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1.
The water uptakes of completely swollen and air dried anion exchange resins were investigated by traditional and also by thermoanalytical measurements. In investigations on the air dried resin samples of HSO4, H2PO4, SO4, HPO4 and PO4 forms, two types of water (strongly and loosely bound) were found. The sequence of water uptake on the resins investigated was compared to the opposite order of the adsorption strengths of the anions and to the entropies of the hydrated anions. A conclusion was made regarding the role of the hydration of the anions in the selectivity sequence of anion exchange.
Zusammenfassung Die Wasseraufnahme vollständig angequollener und lufttrockener Anionenaustauscherharze wurde mittels herkömmlicher sowie auch thermoanalytischer Messungen untersucht. Bei den Prüfungen der lufttrockenen Harzproben in den HSO4-, H2PO4-, SO4-, HPO4-, und PO4-Formen wurden zwei Arten von Wasser gefunden: stark und schwach gebundenes. Die Reihenfolge der Wasseraufnahme wurde mit der umgekehrten Reihenfolge der Adsorptionsstärke der Anionen und mit der Entropie der hydratisierten Anionen verglichen. Schlüsse bezüglich der Rolle der Hydratisierung der Anionen bei der Selektvititätsreihenfolge des Anionenaustausch wurden gezogen.

Résumé On a étudié par des mesures traditionnelles et par analyse thermique l'absorption d'eau par des résines échangeuses anioniques totalement gonflées et séchées à l'air. Lors de l'étude des échantillons de résines séchées à l'air, de formes HSO4, H2PO4, SO4, HPO4 et PO4, on a trouvé deux types d'eau: de l'eau fortement liée et de l'eau faiblement liée. On a comparé l'ordre de l'absorption d'eau des résines étudiées à l'ordre inverse des forces d'adsorption des anions et à l'entropie des anions hydratés. On en tire des conclusions sur le rôle de l'hydratation des anions sur la sélectivité de l'échange anionique.

- , . - HSO4-, H2PO4-, SO4-, HPO4-, PO4- : . . .
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2.
The use of partially quaternized, chloromethylated polystyrene as a covalent scavenger of cholate ion in aqueous media has been demonstrated. The ability of such polymers to scavenge organic anions by covalent as well as by ionic means has important implications in the areas of medicinal and environmental chemistry, which are briefly discussed.  相似文献   

3.
From a solution of sodium polymetaphosphate, strongly basic anion exchange resins can retain a greater amount of polymetaphosphate than that corresponding to the exchange capacity. Sodium ions are held by the polymetaphosphate form of the resin and these sodium ions can be exchanged for other ions.  相似文献   

4.
Organic anion exchange resins, loaded with99Tc pertechnate were incorporated into polymer modified cements and BFS/OPC(9∶1) cements. The composites formed were tested for initial compressive strenghts, underwater and radiation stabilities and leach rates. IAEA standard leach testing was with simulated sea and ground waters. Ground water leaching was also carried out on composites subjected to 1.1 MGy (γ). Polymer modified composites performed better than the BFS/OPC mix under all the conditions studied and, in most cases, were able to encapsulate high resin loading.  相似文献   

5.
碘型离子交换树脂在某些偶极非质子性溶剂的作用下,能有效地催化二氧化碳与环氧丙烷合成碳酸亚丙酯,并能重复使用至少10次而仍能保持较高的催化活性。  相似文献   

6.
In this study, the use of the weakly basic anion exchange resins of phenol-formaldehyde (Amberlyst A 23), polyacrylate (Amberlite IRA 67) and polystyrene (Lewatit MonoPlus MP 62) matrices for removal of the reactive dye Remazol Black B (RBB) from aqueous solution and wastewater were investigated. RBB sorption on the anion exchangers was a time dependent process. Color reduction percentiles of 75.2, 33.9 and 25.1% in wastewater treatment were found after 216 h of phase contact time with Lewatit MonoPlus MP 62, Amberlyst A 23 and Amberlite IRA 67, respectively. Inorganic salts and anionic surfactant action influenced RBB uptake by the anion exchangers. The amounts of dye retained by the anion exchangers increased with a rise in temperature. The maximum sorption capacities calculated from the Langmuir model were 66.4, 282.1 and 796.1 mg g−1 for Amberlite IRA 67, Amberlyst A 23 and Lewatit MonoPlus MP 62, respectively. Regeneration of phenol-formaldehyde and polystyrene resins were possible using 1 M NaOH, 2 M KSCN, 1M KSCN in 40–60% methanol as well as 1 M NaOH in 60% methanol.   相似文献   

