离子交换树脂

简要介绍了离子交换树脂的概念、发展简史、组成、分类、作用原理、合成路线及性能。用表格简列出应用的各个方面,并说明了应用的优、缺点,最后扼要地指出了发展的方向。     

Adsorption of anions to zirconium(IV) and titanium(IV) chemically immobilized on gel-phase

Adsorption behaviors of 25 anions to zirconium(IV) and titanium(IV) chemically immobilized on a gel-phase were studied by ion chromatography and by batch adsorption experiments. The affinities of Zr(IV) to iminodiacetate as an anchoring group and to anions as a sample are much stronger than those of Ti(IV). On a Zr(IV) column, fourteen anions showed no retention, four anions showed pH-dependent retention in a low pH region, and seven anions were irreversibly adsorbed at pH <7. In the last group, fluoride was adsorbed both by the ligand exchange mechanism and the addition mechanism, while phosphate, arsenate and selenite were only by the ligand exchange mechanism. The structures of the adsorbed species are discussed.     

大孔树脂对磺酸类化合物吸附行为的研究

用4种大孔树脂ND-022，ND-900，NDA-99和NDA-100作为吸附剂，分别对水溶液中甲基磺酸钠、苯磺酸钠、对甲基苯磺酸钠和2-萘磺酸钠等磺酸盐进行吸附．探讨了溶液的初始pH值对不同类型树脂吸附磺酸类物质的影响，并通过动态吸附实验研究了SO4^2-对树脂吸附磺酸盐的影响．实验结果表明，复合功能树脂NDA-99对磺酸类化合物具有良好的吸附性能，且其选择性优于弱碱树脂ND-900，这为进一步研究大孔树脂对磺酸类物质的吸附机理和实际工业应用提供了一定的理论依据。     

离子交换树脂在分析化学中的应用

简要评述了离子交换树脂在分析化学中的应用。包括离子交换树脂预富集技术从稀溶液中浓缩痕量离子,离子交换树脂相分光光度法测定微量离子,离子色谱在无机分析中的应用,以及离子交换树脂在有机分析与生化分析中的应用。     

Kinetics Characterization of Ion Release under Dynamic and Batch Conditions. I. Weak Acid and Weak Base Ion Exchange Resins

The aim of the present work is concerned with a study of the kinetics of release of both Ca²⁺ and F⁻ from the corresponding loaded ion-exchange resins (weak acid and weak base character for Ca²⁺ for F⁻, respectively), using both dynamic and batch experimental conditions with an artificial saliva solution as the ion-exchange media at 293 and 310 K. The influence of resin particle size and the temperature were evaluated by the kinetics parameters for the effective rate of release (B) and diffusion coefficient (D). The rate of ion release increases with temperature and decreases with particle size. The experimental data were well fitted by models based on intraparticle diffusion-controlled processes. In dynamic studies, the linear dependence of −log ₁₀(B) with the diameter of the resin particles can be applied for the estimation of B values when resins of low particle size are considered. In batch processes, although resins of low particle size can be studied, a linear relationship was only attained for the case of slow ion-exchange kinetic systems.     

Synthesis and ion exchange behaviour of polyaniline Sn(IV) arsenophosphate: a polymeric inorganic ion exchanger

Incorporation of a polymer material into an inorganic ion exchanger provides a class of hybrid ion exchangers with a good ion exchange capacity, high stability, reproducibility and selectivity for heavy metals. Such a type of ion exchanger ‘polyaniline Sn(IV) arsenophosphate’ has been synthesized by mixing polyaniline into inorganic material. This material is characterized using X-ray, IR, TGA studies in addition to ion exchange capacity, pH-titration, elution and distribution behaviour. On the basis of distribution studies, the material has been found to be highly selective for Pb(II). Kinetic study of exchange for the metal ions has been performed and some physical parameters such as self diffusion coefficient D₀, energy E_a and entropy ΔS* of activation have been determined.     

Steric factor in ligand displacement of zirconium alkoxides dissolved in alcohols

The present study indicates EXAFS direct structural data obtained for zirconium ethoxide, iso- and n-propoxide are alike those for zirconium n-butoxide complexes. This is evident for agreement of structural units of abovementioned alkoxides complexes. Our group developed structural model of n-butoxide earlier. Six interconnected tetramers assemble a structural unit of the alkoxides under study. The tetramers build of zirconium atoms in the highly flattened pyramid corners. Four zirconium atoms are bonded in series by double bridges through oxygen atoms of alkoxide ligands. Two of the four zirconium atoms are bias bonded by single ligand bridges. The distances between pairs of zirconium atoms inside the tetramer are 3.3 and 3.5 Å. Tetramers are linked together also by a single ligand bridges. The distance between zirconium atoms of the two neighbor tetramers is 3.9 Å. Primary particles (tetramer sextet) form aggregates in a solution. Possible shapes of the anisotropically sized aggregates is a large diameter cylinder with small height (a disk), or a small diameter cylinder with large height (a rod). Primary particles composed through ligands. The distance between the neighbor zirconium atoms of different primary particles is 4.8 or 5.1 Å depending on the coordination nature and the neighboring particles number.     

