Download or read book Solvent Extraction of Technetium from Alkaline Waste Media Using Bis 4 4 prime 5 prime tert butyl cyclohexano 18 crown 6 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The crown ether bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6 can be utilized in a solvent-extraction process for the removal of technetium as pertechnetate ion, TcO[sub 4][sup[minus]] from solutions simulating highly radioactive alkaline defense wastes (''tank wastes'') stored at several sites in the United States. The process employs non-halogenated and non-volatile diluents and modifiers and includes an efficient stripping procedure using only water. More than 95% of the pertechnetate present at 6[times] 10[sup[minus]5] M in Melton Valley (Oak Ridge, TN) and Hanford (Washington) tank-waste simulants was removed following two cross-current extraction contacts using 0.02 M bis-4,4'(5')[(tertbutyl)cyclohexano]- 18-crown-6 in 2:1 vol/vol TBP/Isopar[reg-sign] M diluent at 25 C. Similarly, for both simulants, more than 98% of the pertechnetate contained in the solvent was back-extracted following two cross-current stripping contacts using deionized water.

Download or read book Solvent Extraction of Technetium from Alkaline Waste Media Using Bis 4 4prime 5prime tert butyl cyclohexano 18 crown 6 written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solvent Extraction of Technetium from Alkaline Waste Media Using Bis 4 4 5 tert butyl cyclohexano 18 crown 6 written by and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The crown ether bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6 can be utilized in a solvent-extraction process for the removal of technetium as pertechnetate ion, TcO4− from solutions simulating highly radioactive alkaline defense wastes (''tank wastes'') stored at several sites in the United States. The process employs non-halogenated and non-volatile diluents and modifiers and includes an efficient stripping procedure using only water. More than 95% of the pertechnetate present at 6 × 10−5 M in Melton Valley (Oak Ridge, TN) and Hanford (Washington) tank-waste simulants was removed following two cross-current extraction contacts using 0.02 M bis-4,4'(5')[(tertbutyl)cyclohexano]- 18-crown-6 in 2:1 vol/vol TBP/Isopar{reg_sign} M diluent at 25 C. Similarly, for both simulants, more than 98% of the pertechnetate contained in the solvent was back-extracted following two cross-current stripping contacts using deionized water.

Download or read book Solvent Extraction of Technetium from Alkaline Waste Media Using Bis 4 42 52 tert butyl cyclohexano 18 crown 6 written by and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The crown ether bis-4,4(̀5)̀[(tert-butyl)cyclohexano]-18-crown-6 can be utilized in a solvent-extraction process for the removal of technetium as pertechnetate ion, TcO4− from solutions simulating highly radioactive alkaline defense wastes (t̀̀ank wastes̀̀) stored at several sites in the United States. The process employs non-halogenated and non-volatile diluents and modifiers and includes an efficient stripping procedure using only water. More than 95% of the pertechnetate present at 6 × 10−5 M in Melton Valley (Oak Ridge, TN) and Hanford (Washington) tank-waste simulants was removed following two cross-current extraction contacts using 0.02 M bis-4,4(̀5)̀[(tertbutyl)cyclohexano]- 18-crown-6 in 2:1 vol/vol TBP/Isopar{reg_sign} M diluent at 25 C. Similarly, for both simulants, more than 98% of the pertechnetate contained in the solvent was back-extracted following two cross-current stripping contacts using deionized water.

Download or read book Removal of Technetium from Alkaline Nuclear waste Media by a Solvent extraction Process Using Crown Ethers written by and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crown ethers dissolved in suitably modified aliphatic kerosene diluents can be employed to extract technetium as pertechnetate anion (TcO4−) with good extraction ratios from realistic simulants of radioactive alkaline nitrate waste. The modifiers utilized are non-halogenated and non-volatile, and the technetium can be removed from the solvent by stripping using water. The crown ethers bis-4,4(prime)(5(prime))[(tert-butyl)cyclohexano]-18-crown-6 (di-t-BuCH18C6) and dicyclohexano-18-crown-6 (DCH18C6) provide stronger TcO4− extraction than dicyclohexano-21-crown-7 and 4-tert-butylcyclohexano 15-crown-5. Whereas DCH18C6 provides somewhat higher TcO4− extraction ratios than the more lipophilic di-t-BuCH18C6 derivative, the latter was selected for further study owing to its lower distribution to the aqueous phase. Particularly good extraction and stripping results were obtained with di-t-BuCH 18C6 at 0.02 M in a 2:1 vol/vol blend of tributyl phosphate and Isopar{reg_sign} M. Using this solvent, 98.9% of the technetium contained (at 6 x 10−5 M) in a Double-Shell Slurry Feed (DSSF) Hanford tank waste simulant was removed following two cross-current extraction contacts. Two cross-current stripping contacts with deionized water afforded removal of 99.1% of the technetium from the organic solvent.

