Anion-exchange Paper Research Articles

Radioactive iodine waste treatment using electrodialysis with an anion exchange paper membrane

In order to simply and safely treat radioactive iodine waste, a study of the removal of iodide ion from radioactive waste using electrodialysis with an anion exchange paper membrane, in which trimethylhydroxylpropylammonium groups were homogeneously dispersed with high density. In Na 125I and Na 36Cl concentration-cell system, electric ion and water conductances, phenomenological coefficients, have been experimentally determined on basis of nonequilibrium thermodynamics. Prepared paper membrane had higher permselectivity of 125I ion than 36Cl ions by approximately 21%. On the other hand, water flux that was accompanied by an ionic transference in prepared paper membrane was greatly larger than that in typical synthesized membrane. It is suggested that a depression of water mobility is important to practice an ideal radioactive iodide waste electrodialysis system with a novel anion exchange paper membrane.

Effects of co-ions on transport of iodide ions through a non-conventional anion exchange paper membrane

To study the effects of co-ions on iodide ion transport through a novel anion exchange paper membrane containing trimethylhydroxypropylammonium groups with approximately 0.30 meq. g −1 dry-membrane ion exchange capacity, transmembrane potential, membrane conductance and ionic fluxes were measured in the concentration-cell system for seven kinds of iodine salts (1:1-electrolytes) at 10 −3 to 10 −1 mol dm −3. For analysis of ion transport, the electroconductive membrane permeability, representing the solution/membrane ion distribution due to electrostatic effects, and the diffusional membrane permeability, representing the migration speed of ions within the membrane phase, concerning ion pair diffusion, and increasing with co-ion penetration and diffusion, were introduced in terms of linear phenomenological equations. Electroconductive membrane permeabilities of iodide ions were found to increase linearly with increasing hydrated co-ion radii; r 2=0.855, while diffusional membrane permeabilities of iodide ions increased linearly with increasing crystal co-ion radii; r 2=0.899. These results for a paper membrane differ from those of synthetic amphoteric membrane and nanoporus membranes in which ions of both charges penetrate equally, in which membrane permeabilities decreased with increasing co-ion radii. This suggests that iodide ion transport may be partially controlled by co-ion transport dependent on surface cationic charge density rather than ion radii in the anion exchange paper membrane, as the pores are large enough for ions to freely permeate within membrane matrix.

Anion-exchange resins and iron oxide-impregnated filter paper as plant available phosphorus indicators in soils

In order to evaluate soil phosphorus (P) availability to wheat (Triticum aestivum L.), the extraction methods Mehlich 1, encapsulated anion-exchange resin (AER), anion-exchange resin in membrane form (AEM) and iron oxide-impregnated filter paper under water-saturated conditions (Pi) were evaluated in a microplot experiment using twenty soils of the Rio Grande do Sul State, Brazil, with widely varying physico-chemical and mineralogical properties. Determination coefficients (R2) between P amounts accumulated in wheat shoots and grains and soil P amounts determined by the tested methods were (p<0.01) 0.69 for Mehlich-1, 0.88 for AER, 0.84 for AEM, and 0.71 for Pi. Determination coefficients between wheat grain yield and extracted P were somewhat lower for all methods. Considering two soil groups according to their clay content, this relationship was higher for soils with >400 g kg−1 clay and lower for the others. Soil P amounts extracted by the resin methods were, on average, twice higher than those extracted by the Mehlich-1 method. This difference, however, was higher for clayey soils (>400 g kg−1 clay content). Lower correlation coefficients were obtained between P extracted by both resin methods and by the Pi method (0.78 and 0.81) or the Mehlich-1 method (0.73 and 0.76).

Separation of 125I from Radioactive Waste with Anionexchange Membrane Treated with Trimethylhydroxypropylamino Group

The membrane characteristics controlling 125I and 36Cl transport across anion exchange paper membranes are examined using four different ion exchange capacities paper membranes treated with trim ethylhydroxypropylamino group. Nonequilibrium thermodynamic analyses for the paper membrane transport process are carried out based on transmembrane potential, membrane conductance, and ion flux measurements. The electroconductive membrane, permeabilities representing the solution membrane ion distribution due to electrostatic effects, and the diffusional membrane permeabilities, representing the migration speed of ions within the membrane phase, for 125I are higher than those for 36Cl in all cases. In the paper membrane treated with trim ethylhydroxypro-pylamino group, 125I diffusion or 125I solution/membrane distribution process can be improved by increasing the concentration of anion exchange sites in the paper membrane. These findings indicate the potential utility of paper membranes prepared in this way for separating 125I from radioactive waste that has been contaminated with chloride ions. The 125I transport performance of such systems may be improved with the use of other anion-exchange groups.