Ion exchange chromatography of monoclonal antibodies: Effect of resin ligand density on dynamic binding capacity

Dynamic binding capacity (DBC) of a monoclonal antibody on agarose based strong cation exchange resins is determined as a function of resin ligand density, apparent pore size of the base matrix, and protein charge. The maximum DBC is found to be unaffected by resin ligand density, apparent pore size, or protein charge within the tested range. The critical conductivity (conductivity at maximum DBC) is seen to vary with ligand density. It is hypothesized that the maximum DBC is determined by the effective size of the proteins and the proximity to which they can approach one another. Once a certain minimum resin ligand density is supplied, additional ligand is not beneficial in terms of resin capacity. Additional ligand can provide flexibility in designing ion exchange resins for a particular application as the critical conductivity could be matched to the feedstock conductivity and it may also affect the selectivity.     

Ion exchange and ion transport properties of sulfonated organically modified silica hydrogels

Sulfonated ormosil hydrogels (~80% water) were prepared using tetramethyl orthosilicate as a silica precursor and 2(4-chlorosulfonylphenyl)ethyltrichlorosilane to provide sulfonate functionality for ion-exchange and ion conductivity. Ruthenium(III) hexamine was used as a redox probe in electrochemical studies performed on porous carbon fibre paper electrodes impregnated with the gel. The gel-modified electrodes extracted Ru(NH₃)₆³⁺ from solutions in 0.1 M CF₃CO₂Na_(aq) with a partition coefficient of ~36, and with ~100% of the sulfonate sites being accessible for ion exchange. The Ru(NH₃)₆^3+/2+ couple exhibited reversible and facile electrochemistry in the gel, with a Ru(NH₃)₆²⁺ diffusion coefficient of 4.9×10^–8 cm² s^–1 determined by chronoamperometry. This is an order of magnitude higher than the mobility of this complex in Nafion. The hydrogel-modified electrodes were stable for days, and could be repeatedly loaded with Ru(NH₃)₆³⁺.Special Issue to celebrate the 70^th birthday of Professor Zbigniew Galus     

Ion chromatographic determination of some anions and alkaline cations in liquid crystal materials after ultraviolet irradiation

A method was developed for the quantitative determination of inorganic cations and anions present in liquid crystal materials pretreated with ultraviolet irradiation by ion chromatography. The samples were irradiated at less than 20±2 °C and then pretreated with OnGuard RP and P cartridges to remove the interferential organic compounds prior to ion chromatographic analysis for both cations and anions. With a high capacity and very hydrophilic anion exchange column, four anions (fluoride, chloride, bromide, iodide) were determined in 20 min with gradient of sodium hydroxide. By employing a cation exchange column, five cations (sodium, ammonium, potassium, magnesium, calcium) could be determined in 12 min. The spiked recoveries for the cations and anions were 84.0–108.1% and 86.1–108.2%, respectively.     

Ion exchange behaviour of zirconium phosphate with mercury(II) solutions

Ion exchange behaviour of Zr(HPO₄)(NaPO₄)·5H₂O towards HgCl₂ solutions has been examined. Na⁺ and H⁺ ions were released by the exchanger in a ratio which depended on the pH. Uptake and rate of exchange were relatively high considering that Hg is strongly bound to chloride. Higher uptake and faster exchange were obtained by using an expanded phase of α-ZrP in acid Hg(NO₃)₂ solutions. Normal α-ZrP in the same conditions, exhibited low uptake and very slow rate of exchange.     

Green synthesis of polymeric membranes: Recent advances and future prospects

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Ion exchange textiles from the finishing of PET fabrics with cyclodextrins and citric acid for the sorption of metallic cations in water

We describe a chemical method based on the use of cyclodextrins (CDs) and citric acid (CTR) as finishing chemicals for the modification of polyester fibers (PET). It was observed that the reaction between these reactants yielded a cross-linked polymer, by formation of ester functions between the polyol (CD) and the polycarboxylic acid (CTR). This polymer (called polyCTR-CD) permanently coated the PET fibers. The chemical structure of polyCTR-CD consisted of CD moieties and unreacted carboxylate groups. Theses groups resulted from the partial reaction of CTR and yielded ion exchange property to the fibers. The purpose of this paper was to set up the finishing parameters in order to obtain the best possible ion exchange capacity (IEC) of the fabrics. Firstly, we observed that the IEC did not perfectly evolve with the grafting rate (expressed in %-wt) of the fibers; As a matter of fact, we observed that a maximal IEC of 0.4–0.5 mmol/g of fabric was obtained for a compromise between the amount of polyCTR-CD fixed onto the fibers, and its cross-linking rate. In fact, the lesser the cross-linking rate, the more unreacted carboxylic groups remained on the fibers. Second, it was observed that CDs could not be replaced by starch in this process, because the later resulted to inferior IEC values than textiles grafted with CDs and CTR. Finally, the ion exchange finished fabrics were applied in the decontamination of water solutions containing Pb²⁺, Ni²⁺ and Cd²⁺. It was observed that 0.3 mmol of each cation were adsorbed per gram of fabrics.     

