| 1. |
- Almgren, Johanna, et al.
(författare)
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Patients' Health Experiences of Post COVID-19 Condition – A Qualitative Study
- 2022
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Ingår i: International Journal of Environmental Research and Public Health. - Basel : MDPI. - 1661-7827 .- 1660-4601. ; 19:21
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Tidskriftsartikel (refereegranskat)abstract
- Patients who suffer from long-term symptoms of COVID-19, described as post COVID-19 condition, are a new and large group of patients. There is a lack of knowledge concerning health experiences in this patient group. The aim of this study was to explore patients' health experiences of post COVID-19 condition. Data collection was performed through 14 semi-structured interviews. The qualitative content analysis resulted in six sub-categories, three categories, and an overall theme. Patients experienced symptoms of varying duration-ranging from 5-21 months. The results showed that patients' health experiences of post COVID-19 condition moved between uncertainty and new insights. This was shown by patients experiencing: (1) loss of abilities, including losing smell and taste and lacking energy, (2) loss of control, including being foreign to oneself and seeking answers, and (3) revaluation of life, including accepting the transformed body and prioritizing health. This study illustrates that patients living with post COVID-19 condition need to be treated with flexibility, based on each individual's unique challenges and experiences of the symptoms and the consequences for their health. © 2022 by the authors.
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| 2. |
- Aneheim, Emma, 1982, et al.
(författare)
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Extraction experiments after radiolysis of a proposed GANEX solvent - the effect of time
- 2012
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Ingår i: Procedia Chemistry. - : Elsevier BV. - 1876-6196. ; 7, s. 123-129
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Konferensbidrag (refereegranskat)abstract
- In a solvent intended for use within group actinide extraction CyMe4-BTBP and TBP are combined together in cyclohexanone. After irradiating the solvent in acid contact a latency period before extraction reduced the extraction capability of plutonium. This reduction was larger when the solvent was kept in contact with the acid after irradiation. The decrease in plutonium extraction could be an effect of both a reduced extraction performance of CyMe4-BTBP caused by hydrolysis as well as a shift in oxidation state of the plutonium as it was shown that oxidizing Pu(IV) to Pu(VI) decreased the extraction by the solvent. (C) 2012 Elsevier B. V. .. Selection and/or peer-review under responsibility of the Chairman of the ATALANTE 2012 Program Committee
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| 3. |
- Aneheim, Emma, 1982, et al.
(författare)
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Fission product interactions with nitrogen donor ligands used for spent nuclear fuel treatment
- 2013
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387. ; 50:1, s. 154-163
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Tidskriftsartikel (refereegranskat)abstract
- The so called BTBP (bis-triazine bi-pyridine)-type molecules have been developed for liquid-liquid extraction in the advanced reprocessing of used nuclear fuel. One solvent composition that has proven to be promising for such an application is the combination of CyMe4-BTBP and tri-butyl phosphate (TBP) in cyclohexanone. This solvent can extract the actinides successfully but unfortunately some fission products are also co-extracted. One of the most problematic fission products is palladium, but silver and cadmium are also extracted by the proposed solvent, which has been investigated here. In this study it was found that CyMe4-BTBP in cyclohexanone, when extracting palladium from nitric acid, forms complexes that are soluble both in the organic and aqueous phase. The predominant complex observed in both phases established with mass spectrometry and confirmed by NMR is a 1:1 complex, contrary to silver that forms 2:2 complexes and cadmium that forms 1:2 complexes. The nitrate dependency of the palladium extraction from nitric acid into a BTBP containing organic phase was found to be two. However, with higher ionic strengths, such as under process conditions, the palladium was found to be salted out into the organic phase.
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| 4. |
- Aneheim, Emma, 1982, et al.
