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1.
Fiona McLachlan Katie Greenough Andreas Geist Bliss McLuckie Giuseppe Modolo Andreas Wilden 《溶剂提取与离子交换》2016,34(4):334-346
The tridentate diglycolamide ligand N,N,N′,N′-tetraoctyl diglycolamide (TODGA) shows many interesting properties and is a very good extractant for the minor actinides (MAs) and lanthanides but, due to its low loading capacity, requires a phase modifier when used in a solvent extraction process. Consequently, applications of TODGA in conjunction with tri-butyl phosphate (TBP) in novel DIAMEX and SANEX processes for recovering MAs have been reported. However, TODGA and TBP also extract nitric acid and this has a significant influence on process performance. Here new distribution data for the extraction of nitric acid into solvent phases containing TODGA and TBP have been collected and modeled using an equilibrium-based approach accounting for nitric acid activities in the aqueous phase. Models for the extraction of nitric acid using the individual extractants were obtained using a variety of complexes and these were then combined to give the extraction of the mixed TODGA and TBP solvent. Using this approach, the nitric acid extraction of the mixed TODGA/TBP system can be reliably reproduced indicating that no significant synergistic or antagonistic complexes are formed in solution. 相似文献
2.
Abstract A study on plutonium third phase formation in 30% TBP/nitric acid/hydrogenated polypropylene tetramer (HPT) was performed. Characterization studies of HPT indicate its composition to be a mixture of many highly branched alkanes with a volatility close to n‐undecane. This composition results in about a factor of two better resistance to Pu(IV) third phase formation than dodecane. At 7 M nitric acid in the aqueous phase, the presence of Pu(VI) was observed to substantially reduce the organic phase metal concentration necessary to induce phase splitting in both diluents. Spectroscopic investigation of mixed valence systems also suggest a prominent role for Pu(VI) in the formation of the dense organic phase. Accumulation of Pu(VI) in the heavy phase, as well as certain spectral features, suggest that Pu(VI) is forming a different species, possibly a plutonyl trinitrato, with a strong tendency to form third phase. 相似文献
3.
《分离科学与技术》2012,47(10):2065-2074
Abstract Additional information on the organic phase speciation of Np and Pu was obtained in order to further understand the impact on third phase formation. In the Np(VI) extraction system, indications of the presence of a species associated with the absorbance at 1210 nm appears to be consistent with an increased tendency for third phase formation. Attempts to couple this absorption peak to a higher order nitrate species were inconclusive, and further study is required. For Pu(VI), continued evidence has emerged suggesting a role of higher order nitrate species in third phase formation. 相似文献
4.
《分离科学与技术》2012,47(14):2164-2169
This study investigates the equilibrium absorption of water in various solvents and solvent-mixtures being considered for the counter-current solvent extraction of acetic acid from improved Uranium Extraction (UREX+) process solutions. It then seeks to determine if there is any correlation between the equilibrium water content of these solvents and their equilibrium extraction of 0.25 M nitric and 0.025 M acetic acid. The UREX+ process is a proliferation resistant version of the Plutonium Uranium Extraction (PUREX) process. The solvents studied were n-Dodecane (nDD), 1,2 Dichloroethane (DCE), and Phenyltrifluoromethyl Sulfone (FS-13), and mixtures of these solvents with Tributyl Phosphate (TBP). After studying both pure water and acidified aqueous systems, it seems the water absorption mechanism is independent of the diluent used and remains constant with the addition of the 0.25 M nitric and 0.025 M acetic acid. 相似文献
5.
6.
Novel polyfunctional neutral organophosphorus compounds, P(O)-modified N-aryl- carbamoylmethylphosphine oxides, Ph2P(O)CH2C(O)NH-(o-C6H4)(CH2)n-P(O)Ph2 and Ph2P(O)CH2C(O)NH-(m-C6H4)(CH2)n-P(O)Ph2 (n = 1,2), were synthesized and studied as extractants for U(VI), Th(IV) and Ln(III) from HNO3 solutions. The influence of aqueous and organic phases on the extraction efficiency was elucidated and stoichiometry of the complexes extracted was determined. Introduction of an additional phosphoryl group into the phenyl substitutent at the nitrogen atom of diphenyl(N-phenylcarbamoylmethyl)phosphine oxide resulted in an increase of the efficiency of U(VI), Th(IV), Ln(III), and Re(VII) extraction. 相似文献
7.
