidade cultural entre as comunidades judaicas e a sociedade romana na Urbs do século I d.C

O paradigma de circularidade cultural entre a comunidade judaica e a sociedade romana foi construído pela historiografia através da análise do contato sociocultural e embates entre romanos e judeus que, ao longo da história, ocuparam o mesmo espaço em diversas regiões anexadas ao Império Romano. As relações de poder estabelecidas entre Roma e Jerusalém, após a ocupação da Judéia, apontam para uma hierarquização nas relações sociais, culturais e políticas entre romanos e judeus. O conceito de circularidade cultural de Carlo Ginzburg nos permite, a partir da trajetória de Flávio Josefo, identificar a dualidade no mundo social de Josefo, na qual, de um lado estavam as culturas dominantes (sociedade romana) e, do outro, as culturas subalternas (comunidades judaicas) que, apesar da marcação das diferenças, se influenciavam reciprocamente.

Regional variation in the annual feeding cycle of juvenile walleye pollock (Theragra chalcogramma) in the western Gulf of Alaska

Juvenile fish in temperate coastal oceans exhibit an annual cycle of feeding, and within this cycle, poor wintertime feeding can reduce body growth, condition, and perhaps survival, especially in food-poor areas. We examined the stomach contents of juvenile walleye pollock (Theragra chalcogramma) to explain previously observed seasonal and regional variation in juvenile body condition. Juvenile walleye pollock (1732 fish, 37–250 mm standard length) of the 2000 year class were collected from three regions in the Gulf of Alaska (Kodiak, Semidi, and Shumagin) representing an area of the continental shelf of ca. 100,000 km2 during four seasons (August 2000 to September 2001). Mean stomach content weight (SCW, 0.72% somatic body weight) decreased with fish body length except from winter to summer 2001. Euphausiids composed 61% of SCW and were the main determinant of seasonal change in the diets of fish in the Kodiak and Semidi regions. Before and during winter, SCW and the euphausiid dietary component were highest in the Kodiak region. Bioenergetics modeling indicated a relatively high growth rate for Kodiak juveniles during winter (0.33 mm standard length/d). After winter, Shumagin juveniles had relatively high SCW and, unlike the Kodiak and Semidi juveniles, exhibited no reduction in the euphausiid dietary component. These patterns explain previous seasonal and regional differences in body condition. We hypothesize that high-quality feeding locations (and perhaps nursery areas) shift seasonally in response to the availability of euphausiid

可生物降解聚酯及其共聚物的合成

生物降解高分子材料是当今高分子材料领域的研究热点。本论文引入了一种新型的催化剂－Ca催化剂用于合成生物降解高分子PCL及其嵌段共聚物PEO－PCL、PEO－PCL－PEO、PCL－PEO，另外对嵌段共聚物PLLA－PEO的合成也做了探索性的研究。实验结果表明：1、Ca催化剂从氨钙配合物出发制备，利用各种不同的配体对其配位（如已内酯、环氧丙烷和乙腈），并在适当温度下加热陈化，催化活性得到明显的改善。2、Ca催化剂可以高效催化已内酯的聚合。详细讨论了Ca催化剂催化已内酯聚合的聚全条件。在室温至100 ℃，钙催化剂均能有效催化已内酯聚合，单体转化率接近100%。随着单体与催化剂的比值M／I、聚合温度和时间的变化聚合物的分子量MW发生相应的变化。MW与M／I的线性关系说明了钙催化剂聚合已内酯的准活性特征。高的聚合温度可以获得主的转化率，但聚合物分子量却相应降低。在一定的聚合时间内MW随着聚合时间的增加而增加，但如果聚合时间过长MW会有所降低，分子量分布变宽，说明聚合后期随着单体的减少降解反应和微量的酯交换反应显著。最高分子量出现在25万到30万左右。另外，对聚合物做了几种力学测试（强度S、模量E和伸长率σ），发现随着PCL分子量的增加，上述几种力学性能发生相应的变化。MW在20万左右时S＝28MPa，E=256MPa，σ=743%。3、 Ca催化剂既可以制备PEO－PCL嵌段共聚物，也可以制备PCL－PEO嵌段共聚物。在两种共聚物的基础上还可以继续制备三嵌段共聚物。此外，Ca催化剂还可以用于制备嵌段共聚物PLLA－PEO。通过NMR，GPC，DSC等测试手段证明所得的共聚物确实为嵌段共聚物。

