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In this work, luminescent triangular silver nanoparticles were synthesized by radiolytic reduction method. The results showed that by variation of irradiation dose, morphology of silver nanoparticles can be converted from spherical to triangular. These shape variations mainly arise from competition between adsorption rate of polymer chains on (111) facets and reduction rate of the Ag ions along (110) facets during increasing dose. Furthermore, the dramatically enhanced photoluminescence spectra were observed from triangular Ag nanoparticles. This unusual behavior can be explained by excitation of dipolar and quadrupolar resonance in triangular nanoparticles which increase the electric fields at the surface. [ABSTRACT FROM AUTHOR]

The results concerning the reduction of U(VI) adsorbed on anion exchange resin as uranyl chloro complexes and sulfate complexes with V(III) in HCl and HSO solution are presented. The reduction of uranyl sulfate adsorbed on anion exchange resin (UOSO) in 0.05 M sulfuric acid was carried out, the reaction rate being first order with respect to both concentrations: [U(VI)] and [V(III)]. From Arrhenius plot the activation parameters of the reaction between U(VI) and V(III) in sulfuric acid solution were determined: E = 34.9 ± 0.9 kJ/mol; Δ Η = 35.5 ± 0.9 kJ/mol and Δ S = −165.7 ± 3 J/K mol. The reduction reaction rate makes possible the utilization of this reaction for displacement of the uranium adsorption band in a U separation column packed with anion exchange resin. [ABSTRACT FROM AUTHOR]

The present study involves the screening of silver nanoparticles containing carbonized yeast cells isolated from coconut cell sap for efficient adsorption of few long lived radionuclides like Cs, Co, Ru, Pu and Am. Yeast cells containing silver nanoparticles produced through biological reduction were subjected to carbonization (400 °C for 1 h) at atmospheric conditions and their properties were analyzed using fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscope. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells without silver exposure (CCY) did not contain any particles on its surface. The efficiency of CSY and CCY towards the radionuclide adsorption was studied in batch mode at fixed contact time, concentration, and at its native pH. CSY was efficient in removal of Pu (76.75%) and Ru (54.73%) whereas CCY showed efficient removal only for Am (62.89%). Both the adsorbents did not show any retention with respect to Co and Cs. Based on the experimental data, decontamination factor and distribution coefficient ( K) were calculated and, from the values, it was observed that these adsorbents have greater potential to adsorb radionuclides. [ABSTRACT FROM AUTHOR]