Development of MOF-type Hybrid Functionalized Materials for Selective Uranium Extraction

International audienceDifferent types of materials have been developed for the solid/liquid uranium extraction processes, such as functionalized organic polymers, hybrid silica or inorganic adsorbents. In general, these materials exhibit a moderate affinity for uranyl ions and poor selectivity against impurities like iron, vanadium or molybdenum. Moreover, the structural organization deficiency of these materials generates ion diffusion issues inside the material. Therefore, the aim of our study is to developed novel efficient and organized materials, stable in the acid media encountered in uranium extraction processes.Metal organic frameworks (MOFs) are hybrid crystalline materials consisting of an inorganic part (cluster or metal ions) and tailored organic linkers connected via coordination bonds. These hierarchical materials have exceptional surface area, thermal stability and a large variety of tunable structures. However, due to the reversibility of constitutive coordination bonds, MOFs have moderate stability in strongly complexing or acidic media. Only few of them are known to be stable in aqueous media and only one example is described in strong acidic media. However, these conditions are very often encountered in the environmental pollution remediation of mine wastewaters. To tackle the challenge of developing MOFs adapted for uranium extraction from acid mine waters, we have investigated the stability of several materials. To ensure a good stability we have synthetized and characterized different materials based on highly coordinated metal clusters, such as LnOFs and Zirconium based materials. Among the latter, the UiO family shows a great stability in sulfuric acid media even in the presence of 1.4 M sodium sulfate at pH 2. However, the stability in phosphoric media is reduced due to the high affinity between zirconium and phosphate ligand. Based on these results, we have developed a tertiary amine functionalized MOF denoted UiO-68-NMe2 particularly adapted for the extraction of anionic uranyl(VI) sulfate complexes mainly present in the acid mine solutions. The adsorption capacity of the material has been determined upon varying total sulfate concentration, contact time and uranium concentration. The extraction tests put in evidence different phenomena due to the complexity of the extraction media and the interaction between the MOF and sulfate anion. Finally, the extraction mechanisms and the interaction between uranyl and the MOF structure have been investigated. The functionalized material UiO-68-NMe2 has been characterized in the presence and absence of uranium by FT-IR, UV and Raman techniques. Moreover, the stability of the protonated amino functionalized MOF has been evaluated. The synthesis, characterization and evaluation of this type of hybrid material, particularly adapted for uranium extraction in sulfuric acid media by an anionic exchange mechanism, paved the way for the development of novel metal organic frameworks functionalized by different other chelating motifs, such as bifunctional ligands showing an enhanced affinity and selectivity for uranium in acid and complexing media. Work in this direction is currently in progress

Élaboration de matériaux hybrides fonctionnalisés de type MOF pour l'extraction sélective de l'uranium

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Enhanced extraction of rare earth elements by novel tuned diglycolamides

International audienceRare earth elements (REE) are essential for our modern economy, in relation to the development of new energy and communication technologies, however their recycling from electronic waste and end-of-life products (such as permanent NdFeB magnets, Ni-MH batteries, etc.) is still not sufficiently developped.1 Although substitution of these materials by less critical ones is growing faster and faster especially in Japan efficient and eco-designed recycling processes will be of great importance in a near middle term. Depending on their technoeconomics efficiency and environmental footprint, hydrometallurgical processes enabling the recovery of separated elements could be of particular interest.Typically these processes include a first pretreatment (crushing, milling, sieving,) followed by an acidic leaching step (with possibly selective precipitation substeps) and a solvent extraction step (SX) in order to separate and purify the REE.2 Recently, diglycolamides (DGAs) appeared as a very interesting group of extractants for the recovery of trivalent lanthanides from nitric acid solutions, particularly in the presence of metal ions commonly found in waste products.3 The TODGA extractant (N,N,N',N'-tetraoctyl diglycolamide) was successfully used for designing a full REE recycling SX process from used permanent magnets.4 Nevertheless its performances have not yet been validated against upscaling tests.Most works concerning the group of DGAs dealt with symmetrical extractants exhibiting different separation efficiencies for REE in nitric acid media. The chain length modification on one side of the DGA (asymmetrical DGAs) can lead to important variation in selectivity during the Eu/Am separation.5 Recently, new dissymmetrical DGAs with very short chains were reported for REE extraction, such as for instance MODGA (N,N'-dimethyl-N,N'dioctyl-diglycolamide),6 however their solubility in industrial diluents is rather limited.The present work describes the organic synthesis of several novel DGAs and their solvent extraction behaviour towards REE in several aqueous acid media which could increase the industrial interest of such SX process. These new ligands displayed a remarkable improvement of REE extraction efficiency compared to reference TODGA in acid media, while presenting a good solubility in industrial aliphatic diluents. Furthermore, the separation factors of REE towards major impurities such as Fe3+ are substantially improved. Figure Distribution ratio of a novel DGA compared to TODGA in an acid solutionNevertheless it will be of primary importance to check whether the REE can be quantitatively de-extracted from the organic phase without any impurity. These promising results will also contribute to the design of an optimized SX process for the separation of REE

DNAJB9 Is a Specific Immunohistochemical Marker for Fibrillary Glomerulonephritis

Fibrillary glomerulonephritis (FGN) is a rare disease with unknown pathogenesis and a poor prognosis. Until now, the diagnosis of this disease has required demonstration of glomerular deposition of randomly oriented fibrils by electron microscopy that are Congo red negative and stain with antisera to Igs. We recently discovered a novel proteomic tissue biomarker for FGN, namely, DNAJB9. Methods: In this work, we developed DNAJB9 immunohistochemistry and tested its sensitivity and specificity for the diagnosis of FGN. This testing was performed on renal biopsy samples from patients with FGN (n = 84), amyloidosis (n = 21), a wide variety of non-FGN glomerular diseases (n = 98), and healthy subjects (n = 11). We also performed immunoelectron microscopy to determine whether DNAJB9 is localized to FGN fibrils. Results: Strong, homogeneous, smudgy DNAJB9 staining of glomerular deposits was seen in all but 2 cases of FGN. The 2 cases that did not stain for DNAJB9 were unique, as they had glomerular staining for IgG only (without κ or λ) on immunofluorescence. DNAJB9 staining was not observed in cases of amyloidosis, in healthy subjects, or in non-FGN glomerular diseases (with the exception of very focal staining in 1 case of smoking-related glomerulopathy), indicating 98% sensitivity and > 99% specificity. Immunoelectron microscopy showed localization of DNAJB9 to FGN fibrils but not to amyloid fibrils or immunotactoid glomerulopathy microtubules. Conclusion: DNAJB9 immunohistochemistry is sensitive and specific for FGN. Incorporation of this novel immunohistochemical biomarker into clinical practice will now allow more rapid and accurate diagnosis of this disease

Sonocatalysis: a potential sustainable pathway for the valorization of lignocellulosic biomass and derivatives

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