(författare)
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Studies of a Solvent for GANEX Applications Containing CyMe4-BTBP and DEHBA in Cyclohexanone
- 2012
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Ingår i: Separation Science and Technology. - : Informa UK Limited. - 1520-5754 .- 0149-6395. ; 47:5, s. 663-669
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Tidskriftsartikel (refereegranskat)abstract
- Research focus within separation for transmutation in Europe today lies in the development of a solvent extraction separation process called GANEX (Group ActiNide EXtraction). In this type of process the actinides should be extracted as a group and separated from the lanthanides and the other fission and corrosion/activation products. One GANEX process has been developed combining the two extractants bis-triazine-bi-pyridine (BTBP) and tri-butyl phosphate (TBP) in cyclohexanone. In previous work the TBP has been successfully substituted with N,N-di-2-ethylhexylbutyramide (DEHBA). In this paper, this exchange has been further studied investigating also fission product extraction as well as hydrolytic and radiolytic stability and acid extraction.
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| 5. |
- Aneheim, Emma, 1982, et al.
(författare)
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Technetium chemistry in a novel group actinide extraction process
- 2013
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 296:2, s. 743-748
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Tidskriftsartikel (refereegranskat)abstract
- A newly developed method for advanced reprocessing of used nuclear fuel is the Group ActiNide EXtraction (GANEX) process. It is a liquid-liquid extraction process that aims at extracting all the actinides as a group from dissolved used nuclear fuel. This extraction can either be performed after a removal of the bulk uranium or directly on the dissolution liquor. At Chalmers University of Technology in Sweden a solvent that utilizes tributyl-phosphate (TBP) and a molecule from the bis-triazine bipyridine (BTBP) class of ligands dissolved in cyclohexanone has been developed for the use in a GANEX process. Previously the system has not been tested with the presence of technetium that is one of the major fission products. Technetium is often considered a problem within reprocessing since it has a chemical behaviour that differs from most other elements in the spent fuel. Therefore, a special emphasis was put on the investigation of technetium in the selected GANEX system. It was shown that technetium is readily extracted by the GANEX solvent and that cyclohexanone is the main extractant when no other metals were present in the system. It was also found that the presence of uranium decreased the overall technetium extraction despite a slight co-extraction with TBP, while irradiation of the GANEX solvent to large doses ([>1 MGy) increased its technetium extraction capability. It was also discovered that an increased nitrate concentration in the aqueous phase and an addition of other fission products both inhibited the technetium extraction even though fission product loading most likely changed the extraction mechanism to co-extraction by BTBP.
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| 6. |
- Bauhn, Lovisa, 1981, et al.
(författare)
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A micro hot test of the Chalmers-GANEX extraction system on used nuclear fuel
- 2013
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Ingår i: International Nuclear Fuel Cycle Conference, GLOBAL 2013: Nuclear Energy at a Crossroads. ; 1, s. 335-340
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Konferensbidrag (refereegranskat)abstract
- In the present study, a "micro hot test" has been performed using the Chalmers-GANEX (Group ActiNide EXtraction) system for partitioning of used nuclear fuel. The test included a pre-extraction step using N,N-di-2- ethylhexylbutyramide (DEHBA) in n-octanol to remove the bulk part of the uranium. This pre-extraction was followed by a group extraction of actinides using the mixture of TBP and CyMe4-BTBP in cyclohexanone as suggested in the Chalmers-GANEX process, and a three stage stripping of the extracted actinides. Distribution ratios for the extractions and stripping were determined based on a combination of γ- and α-spectrometry, as well as ICP-MS measurements. Successful extraction of uranium, plutonium and the minor actinides neptunium, americium and curium was achieved. However, measurements also indicated that co-extraction of europium occurs to some extent during the separation. These results were expected based on previous experiments using trace concentrations of actinides and lanthanides. Since this test was only performed in one stage with respect to the group actinide extraction, it is expected that multi stage tests will give even better results.
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| 7. |
- Ekberg, Christian, 1967, et al.
