Quinolinephosphomolybdate as ion exchanger: synthesis,characterization, and application in separation of <Superscript>90</Superscript>Y from <Superscript>90</Superscript>Sr

An inorganic ion exchanger, quinolinephosphomolybdate has been synthesized and characterized by elemental analysis, infrared (IR) and X-ray diffraction (XRD) spectroscopy. This compound is highly stable toward thermal, chemical and radiation dose. This has been employed in the separation of carrier-free ⁹⁰Y from its parent ⁹⁰Sr from an equilibrium mixture. The absorbed daughter was recovered by using 0.0284 mol L⁻¹ ascorbic acid solutions at pH 5.0 as eluting agent.     

Ion Chromatographic Separation on Silica Grafted with Benzo-18-C-6 Crown Ether

Abstract

Benzo-18-C-6 crown ether has been grafted on silica gel modified with a spacer. By very carefull control of each step of the synthesis an exchanger for alkali and alkaline earth cations with high capacity and low equilibrium time has been prepared. The chromatographic behavior of alkali and alkaline earth metal halides on this benzo-18-C-6 crown ether modified silicas was investigated with water as the mobile phase. With alkali metal chlorides, very good separations are obtained in less than 30 minutes. With alkaline earth metal chlorides, very good separations are also obtained except for Ca²⁺/Mg²⁺. Separations are also observed with mixtures of alkali and alkaline earth cations. Moreover, a very efficient separation of anions is observed, partly as a result of the hydrophobic character of the exchanger.     

Tetra(diethyl)amide-p-tert-butyl-thiacalix[4]arene in Cone Conformation: Synthesis and Binding Properties with Alkali,Alkaline Earth,Heavy and Transition Metal Ions

Tetra(diethyl)amide-p-tert-butylthiacalix[4]arene 1a in the cone conformation was synthesized and its binding properties towards a large variety of metal ions were established on the basis of liquid–liquid and solid–liquid extraction as well as complexation experiments. This compound is a less efficient and selective compound than the “classical” tetra(diethyl)amide-p-tert-butylcalix[4]arene 3 in the cone conformation for alkali and alkaline earth metal ions. However, Pb²⁺ is selectively extracted and complexed within heavy and transition metal ions.     

Synthesis, characterization and ion exchange properties of the framework sodium titanium germanate Na3H(TiO)3(GeO)(GeO4)3·7H2O

Sodium titanium germanate with a semicrystalline framework (STG) of the formula Na₃H(TiO)₃(GeO)(GeO₄)₃·7H₂O was synthesized under mild hydrothermal conditions and its proton form, H₄(TiO)₃(GeO)(GeO₄)₃·8H₂O (STG-H), was prepared by acid treatment of the sodium compound. The STG was characterized by elemental analysis, TGA, FT-IR, and X-ray powder diffraction. A comparative ion exchange examination of the STG-H towards alkali and alkaline earth metals in a broad pH and concentration range was carried out. It was found that the STG is a moderately weak cation exchanger, possessing high ion exchange capacity (up to 4.0 meq/g) and showing preference for heavy alkali and alkaline earth metals. The STG selectivity towards Cs⁺ and Sr²⁺ ions in the presence of competitive metal ions and certain organic compounds was also studied. The data obtained suggest that the sodium titanium germanate is a more selective exchanger for Sr²⁺ ion than its titanium silicate analogue, K₃H(TiO)₄(SiO₄)₃·4H₂O.     

Zirconium arsenophosphate as an ion exchanger

Zirconium arsenophosphate (ZAP) a new inorganic ion exchanger has been synthesized under varying conditions of precipitation. The material possesses good chemical and thermal stabilities and regeneration power. It shows no breakdown on irradiation with a gamma dose of ～10⁹ rad. ZAP shows high affinity for univalent ions like Rb⁺, Ag⁺ and Tl⁺. The Kd-values have been determined for a number of metal ions from acid media. The stoichiometry of metal ion uptake was checked using almost carrier-free radiotracers. Sixteen binary/ternary separations of metal ions are reported on a ZAP column.     