7.
Pellicular, macroreticular and microreticular (gel-type) anion exchange resins were compared for the separation of plutonium from nitric acid solutions of mixed plutonium-uranium. AS Pellionex SAX (pellicular resin) and Amberlite IRA-93 (weak base macroreticular anion exchange resin) were found to have better uranium washing and plutonium eluting characteristics than any of the resins tested. However, the capacity of the pellicular resin was much lower than the other resins.  相似文献   

8.
Protein adsorption equilibria and kinetics are obtained experimentally for two multimodal cation exchange resins—Nuvia cPrime, which is based on a polymeric matrix, and Capto MMC, which is based on an agarose matrix. In both resins, the ligand contains a phenyl group, a carboxyl group, and a peptide bond but with a different arrangement. Transmission electron microscopy and inverse size exclusion chromatography indicate a bimodal distribution of pores in Nuvia cPrime, including small pores with 10 nm radius and pores larger than 400 nm, and a monodispersed distribution of pores in Capto MMC, averaging 32 nm in radius. Potentiometric titration curves show similar buffering ranges and pK a values for the ligands in both resins and a slightly higher ligand density for Nuvia cPrime. Equilibrium binding capacities for lysozyme and a monoclonal antibody (mAb) are also similar for both resins at comparable pH and salt concentrations, although Capto MMC shows a weaker dependence on salt concentration as a result of its more hydrophobic character. The main difference is the adsorption kinetics of the mAb, which is the larger of the two proteins studied. For both resins, as shown by means of confocal laser scanning miscopy, the adsorption kinetics is controlled by pore diffusion. Capto MMC with its smaller pores has a slower rate of mass transfer than Nuvia cPrime. As a result, for the mAb, much higher column dynamic binding capacities are obtained for Nuvia cPrime than for Capto MMC.  相似文献   

9.
Kinetics of two successive thermal decomposition reaction steps of cationic ion exchange resins and oxidation of the first thermal decomposition residue were investigated using a non-isothermal thermogravimetric analysis. Reaction mechanisms and kinetic parameters for three different reaction steps, which were identified from a FTIR gas analysis, were established from an analysis of TG analysis data using an isoconversional method and a master-plot method. Primary thermal dissociation of SO3H+ from divinylbenzene copolymer was well described by an Avrami–Erofeev type reaction (n = 2, g(α) = [?ln(1 ? α)]1/2]), and its activation energy was determined to be 46.8 ± 2.8 kJ mol?1. Thermal decomposition of remaining polymeric materials at temperatures above 400 °C was described by one-dimensional diffusion (g(α) = α 2), and its activation energy was determined to be 49.1 ± 3.1 kJ mol?1. The oxidation of remaining polymeric materials after thermal dissociation of SO3H+ was described by a phase boundary reaction (contracting volume, g(α) = 1?(1 ? α)1/3). The activation energy and the order of oxygen power dependency were determined to be 101.3 ± 13.4 and 1.05 ± 0.17 kJ mol?1, respectively.  相似文献   

10.
(1)H NMR spectroscopy and powder X-ray diffraction have been used to explore the details of anion exchange reactions of two layered hydroxy double salts (HDSs), zinc copper hydroxy acetate (ZCA), nickel zinc hydroxy acetate (NZA), and a related layered material, zinc hydroxy acetate (ZHA), at room temperature (21-22 degrees C). Reactions that followed Avrami-Erofe'ev kinetics with respect to temporal profiles for acetate release, ZCA with butyrate (k = 1.7 x 10(-3) s(-1)), and octanoate (k = 0.79 x 10(-3) s(-1)) anions, as well as ZHA with octanoate (k = 2.6 x 10(-3) s(-1)), demonstrate that rate constants for acetate release are influenced by the exchange anion relative size as well as by the solid precursor structure/composition. The reaction of NZA with octanoate deviated from expected Avrami-Erofe'ev behavior, with evidence for an intermediate species in the solid phase that may influence the rate of acetate release into solution. The reaction of ZCA with formate anions exhibited a unique zeroth-order kinetics release of acetate, providing the possibility of developing tunable nanostructured anion release sources by use of variations in the size of the exchange species.  相似文献   

11.
The resistance against radiation of the tertiary pyridine resins synthesized for the treatment of spent nuclear fuels and high level radioactive waste was evaluated. After irradiation at 10 MGy, only approximately 10% or less of the exchange groups were lost in HCl solutions regardless of their concentrations, while 3040% were lost in HNO3. The pyridine resin has shown remarkable resistance against radiation particularly in HCl solution. It has been revealed that the decomposition of pyridine type resins results from the scission of the principal chains. An irradiation study was conducted also on the quaternary ammonium resins. Quatemization ratio was found to be reduced in HNO3 solutions at 10 MGy irradiation.  相似文献   