The intercalation of cetyltrimethylammonium cations into muscovite by a two-step process: I. The ion exchange of the interlayer cations in muscovite with Li

A new method to prepare alkylammonium ions-intercalated muscovite is reported. It has been obtained in a two-step process: the first step is the inorganic ion exchange, which allows the ion exchange of interlayer cations in muscovite with Li⁺ in a melting condition of LiNO₃. It was found that in the LiNO₃ treatment process most of the interlayer cations were replaced by Li⁺, and a large amount of water entered the interlayer space of muscovite. Therefore the spacing of muscovite (001) plane d₍₀₀₁₎ was enlarged from 19.92 to 24.16 Å, which could allow for the intercalation of organic cations. SEM shows that the LiNO₃ treatments have little effect on the size of muscovite platelets. TEM and FTIR confirm that not only the chemical composition but also the structure of the aluminosilicate layer has not been changed by the LiNO₃ treatments.     

Hydrophobic and cation exchange mechanisms in the retention of basic compounds in a polymeric column

A cation exchange retention mechanism concomitant with the well-known hydrophobic partition mechanism in a polymeric column has been observed and investigated. This exchange process is attributed to ionization of some acidic sites present in the polymer column at basic mobile phase pH values. Several drugs of different basicity have been chromatographed on a polymeric PLRP-S column with methanol-water and acetonitrile-water mobile phases. The cation exchange between the protonated basic drug and the buffer cations (Na+, K+ and BuNH4+) is observed at the pH range where the protonated drug and the ionized sites of the column coexist. This process produces a shift of the retention versus pH plot of the base to pH values lower than those expected from the pKa of the base as well as a maximum in the plot at basic pH values. These effects are more pronounced for acetonitrile-water mobile phases.     

Separation of Neutral Amino Acids with Ligand Exchange Resins

Four neutral amino acids (Gly, Ala,.Val and Leu) were separated with ligand exchange resins. The separation capacity of the ligand exchange resins is compared with that of common ion exchange resins. The effects of eluent, column temperature, and central metal ions of the support on the separation are studied. The relationship between matrix structure of resins and their separation capacity is analysed.     

A new family of delocalized lipophilic cations

A new family of delocalized lipophilic cations containing one to three carbimino, sulfimino and phosphinimino units with Cl⁻, Br⁻, HF₂⁻ and Me₃SiF₂⁻ as counterions has been designed. The compounds synthesized demonstrate high performance and thermal stability in the ‘Halex’ fluorination reactions. For the first time sulfur tetrachloride pregenerated at −78°C was successfully applied in reactions with N-nucleophiles to afford straightforwardly sulfonium chlorides with three S-N bonds.     

Extraction and determination of pyridinium ionic liquid cations in environmental water samples by using strong cation exchange solid phase extraction and ion chromatography

This paper presents a novel analytical method for the determination of pyridinium ionic liquid cations in environmental water samples by ion chromatography coupled with solid phase extraction. The water samples were purified and enriched by a sulphonic acid extraction column, and then the impurities were washed with 10 mL water – 20% (v/v) acetonitrile solution and the analytes eluted with 0.5 mol L^?1 phosphoric acid – sodium dihydrogen phosphate buffer solution – 55% methanol. The eluted analytes were determined by ion chromatography with 3.0 mmol L^?1 methane sulphonic acid – 8% acetonitrile as the mobile phase and direct conductivity detection. Three pyridinium cations were completely separated in 20 min and the retention mechanism basically conforms to the ion exchange mode. The newly developed method has been successfully applied to the analysis of pyridinium cations in spiked environmental water samples, which provided satisfactory recoveries in the range of 98.8% to 100.0% with the relative standard deviations less than 2.8%. The concentration of 0.004 to 0.01 mg L^?1 in water samples can be preconcentrated by this method. The method is accurate, reliable, simple and practical. This research provides a new reference for detecting ionic liquid cations in environmental water samples and studying the environmental risk assessment of ionic liquids.     

Exchange of alkaline earth cations with the butylamine intercalate of α-zirconium phosphate

The ion uptake behavior of the butylamine intercalate of -zirconium phosphate, Zr(HPO₄) · H₂O, towards alkaline earth cations has been examined. The rates of uptake are in the order Sr²⁺Ca²⁺>Ba²⁺Mg²⁺. Because of the high pH afforded by the amine intercalate, the exchanged phase is always the fully exchanged one, ZrM(PO₄)₂·nH₂O. The values ofn were found to be 4 for Mg²⁺ and Ca²⁺, 3 for Sr²⁺ and 2 for Ba²⁺. Uptake of ions is quantitative to about 6 meq/g loading when no excess amine is present. Sharply reduced loadings occur in the presence of excess of free amine. A solution containing equal amounts of Ca²⁺ and Mg²⁺ yields a new solid solution phase with a 12.6 Å spacing.