Download or read book Alkaline side Extraction of Technetium from Tank Waste Using Crown Ethers and Other Extractants written by and published by . This book was released on 1996 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemical development of a new crown-ether-based solvent-extraction process for the separation of (Tc) from alkaline tank-waste supernate is ready for counter-current testing. The process addresses a priority need in the proposed cleanup of Hanford and other tank wastes. This need has arisen from concerns due to the volatility of Tc during vitrification, as well as 99Tc's long half-life and environmental mobility. The new process offers several key advantages that direct treatability--no adjustment of the waste composition is needed; economical stripping with water; high efficiency--few stages needed; non-RCRA chemicals--no generation of hazardous or mixed wastes; co-extraction of 9°Sr; and optional concentration on a resin. A key concept advanced in this work entails the use of tandem techniques: solvent extraction offers high selectivity, while a subsequent column sorption process on the aqueous stripping solution serves to greatly concentrate the Tc. Optionally, the stripping solution can be evaporated to a small volume. Batch tests of the solvent-extraction and stripping components of the process have been conducted on actual melton Valley Storage Tank (MVST) waste as well as simulants of MVST and Hanford waste. The tandem process was demonstrated on MVST waste simulants using the three solvents that were selected the final candidates for the process. The solvents are 0.04 M bis-4,4(prime)(5(prime))[(tert-butyl)cyclohexano]-18-crown-6 (abbreviated di-t-BuCH18C6) in a 1:1 vol/vol blend of tributyl phosphate and Isopar{reg_sign} M (an isoparaffinic kerosene); 0.02 M di-t-BuCH18C6 in 2:1 vol/vol TBP/Isopar M and pure TBP. The process is now ready for counter-current testing on actual Hanford tank supernates.

Download or read book Developing and Testing an Alkaline side Solvent Extraction Process for Technetium Separation from Tank Waste written by and published by . This book was released on 1997 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineering development and testing of the SRTALK solvent extraction process are discussed in this paper. This process provides a way to carry out alkaline-side removal and recovery of technetium in the form of pertechnetate anion from nuclear waste tanks within the DOE complex. The SRTALK extractant consists of a crown ether, bis-4,4'(5')[(tert-butyl)cyclohexano] -18-crown-6, in a modifier, tributyl phosphate, and a diluent, Isopar{reg_sign}L. The SRTALK flowsheet given here separates technetium from the waste and concentrates it by a factor often to minimize the load on the downstream evaporator for the technetium effluent. In this work, we initially generated and correlated the technetium extraction data, measured the dispersion number for various processing conditions, and determined hydraulic performance in a single-stage 2-cm centrifugal contactor. Then we used extraction-factor analysis, single-stage contactor tests, and stage-to-stage process calculations to develop a SRTALK flowsheet. Key features of the flowsheet are (1) a low organic-to-aqueous (O/A) flow ratio in the extraction section and a high O/A flow ratio in the strip section concentrate the technetium and (2) the use of a scrub section to reduce the salt load in the concentrated technetium effluent. Finally, the SRTALK process was evaluated in a multistage test using a synthetic tank waste. This test was very successful. Initial tests with actual waste from the Hanford nuclear waste tanks show the same technetium extractability as determined with the synthetic waste feed. Therefore, technetium removal from actual tank wastes should also work well using the SRTALK process.

Download or read book Ion Exchange Technology I written by Inamuddin Dr. and published by Springer Science & Business Media. This book was released on 2012-06-02 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion-exchange Technology I: Theory and Materials describes the theoretical principles of ion-exchange processes. More specifically, this volume focuses on the synthesis, characterization, and modelling of ion-exchange materials and their associated kinetics and equilibria. This title is a highly valuable source not only to postgraduate students and researchers but also to industrial R&D specialists in chemistry, chemical, and biochemical technology as well as to engineers and industrialists.