离子色谱法分析金属离子的研究进展

综述了离子色谱法(IC)分析金属离子的研究进展,对目前应用于分析金属离子的阳离子交换IC、阴离子交换IC和螯合离子色谱进行了评述。阳离子交换IC是IC分析金属离子的主要形式,固定相为强酸(磺酸)型阳离子交换剂和弱酸(羧酸)型阳离子交换剂,结合适当的检测方法,阳离子交换IC可以测定碱金属、碱土金属、过渡金属、稀土离子、铵离子及低相对分子质量的有机胺类分子等。阴离子交换IC可以分析碱土金属、过渡金属、稀土离子等,对金属离子的分析具有更好的选择性,并可以实现金属离子和无机阴离子的同时测定。螯合离子色谱可以对复杂基体中的痕量金属离子进行测定。引用文献125篇。     

Diazo-coupled calix[4]arenes for qualitative analytical screening of metal ions

New chromogenic diazophenylcalix[4]arenes 1 and 2 were synthesized in cone conformation. Compound 1 with the ortho-carboxyl groups in CH₃CN solution preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in absorption spectra are observed in the presence of alkali metal ions. While 2 with the ortho-ester groups shows selective complexation properties towards transition metal ions over alkali and alkaline earth metal ions. The detection of metal ions gives rise to bathochromic shifts in the absorption spectra (from orange/yellow to red), which is clearly visible even to the naked eye. According to the selective color changes using both receptors upon cation complexation, one can set up a qualitative analytical routine to screen alkali, alkaline earth, and transition metal ions.     

Highly selective fluorescent chemosensor for Na<Superscript>+</Superscript> based on pyrene-modified calix[4]arene derivative

A novel calix[4]arene derivative with pyrene fluorophores at the upper rim and tetraester ionophores at the lower rim was synthesized in six steps, and its structure was proved by NMR and ESI-MS spectroscopies. Furthermore, the chemosensing behavior of the host compound for alkali and alkaline earth metal ions was investigated by fluorescence spectroscopy. The obtained results show that the calixarene host can selectively bind sodium ion with the complexation stability constant of 2190 mol⁻¹·L. The complexation with sodium ion can pronouncedly induce the excimer emission to decrease and the monomer emission to increase, whereas the addition of the other alkali and alkaline earth metal ions does not cause appreciable changes in the fluorescence spectrum of the host compound. The present calix[4]arene derivative displays potential application as fluorescent chemosensor for sodium ion. Supported by the National Natural Science Foundation of China (Grant Nos. 20421202, 20673061 & 20703025) and the 111 Project (Grant No. B06005)     

The importance of cerium substituted phosphates as cation exchanger-some unique properties and related application potentials

Seven different samples of an inorganic ion exchanger, cerium phosphate, suitable for column use have been prepared under varying conditions. The property of these exchangers has been characterized by Inductively Coupled Plasma Spectroscopy. These exchangers are stable in water, dilute mineral acids, ethanol, methanol, acetone and ether. However, in concentrated HCl and HNO(3) they decompose. They retain about 50% of their exchange value after drying at 80 degrees C, and can be regenerated twice without any decrease in exchange capacity. The distribution coefficient measurements for alkaline earth metals, tellurium, iodine and molybdenum using these seven ion exchangers were studied. This revealed the relative affinity for each exchanger, where the sorption in general was most effective at pH 6-8. The titration curves of cerium phosphate (disodium) with alkaline earth metals showed that the selectivity sequence Ba(2+)>Sr(2+)>Ca(2+)>Mg(2+) is observed. Furthermore, it could be deduced that the adsorption of alkaline earth metal cations greatly depends on the cation. These studies have also shown that cerium phosphates with divalent ions are strongly preferred to monovalent ones. Therefore, as for the cerium phosphates with large monovalent ions, the lack of exchange for Ba(2+), Mg(2+) or other alkali earth metal ions should be essentially due to steric hindrance and this could include any one of the following: the large crystalline radius of metal ions or large hydrated ionic radius and high energy of hydration for other divalent ions. Three binary separations of Te(IV)-Mo(VI), Te(IV)-I(I) and Mo(VI)-I(I) has been developed and the recovery ranging from 90 to 100% has been achieved on cerium phosphate (disodium) columns.     

Synthesis and characterization of a new phase of zirconium phosphate for the separation of metal ions

The tetravalent metal acid (TMA) salt amorphous zirconium phosphate (ZP), an inorganic ion exchanger, has been synthesized by sol-gel method. The material has been characterized by elemental analysis (ICP-AES), thermal analysis (TGA, DSC), FT-IR and X-ray diffraction studies. Chemical resistivity of the material in various media-acids, bases and organic solvents has been assessed. The Na⁺ ion exchange capacity (IEC) and the effect of heating on the IEC have been determined, and showed the distribution and elution behavior of ZP towards several metal ions in different electrolyte media/concentrations. Based on the distribution studies, a few binary metal ion separations have been achieved.     

