Download or read book Ionic Liquid and Supercritical Fluid Hyphenated Techniques for Dissolution and Separation of Lanthanides Actinides and Fission Products written by and published by . This book was released on 2012 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project is investigating techniques involving ionic liquids (IL) and supercritical (SC) fluids for dissolution and separation of lanthanides, actinides, and fission products. The research project consists of the following tasks: Study direct dissolution of lanthanide oxides, uranium dioxide and other actinide oxides in [bmin][Tf2N] with TBP(HNO3){sub 1.8}(H2O){sub 0.6} and similar types of Lewis acid-Lewis base complexing agents; Measure distributions of dissolved metal species between the IL and the sc-CO2 phases under various temperature and pressure conditions; Investigate the chemistry of the dissolved metal species in both IL and sc-CO2 phases using spectroscopic and chemical methods; Evaluate potential applications of the new extraction techniques for nuclear waste management and for other projects. Supercritical carbon dioxide (sc-CO2) and ionic liquids are considered green solvents for chemical reactions and separations. Above the critical point, CO2 has both gas- and liquid-like properties, making it capable of penetrating small pores of solids and dissolving organic compounds in the solid matrix. One application of sc-CO2 extraction technology is nuclear waste management. Ionic liquids are low-melting salts composed of an organic cation and an anion of various forms, with unique properties making them attractive replacements for the volatile organic solvents traditionally used in liquid-liquid extraction processes. One type of room temperature ionic liquid (RTIL) based on the 1-alkyl-3-methylimidazolium cation [bmin] with bis(trifluoromethylsulfonyl)imide anion [Tf2N] is of particular interest for extraction of metal ions due to its water stability, relative low viscosity, high conductivity, and good electrochemical and thermal stability. Recent studies indicate that a coupled IL sc-CO2 extraction system can effectively transfer trivalent lanthanide and uranyl ions from nitric acid solutions. Advantages of this technique include operation at ambient temperature and pressure, selective extraction due to tunable sc-CO2 solvation strength, no IL loss during back-extraction, and no organic solvent introduced into the IL phase.
Download or read book Actinide and Lanthanide Species in Ionic Liquid and in Supercritical CO2 written by Yu-Jung Liao and published by . This book was released on 2012 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: When UO2 and Nd2 O3 are dissolved in [Bmim][Tf2 N] containing TBP(HNO3 )1.8 (H 2 O)0.6 , the major uranyl and neodymium species are identified to be UO2 (NO3 )2 (TBP)2 and Nd(NO 3 )3 (TBP)3 in the IL phase, respectively. The solubilities and distribution ratios of UO2 (NO3 )2 (TBP) 2 and Nd(NO3 )3 (TBP)3 in sc-CO 2 phase are also measured by a high-pressure fiber-optic cell connected to a CCD array detector. The separation of uranyl and neodymium species from IL phase to sc-CO2 phase can be achieved by ligand exchange with a N,N,N'N'-tetrabutyldiglycolamide (TBDGA) in the IL solution. Complexes of (UO2 )2+ and Nd3+ with TBDGA are not soluble in sc-CO2 and Nd3+ forms a stronger complex with TBDGA than (UO2 )2+ in [Bmim][Tf2 N]. Competition between (UO2 )2+ and Nd3+ in this ligand exchange process provides a means for separation of UO 2 (NO3 )2 (TBP)2 and Nd(NO3 ) 3 (TBP)3 in the IL/sc-CO2 coupled extraction process. With a proper ratio of TBDGA to uranium and neodymium, the separation factor of [UO22+ ]/[Nd3+ ] can be as large as about 50. The IL/sc-CO2 hyphenated extraction techniques described in this dissertation may have potential applications in dissolution/extraction/separation of lanthanides and actinides existed in spent nuclear fuel and other nuclear wastes.
Download or read book Ion Exchange and Solvent Extraction written by Yitzhak Marcus and published by CRC Press. This book was released on 2004-07-23 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 17 in the Ion Exchange and Solvent Extraction series represents the vanguard of research on solvent extraction. It covers the principles of electrolyte extraction and other subjects of increasing interest to the field. This volume begins with pharmaceutical applications of supercritical fluid solvents, particularly supercritical carbon dioxide. It also contains chapters on liquid ion exchangers and relevant experiment protocols, SCF applications in drug formulation and pollution reduction, exploiting SCF as reaction media, applications of metal bis(dicarbollide) in analytical chemistry and radioactive waste treatment, and synergistic extraction of metal ions. Volume 17 discusses the ion exchange isothermal supersaturation technique, metal separation via pH-induced parametric pumping, modeling of ion exchange kinetics for ultrapure water, and the engineering of activated carbons and carbonaceous materials for removal of metal ions and organic micropollutants in water. Volume 17 cover topics that include supercritical fluid applications, applications of metal bis(dicarbollide), and synergistic extraction of metal ions.