(författare)
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The structures of CyMe4-BTBP complexes of americium(III) and europium(III) in solvents used in solvent extraction, explaining their separation properties
- 2015
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 44:42, s. 18395-18402
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Tidskriftsartikel (refereegranskat)abstract
- Separation of trivalent actinoid (An(III)) and lanthanoid (Ln(III)) ions is extremely challenging due to their similar ionic radii and chemical properties. Poly-aromatic nitrogen compounds acting as tetradentate chelating ligands to the metal ions in the extraction, have the ability to sufficiently separate An(III) from Ln(III). One of these compounds, 6,6'-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzol[1,2,4]triazin-3-y l)-[2,2]bipyridine, CyMe4-BTBP, has proven to be resistant towards acidic environments and strong radiation from radioactive decomposition. EXAFS studies of the dicomplexes of CyMe4-BTBP with americium(III) and europium(III) in nitrobenzene, cyclohexanone, 1-hexanol, 1-octanol and malonamide (DMDOHEMA) in 1-octanol have been carried out to get a deeper understanding of the parameters responsible for the separation. The predominating complexes independent of solvent used are [Am(CyMe4-BTBP)(2)(NO3)](2+) and [Eu(CyMe4-BTBP)(2)](3+), respectively, which are present as outer-sphere ion-pairs with nitrate ions in the studied solvents with low relative permittivity. The presence of a nitrate ion in the first coordination sphere of the americium(III) complex compensates the charge density of the complex considerably in comparison when only outer-sphere ion-pairs are formed as for the [Eu(CyMe4-BTBP)(2)](3+) complex. The stability and solubility of a complex in a solvent with low relative permittivity increase with decreasing charge density. The [Am(CyMe4-BTBP)(2)(NO3)](2+) complex will therefore be increasingly soluble and stabilized over the [Eu(CyMe4-BTBP)(2)](3+) complex in solvents with decreasing relative permittivity of the solvent. The separation of americium(III) from europium(III) with CyMe4-BTBP as extraction agent will increase with decreasing relative permittivity of the solvent, and thereby also with decreasing solubility of CyMe4-BTBP. The choice of solvent is therefore a balance of a high separation factor and sufficient solubility of the CyMe4-BTBP ligand.
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| 8. |
- Ekberg, Christian, 1967, et al.
(författare)
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Thermodynamics of Dissolution for Bis(triazine)-Bipyridine-Class Ligands in Different Diluents and Its Reflection on Extraction
- 2010
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Ingår i: Journal of Chemical & Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 55:11, s. 5133-5137
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Tidskriftsartikel (refereegranskat)abstract
- Hydrochemical separation processes are one of the methods used for the treatment of spent nuclear fuel. Solvent extraction is also used in many other non-nuclear applications like the mining industry. In the nuclear case, hydrochemical separation processes are already employed in the world today for the recovery of uranium and plutonium. The method is however also considered for future separation systems for use in combination with the transmutation of the minor actinides. In a hydrochemical separation process the two phases are the pregnant (usually) aqueous feed and the organic phase comprising a diluent together with one or more extractants. One such class of extractants developed for partitioning and transmutation purposes is the bis(triazine)-bipyridine-type (BTBP) molecules. When assessing the feasibility and loading properties of such an extraction system, the solubility of the ligands is of the outmost importance. The understanding of whether the dissolution is enthalpically or entropically driven will also help the understanding of the differences in extraction observed between various diluents and temperatures. In this paper the enthalpy and entropy of dissolution of the BTBP-class ligands have been determined for different diluents. It has also been shown that it is possible to predict the extraction behavior of these molecules in the selected diluent once the solubility is known.
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| 9. |
- Halleröd, Jenny, 1987, et al.
(författare)
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Development of the Chalmers grouped actinide extraction process
- 2015
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Ingår i: Nukleonika. - : Walter de Gruyter GmbH. - 1508-5791 .- 0029-5922. ; 60:4, s. 829-835
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Tidskriftsartikel (refereegranskat)abstract
- Several solvents for Grouped ActiNide EXtraction (GANEX) processes have been investigated at Chalmers University of Technology in recent years. Four different GANEX solvents; cyclo-GANEX (CyMe4--BTBP, 30 vol.% tri-butyl phosphate (TBP) and cyclohexanone), DEHBA-GANEX (CyMe4-BTBP, 20 vol.% N,N-di-2(ethylhexyl) butyramide (DEHBA) and cyclohexanone), hexanol-GANEX (CyMe4-BTBP, 30 vol.% TBP and hexanol) and FS-13-GANEX (CyMe4-BTBP, 30 vol.% TBP and phenyl trifluoromethyl sulfone (FS-13)) have been studied and the results are discussed and compared in this work. The cyclohexanone based solvents show fast and high extraction of the actinides but a somewhat poor diluent stability in contact with the acidic aqueous phase. FS-13-GANEX display high separation factors between the actinides and lanthanides and a good radiolytic and hydrolytic stability. However, the distribution ratios of the actinides are lower, compared to the cyclohexanone based solvents. The hexanol-GANEX is a cheap solvent system using a rather stable diluent but the actinide extraction is, however, comparatively low.