SDS/正丁醇/煤油/水微乳液体系的相转变研究 总被引:2,自引:0,他引:2
利用不同的盐类,实现了十二烷基硫酸钠(SDS)/正丁醇/有机污染物(煤油)/水微乳液的制备,并考察了微乳液的相转变过程.实验结果表明随着正丁醇和各种盐类浓度的增加,微乳液都经历Winsor Ⅰ →WinsorⅢ→Winsor Ⅱ型的相转变过程,但是形成WinsorⅢ型微乳液时,各种盐的盐宽和范围均不同,并且每种盐形成W... 相似文献
8.
Binary solutions of tri-n-butyl phosphate (TBP) or tri-iso-amyl phosphate (TiAP) in n-dodecane or n-tetradecane (1.1 M) as diluents have been investigated for third phase formation in the extraction of Th(NO3)4 from its solutions with 1 M or 5 M HNO3 as a function of equilibrium aqueous phase Th(IV) concentration ([Th(IV)]aq,eq) at 303 K. Extraction isotherms for the extraction of Th(IV) and HNO3 have been generated with respect to [Th(IV)]aq,eq. The difference in density between the third phase and the diluent-rich phase as well as the diluent-rich phase and the pure diluent, ratio of volume of the diluent-rich phase to that of the third phase have also been determined over a wide range of [Th(IV)]aq,eq in the triphasic region. An attempt has also been made to determine the extractant concentrations in the third phase and the diluent-rich phase in the extraction of Th(NO3)4 by the above solvents from its saturated solutions with 1 M and 5 M HNO3. 相似文献
9.
《分离科学与技术》2012,47(8):1186-1191
The extraction behavior of Am(III) and Eu(III) in a solution of tetra-octyldiglycolamide (TODGA), bis(2-ethylhexyl)phosphoric acid (HDEHP), and n-dodecane (n-DD) was studied to understand the role of TODGA and HDEHP in the combined solvent system. The extraction behavior of these metal ions was compared with those observed in TODGA/n-DD and HDEHP/n-DD. The effect of various parameters such as concentrations of HNO3, TODGA, and HDEHP on the distribution ratio of Am(III) and Eu(III) was studied. Synergistic extraction of both the metal ions observed at lower acidities (<2.0 M) was attributed to the involvement of TODGA and HDEHP for extraction. However, the extraction of Am(III) and Eu(III) in the combined solvent was comparable with that observed in TODGA at higher acidities. The slope analysis of the extraction data confirmed the involvement of both the extractants at all acidities investigated in the present study. 相似文献
10.
Alternative mass action models were assumed to study competitive equilibria for nitric acid and water extraction in the range of 0-8.4 M nitric acid. Those models yielding the best data fits suggest that tri-n-butyl phosphate (TBP) and hydrocarbon phases contain several complexes. Four complexes appear to result from the association of nitric acid and water with the TBP dimer: [TBP]2[H20]O] 4 [TBP] 2 HN03H2O, [TBP] 2[HNO3] 2[H2O] 2, and [TBP] 2 HNO3 [H2O] 3. One complex, TBP HNO3, apparently predominates from the association of nitric acid with the TBP monomer. The TBP monomer primarily coordinates with nitric acid. The TBP dimer appears to coextract nitric acid and water together. This model gives an excellent fit to nitric acid extraction data in this concentration range and does well at predicting water extraction. 相似文献
11.
A simple model is developed to predict the formation of bromate ion as well as hypobromous acid/hypobromite ion through the hydroxyl radical pathway. For simplicity of the model, hydroxyl radical concentrations are represented by the concentration ratio of hydroxyl radical to dissolved ozone under the different pH conditions. A kinetic analysis is conducted to evaluate the ratio under the different pH conditions based on the experimental data. The different extent of the ratio by one pH unit is found to be 3–4 times. This model can favorably simulate the formations of bromate ion as well as hypobromous acid/hypobromite ion in spite of the simplicity of the model. So it is likely that this model will be applicable to the prediction of bromate ion formation in water purification process such as drinking water treatment by introducing the concentration ratio of hydroxyl radical to dissolved ozone. 相似文献
12.