Transport of 125I and 36Cl across an anion-exchange paper membrane

The membrane characteristics controlling 125I and 36Cl transport across anion-exchange paper membranes are examined using three different paper membranes treated with different anion exchange groups: a trimethylhydroxypropylamino group, a diethylaminoethyl group, and a 50% quaternary diethylaminoethyl group. The membrane permeability for 125I is higher than that for 36Cl in all cases. Treatment with trimethylhydroxypropylamino group improves the 125I diffusion process, and the use of 50% quaternary diethylaminoethyl group improves the 125I solution/membrane distribution process.

Influence of glucose and urea on 125I transport across an anion exchange paper membrane

In order to study the influence of glucose and urea on the 125I transport across an anion exchange paper membrane, the transmembrane potential, the fluxes, and the concentrations of 125I, glucose and urea within the membrane were measured in the Na 125I concentration-cell system containing glucose or urea. Glucose and urea increased the membrane/solution distribution of the iodide ion, but scarcely affected the diffusion process of iodide ion within the membrane.

Removal of 125I from radioactive experimental waste with an anion exchange paper membrane

The behavior of radioactive iodide and chloride ions through an anion exchange paper membrane to remove 125I from radioactive experimental waste has been studied with nonequilibrium thermodynamic analyses. Anion exchange paper membrane was found to be electroconductively more permeable to iodide ion than to chloride ion. The iodide ion bound more strongly to the anion exchange site within a membrane phase than the chloride ion by more than twice. The results suggested that an anion exchange paper membrane was appropriate for the filtration removal system.

濾紙膜を用いた放射性実験廃液からの&lt;SUP&gt;125&lt;/SUP&gt;Iの濾過型除去

The characteristics of an anion exchange paper membrane and an activated carbon loaded paper membrane to remove 125I from radioactive experimental waste in filtration system have been studied with various solutions which were filtrated. These paper membranes have the large solution fluxes in comparison with the column loaded with the anion exchange resin or the activated charcoal though the former totally bound less iodide ion than the latter. These feature suggest that the paper membranes might be utilized to treat a large quantity of radioactive waste, in which 125I concentration slightly exceeded the dose limit. Notably, the anion exchange paper membrane possesses the three outstanding characteristics; 1) the rapid binding to the 125I ion, 2) less influence of the substances, e.g. cell fragments, coexisted in the solutions on the 125I adsorption than the activated carbon loaded paper membrane, and 3) higher selective adsorption to iodide ion than to the bromide and chloride ions. The results suggested that an anion exchange membrane might be appropriate for the filtration remov-ing system.

Separation and purification of dolichol and dolichyl phosphate by anion-exchange paper chromatography: Application to cultured cells

Dolichyl phosphate, dolichol C80–105 (dolichol 17:dihydroheptadecaprenol-dolichol 21:dihydrohexeicosaprenol), and dolichol C55 (dolichol 11:dihydroundecaprenol) were separated by anion-exchange paper chromatography. Squalene, sterols, phospholipids, anionic glycolipids, and glycerol did not migrate as dolichyl phosphate, dolichol C80–105, and dolichol C55 under our elution conditions. However, since the R f of triglycerides was similar to that of dolichol C80–105, saponification, prior to chromatography, removed traces of triglycerides. Silica gel thin-layer chromatography (TLC) allowed the separation of dolichol C80–105 from dolichol C55, whereas dolichyl phosphate was eluted with other lipids. Incubation of spontaneously transformed cells derived from rat astrocytes primary cultures with [2- 14C]acetate, saponification of the extracted lipids, and anion-exchange paper chromatography revealed the presence of radioactive dolichyl phosphate and dolichol C80–105 (15 pmol/mg protein). Extraction of labeled dolichyl phosphate followed by acid phosphatase treatment and subsequent analysis on TLC confirmed the identity of dolichyl phosphate since all the radioactivity was associated with dolichol C55. Treatment of the transformed cells with 30 μ m 7-ketocholesterol or 7β-hydroxycholesterol stimulated markedly (two- to threefold) the incorporation of [2- 14C]acetate in both dolichol C80–105 and dolichyl phosphate. These data demonstrate that anion-exchange paper chromatography is technically suitable for the separation and analysis of dolichol C55, dolichol C80–105, and dolichyl phosphate in cultured cells prelabeled with radioactive precursors.