Download or read book Advanced Separation Techniques for Nuclear Fuel Reprocessing and Radioactive Waste Treatment written by Kenneth L Nash and published by Elsevier. This book was released on 2011-03-15 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced separations technology is key to closing the nuclear fuel cycle and relieving future generations from the burden of radioactive waste produced by the nuclear power industry. Nuclear fuel reprocessing techniques not only allow for recycling of useful fuel components for further power generation, but by also separating out the actinides, lanthanides and other fission products produced by the nuclear reaction, the residual radioactive waste can be minimised. Indeed, the future of the industry relies on the advancement of separation and transmutation technology to ensure environmental protection, criticality-safety and non-proliferation (i.e., security) of radioactive materials by reducing their long-term radiological hazard.Advanced separation techniques for nuclear fuel reprocessing and radioactive waste treatment provides a comprehensive and timely reference on nuclear fuel reprocessing and radioactive waste treatment. Part one covers the fundamental chemistry, engineering and safety of radioactive materials separations processes in the nuclear fuel cycle, including coverage of advanced aqueous separations engineering, as well as on-line monitoring for process control and safeguards technology. Part two critically reviews the development and application of separation and extraction processes for nuclear fuel reprocessing and radioactive waste treatment. The section includes discussions of advanced PUREX processes, the UREX+ concept, fission product separations, and combined systems for simultaneous radionuclide extraction. Part three details emerging and innovative treatment techniques, initially reviewing pyrochemical processes and engineering, highly selective compounds for solvent extraction, and developments in partitioning and transmutation processes that aim to close the nuclear fuel cycle. The book concludes with other advanced techniques such as solid phase extraction, supercritical fluid and ionic liquid extraction, and biological treatment processes.With its distinguished international team of contributors, Advanced separation techniques for nuclear fuel reprocessing and radioactive waste treatment is a standard reference for all nuclear waste management and nuclear safety professionals, radiochemists, academics and researchers in this field. - A comprehensive and timely reference on nuclear fuel reprocessing and radioactive waste treatment - Details emerging and innovative treatment techniques, reviewing pyrochemical processes and engineering, as well as highly selective compounds for solvent extraction - Discusses the development and application of separation and extraction processes for nuclear fuel reprocessing and radioactive waste treatment
Download or read book Utilizing Supercritical CO2 and Ionic Liquids for the Extraction of Actinides and Lanthanides written by Donna Ly Quach Baek and published by . This book was released on 2014 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supercritical carbon dioxide (sc-CO2) and room temperature ionic liquids (RTILs) were used as non-conventional solvents for the investigation of actinide and lanthanide extraction and separation in this dissertation. Nuclear waste management is traditionally facilitated by the Plutonium Uranium Reduction EXtraction process, better known as the PUREX process. The drawback to this important process is the production of hazardous organic and aqueous waste. RTILs and sc-CO2 have inherent benefits over using hydrocarbon solvents, such as low volatility and minimizing secondary liquid waste generation. A brief review of actinide and lanthanide extraction and separation using traditional solvents, sc-CO2, and RTILs is presented. To be able to optimize extraction efficiencies, the understanding of solvation, speciation, and complexation behavior of lanthanides and actinides in RTILs, sc-CO2 and RTIL/sc-CO2 mixtures is important. Thus, the coordination of U(VI) with nitrate and TBP dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4MIM][Tf2N]) containing tetrabutylammonium nitrate (TBAN), nitric acid, or TBAN and TBP via ATR-FTIR and UV-Vis spectroscopy was studied. Tristructual isotropic (TRISO) fuel particles are used in very high temperature reactors to achieve higher burnup levels; however, recycling techniques have not been fully developed. Included in this dissertation is an investigation using sc-CO2 with TBP to extract U(VI) from TRISO fuel particles, which have been exposed to gamma irradiation. Also, mechanical crushing of TRISO fuel particles is currently the only method to expose the uranium for extraction; thus radioactive contamination is an issue. Ultrasound was applied to TRISO fuel particles in an enclosed pressure vessel in the attempt to fracture the fuel in liquid CO2 and extract U(VI). Furthermore, various actinides and lanthanides are present in used nuclear fuel that need to be extracted and separated from each other to recover uranium as the product and reduce the radiotoxicity of the waste requiring storage. The extraction and separation of uranium from the actinides neptunium, plutonium and americium and the lanthanide series were studied. These species were extracted from a range of nitric acid concentrations, in the absence of, or in the presence of, a number of traditional reducing and/or complexing agents by sc-CO2 modified with TBP to demonstrate the separation of these metals from uranium under sc-CO2 conditions.