12.
With fully micellar bound substrates reactions of OH- with benzoic anhydride, Bz(2)O, and of Br- with methyl naphthalene-2-sulfonate, MeONs, in micellized sulfobetaines are strongly inhibited by NaClO4 which displaces the nucleophilic anions from the micellar pseudophases. Micellar incorporations of ClO4- and Br- are estimated with an ion-selective electrode and by electrophoresis, and partitioning of Br- between water and micelles is related to changes in NMR spectral (79)Br- line widths. Extents of inhibition by ClO4- of these nucleophilic reactions in the micellar pseudophase are related to quantitative displacement of the reactive anions from the micelles by ClO4-. The kinetic data are correlated with physical evidence on the strong interactions between sulfobetaines and ClO4-, which turn sulfobetaine micelles anionic and effectively provoke displacement of OH- and Br-.  相似文献   

13.
A new methodology to immobilize ionic liquids through the use of a bridged silsesquioxane N-(3-triethoxysilylpropyl), N(3)-(3-trimethoxysilylpropyl-4,5-dihydroimidazolium iodide that incorporates an ionic functionality for the assembly of novel periodic mesoporous organosilica (PMO) materials has been developed. The resulting PMO materials were investigated for use as novel anion exchange resins for the separation of perrhenate anions in aqueous solution. As compared with cetyltrimethylammonium chloride, 1-hexadecane-3-methylimidazolium bromide has been demonstrated to be a more efficient surfactant template for the generation of mesopores and surface areas for such PMO materials.  相似文献   

14.
Further studies on the application of an AER (A(-) form) method broadened the anion exchange scope of representative ionic liquids and bis(imidazolium) systems. Depending on the hydrophobicity nature of the targeted imidazolium species and counteranions, different organic solvents were used to swap halides for assorted anions, proceeding in excellent to quantitative yields.  相似文献   

15.
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17.
D301R树脂吸附-解吸钼的行为研究   总被引:3,自引:0,他引:3  
对D301R型阴离子交换树脂吸附-解吸钼的条件进行了研究,采用静态法试验了pH值、钼的浓度等因素对该树脂吸附钼的影响;采用动态法讨论了该树脂对钼的饱和吸附量、解吸剂及其浓度对解吸钼的影响。结果表明在pH2.5,钼的浓度为20g/L时吸附效果最好,树脂对钼的饱和吸附量为1020mg/g,而采用150g/L NaOH溶液解吸钼效果最佳。  相似文献   

18.
The curing kinetics of lignin-novolac and methylolated lignin-novolac resins were studied using non-isothermal methods employing differential scanning calorimetry (DSC) at different heating rates. The Belichmeier, Ozawa and Kissinger methods were applied, which give the kinetic parameters of the curing process studied. In addition, the model-fitting Coats-Redfern method was used to analyze the experimental data. The kinetic study evaluated the effect of the lignin (softwood ammonium lignosulfonate), methylolated or not, on the resin curing process. Results for lignin-novolac and modified lignin-novolac resins were compared with a commercial novolac resin as a reference. When lignosulfonate is modified by methylolation and is incorporated in the novolac resin, there is an important reduction in activation energy. The lignin-novolac showed slightly higher values of activation energy than methylolated-lignin resins, but lower values than commercial resins. This behavior has been attributed to the extra methyol groups introduced by lignosulfonate.  相似文献   

19.
A fast ion chromatographic system is described which uses shorter column lengths and compares various eluent profiles in order to maximise the performance without sacrificing the chromatographic resolution. Both isocratic and gradient elution profiles were considered to find the most efficient mode of separation. The separation and determination of seven target anions (chloride, chlorate, nitrate, chromate, sulfate, thiocyanate and perchlorate) was achieved using a short (4 mm ID, 50 mm long) column packed with Dionex AS20 high-capacity anion exchange material. A hydroxide eluent was used at an initial concentration of 25 mM (at a flow-rate of 1.0 mL/min) and two performance maxima were found. The maximum efficiency occurred at a normalised gradient ramp rate of 5 mM/t0, resulting in a peak capacity of 16, while the fastest separation (<3 min) occurred at a normalised ramp rate of 30 mM/t0. The retention time, peak width and resolution using the different eluent profiles on varying column lengths is also compared. Further investigations in this study determined that the highest peak capacity separation under gradient conditions could be approximated using an isocratic separation. The advantage of using this novel approach to approximate the maximum efficiency separation removes the need for column re-equilibration that is required for gradient elution resulting in faster analyses and enhanced sample throughput, with benefits in particular for multidimensional chromatography.  相似文献   

20.
Conclusions An estimate was made of the effective distance of charge transfer and the effective frequency of the solvent polarization fluctuations from an analysis of the experimental activation energies of a number of symmetrical redox reactions between complex ions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2155–2157, September, 1973.  相似文献   

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