偏钛酸型锂离子交换剂表面性质与选择吸附性研究

本文采用Li渗入于TiO2经高温热力学重结晶制备偏钛酸型锂离子交换剂,其对碱金属、碱土金属溶液中的Li+ 具有特殊选择吸附性,其次序为Li+>Mg2+>Ca2+>Na+,K+。对交换剂表面性质以及Li+ 在固-液界面的选择吸附特性进行了研究。通过对某气田卤水提锂实验表明:该交换剂对低Li+ 含量卤水中Li+ 的选择性吸附效果显著,对Mg2+、Ca2+、Na+、K+ 的分离效果好,Li+ 的富集倍数达9倍,并具有较好的循环稳定性。     

On solute-mercury interactions in dilute amalgams of main group metals

The paper challenges the concept of intermetallic compound formation in dilute (mole fraction <10⁻³) amalgams of s-block metals. Although the formation of these amalgams is strongly exothermic the generated energy is much lower than the Fermi level difference between pure solutes and mercury. Thermodynamic considerations suggest that the energy of metal ions is higher in amalgams than in pure s-block metals. Repulsive interactions between the cores of these metals and mercury ions are responsible for abnormally low diffusion coefficients of alkali and alkaline earth metals in mercury. The mercurophobic character of alkali metal ions demonstrates itself in the strong adsorption of these metals on the Hg-vacuum interface, and in the high rates of ion exchange between electrolytic solutions and amalgams.     

Weak alkali and alkaline earth metal complexes of low molecular weight ligands in aqueous solution

This work is aimed at reviewing the chemical literature dealing with thermodynamic aspects of the weak complex formation (species with log K values less than about 3) between alkali and alkaline earth metal ions with low molecular weight inorganic and organic ligands in aqueous solution. The following ligands (up to hexavalent anions) were examined in detail: (i) hydroxide, chloride, sulfate, carbonate and phosphate as inorganic, and (ii) carboxylates, amines, amino acids, complexones and nucleotides as organic ligands. The paper also identifies the main reasons responsible for the dispersion of the stability data on ion pairs in the literature. When possible, the trend of stability for the different metal ions interacting with the same ligand will be considered to find predictive interaction relationships. Since the stability of weak alkali and alkaline earth metal complexes are mainly due to electrostatic interaction, simple empirical relationships were obtained between log K and the charge of the anionic ligand. The interest for alkali and alkaline earth cations rises since they are used in study of basic science as components of the supporting electrolyte and are widely diffused in natural fluids. Some examples of application of this science were presented too, to show the role of weak complex formation in the modelling process of natural systems.     

Modification of sulfonated polyphenylquinoxaline by alkali and alkaline earth metal cations

Salts of sulfonated polyphenylquinoxaline (SPPQ) containing alkaline earth metal ions—Mg²⁺, Ca²⁺, and Ba²⁺—were synthesized. The paper considers their solubilities, the properties of solutions, and thermal stability in comparison with analogous characteristics of SPPQ salts with alkali metals. The introduction of alkaline earth metal cations into SPPQ affords soluble polymeric salts having high thermal stability. Solutions of SPPQ salts in N-methylpyrrolidone (N-MP) containing Mg²⁺, Ca²⁺, and Ba²⁺ ions do not exhibit polyelectrolyte properties, unlike solutions of SPPQ salts in which the counterions are Li⁺, Na⁺, and K⁺. Solutions of SPPQ and its salts in N-MP can be converted to water-soluble form by dialysis. This opens up new prospects for using the polymeric salts.     

Synthesis and ion-exchange properties of crystalline titanium and zirconium phosphates

The preparation of novel types of inorganic ion-exchangers, titanium and zirconium phosphates and their ion-exchange properties towards strontium ions, are reported and discussed. Ti(HPO₄)₂·2H₂O is shown to be very stable to hydrolysis and to have high exchange capacity in strongly acid medium. In the case of zirconium phosphate, the titration curves with alkaline earth metal hydroxides are strongly affected by hydrolysis of the exchanger and precipitation of insoluble phosphate. The degree of conversion of the exchanger at which phosphate precipitation begins was found to be 80% for Sr²⁺. The comparison of Ti(HPO₄)₂·2H₂O with the corresponding zirconium phosphate dihydrated phase suggests that the former possesses a lattice structure different from that reported for the monohydrated exchanger.This revised version was published online in November 2005 with corrections to the Cover Date.     