Download or read book Recent Progress In Actinides Separation Chemistry Proceedings Of The Workshop On Actinides Solution Chemistry Wasc 94 written by Zenko Yoshida and published by World Scientific. This book was released on 1997-05-03 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together some of the latest developments in solution chemistry and separation chemistry of f-block elements, which include (i) new solvent extraction systems and extractants for the separation of actinide and lanthanide elements, (ii) novel approach for fundamental solution chemistry study of solvent extraction reactions, and (iii) separation methods of new principle for f-block elements.
Download or read book Fission Product Separation Based on Room Temperature Ionic Liquids written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During the previous funding cycle for this project, we investigated the electrochemistry of Cs(I) in air and moisture-stable ionic liquids both with and without the addition of BOBCalixC6. These investigations revealed that the electrochemical windows of the dialkylimidazolium bis[(trifluoromethyl)sulfonyl]imide ionic liquids do not permit the direct electrochemical reduction of Cs(I), even when Hg electrodes are employed, because these organic cations are reduced at less negative potentials than Cs(I). However, Cs(I) coordinated by BOBCalixC6 can be electrolytically reduced to Cs(Hg) in tetraalkylammonium-based room-temperature ionic liquids such as tri-1-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide (Bu3MeN+Tf2N- ) at Hg electrodes. Because this reduction process does not harm either the ionic liquid or the macrocycle, it is a promising method for recycling the cesium extraction system. The previous studies mentioned above were carried out under an inert atmosphere, i.e., in the absence of H2O and O2. However, it may not be economically feasible or even possible to carry out the recycling process in the absence of these contaminants during large-scale processing of aqueous tank waste. Thus, as described in our proposal, we have begun an investigation of the electrochemical recovery of Cs from the Bu3MeN+Tf2N- + BOBCalixC6 extraction system in an air atmosphere containing various amounts of water and oxygen. Our recent preliminary results were very surprising because they indicated that the electrochemical extraction process is relatively insensitive to the presence of small amounts of moisture even when the moisture content of the ionic liquid approaches 1000 ppm. Furthermore, we have found that the ''wet'' ionic liquid can be easily dehydrated under reduced pressure or by sparging with dry nitrogen gas without the need for heat or any other specialized treatment.
Download or read book Analytical Supercritical Fluid Extraction written by Maria D. Luque de Castro and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in analytical chemistry have turned it into a virtually unrecognizable science compared to a few decades ago, when it lagged behind other sciences and techniques. However, advances in analytical science have been far from universal: while innovations in instrumentation and data acquisition and processing systems have reached unprecedented levels thanks to parallel breakthroughs in computer science and chemo metrics, progress in preliminary operations has been much slower despite their importance to analytical results. Thus, such clear trends in analytical process development as automation and miniaturization have not reached preliminary operations to the same extent, even though this area is pro bably in the greatest need. Improvement in preliminary operations is thus an urgent goal of analytical chemistry on the verge of the twenty first century. Increased R&D endeavours and manufacture of commercially available automatic equipment for implementation of the wide variety of operations that separate the uncollected, unmeasured, untreated sample from the signal measuring step are thus crucial on account of the wide variability of such operations, which precludes development of all-purpose equipment, and the complexity of some, particularly relating to solid samples. Supercritical fluid extraction opens up interesting prospects in this context and is no doubt an effective approach to automatioI1 and mini aturization in the preliminary steps of the analytical process. The dramatic developments achieved in its short life are atypical in many respects.
Download or read book The Separation of Lanthanides and Actinides in Supercritical Fluid Carbon Dioxide written by and published by . This book was released on 2015 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supercritical fluid carbon dioxide presents an attractive alternative to conventional solvents for recovery of the actinides and lanthanides. Carbon dioxide is a good solvent for fluorine and phosphate-containing ligands, including the traditional tributylphosphate ligand used in process-scale uranium separations. Actinide and lanthanide oxides may even be directly dissolved in carbon dioxide containing the complexes formed between these ligands and mineral acids, obviating the need for large volumes of acids for leaching and dissolution, and the corresponding organic liquid-liquid solvent extraction solutions. As a result, examples of the application of this novel technology for actinide and lanthanide separations are presented.
Download or read book Fission Product Separation Based on Room Temperature Ionic Liquids written by A. C. III. Buchanan and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are (a) to synthesize new ionic liquids tailored for the extractive separation of Cs + and Sr 2+; (b) to select optimum macrocyclic extractants through studies of complexation of fission products with macrocyclic extractants and transport in new extraction systems based on ionic liquids; (c) to develop efficient processes to recycle ionic liquids and crown ethers; and (d) to investigate chemical stabilities of ionic liquids under strong acid, strong base, and high-level-radiation conditions.