Simultaneous sequencing of RNA by solid-phase chemical degradation using DE 81 anion-exchange paper

A solid-phase chemical degradation method for simultaneous sequencing of RNA and RNA fragments has been developed using Whatman DE 81 anion-exchange paper as the support. The approach involves the following operations: (1) immobilization of the 3′-end labeled RNAs or RNA fragments on DE 81 paper; (2) washing; (3) modification reactions; (4) washing; (5) sorting of the paper segments; (6) aniline reaction; (7) lyophilization; (8) desorption of the RNA by TEAB; and (9) lyophilization.

Optimized conditions for solid-phase sequencing: simultaneous chemical cleavage of a series of long DNA fragments immobilized on CCS anion-exchange paper

A solid-phase method for simultaneous sequencing often or more long DNA fragments has been developed, using as support the cellulose matrix for chemical sequencing (CCS), anion-exchange paper [Rosenthal et al., Nucl. Acids Res. 13 (1985) 1173–1184]. We optimized several of the seven steps which include: (i) immobilization; (ii) washing; (iii) modification; (iv) washing; (v) sorting of the paper segments; (vi) piperidine reaction and chemical elution, and (vii) lyophilization. During carrier-supported chemical cleavage with dimethylsulfate (DMS) (G), HCOOH (A + G), KMnO 4 (T > Pu) and NH 2OH (C), losses of immobilized DNA are very low. DNA fragments ranging in length from several hundred bp up to 6 kb can be effectively chemically eluted from CCS paper during the piperidine reaction with an efficiency of more than 90%. Because no DNA salt elution and ethanol precipitation steps are necessary the method is rapid, convenient and allows complete automation.

Thrombin induces the rapid formation of inositol bisphosphate and inositol trisphosphate in human platelets

Human platelets prelabeled with [ 3H]inositol were exposed to thrombin. The aqueous soluble inositol phosphates were separated by anion exchange column chromatography, paper chromatography or high-performance liquid chromatography, and identified by cochromatography with authentic standard substances. Thrombin immediately induces the rapid formation of inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate. Accumulation of inositol-1-monophosphate and inositol-2-monophosphate occurs later after a time lag of 10 sec. The results indicate that the phospholipase C induced polyphosphoinositide hydrolysis rather than the phosphatidylinositol hydrolysis is the triggering event for platelet activation, and support the concept of inositol 1,4,5-trisphosphate as putative second messenger.

Solid-phase methods for sequencing of nucleic acids I. Simultaneous sequencing of different oligodeoxyribonucleotides using a new, mechanically stable anion-exchange paper.

A solid-phase method for simultaneous sequencing of large numbers of oligodeoxyribonucleotides has been developed using a new, mechanically stable anion-exchange paper. The excellent mechanical properties of the polymer allow the processing of several paper segments in one reaction vessel or to carry out all necessary operations on a larger area of the paper. In addition, DNA material can be chemically eluted from the new carrier during the piperidine reaction, thus avoiding salt elution of DNA and subsequent ethanol precipitation steps - a prerequisite for sequencing oligonucleotides. The approach involves 7 operations including: i) immobilization; ii) washing; iii) modification; iv) washing; v) sorting of the papers; vi) piperidine reaction and chemical elution and vii) lyophilization. All steps can be carried out in 4 to 5 hours independently of the number of oligonucleotides to be sequenced. It is also possible to sequence small oligonucleotides with 3 to 4 base pairs. The method can be fully automated.

Determination of traces of mercury and barium in mineral-containing water by selective retention on ion-exchange papers and x-ray fluorescence spectrometry

Mercury(II) is collected from dilute hydrochloric acid solutions on anion-exchange paper disks; barium ions are collected on cation-exchange paper disks after separation by coprecipitation with lead chromate and dissolution of the precipitate in 1,2-diaminocyclohexanetetraacetic acid which also serves as masking agent. The disks are then subjected to x-ray fluorescence spectrometry. The method is satisfactory for mg kg −1 levels of the two ions in the presence of large amounts of sodium, calcium and magnesium ions (e.g., in synthetic sea water and Contrexeville water). Various procedural modifications are discussed.

Comparative evaluation of two substrates for urinary determination of p-aminobenzoic acid by room-temperature phosphorimetry

Filter paper (S & S 903) impregnated with diethylenetriaminopentaacetic acid, and Whatman DE-81 anion-exchange paper are evaluated for quantitation of urinary p-aminobenzoic acid. The two substrates are compared with respect to drying characteristics, pH variations, heavy atom effect, and some other variables. Impregnated S & S 903 paper is superior in terms of drying characteristics and background interferences but DE-81 has several advantages including lower detection limit, wider pH range, and ready availability. Although both substrates seem applicable to clinical application, DE-81 is probably more useful.

