Synthesis of plutonium dioxide by citric acid-assisted Solution Combustion Synthesis

International audiencePlutonium dioxide synthesis is an essential step in fuel reprocessing, Solution Combustion Synthesis method (SCS) can offer advantages on fuel preparation. This study reports for the first time the synthesis of PuO$_2$ by SCS with citric acid. It allows to determine an optimal ratio for citric acid over plutonium ratio (CA/Pu=1.1) for PuO$_2$ synthesis, leading to oxides with SCSs characteristic morphologies

Zirconium(IV)–Benzene Phosphonate Coordination Polymers: Lanthanide and Actinide Extraction and Thermal Properties

International audienc

Dynamical and Structural Properties of Water in Silica Nanoconfinement – Impact of Pore Size, Ion Nature and Electrolyte Concentration

International audienc

Reinforced silica monoliths functionalised with metal hexacyanoferrates for cesium decontamination: a combination of a one-pot procedure and skeleton calcination

International audienceThe nuclear plant accident of Fukushima Daiichi occurred following a tsunami on March 11th 2011 and gave rise to the production of large volume aqueous outflows containing radioactive cesium and seawater. This problem urged researchers to develop materials suitable for high flux continuous sorption processes able to promote the selective entrapment of cesium while sodium is widely present in the contaminated outflows. This work is focused on the achievement of silica monoliths with hierarchical porosity (meso-and macropores) combining on one hand enhanced mechanical strength thanks to a calcination step and on the other hand a one-pot functionalisation procedure in order to insert metal hexacyanoferrate (MHCF) particles inside the pores. This combination is generally difficult to achieve due to the MHCF alteration for temperatures above 200 C. However, these problems can be avoided following the procedure described in this paper. Finally synthetic routes for meso/macroporous silica monoliths functionalised with sorbent particles highly selective towards cesium, CoHCF, CuHCF and ZnHCF are described. The weight ratio of MHCF reaches 7.1% wt with a total cesium sorption capacity of 24.1 mg g -1 in the case of monoliths functionalised with ZnHCF. This value is not altered by the presence of sodium in the aqueous solution. MHCF particles are located mainly inside the macropores while the mesopore network allows for a high exchange surface between the aqueous outflows and MHCF particles embedded in the monoliths

Biosourced adsorbent prepared with rice husk part 1: A complete understanding of the structure of materials, the major role of mineral impurities for metal extraction

Rice husk is a global agricultural co-product and is already the subject of several studies, notably for wastewater treatment. Rice husk is composed of 3 types of components: amorphous silica, organic biopolymers and others (salts, oxides…). Depending on the treatment, rice husk becomes either a carbon-free material or a mixed carbon/silica biochar. In this paper, a thorough characterisation of rice husk was carried out by SEM, TEM, TGA, XRF, XRD, XPS, FTIR, SAXS, SANS, NMR and N2 adsorption-desorption. The results show that silica can be present as dense silica or silica nanoparticles and that native organic matter can be converted to turbostratic carbon. This carbon “drowns” the silica nanoparticles and prevents them from sintering. Particular attention is paid to impurities which play a crucial role in several properties. They are present in different forms, such as CaCO3, KCl or Al2O3 or in the silica lattice. They can be removed, but if retained, they induce sintering and crystallisation of the silica nanoparticles, resulting in a decrease in specific surface area from 330 m2.g−1 to 15 m2.g−1. Moreover, the sorption efficiency of the materials is strongly dependent on the presence of impurities since the extraction rate drops drastically from 99% to <0.5% when the impurities are removed. The maximum capacity reached for nickel is 11.7 mg.g−1

Elaborating ordered silicon carbide nanorods by preceramic polymer nanocasting

International audienc

Conversion of actinide nitrate surrogates into oxide using combustion synthesis process: A facile approach

International audienc

Investigation of capillary ion chromatography for nuclear prospects

International audienceThe recent development of commercial capillary ion chromatography (Cap-IC) systems provides a major opportunity to increase the reactivity of laboratories and to reduce the amount of radioactive effluents produced from the chromatographic analyses in the nuclear field. As the column replacement in a radioactive environment is tedious, the retention behavior of IC columns was investigated at capillary scale to anticipate this operation

Structure evolution of mesoporous silica under heavy ion irradiations of intermediate energies

International audienc

Structure evolution of mesoporous silica SBA-15 and MCM-41 under swift heavy ion irradiation

International audienceTwo types of mesoporous silica pellets, SBA-15 and MCM-41, were prepared and irradiated by 20Ne 278 MeV (max. fluence = 2.5 × 1014 ion/cm2) and 36Ar 493 MeV beams (max. fluence = 1 × 1013 ion/cm2). Irradiated and non-irradiated samples were characterized by nitrogen adsorption/desorption analysis, small angle X-ray scattering, and infrared spectrometry. The different behaviours of the two materials under different conditions are observed and discussed. We point out that SBA-15 is more robust than MCM-41 under irradiation