协同萃取方法分离稀土元素的热力学及动力学

本论文以有效的萃取和分离稀上元素为目的，研究和开发了几种新的有效的协同萃取体系，并详细研究了其对稀土元素的萃取和分离性能，在热力学研究的基础上进一步考察其动力学和界面性质，为其在实际中的应用奠定基础；同时探讨了加入氨梭络合剂的方法实现稀土元素的分离。研究了有机腾酸类萃取剂cyanex272与有机梭酸类萃取剂CA-100、CA-12构成的协同萃取体系，考察了混合体系在盐酸介质中对稀土元素的协同萃取规律，详细研究了它们对Y,Er,Sc单独及协同萃取的反应机理及反萃性能，稀土元素之间的分离系数表明：此体系对稀土元素具有较好的选择性。2．研究了有机磷酸类萃取剂EHEHPA与中性萃取剂Cyanex923协同萃取体系对稀土元素的协萃效应规律，并考察了其对La，Nd，Gd的协萃反应机理及反萃取性能，讨论了稀土的分离可能性。3．采用加入氨梭络合剂的方法改进单独的CA-100体系，对两种料液进行实验，确定最佳分离条件，研究表明：本方法适合于选择性分离和提纯含有少量重稀土杂质的Y溶液，具有很好的应用前景。4．研究了CA-100＋Cyonex272协同萃取Y,Yb的动力学性质，通过考察各种因素对萃取速率的影响，确定其对Y,Yb的萃取动力学为扩散控制过程，并得到了其对从Yb的萃取速率方程，讨论了Y,Yb动力学分离的可能性。5．研究了CA-100+Cyanex272-庚烷体系的界面性质，讨论了水相酸度、温度、稀释剂等各种因素的对界而性质影响，发现此体系具有良好的界面性质，能够定性地解释其协同萃取稀土的热力学和动力学特征。

Cyanex 302萃取轻、中和重稀土热力学、动力学及其界面性质的研究

本文系统研究了酸性单硫代磷酸萃取剂Cyanex302萃取抗、忆、斓和礼的单一体系热力学，钦、钻和饵的协同萃取热力学，抗、忆、斓和礼的动力学机理及其各种因素影响下的界面活性，在以下四个方面得到了具有学术意义和应用前景的结果。1．推导了Cyanex302萃取Sc（111），Y（111），La（111）和Gd（111）的平衡方程式，比较了Cyanex302与纯化后Cyanex302对稀土的萃取性能和分离选择性。以斓为例，深入探讨了Cyanex302中不同组份在萃取过程中的地位和作用，明确了cyanex302与TOPO混合对稀土元素萃取具有明显的协同效应，推测了纯化cyanex302与TOPO混合萃取悯的热力学机理，计算了协萃系数，确定了萃合物组成。2．探讨了Cyanex302与不同类型（酸性，中性和胺类）萃取剂混合对钦、钻、饵的萃取性能。比较了Cyanex302与不同类型萃取剂等物质的量混合后，对三种稀土元素萃取能力的强弱顺序和分离选择性顺序。明确cyanex302与不同类型萃取剂混合可以构成协萃和反协萃体系，计算了协萃体系的协萃系数。以cyanex302与CA-100萃取YCl3为例，推导了协萃机理，确定了协萃配合物的组成。3．借助于不同的数据处理方法研究了cyanex302萃取杭、钻、斓和锐的动力学，考察了各种因素对萃取速率的影响，获得不同方法下的速率方程，得出不同的萃取机理。比较了Cyanex302正向萃取和反萃取YCl_3的动力学方程，得出一些具有指导意义的结论。Vll4．用不同的数学处理方法研究了Cyanex302在没有离子强度维持下各种稀释剂对界面活性的影响，比较了各种数据处理方法下结论的不同，分析了不同稀释剂对Cyanex302界面活性影响的原因。重点讨论了CyaneX302-庚烷-（H，Na）Cl体系中温度、水相酸度和离子强度对界面活性的影响，把界面吸附与萃取动力学相结合，探讨了二者之间的关系。

Solvent impregnated resin prepared using task-specific ionic liquids for rare earth separation

A novel bifunctional task-specific ionic liquid (TSIL), i.e. [trialkylmethylammonium][sec-nonylphenoxy acetate] ([A336] [CA-100]) was impregnated on intermediate polarized XAD-7 resin, and the prepared solvent impreganated resin (SIR) was studied for rare earth (RE) separation. Adsorption ability of the SIR was indicated to be obviously higher than that prepared by [A336][NO3] because of the functional anion of [A336][CA-100]. Adsorption kinetics, adsorption isotherm, separation and desorption of the SIR were also studied.