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Indian nuclear energy program adopts the closed fuel cycle, which involves reprocessing of the spent fuel and offers an option for the recovery of valuables from radioactive waste. Some of the useful isotopes present in radioactive wastes, of societal and industrial applications, are 137Cs, 90Sr, Platinum Groups Metals (PGMs: Pd, Rh, and Ru), 238Pu, 241Am, etc. Among PGMs, Ru is used in electrical, electrochemical industries and radioactive isotope of Ru is being applied for the treatment of eye cancer. In the present work, we are focusing on the pre-concentration of Ru from aqueous media by sorption method. Sorption studies were carried out using inactive Ru as well as its radiotracers. EDXRF, γ-ray spectrometry and spectrophotometry were used as the tools for monitoring the sorption processes. For preliminary studies, polyaniline and manganese dioxide were used as sorbents. The sorption was found to be better using polyaniline. For the ease of separation process, composite polymers of aniline with tetraethoxysilane were synthesized and used. The composites were characterized using SEM-EDS, FTIR and elemental analysis techniques. Sorption studies with and without presence of Zr were done with the aim of separation of radioactive Ru from irradiated Zr alloy and recovery of Ru. [ABSTRACT FROM AUTHOR]

Abstract: Polyaniline (PAni) was synthesized by a chemical oxidation of aniline, using ammonium persulphate in 1M HCl and was investigated for radiation stability. The chloride salt as well as the base form of PAni (in air, water and HCl media) was subjected to gamma radiation using a 60Co source. Radiation induced effect on the stability of PAni was evaluated by the data obtained from elemental analysis and Fourier Transform Infrared (FT-IR) spectroscopy. Anion exchange capacities of PAni before and after gamma irradiation were determined by the neutron activation analysis technique from the measured chloride activity. The ion exchange capacity decreased with increase in the absorbed dose. Chloride form of PAni was more stable towards gamma-radiation compared to the base form. [Copyright &y& Elsevier]

Initially, Polyaniline (PAni) was synthesized in the powder form by chemical oxidative polymerization of aniline with ammonium persulphate in HCl medium. Further, composites of PAni with beads of silica gel, styrene-divinyl benzene resin beads and calcium alginate were prepared by in-situ chemical polymerization of aniline. Pre-formed base-PAni and tetraethoxysilane were used as precursors for the synthesis of PAni-siloxane composite disks. Ion exchange capacity of PAni powder was found to be 3.25 ± 0.084 meq g−1. PAni powder and its composites were characterized by elemental analysis, UV–visible and FTIR spectroscopy, TG-DSC, SEM, molecular weight and ion exchange capacity measurements. All the composites, except the alginate, were found to be thermally more stable than the powder form of PAni. The composite beads can be applied for future studies in the column mode of operations. Preliminary evaluation of the PAni-siloxane disc for arsenic sorption from aqueous solutions showed promising results. These disks are easy to handle, durable and the sorbed species can be directly quantified, i.e., without post-sorption processing, by energy dispersive X-ray fluorescence spectrometry. [Display omitted] • PAni powder as well as its composites was synthesized via the chemical route. • PAni was characterized by elemental analysis, FTIR, molecular weight, ion exchange. • Silica gel, XAD, calcium alginate and tetraethoxy silane were used as substrates. • Composites were characterized by SEM, thermal analysis, UV–visible & FTIR spectra. [ABSTRACT FROM AUTHOR]