Takahiro Yokota Satoshi Sakaguchi Yasutaka Ishii 《Advanced Synthesis \u0026amp; Catalysis》2002,344(8):849-854
The oxidative coupling reaction of benzene to biphenyl was examined by the use of a Pd(OAc)2/molybdovanadophosphoric acid/O2 system under mild conditions. Pd(OAc)2 combined with two different types of molybdovanadophosphoric acids exhibited the highest catalytic activity for the biphenyl synthesis. The best turn‐over number (TON) of Pd(OAc)2 and the yield of biphenyl reached 109 and 14.3% based on the benzene used, respectively. The rate‐determining step of the coupling was found to be the reoxidation step of the reduced molybdovanadophosphoric acid by molecular oxygen. 相似文献
13.
Emily Campbell Vanessa E. Holfeltz Gabriel B. Hall Kenneth L. Nash Gregg J. Lumetta 《溶剂提取与离子交换》2018,36(4):331-346
The diglycolamide extractant T2EHDGA has proven to be promising for the separation of lanthanides and minor actinides in high-level nuclear waste reprocessing. This neutral extractant has shown significant extraction capacity for HNO3 into the nonpolar organic phase, along with hyper-stoichiometric nitrate dependence on extraction of trivalent f-elements. The transport behavior of T2EHDGA/n-dodecane toward trivalent lanthanides is not well understood. This work found a significant increase in distribution ratios for Eu(III) extracted from aqueous HNO3 media compared with that from NaNO3. The extraction of Eu(III) from HNO3 results in a different thermodynamic product than predicted by classic solvent extraction of 3:1 ligand–metal complex as observed with NaNO3 in FTIR and UV-vis spectroscopy. Experimental distribution measurements in conjunction with mass-action modeling using the solvent extraction modeling program SXLSQI suggest participation of 1 to 2 HNO3 molecules in the Eu(III)/T2EHDGA complex upon extraction from HNO3 media, indicative of a mechanism change responsible for the enhanced extraction behavior toward lanthanides in the presence of HNO3. 相似文献
14.
F. Comelles J. Sánchez-Leal J. J. González 《Journal of surfactants and detergents》2007,10(3):137-144
The influence of surfactant structure on the formation of lamellar liquid crystals with very low surfactant concentration
was investigated for systems composed of oleic acid, diethyleneglycol ethyl ether and water. Surfactants belonging to anionic
and cationic families were checked: phosphated oleyl ether 3 EO (PO3EO), triethanolamine oleate (TEAO) and sodium lauryl ether sulphate (SLES) as anionic surfactants and two alkyl trimethylammonium
bromide type (C12TAB and C14TAB) as cationic surfactants. For each of the surfactants, the appropriate relationships between surfactant, oleic acid and
glycol to furnish lamellar liquid crystals when these basic compositions were further diluted with water were established.
The appropriate ranges of dilution allowing the liquid crystal formation were also determined. These liquid crystals presented
an attractive appearance because of their transparency and high viscosity, although in the beginning of its formation, a short
range of less viscous compositions (so called liquid/gel compositions) appears in some cases. Through water dilution, the
initial surfactant percentages are noticeably reduced being possible liquid crystals with 2–5 wt% of surfactant.
相似文献
F. ComellesEmail: |
15.
从经济效益、节能减排、设备腐蚀、换热器的换热效果变化、水质要求以及循环水易于结垢所带来的影响等方面,较全面地阐述了双加压制稀硝酸工艺中二次水改一次水的利与弊. 相似文献
16.