Mercury(II) and silver(I) receptors based on tetrathiacalix[4]arene hydrazones

The extraction ability of phenyl hydrazone derivatives of cone- and 1,3-alternate tetrathiacalix[4]arenes towards to some alkali, alkaline earth, transition and heavy metal ions has been investigated by picrate extraction method. The synthesized cone-tetrathiacalix[4]arene hydrazones show a high efficiency coupled with an excellent selectivity towards for Ag⁺ and Hg²⁺ ions. The stoichiometry of complexes and the extraction constants have been determined. The influence of calix[4]arene platform’s structure and the electron donor substituents in phenyl fragments on the extraction efficiency has been discussed.     

Cesium and strontium exchange by the framework potassium titanium silicate K3HTi4O4(SiO4)3·4H2O

Potassium titanium silicate with a semicrystalline framework of the formula K₃HTi₄O₄(SiO₄)₃·4H₂O has been prepared under mild hydrothermal conditions and its protonic form, H₄Ti₄O₄(SiO₄)₃·8H₂O, was obtained by acid treatment of the potassium compound. A comparative ion exchange testing of the H₄Ti₄O₄(SiO₄)₃·8H₂O towards alkali and alkaline earth metals in a broad pH and concentration range was carried out. It was found that potassium titanium silicate is a moderately weak cation exchanger, possessing high ion exchange capacity (up to 4–5 meq/g) and showing preference for heavy alkali and alkaline earth metals uptake. The selectivity of K₃HTi₄O₄(SiO₄)₃·4H₂O towards Cs⁺ and Sr²⁺ ions in alkaline and acid media in the presence of competitive inorganic ions and certain organic compounds was also studied. The data obtained suggest that despite the existence of well defined tunnel structure with parameters fitting for cesium ion in the K₃HTi₄O₄(SiO₄)₃·4H₂O, potassium titanium silicate could remove cesium (and strontium) efficiently only under some specific conditions, namely, at pH close to neutral and in the absence of competitive ions and especially of organic complexing agents.     

New Tripodal Ligands Containing Aza-Thioethers as Selective Extractants for Silver(I)

A new series of tripodal receptors bearing imine and thioether units, have been synthesized in high yields by simple condensation method. The binding properties of these ligands towards alkali, alkaline earth and transition metal ions have been established by extraction and transport experiments. These podands have highest extraction and transport rate for Ag(I). The complexation of Ag(I) with the receptors has been established using ¹H-and ¹³C-NMR spectroscopy.This revised version was published online in July 2005 with a corrected issue number.     

Application of a Zeolite-Poly(vinyl chloride) Electrode to Potentiometric Studies of Alkali Metal Ions

Potentiometric electrodes based on the incorporation of zeolite particles into poly(vinyl chloride) (PVC) membranes are described. The electrode characteristics are evaluated regarding the response towards alkali ions. PVC membranes plasticized with dibutyl phthalate and without lipophilic additives (co-exchanger) are used throughout this study. The electrode exhibits a Nernstian response over the alkali metal cation concentration range of 1.0 × 10^?4 to 1.0 × 10^?1 M with a slope of 57.0 ± 0.9 mV per decade of concentration with a working pH range 3.0–9.0 and a fast response time of ≤15 s. The selectivity coefficients for cesium ion as test species with respect to alkaline earth, ammonium, and some heavy metal ions are determined. The proposed zeolite-PVC electrode is applied to the determination of ionic surfactant.     

Proton ionizable crown compounds. 18. Comparison of alkali metal transport in a H2O-CH2Cl2-H2O liquid membrane system by four proton-ionizable macrocycles containing the dialkylhydrogenphosphate moiety

The macrocycle-mediated fluxes of alkali, alkaline earth, and several transition metal cations have been determined and compared in a H₂O-CH₂Cl₂-H₂O liquid membrane system using four water-insoluble macrocycles containing a dialkylhydrogenphosphate moiety. Transport of alkali metal cations by these ligands was greatest from a source phase pH = 12 or above into an acid receiving phase (pH = 1.5). Very low fluxes were observed for the transport of the alkaline earth cations and all transition metal ions studied except Ag⁺ and Pb²⁺ which were transported reasonably well by these new macrocycles.Deceased: September 5, 1987.