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| 10. |
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| 11. |
- Halleröd, Jenny, 1987, et al.
(författare)
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Stability of phenyl trifluoromethyl sulfone as diluent in a grouped actinide extraction process
- 2015
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 304:1, s. 287-291
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Tidskriftsartikel (refereegranskat)abstract
- In this work, stability experiments have been performed on a phenyl trifluoromethyl sulfone based solvent containing 6,6'-bis(5,6-dialkyl-[1,2,4-]triazin-3-yl)-2,2'-bipyridine and tri-butyl phosphate. This solvent is intended to be used in a grouped actinide extraction process for partitioning and transmutation purposes. The distribution ratio for americium was determined to approximately 20 and for europium approximately 0.26 giving a separation factor of 77. The solvent maintain good distribution ratios and separation factors during both gamma irradiation of 6.6 kGy h(-1) for up to 24 h and acid contact for up to 6 weeks at room temperature.
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| 12. |
- Lindberg, Helena, et al.
(författare)
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Risk stratification score screening for infective endocarditis in patients with Gram-positive bacteraemia
- 2022
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 54:7, s. 488-496
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Tidskriftsartikel (refereegranskat)abstract
- Background: A feared cause of bacteraemia with Gram-positives is infective endocarditis. Risk stratification scores can aid clinicians in determining the risk of endocarditis. Six proposed scores for the use in bacteraemia; Staphylococcus aureus (PREDICT, VIRSTA, POSITIVE), non-β-haemolytic streptococci (HANDOC) and Enterococcus faecalis (NOVA, DENOVA) were validated for predictive ability and the utilization of echocardiography was investigated. Methods: Hospitalized adult patients with Gram-positive bacteraemia during 2017–2019 were evaluated retrospectively through medical records and the Swedish Death Registry. Baseline and score-specific data, definite endocarditis and echocardiographies performed were recorded. Sensitivity, specificity, negative and positive predictive values and echocardiography utilization were determined. Results: 480 patients with bacteraemia were included and definite endocarditis was diagnosed in 20 (7.5%), 10 (6.6%), and 2 (3.2%) patients with S. aureus, non-β-haemolytic streptococci and E. faecalis, respectively. The sensitivities of the scores were 80–100% and specificities 8–77%. Negative predictive values of the six scores were 98–100%. VIRSTA, HANDOC, NOVA and DENOVA identified all, the PREDICT5 score missed 1/20 and the POSITIVE score missed 4/20 cases of endocarditis. Transoesophageal echocardiography was performed in 141 patients (29%). Thus, the risk stratification scores suggested an increase of 3–63 (7–77%) investigations with echocardiography. Conclusions: All scores had negative-predictive values over 98%, therefore it can be concluded that PREDICT5, VIRSTA, POSITIVE, HANDOC and DENOVA are reasonable screening tools for endocarditis early on in Gram-positive bacteraemia. The use of risk stratification scores will lead to more echocardiographies.
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| 13. |
- Löfström, Emma, et al.