净化系统稀硫酸用于湿法磷酸萃取系统 总被引:1,自引:0,他引:1
吴建明 《硫磷设计与粉体工程》2001,(4):26-26
我厂 2 8 0kt/a硫铁矿焙烧、稀酸净化、两转两吸制酸系统 ,自 1995年底投料试车以来 ,净化所产稀硫酸曾直接送到污水处理系统 ,用石灰乳中和后经压榨排弃滤饼 ,或经斜板沉降器处理后再送污水处理。据粗略统计 ,1999年污水处理所耗石灰、聚丙烯酰胺、滤布及滤饼外运等费用达 12 0余万元。若遇设备故障还不能保证外排污水 pH值为 6~ 9的要求。真是一个既花钱、费力 ,又伤脑筋的问题。针对这个问题 ,我们设计了一套稀硫酸回收净化系统。回收的稀硫酸直接加入磷酸反应槽代替部分浓硫酸 ,以降低湿法磷酸的成本 ,减少污水处理费用 ,减少外排… 相似文献
17.
《分离科学与技术》2012,47(9):1335-1341
This paper deals with the studies on the separation and recovery of plutonium from nitric acid medium using Di-nonyl phenyl phosphoric acid (DNPPA) in n-paraffin as an extractant system. The different extraction parameters were investigated. The percentage extraction of plutonium decreased with increase in nitric acid concentration. The optimum solvent concentration for quantitative separation of plutonium from aqueous feed solution was 0.15 M of DNPPA whereas n-paraffin/n-dodecane was the most suitable of diluents with an organic to aqueous phase ratio of 1:1. Among the various strippants used, 0.5 M solution of (NH4)2CO3 was found to be the most suitable for back extraction of plutonium from the loaded organic phase. The developed method was used to separate and recover plutonium from actual wash solution of ion exchange column used for plutonium purification. More than 73% of plutonium was separated from 7 M HNO3 wash solution using 0.15M of DNPPA in n-dodecane. 相似文献
18.
Abstract Thermodynamic parameters (ΔG, ΔH, and ΔS) for the extraction of trivalent f-elements, M(III) (M = Am, Eu), with N,N,N',N'-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) were determined in nitric acid/n-dodecane extraction system. The extraction of M(III) with TODGA was more exothermic than those with octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) and dihexyl-N,N-diethylcarbamoylmethyl phosphonate (DHDECMP). The difference in ΔH between the extractants was attributed to the difference in the binding mode between them, i.e. tridentate (TODGA) and bidentate (CMPO and DHDECMP). In addition, from the results of luminescence lifetime measurement, it was found that the inner-sphere of extracted Eu(III) was dehydrated completely, and occupied by TODGA and/or NO3 ?. 相似文献
19.
《分离科学与技术》2012,47(12):1748-1753
This paper deals with the studies on the separation and recovery of thorium and 233-uranium from nitric acid medium using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester/n-dodecane as an extractant system. The different extraction parameters were investigated. The distribution ratio of thorium decreased with increase in nitric acid concentration. The optimum solvent concentration for quantitative separation of thorium from aqueous feed solution was 0.75 M of PC88A whereas dodecane was the most suitable of diluents with an organic to aqueous phase ratio of 1:1. Among the various strippants used, 2 M solution of (NH4)2CO3 was found to be the most suitable for back extraction of thorium. The developed method was used to recover thorium and 233U from radioanalytical waste generated during thorium analysis by ethylene diamine tetraacetic acid (EDTA) titremtric method and recoveries for both Th and U were more than 85%. 相似文献
20.
The recent developments of zeolite chemistry are characterized by the appearance of attempts to explain certain properties of these porous crystalline solids in terms of general chemical properties developed for other solids or even for other states of matter. Transition metal complexes in zeolites sometimes exhibit the same properties as in more conventional solvents [1]. Thus the zeolite behaves as a mono to polydentate macroligand of the transition metal ion [2]. Although numerous observations [2] underline the role of the zeolite as a solid solvent or as a common solid matrix, its unique properties in terms of structure or cage geometry should not be overlooked. Indeed, the appropriate activation of Ru(III) hexammine in faujasite-type zeolites gives a very active water gas-shift catalyst [3]. A cationic Ru-complex seemed to be formed under these conditions, having no homogeneous equivalent, and its stabilization requires the specific geometry of a faujasite supercage. 相似文献