The use of ion-exchange filters for the determination of iodide in milk by X-ray fluorescence spectrometry.

An X-ray fluorescence spectrometric method has been developed for the quantitative determination of iodide in milk which makes use of anion-exchange filters for the isolation and concentration of iodide from the liquid samples. The milk is deproteinized with trichloroacetic acid, filtered then passed through an anion-exchange paper disc to remove the iodide. The disc is removed, dried then analysed by X-ray fluorescence spectrometry. Six samples, consisting of homogenized, 2% fat and skim milk were analysed and found to contain between 0.37-0.67 ppm iodide. Detection limits in milk were estimated to be 0.05 ppm.

Bestimmung von refraktärmetallen in pflanzlichem material durch röntgenfluoreszenzanalyse nach anreicherung

An x-ray fluorescence spectrometric method is described for determining molybdenum, tungsten, niobium and tantalum in plant material. The sample is decomposed with nitric acid, hydrogen peroxide and hydrofluoric acid, and the refractory metals are collected on an anion-exchange paper and quantified by wavelength-dispersive x-ray fluorescence spectrometry. The decomposition of the sample and the enrichment of the elements on the ion-exchange paper including the mutual interference of the elements were investigated by using the radiotracer technique. In all cases, recoveries exceeded 95%. For about 1 g of sample material, limits of detection between 0.3 μg g −1 (Mo) and 0.6 μg g −1 (Ta) are achieved. After the same decomposition procedure, molybdenum was also determined by flame atomic absorption spectrometry; the sensitivity was 0.7 μg ml −1 for 1% absorption. The results for molybdenum and tungsten obtained on different grass samples are discussed in detail. The accuracy of the technique was checked for molybdenum and tungsten by instrumental neutron activation analysis; the results agreed within 5–11%.

Determination of zirconium, molybdenum, hafnium, and tungsten in niobium and tantalum by x-ray fluorescence spectrometry after separation from matrix and preconcentration

A method for the determination of Zr, Mo, Hf, and W in niobium and tantalum is described. This method is based on the removal of the matrix elements by extraction with diantipyrylmethane in dichlorethane from HF medium followed by the collection of the elements to be determined on an anion exchange paper suitable for X-ray fluorescence measurement. The recovery studies were carried out with the radiotracer technique. The recoveries for the individual elements with regard to the whole procedure are between 83.1 +/- 2.3% (Mo) and 93.9 +/- 1.4% (Hf). Limits of detection for all four elements ranged from 0.2 to 0.25 ..mu..g/g. This method was applied to the analysis of samples of different purity grade and the results are compared with those obtained by activation analysis.

A simplified assay of enzymes catalyzing ATP-pyrophosphate exchange reactions

The ATP-pyrophosphate exchange reaction is a widely used method for determination of the activity of enzymes forming enzyme-adenylate intermediates in the course of their catalytic action (1–4). For separation of the labeled ATP formed in the enzyme-catalyzed reaction from the labeled pyrophosphate, the adsorption of ATP on activated Norit is generally used. This method, however, is rather time consuming (considering the extensive washings required for the removal of pyrophosphate from Norit), and its reproducibility is highly dependent on pretreatment of charcoal with acid, Another method of separation applies anion-exchange paper (5). According to our experience, separation on DEAE-cellulose paper (Whatman DE 81) is not sufficient. The present paper describes a simple and reproducible thin-layer chromatographic method for the separation of ATP and pyrophosphate. The system consists of commercial chromatoplates precoated with strong anion-exchange resin (Ionex-25 SB-Ac or Fixion 2X8) and 0.1 m aqueous sodium pyrophosphate, pH 8, as developing solvent.

I. Particle size effects

Abstract Fused calcium-magnesium phosphate in four size ranges and powdered superphosphate were compared as phosphate sources in pot culture and incubation experiments. When the fertilisers were mixed through the soil, 100–120 mesh and finer than 200 mesh BSS sieve size ranges of fused phosphate were identical, and were equivalent to superphosphate finer than 30 mesh as phosphate sources for ryegrass. Size ranges 30–52 and 16–25 mesh were progressively inferior, yielding total phosphorus uptakes which were 74% and 46% respectively of that from the finer fractions. Anion exchange paper tests showed that in 16 days fused phosphate particles finer than 100 mesh reacted almost completely with moist soil, whereas particles from the two coarser fractions persisted as discrete phosphatic particles for up to 244 days.