(författare)
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Dynamics of IgG-avidity and antibody levels after Covid-19
- 2021
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Ingår i: Journal of Clinical Virology. - Amsterdam : Elsevier. - 1386-6532 .- 1873-5967. ; 144
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Tidskriftsartikel (refereegranskat)abstract
- Background: A potentially important aspect of the humoral immune response to Covid-19 is avidity, the overall binding strength between antibody and antigen. As low avidity is associated with a risk of re- infection in several viral infections, avidity might be of value to predict risk for reinfection with covid-19. Objectives: The purpose of this study was to describe the maturation of IgG avidity and the antibody-levels over time in patients with PCR-confirmed non-severe covid-19. Study design: Prospective longitudinal cohort study including patients with RT-PCR confirmed covid-19. Blood samples were drawn 1, 3 and 6 months after infection. Antibody levels and IgG-avidity were analysed. Results: The majority had detectable s- and n-antibodies (88,1%, 89,1%, N = 75). The level of total n-antibodies significantly increased from 1 to 3 months (median value 28,3 vs 39,3 s/co, p<0.001) and significantly decreased from 3 to 6 months (median value 39,3 vs 17,1 s/co, p<0.001). A significant decrease in the IgG anti-spike levels (median value 37,6, 24,1 and 18,2 RU/ml, p<0.001) as well as a significant increase in the IgG-avidity index (median values 51,6, 66,0 and 71,0%, p<0.001) were seen from 1 to 3 to 6 months. Conclusion: We found a significant ongoing increase in avidity maturation after Covid-19 whilst the levels of antibodies were declining, suggesting a possible aspect of long-term immunity. © 2021 The Authors. Published by Elsevier B.V.
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| 14. |
- Löfström, Emma, et al.
(författare)
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Health-related quality of life and long-term symptoms among patients with non-severe covid-19–a prospective cohort study
- 2023
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Ingår i: Infectious Diseases. - Oxfordshire : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 55:4, s. 272-281
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Tidskriftsartikel (refereegranskat)abstract
- Background: The vast majority of covid-19 patients experience non-severe disease. Nonetheless, long-term symptoms may be common and the impact on quality of life is uncertain. This study aims to examine these aspects in a prospective, longitudinal cohort. Methods: Non-hospitalised patients with PCR-confirmed covid-19 were prospectively invited to self-report assessments of background data, symptoms and recovery, illness perception (BIPQ) and health-related quality of life (HR-Qol) measured by EQ5D-VAS. Results: 154 patients were included (mean age 46 years, 69% female). The majority of participants (65%) had symptoms for 1–4 weeks and 12% more than 6 months. The most common symptoms were initially malaise, fatigue, headache, fever and cough and the most common long-term symptoms were impaired physical condition, fatigue, anosmia and headache. The BIPQ index had a negative correlation with the EQ5D-VAS score after the infection, but not with long-term symptoms. Mean differences in the EQ5D-VAS score were significantly lower after the infection and patients with long-term symptoms had a more pronounced negative effect in EQ5D-VAS scores. Conclusion: We found that most patients with non-severe covid-19 reported symptoms for 1–4 weeks and approximately 10% developed long-term symptoms. Non-severe covid-19 seems to have a negative influence on HR-Qol, especially in patients with long-term symptoms and with a greater burden from the disease. None of the initial symptoms could predict the presence of long-term symptoms. © 2023 Society for Scandinavian Journal of Infectious Diseases.
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| 15. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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A Comparison of Americium Extractions as a Function of Time using Two Bis-Triazine-Bipyridine Ligands in Long-Chained Alcohol Diluents
- 2014
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Ingår i: Separation Science and Technology. - : Informa UK Limited. - 1520-5754 .- 0149-6395. ; 49:13, s. 2060-2065
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Tidskriftsartikel (refereegranskat)abstract
- The rate of americium mass transfer between the aqueous and organic phase in a solvent extraction system has been investigated. The ligand used is CyMe4-BTBP and the diluents are long-chained alcohols. The results are compared with earlier reported data using C5-BTBP as ligand. In the C5-BTBP system the rate of the extraction could be correlated with the interfacial tension of the system, while not in the CyMe4-BTBP system. In the CyMe4-BTBP system a high (> 12) or low (
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| 16. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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A reinterpretation of C5-BTBP extraction data, performed in various alcohols
- 2013
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 296:2, s. 733-737
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Tidskriftsartikel (refereegranskat)abstract
- The separation of trivalent actinides from trivalentlanthanides present in used nuclear fuel can beachieved by using solvent extraction and the BTBP class ofligands. This separation is relevant for the advancedreprocessing of the used fuel. The choice of diluents insuch BTBP based systems has shown to affect the extractionas well as the separation. Long chained alcohols havepreviously been investigated as such diluents, showing thatthe americium extraction is higher into alcohols havingshorter chains (hexanol, and heptanol) than in longerchained ones (nonanol and decanol). In this work it isshown that not only the distribution ratio, but also thecontact time needed before reaching extraction equilibriumis shorter when using shorter chain length of the alcoholdiluent. It is also shown that the rate of extraction can becorrelated to the interfacial tension between the diluent andthe aqueous phase. A low interfacial tension gives a fastextraction while an extraction system with higher interfacialtension needs a longer time of phase contact in order toreach extraction equilibrium.
