A test method for determining palladium in chloride solutions on the solid phase of a fibrous anion exchanger

The sorption of palladium(II) from chloride solutions on polyacrylonitrile fiber filled with the AV-17 anion exchanger (PANF-AV-17) and its subsequent determination with p-nitrosodiethylaniline on the solid phase were studied. The results of determining palladium with this reagent on the solid phase of polyacrylonitrile fiber filled with the KU-2 cation exchanger and the AV-17 anion exchanger were compared. A test method was developed for determining palladium on the PANF-AV-17 solid phase. Sorption was performed in the batch mode; the analytical signal was estimated by measuring the diffuse reflection coefficient or visually using a color scale. The detection limit was 0.005 µg/mL; the range of the calibration scale was 0–0.2 µg/mL at the volume of the test solution 10–20 mL. The accuracy of the procedure was verified by the added-found method in the analysis of tap water and a standard reference sample of natural sodium chloride water. The relative standard deviation was no more than 25%; the time of the analysis of 5 or 6 samples was 25–30 min.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 85–90.Original Russian Text Copyright © 2005 by Dedkova, Shvoeva, Savvin.     

Determination of Mercury(II) with Dithizone by Diffuse Reflectance Spectrometry on a Fibrous Anion Exchanger

The possibility of the determination of mercury(II) with dithizone on the solid phase of a fibrous ion-exchange material filled with the AV-17 anion exchanger was studied. Mercury is adsorbed as an anionic complex. The sorption of mercury as chloride, iodide, sulfate, thiosulfate, nitrate, and EDTA complexes was studied. A procedure was proposed for the sorption–spectrometric determination of mercury with dithizone on a solid phase after sorption as the chloride complex. For improving the selectivity of the method, EDTA is added to the solution. The determination is affected only by Pd(II). The time of analysis is 15 min. The procedure was tested in the analysis of tap and river water and a solution modeling natural water.     

Sorption-spectroscopic determination of selenium using a PANV-AV-17 fibrous ion-exchanger

The possibility of determining selenium on the solid phase of polyacrylonitrile fibers impregnated by an AV-17 anion-exchanger ([PANV-AV-17]) were examined by virtue of diffuse reflectance spectroscopy. Reactions of a complex formation between selenium(IV) and organic reagents on solid phase as well as the formation of an elemental selenium sol both on the solid phase and in solution followed by absorption were studied. The best analytical parameters were achieved in the adsorption of selenium sol formed in solution upon the addition of ascorbic acid. The comparison of the batch and dynamic adsorption modes revealed greater advances of the dynamic one. The optimal conditions for determining selenium were proved as follows: the formation of a selenium sol in a 1% ascorbic acid solution at pH 2 and dynamic adsorption at a flow rate of 5 mL/min. A procedure was developed for determining selenium with a limit of detection of 0.1 mg/L. The procedure was validated by the added-found method in the analysis of river and well natural waters and also the standard specimen OSO-200-90, which also contained As, Bi, Sb, and PO₄³⁻. The duration of analysis for 5–6 samples of the volume 100 mL was 30 min approximately, RSD < 20%.     

Linear and nonlinear optical properties of dye-doped KDP crystals: Effect of thermal treatment

Potassium dihydrogen phosphate crystals (KDP, KH₂PO₄) doped with the organic xylenol orange (XO) dye are grown, the XO concentration in the crystal matrix is about 10 ppm. The spectral and luminescent properties of nominally pure, dye-doped and dye-doped/annealed at 150 °C crystals (KDP, KDP:XO and KDP:XO_an) were measured. The annealing temperature effect on the degree of dye protonation in the crystal matrix is established. Analysis of the IR-absorption spectra reveals a strong interaction between the incorporated dye molecules and the hydrogen subsystem of the matrix. The nonlinear optical (NLO) properties of KDP, KDP:XO and KDP:XO_an crystals are studied within the self-action effect of picosecond laser pulses at 532 nm. The mechanism of photoinduced bleaching and the effects of laser beam self-focusing (in KDP) and self-defocusing (in KDP:XO and KDP:XO_an) are supposed to be due to resonance excitation of the subsystems of intrinsic defects and dye molecules, correspondingly. For KDP:XO_an it is shown that thermal annealing of intrinsic crystal defects leads to domination of more effective NLO response of the subsystem of dye molecules that is correlated with photoluminescence data.     

Effect of complexants on the adsorption and color reactions of lanthanum(III), uranium(VI), thorium(IV), and zirconium(IV) with Arsenazo M in the solid phase of an ANKB-50 fibrous ion-exchanger

The effect of complexants—acetic, aminoacetic, tartaric, malonic, and oxalic acids; EDTA; and Na₂CO₃—on the adsorption and subsequent determination of thorium(IV), lanthanum(III), uranium(VI), and zirconium(IV) with Arsenazo M in the solid phase of polyacrylonitrile fiber filled with an ANKB-50 anion exchanger was studied. Complexing agents were introduced into the solution at the step of metal ion adsorption. It was shown that zirconium and uranium interacted with the iminodiacetate groups of the adsorbent in the course of adsorption; the adsorption of elements from 10^?3 to 10^?2 M complexant solutions (except for tartaric and oxalic acids and EDTA) under the optimum conditions was enhanced as compared to their adsorption from pure solutions; complexation with Arsenazo M in the solid phase proceeded at a higher acidity than in the solution. When the elements were present simultaneously, their total concentration and individual thorium could be determined from malonic acid solutions with Arsenazo M by varying the concentration of acid and the adsorption pH.     

Sensitivity and selectivity of the reaction of vanadium(V) with 4-(2-Pyridylazo)resorcinol on a solid support containing anion-exchange groups and modified with 8-hydroxyquinoline or 8-hydroxyquinoline-5-sulfonic acid

The effect of the modification of a solid support with 8-hydroxyquinoline (HQ) and 8-hydroxyquinoline-5-sulfonic acid (HQ-SFA) on analytical characteristics of the reaction of vanadium(V) with 4-(2-pyridylazo)resorcinol (PAR) on a solid phase was studied for polyacrylonitrile fiber filled with the AV-17 anion exchanger. Diffuse reflection spectra of the initial and modified supports and of vanadium(V) complexes of PAR on these supports were recorded. It was found that vanadium reacts with PAR on modified supports only in acid solutions. The conditions for the adsorption of vanadium and the dependences of the analytical signal on the acidity of the PAR solution and on the concentration of the modifier on the support were determined. The limits of vanadium detection by the reaction with PAR were calculated (0.5 and 1 ng/mL for AV-17-HQ and AV-17-HQ-SFA, respectively). The selectivity of the reaction of vanadium with PAR on modified supports was estimated with respect to copper, aluminum, iron(III), and zinc. It was found that the modification of the support with HQ and HQ-SFA impairs the analytical characteristics of the reaction of vanadium with PAR on the solid phase and that the use of modified supports for the color reaction of vanadium with PAR is inappropriat     

Discrete mathematical model of a sheet electron beam in a decaying magnetic field

A discrete model of a sheet electron beam is developed in a weakly relativistic approximation. A 3D simulation of the sheet electron beam with cyclotron rotation in an axially symmetric static magnetic field under time-periodic conditions of entry is performed. The velocity spread in the beam and the efficiency of converting the energy stored in the beam into DC power depending on the beam perveance are calculated.