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Results for “ION EXCHANGE RESINS”

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At least 685 records · Page 38Linked to original sources
PubMed2005

High-speed ion-exclusion chromatography of dissolved carbon dioxide on a small weakly acidic cation-exchange resin column with ion-exchange enhancement columns of conductivity detection.

The high-speed ion-exclusion chromatographic determination of dissolved carbon dioxide, i.e., carbonic acid, hydrogencarbonate or carbonate, with conductivity detection was obtained using a small column packed with a weakly acidic cation-exchange resin in the H+-form (40 mm long x 4.6 mm i.d., 3 microm-particle and 0.1 meq./ml-capacity). Two different ion-exchange resin columns, which were a strongly acidic cation-exchange resin in the K+-form and a strongly basic anion-exchange resin in the OH- -form, were connected after the separation column. The sequence of columns could convert dissolved carbon dioxide to KOH having high conductivity response. The enhancement effect for dissolved carbon dioxide could retain even on the vast chromatographic runs, by using the enhancement columns with high ion-exchange capacity above 1.0 meq./ml. The retention time was in 60 s at flow-rate of 1.2 ml/min. The calibration graph of dissolved carbon dioxide estimated as H2CO3- was linear in the range of 0.005-10 mM. The detection limit at signal to noise of 3 was 0.15 microM as H2CO3-. This method was applicable to several rainwater and tap water samples.

Carbon Dioxide↗
PubMedDate not supplied

[Elimination of phenylalanine from amino acid mixtures obtained from yeast hydrolysates and autolyzates].

In order to obtain amino acid mixtures devoid of phenylalanine, adsorption of aromatic amino acids was studied during their chromatography on ion-exchange resin IA-Ip. When 40 g of the amino acid mixture were passed through 400 ml of the swollen ion-exchange resin, phenylalanine and tyrosine were eliminated and 67% of dry substance were yielded. Ion-exchange resin adsorbed phenylalanine and tyrosine could be regenerated. The use IA-Ip is advantageous as compared with that of ion-exchange resin Amberlite IR-45 and activated charcoal.

Adsorption↗
PubMed1961

Ionic requirements of Treponema pallidum. III. Divalent ions.

Doak, G. O. (University of North Carolina, Chapel Hill), Leon D. Freedman, and John W. Clark, Jr. Ionic requirements of Treponema pallidum. III. Divalent ions. J. Bacteriol. 82:909-912. 1961.-Suspensions of Treponema pallidum, prepared by extracting the testes of syphilitic rabbits with normal rabbit serum or with a culture medium, were shaken with Amberlite IRC-50 resin in the sodium ion form. This procedure did not noticeably reduce the number of motile organisms, but markedly decreased their ability to survive in vitro. The addition of calcium, strontium, or barium ions to the treated suspensions largely restored this loss of motility. These same ions, when added to suspensions of T. pallidum not treated with the ion exchange resin, were without effect. Magnesium ion also had a beneficial effect, but considerably less than that produced by calcium ion. Cobaltous, manganous, ferrous, and zinc ions gave no beneficial effect, and, except for manganous ion, were toxic to the organisms at 5 x 10(-3)m.

Animals↗
PubMed2006

Separation and recovery of lead from a mixture of some heavy metals using Amberlite IRC 718 chelating resin.

A weakly acidic ion exchanger resin containing the iminodiacetate group has been used to separate and recover metal ion from their mixtures. Batch and column methods were applied for the separation studies. Previous study on the kinetics and thermodynamics shows that the selectivity of this resin for transition metals was quite high as compared to that of alkaline earth metals. The efficiency of this resin in different experimental conditions was established and because of the large difference in the distribution coefficient values separation of the metal ions from their mixture was performed.

Alloys↗
PubMed2003

The effect of resin particle size on the rate of ion release: interactions in mixed bed systems.

The aim of the present study is to evaluate the influence of resin particle sizes on the rate of ions release from a mixture of ion-exchange resins (named NMTD) which supplies calcium, fluoride, and phosphate ions as the main mineral content, and to elucidate the different phenomena taking place through the related ion-exchange process. The final goal of the study, related to dental application (enamel restoration), is to limit the particle size range, since the rate of ion release is a key parameter in the successful achievement of such objective. Weak-type ion-exchange resins, loaded with the appropriate ions, were ground and sieved into granulometric fractions of bead diameters of 0.1-0.075, 0.075-0.063, and 0.063-0.05 mm. Particle size was controlled by a laser diffraction particle distribution analyzer. The experiments on the kinetics of ions release were carried out under batch conditions in artificial saliva desorption solution thermostatized at 37 degrees C. The release of Ca(2+) and F(-) was determined by corresponding ion-selective electrodes automatically controlled, whereas H(2)PO(4)(-) was measured spectrophotometrically by the inductively coupled plasma-optical emission technique (ICP-OES). The results of this study show that the process of ion-exchange for the different particle size fractions of resins is critical for the study of the kinetics release of the ions immobilized in the corresponding mixed bed polymeric matrices. In fact, despite the apparent narrow range of particle sizes of the mixed bed systems studied, appreciable differences in the rate of ions release are obtained. Since the ion release rate is depending on the contact surface, an increase of factor of 2 in particle size represents an increase of an order of magnitude of the resin contact surface due to the resin porosity. In this concern, it has been observed that the rate of ions release increases when particle size decreases. The interactions occurring during the ion release from the mixed bed resins (containing calcium-, fluoride-, and phosphate-loaded resins) can be interpreted by the following phenomena: H(2)PO(4)(-), which hardly modifies its rate of release in the presence of Ca(2+) and F(-) in the mixture, promotes a considerable increase in the rate of Ca(2+) release due to the formation of a calcium dihydrogen phosphate soluble complex. F(-) also produces an acceleration in the rate of Ca(2+) release due to the formation of solid CaF(2 )on the surface of cationic resin particles, which in contrast leads to a decrease in the rate of F(-) release.

Journal Article↗
PubMed2006

A comparison of low-cost biosorbents and commercial sorbents for the removal of copper from aqueous media.

Three biosorbents, crab carapace, the macroalgae Fucus vesiculosus and peat were compared with two commercial materials, an activated-carbon and an ion-exchange resin for the removal of copper from aqueous media. Kinetic models of Lagergren first-order, pseudo-second order and intraparticular diffusion were used to model the data. The process for all materials is best represented by the pseudo-second order rate model. Langmuir and Freundlich isotherms were used to describe the sorption equilibrium data. Maximum uptake values were 79.4, 114.9 and 71.4 mg g(-1) for crab carapace, F. vesiculosus and ion-exchange resin, respectively. Langmuir and Freundlich isotherm models could not be fitted to the experimental data for peat and activated-carbon. Ion-exchange was calculated to contribute approximately 75%, 77% and 44% to the total biosorption by crab carapace, F. vesiculosus and peat, respectively. The removal efficiencies of crab carapace and F. vesiculosus were >95% and comparable with those achieved using ion-exchange resin. Results from this study suggest that both crab carapace and F. vesiculosus are efficient and effective biosorbent materials for the removal of copper from aqueous solutions and given that they are also low-cost, may be considered viable alternatives to activated-carbon and ion-exchange resin.

Absorption↗