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| 17. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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Comparison of the Extraction as a Function of Time in two GANEX solvents -Influence of Metal Loading, Interfacial Tension and Density
- 2013
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 31:6, s. 604-616
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Tidskriftsartikel (refereegranskat)abstract
- Two Group ActiNide EXtraction solvents for the extraction of actinides from used nuclear fuel for transmutation purpose have been compared. The solvent studied more precisely comprises cyclohexanone, tributylphosphate and a molecule from the bis-triazine bi-pyridine family, whilethe alternative utilizes di-ethyl-hexyl butyramide instead of tributylphospate. The focus of the comparison has been on the kinetics of the extraction of americium and europium, and the influence of an increased metal content on their separation factor. Both systems showed to maintain the equilibrium separation factor up to an europium concentration of 1 mM and their SFAm/Eu is decreased with a prolonged phase contact.
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| 18. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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Diluent effects in solvent extraction
- 2010
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Ingår i: Proceedings of the First ACSEPT International Workshop Lisbon, Portugal, 31 March – 2 April 2010.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The fact that the choice of organic diluent is important for a solvent extraction process goes without saying. Several factors, such as e.g. price, flash point, viscosity, polarity etc. each have their place in the planning of a solvent extraction system.This high number of variables makes the lack of compilations concerning diluent effects to an interesting topic. Often the interest for the research concerning a specific extraction system focuses on the extractant used and the complexes built up during an extraction. The diluents used are often classical ones, even if it has been shown that choice of diluent can affect extraction as well as separation in an extraction system. An attempt to point out important steps in the understanding of diluent effects in solvent extraction is here presented. This large field is, of course, not summarized in this article, but an attempt is made to present important steps in the understanding of diluents effects in solvent extraction. Trying to make the information concerning diluent effects and applications more easily accessible this review offers a selected summarizing of literature concerning diluents effects in solvent extraction.
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| 19. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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Extraction thermodynamics of Am(III) and Eu(III) using CyMe4-BTBP in various organic diluents
- 2014
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Ingår i: Journal of Chemical Thermodynamics. - : Elsevier BV. - 0021-9614 .- 1096-3626. ; 76, s. 64-69
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Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic parameters (ln KEx, ΔH0 and ΔS0) for the extractions of americium and europium using CyMe4-BTBP in three various diluents (cyclohexanone, hexanol and nitrobenzene) have been studied. The stoichiometry of the complexes was obtained by slope analysis of the distribution ratios of the metals as a function of the ligand concentration. The influence on temperature on the americium/europium separation was investigated for process development causes.In cyclohexanone it was shown that the stability of the (1:2) complex is stronger in the americium case than in the europium case where the (1:1) seems to dominate. Similarly; the 1:2 complex are more dominant in the case of americium compared to in the europium complex in hexanol as well. In nitrobenzene both the metals form 1:1 complexes. The extractions of both the nuclides in the three diluents are exothermic. However, since the europium complexes in hexanol and cyclohexanone were shown to contain both 1:1 and 1:2 complexes no further evaluation of those two systems in particular could be made. The enthalpy for the nitrobenzene system differs radically compared to the two others, having a more prominent decrease in ΔH 0 (for example View the MathML source = −44 ± 6.2 (kJ · mol−1) in nitrobenzene compared to View the MathML source = −19 ± 1.1 (kJ · mol−1) in hexanol). In the entropies of the system no differences is seen when comparing the diluents cyclohexanone and hexanol, however, there is a difference in ΔS0 between the two and nitrobenzene, were the change in entropy is negative in the nitrobenzene system and positive in the other two diluents.In addition, it was shown that the temperature affected the separation factor of americium from europium. The separation factors decreases in all the three systems as the temperature increases. This is of importance during process development purposes.