Download or read book Phonetics Theory and Application written by William R. Tiffany and published by McGraw-Hill Humanities, Social Sciences & World Languages. This book was released on 1977 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Syrups and Molasses written by George L. Teller and published by . This book was released on 1895 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrogen Storage written by Jianjun Liu and published by BoD – Books on Demand. This book was released on 2012-09-05 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen, as an energy carrier, is widely regarded as a potential cost effective, renewable, and clean energy alternative to petroleum in order to mitigate energy shortage and global climate warming issues that the world is currently facing. However, storage of hydrogen is a substantial challenge, especially for applications in vehicles with fuel cells that use proton-exchange membranes (PEMs). Therefore, scientific community has started focusing their research activities on developing advanced hydrogen storage materials through nanotechnology. The book presents a wide variety of nanostructured materials used for application in hydrogen storage, covering chemical and physical storage approaches. The research topics include computational design, synthesis, processing, fabrication, characterization, properties and applications of nanomaterials in hydrogen storage systems.

Download or read book Plant Extracts written by Raffaele Capasso and published by MDPI. This book was released on 2021-04-29 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant extracts are widely used for therapeutic purposes. The vegetal origin of these products satisfies people’s desire to cure themselves with natural drugs; this aspect, together with effectiveness and regulatory opportunities, is the base of the broad modern use of medicinal plants. Traditional uses and novel biological effects allow the availability of an extraordinarily high number of different compounds with formidable therapeutic potential. Nevertheless, pitfalls are hidden behind poor pharmacological and toxicological knowledge of plant extracts, nonstandardized methods of extraction, and undefined and nonrepeatable qualitative and quantitative composition. In this context, novel experimental studies on plant products and appreciated and are necessary to reinforce the scientific soundness of phytotherapy. This book aims to respond to this medical need comprehensively highlighting the newest discoveries in vegetal resources with an emphasis on pharmacological activity.

Download or read book Ion Exchange Membrane Electrodialysis written by Yoshinobu Tanaka and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Industrial application of ion exchange membranes started from saline water desalination. However, now it extends widely in many fields such as drinking water or wastewater treatment, demineralisation of amino acid, whey, sugar liquor, recovery of useful components, treatment of organic substances and contributes to the improvement of our standard of living. The application of ion exchange membranes must expand further if we pay attention to unique functions of the membranes for separating ionic species from non-ionic substances or other kinds of ionic species. This book discusses the performance of an electrodialyser from the stand point of fundamental and practical views.

Download or read book Lewis Basicity and Affinity Scales written by Christian Laurence and published by John Wiley & Sons. This book was released on 2009-12-23 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Lewis concept of acids and bases is discussed in every general, organic and inorganic chemistry textbook. This is usually just a descriptive treatment, as it is not possible to devise a single numerical scale suitable for all occasions. However quantitative Lewis acid-base chemistry can be developed by compiling reaction-specific basicity scales which can be used in specific branches of chemistry and biochemistry. Lewis Basicity and Affinity Scales: Data and Measurementbrings together for the first time a comprehensive range of Lewis basicity/affinity data in one volume. More than 2400 equilibrium constants of acid-base reactions, 1500 complexation enthalpies, and nearly 2000 infrared and ultraviolet shifts upon complexation are gathered together in 25 thermodynamic and spectroscopic scales of basicity and/or affinity. For each scale, the definition, the method of measurement, an exhaustive database, and a critical discussion are given. All the data have been critically examined; some have been re-measured; literature gaps have been filled by original measurements; and each scale has been made homogeneous. This collection of data will enable experimental chemists to better understand and predict the numerous chemical, physical and biological properties that depend upon Lewis basicity. Chemometricians will be able to apply their methods to the data matrices constructed from this book in order to identify the factors which influence basicity and basicity-dependent properties. In addition, measured experimental basicities and affinities are essential to computational chemists for the validation, calibration and establishment of reliable computational methods for quantifying and explaining intermolecular forces and the chemical bond. Lewis Basicity and Affinity Scales: Data and Measurement is an essential single-source desktop reference for research scientists, engineers, and students in academia, research institutes and industry, in all areas of chemistry from fundamental to applied research. "The book is a noteworthy piece of work and represents a timely and vast accumulation of knowledge regarding Lewis bases that brings together accurate thermodynamic and spectroscopic data on typical reference Lewis acids. As such, it should serve as a useful and general guide to basicity." J. AM. CHEM. SOC. 2011, 133, 642

