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  • Author or Editor: M. Mallah x
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Abstract  

This study deals with durable borosilicate glasses for the immobilizing of radioisotopes from nuclear waste streams generated by a radiopharmaceutical production unit. In this regard, different boron frits (glasses) and waste-loaded glasses were prepared under various experimental conditions. The effects of some parameters such as melting temperature, cooling procedure and various raw materials were investigated. The best composition of the frits as well as the best glass/waste ratio was determined to optimize the immobilization process. All experiments were performed in non-active bench scale.

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Abstract  

A new preconcetration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol (PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78 were obtained for Sm, Eu, Gd and Dy, respectively.

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Abstract  

In the present work, results of γ-irradiation on normal and functionalized SBA-15 by aurintricarboxylic acid have been reported. Characterization of normal and functionalized SBA-15 particles before and after γ-irradiation was carried out using Fourier-transform infrared technique. Aurintricarboxylic acid ligand connected to SBA-15 was also analyzed using UV/Vis spectrophotometer. The modified sorbent was then used as a new sorbent for separation of trace amounts of praseodymium and lutetium ions from nuclear waste waters in batch techniques. Based on the results of distribution coefficients determination, and investigation of sorption process in various conditions, the parameters were optimized for separation lanthanides. It can be concluded that the functionalized SBA-15 is a promising sorbent for praseodymium and lutetium cations.

Open access

Summary  

This study deals with the treatment of Cs+and Sr2+by using natural clinoptilolite from Ardakan region (Yazd province) of Iran and its relevant zeolite P as well as the vitrification process for immobilizing the Cs and Sr radionuclides in borosilicate glass matrices. The evaluation of various samples was carried out using X-ray techniques (XRF, XRD) as well as atomic absorption spectroscopy (AAS) for leaching experiments.

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Summary

A rapid and reliable analytical procedure has been developed for the separation and analysis of dioxouranium, thorium, gold, and mercury by micellar electrokinetic chromatography (MEKC) using bis(acetylacetone)ethylenediamine (H2AA2en) as complexing reagent. Under the optimized conditions (64 mm borate buffer containing 12.25 mm SDS and 13% acetonitrile, pH 8.0, 25 kV, 311 nm as detection wavelength) the ions were separated within 5.0 min. Linear dynamic ranges were 1–5, 8–42, 10–50, and 2–40 μg mL−1, respectively, for gold, mercury, thorium, and uranium and the respective detection limits were 0.66, 3.33, 1.6, and 3.3 μg mL−1. The applicability of method has been evaluated by application to uranium and thorium from ore samples.

Open access

Summary

Bis(salicylaldehyde) orthophenylenediamine (BSOPD) is reported here as a complexing reagent for simultaneous determination of six metal ions, gold, chromium, iron(II)/(III), uranyl, and nickel, by capillary zone electrophoresis. The pre-derivatized complexes were injected onto 50 cm bare silica capillary (i.d. 75 µm) with background electrolyte 50 mM citrate:oxalate buffer in 1:1 at pH 4. All metal ions were separated within 15 min including coexisted ions at applied voltage of −15 kV at detection wavelength of 250 nm. Under the abovementioned conditions, limits of quantification and detection were found to be 0.5, 1.0, 1.0, 10.0, 1.0, and 10.0 µg mL−1; and 0.16, 0.33, 0.33, 3.33, 0.33, and 3.33 µg mL−1 for Au(III), Cr(VI), Fe(III), Fe(II), UO2(II), and Ni(II), respectively. Linear calibration graphs were obtained in the ranges of 0.5–100, 1–200, 10–100, 1–100, 1–100, and 10–200 µg mL−1 with the correlation coefficient values 0.9964, 0.9948, 0.9900, 0.9999, 0.9992, and 0.9918 for Au(III); and Cr(VI), Fe(III), Fe(II), UO2(II), and Ni(II), respectively. Applicability of the method has been evaluated by determining gold from wastewater samples of goldsmith factories and uranyl from ore samples. The developed method was also used for the determination of chromium in selected environmental waters (drinking and polluted). The data obtained with developed method were compared with those obtained from atomic absorption spectroscopy, and the results of the analysis were found to be in good agreement.

Open access