Download or read book Fission Product Separation Based on Room Temperature Ionic Liquids written by Huimin Luo and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are (a) to synthesize new ionic liquids tailored for the extractive separation of Cs + and Sr 2+; (b) to select optimum macrocyclic extractants through studies of complexation of fission products with macrocyclic extractants and transport in new extraction systems based on ionic liquids; (c) to develop efficient processes to recycle ionic liquids and crown ethers; and (d) to investigate chemical stabilities of ionic liquids under strong acid, strong base, and high-level-radiation conditions.
Download or read book Separation of Fission Products Based on Ionic Liquids written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The applications of ionic liquids (ILs) as new separation media have been actively investigated recently. The most commonly studied class of ILs for such applications is based on dialkyl imidazolium cations. In comparison with conventional molecular solvents, ILs exhibit enhanced distribution coefficients for a number of complexing neutral ligands in extraction of metal ions from aqueous solutions. The effect of the alkyl chain length of imidazolium cations on the distribution coefficients of solvent extraction using crown ethers was the subject of a number of the previous investigations. The distribution coefficients have been found to decrease with the alkyl chain length of the IL cations. This observation implies that the extraction process also involves the exchange of the IL cations with metal ions. The longer the alkyl chain lengths of the IL cations are, the more hydrophobic the IL cations are and the more difficult to be transported into aqueous phases via ion exchange. Accordingly, the ion-exchange process is another unique property of IL-based extractions involving charged species. Here, we report the investigation about the effect of the variation of IL anions on the solvent extraction of metal ions using crown ethers as extractants. The elucidation of different solvation effects involved in ionic liquids could lead to optimized separation media for these novel solvents.
Download or read book 81929 Fission Product Separation Based on Room Temperature Ionic Liquids written by Robin D. Rogers (U.S.) and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project has demonstrated that Sr2+ and Cs+ can be selectively extracted from aqueous solutions into ionic liquids using crown ethers and that unprecedented large distribution coefficients can be achieved for these fission products. The volume of secondary wastes can be significantly minimized with this new separation technology. Through the current EMSP funding, the solvent extraction technology based on ionic liquids has been shown to be viable and can potentially provide the most efficient separation of problematic fission products from high level wastes. The key results from the current funding period are the development of highly selective extraction process for cesium ions based on crown ethers and calixarenes, optimization of selectivities of extractants via systematic change of ionic liquids, and investigation of task-specific ionic liquids incorporating both complexant and solvent characteristics.
Download or read book Fission Product Separation Based on Room Temperature Ionic Liquids written by Huimin Luo and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are (a) to synthesize new ionic liquids tailored for the extractive separation of Cs + and Sr 2+; (b) to select optimum macrocyclic extractants through studies of complexation of fission products with macrocyclic extractants and transport in new extraction systems based on ionic liquids; (c) to develop efficient processes to recycle ionic liquids and crown ethers; and (d) to investigate chemical stabilities of ionic liquids under strong acid, strong base, and high-level-radiation conditions.
Download or read book Novel Fission Product Separation Based on Room Temperature Ionic Liquids written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: U.S. DOE's underground storage tanks at Hanford, SRS, and INEEL contain liquid wastes with high concentrations of radioactive cesium-137 and strontium-90. Because the primary chemical components of alkaline supernatants are sodium nitrate and sodium hydroxide, the majority of this could be disposed of as low level waste if radioactive cesium-137 and strontium- 90 could be selectively removed. The underlying goal of this project was to investigate the application of ionic liquids as novel solvents for new solvent extraction processes for separation of cesium-137 and strontium-90 from tank wastes. Ionic liquids are a distinct sub-set of liquids, comprising only of cations and anions they are proving to be increasingly interesting fluids for application in systems from electrochemistry to energetic materials, and are also rapidly establishing their promise as viable media for synthesis and separations operations. Properties including low melting points, electrochemical conductivity, wide liquid ranges, lack of vapor-pressure, and chemical tunability have encouraged researchers to explore the uses of ILs in place of volatile organic solvents. The most promising current developments arise from control of the unique combinations of chemical and physical properties characteristic of ionic liquids.
Download or read book Phase Equilibria in Ionic Liquid Facilitated Liquid liquid Extractions written by Anand Bharti and published by CRC Press. This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is aimed to give a comprehensive idea about ionic liquid based separation techniques. The glimpse of thermodynamic predictive models along with global optimization techniques will help readers understand the separation techniques at molecular and macroscopic levels. Further, the database predicted by a-priori basis thermodynamic models will give the readers a ready-to-use database for scientific and engineering calculations. This will be very useful as a-priori based predictions give more emphasize on hydrogen-bonded systems. Particle Swarm Optimization (PSO) technique will eventually help the readers to apply an optimization to an extraction process.
Download or read book written by and published by . This book was released on 1947 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