Download or read book Green Solvents II written by Ali Mohammad and published by Springer Science & Business Media. This book was released on 2012-03-19 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: The conventional solvents used in chemical, pharmaceutical, biomedical and separation processes represent a great challenge to green chemistry because of their toxicity and flammability. Since the beginning of “the 12 Principles of Green Chemistry” in 1998, a general effort has been made to replace conventional solvents with environmentally benign substitutes. Water has been the most popular choice so far, followed by ionic liquids, surfactant, supercritical fluids, fluorous solvents, liquid polymers, bio-solvents and switchable solvent systems. Green Solvents Volume I and II provides a throughout overview of the different types of solvents and discusses their extensive applications in fields such as extraction, organic synthesis, biocatalytic processes, production of fine chemicals, removal of hydrogen sulphide, biochemical transformations, composite material, energy storage devices and polymers. These volumes are written by leading international experts and cover all possible aspects of green solvents’ properties and applications available in today’s literature. Green Solvents Volume I and II is an invaluable guide to scientists, R&D industrial specialists, researchers, upper-level undergraduates and graduate students, Ph.D. scholars, college and university professors working in the field of chemistry and biochemistry.

Download or read book Green Solvents I written by Ali Mohammad and published by Springer Science & Business Media. This book was released on 2012-03-13 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: The conventional solvents used in chemical, pharmaceutical, biomedical and separation processes represent a great challenge to green chemistry because of their toxicity and flammability. Since the beginning of “the 12 Principles of Green Chemistry” in 1998, a general effort has been made to replace conventional solvents with environmentally benign substitutes. Water has been the most popular choice so far, followed by ionic liquids, surfactant, supercritical fluids, fluorous solvents, liquid polymers, bio-solvents and switchable solvent systems. Green Solvents Volume I and II provides a throughout overview of the different types of solvents and discusses their extensive applications in fields such as extraction, organic synthesis, biocatalytic processes, production of fine chemicals, removal of hydrogen sulphide, biochemical transformations, composite material, energy storage devices and polymers. These volumes are written by leading international experts and cover all possible aspects of green solvents’ properties and applications available in today’s literature. Green Solvents Volume I and II is an invaluable guide to scientists, R&D industrial specialists, researchers, upper-level undergraduates and graduate students, Ph.D. scholars, college and university professors working in the field of chemistry and biochemistry.

Download or read book The Warsaw Orphan written by Kelly Rimmer and published by Harlequin. This book was released on 2021-06-01 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instant New York Times bestseller! Inspired by the real-life heroine who saved thousands of Jewish children during WWII, The Warsaw Orphan is Kelly Rimmer’s most anticipated novel since her bestselling sensation, The Things We Cannot Say. “Gripping… This one easily stands on its own.” —Publishers Weekly “Heart-stopping.” – Lisa Wingate, #1 New York Times Bestselling Author “A surefire hit.” – Kristin Harmel, #1 New York Times Bestselling Author In the spring of 1942, young Elzbieta Rabinek is aware of the swiftly growing discord just beyond the courtyard of her comfortable Warsaw home. She has no fondness for the Germans who patrol her streets and impose their curfews, but has never given much thought to what goes on behind the walls that contain her Jewish neighbors. She knows all too well about German brutality--and that it's the reason she must conceal her true identity. But in befriending Sara, a nurse who shares her apartment floor, Elzbieta makes a discovery that propels her into a dangerous world of deception and heroism. Using Sara's credentials to smuggle children out of the ghetto brings Elzbieta face-to-face with the reality of the war behind its walls, and to the plight of the Gorka family, who must make the impossible decision to give up their newborn daughter or watch her starve. For Roman Gorka, this final injustice stirs him to rebellion with a zeal not even his newfound love for Elzbieta can suppress. But his recklessness brings unwanted attention to Sara's cause, unwittingly putting Elzbieta and her family in harm's way until one violent act threatens to destroy their chance at freedom forever. From Nazi occupation to the threat of a communist regime, The Warsaw Orphan is the unforgettable story of Elzbieta and Roman's perilous attempt to reclaim the love and life they once knew. Don’t miss Kelly Rimmer’s next historical suspense, The Paris Agent, coming July 2023! For more by Kelly Rimmer, look for: Before I Let You Go The Things We Cannot Say Truths I Never Told You The German Wife