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| 20. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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Hexanoic acid as an alternative diluent in a GANEX process: feasibility study
- 2014
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 290:3, s. 1261-1266
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Tidskriftsartikel (refereegranskat)abstract
- Used nuclear fuel is radiotoxic for mankind andits environment for a long time. However, if it can betransmuted, the radiotoxicity as well as its heat load arereduced. Before a transmutation the actinides within theused fuel need to be separated from the fission, corrosionand activation products. This separation can be achieved byusing the liquid–liquid extraction technique. One extractionprocess that can be used for such a separation is the GroupActiNide EXtraction (GANEX) process. One GANEXprocess that can successfully accomplish the separationutilizes the diluent cyclohexanone in combination with theextractant tributylphosphate (TBP) (30 % vol) and a secondextractant, CyMe4-BTBP (10 mM). However, thereare some issues when using cyclohexanone as diluent. Inthis work an alternative diluent has therefore been tried inorder to determine if it can replace cyclohexanone. Thediluent used was hexanoic acid. In a system containing10–12 mM CyMe4-BTBP and 30 % vol TBP in hexanoicacid with the aqueous phase 4 M HNO3, the distributionratios for americium and curium are unfortunately low(DAm = 1.1 ± 0.27, DCm = 1.6 ± 1.81). The concentrationof CyMe4-BTBP ligand, the extractant of curium andamericium, could unfortunately not be increased, becauseof limited solubility in hexanoic acid. The distributionratios for fission, corrosion and activation products werelow for most metals; however, cadmium, palladium andmolybdenum all unfortunately have distributions ratiosabove 1. To conclude, low americium and curium extractionsindicate that hexanoic acid is not a suitable diluentwhich could replace cyclohexanone in a GANEX process
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| 21. |
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| 22. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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Solvent effects on the extraction rate in proposed GANEX processes
- 2011
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Ingår i: 19th international solvent extraction conference, ISEC 2011.
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Konferensbidrag (refereegranskat)abstract
- A group actinide extraction process (GANEX) for reprocessing of used nuclear fuel has earlier been presented using the diluent cyclohexanone and combining the extractant molecules tri-butyl phosphate (TBP) and 6,6’-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo-[1,2,4] triazin-3-yl)-[2,2’]bipyridine (CyMe4-BTBP). This GANEX process shows high potential for the separation of trivalent actinides from trivalent lanthanides. In order to improve this process an alternative solvent has been recently presented where the TBP molecule is replaced with a mono-amide ligand, di(2-ethylhexyl) butyramide (DEHBA). One of the advantages with the amide is that it is has previously shown good extraction of uranium and plutonium.One important step in the evaluation and comparison of these two proposed processes is the rate of the extraction. The GANEX solvent using TBP has in this paper been shown to have a faster mass transfer than the solvent containing DEHBA. This is explained with the surfactant property of the TBP molecule. This property makes the surface to volume ratio during mixing higher in the TBP based solvent. However, from this investigation, no conclusion can be drawn whether the rate determining step of the extraction is the diffusion or the chemical reactions taking place. To achieve this information more research is needed.
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| 23. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
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The Extraction of Silver and the effect of Diluent, Ligand side group and Solvent composition
- 2012
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Ingår i: Procedia Chemistry. - : Elsevier BV. - 1876-6196. ; 7, s. 239 - 244
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Konferensbidrag (refereegranskat)abstract
- Solvent extraction and the so called BTBP class of ligands can be used for the separation of the actinides fromthe rest of used nuclear fuel. One troublesome co-extracting element in this separation is silver.Therefore, two different BTBP molecules, having different side groups have been investigated. It was shown thatthe silver distribution ratio is higher using the CyMe4-BTBP than theC2 -BTBP ligand. In additionalexperiments, it was shown that no water soluble silver complex is formed in the CyMe4 system and that thecomplex is one ligand / metal. No effect of varying the diluent/solvent was proven
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