共查询到20条相似文献,搜索用时 548 毫秒
1.
S. K. Pathak Suman Kumar Singh Arvind Mahtele S. C. Tripathi 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):597-603
This paper describes the studies on the extraction of molybdenum (VI) from aqueous nitric acid medium by (2-ethylhexyl) phosphonic
acid, mono (2-ethylhexyl) ester (PC-88A). The extraction affecting parameters such as concentration of HNO3 in aqueous feed, effect of concentration of extractants, effect of diluents, and molybdenum concentration in the aqueous
phase are investigated to optimize the extraction conditions for the quantitative separation of molybdenum from nitric acid
medium. With increase of HNO3 concentration in aqueous phase, percentage extraction was found to be decreased in all the cases. Percentage extraction of
molybdenum increases with increase in PC-88A concentration till the 0.15 M of PC88A, and after that it becomes constant. Kerosene
and n-dodecane was found to be most suitable diluents. Among the various strippants used 0.2 M (w/v) solution of Na2CO3 and 0.2 M (w/v) solution (NH4)2CO3 are found to be the equally suitable for stripping of molybdenum from the loaded organic phase. The stripping of molybdenum
from loaded organic layer by various reagents followed the order: (NH4)2CO3 >Na2CO3 >0.1 M sodium salt of EDTA >2 M NaOH >8 M HNO3. The optimized process conditions are employed to extract molybdenum (VI) from actual Davies–Gray waste as well as from diluted
high level waste generated in the purex stream. More than 94% Mo(VI) was extracted from radioanalytical as well as from high
level waste of purex process and quantitative recovery was achieved in both the cases when 0.2 M sodium carbonate was used
as stripping agent. 相似文献
2.
M. Wiśniewski M. B. Bogacki J. Szymanowski 《Journal of Radioanalytical and Nuclear Chemistry》1996,208(1):195-206
The extraction of sulphuric acid from solutions containing hydroxylamine sulphate and ammonium sulphate with Cyanex 923 and the acid stripping from loaded Cyanex 923 are studied at 20 and 50°C. The effect of the numbers of extraction and stripping stages and the volume phase ratios in extraction and stripping upon sulphuric acid recovery is discussed. The process can be design to obtain a high or low recovery of sulphuric acid but with its low or high concentration, respectively. 相似文献
3.
G. R. Anpilogova R. A. Khisamutdinov L. G. Golubyatnikova Yu. I. Murinov 《Russian Journal of Applied Chemistry》2016,89(2):206-211
Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions of varied composition was studied using commercial reagents propiconazole and penconazole as extractants. The ranges of hydrochloric acid concentrations for effective extraction and highly selective separation of platinum metals from Al(III) and Ni(II) with propiconazole (toluene with 15 vol % n-decanol as deluent) and penconazole (chloroform) were determined. The conditions for 10-fold selective concentration of platinum metals with recovery of more than 99.9% of metal ions into the organic phase were found. The conditions for quantitative (>99%) stripping of platinum(IV) with a hydrochloric acid solution of thiourea and palladium(II) with ammonia solution were determined. The results obtained can be used for optimizing the modes of selective recovery of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of alumina-supported platinum-rhenium, platinum-nickel, and palladium catalysts. 相似文献
4.
J. Szymanowski 《Journal of Radioanalytical and Nuclear Chemistry》1996,208(1):183-194
The development of copper hydrometallurgy is presented and various processes proposed for copper recovery from sulphide concentrates are discussed. Leaching, extraction and stripping are considered, including reagents and processes. The extraction of copper from chloride solutions is discussed. Various extractants are presented and their use for copper transfer from chloride solutions to the organic phase and back to chloride and to sulphate solutions is discussed. 相似文献
5.
《印度化学会志》2023,100(9):101081
This study explores the use of novel green emulation liquid membranes (GELMs) for the simultaneous extraction and stripping of Cd (II) from aqueous solutions. A solute is transported through the membrane due to the presence of the carrier and then concentrated in the internal phase. Soybean, sunflower, corn, and canola oils were used to form green substitutes to petroleum-based organic diluents for use as GELMs. Bis-(2-ethylhexyl) phosphate (D2EHPA), tri-butyl- phosphate (TBP), and trioctylamine (TOA) were the extractants, span 80 was the emulsifier, and HCl or H2SO4 was used as the stripping agent. The best conditions for maximum extraction efficiency (98.68%), stripping efficiency (97.14%), and lowest membrane breakage (0.9%) were achieved using a mixture of sunflower oil and kerosene in the ratio of 70:30. The other optimum values of the variables were: 2% (v/v) Span 80, 10 min emulsification time, 12700 rpm emulsification speed, 400 rpm of agitation speed, 5% (v/v) D2EHPA, an external phase pH was 3.5, an internal phase of 0.25 M HCl, and 5:1 of the treat ratio (external phase to emulsion) at 10 min contact time. The synthesized membrane was reused eight times, with approximately the same efficiency and no significant breakage during the first seven cycles. 相似文献
6.
Volkan Eyupoglu Halil Ibrahim Turgut Recep Ali Kumbasar 《Journal of Dispersion Science and Technology》2018,39(6):802-813
The study was to determine selective removal and recovery of Cr(VI) from acidic media by solvent extraction (SX) using asymmetric imidazolium-based room temperature imidazolium bromide salts (ARTILs) as the extractants. The relevant parameters on the extraction and the stripping of Cr(VI) were investigated to identify optimum conditions. The optimum conditions were determined as equilibration time 5 minutes, acid concentration and type 0.5?mol/L H2SO4, stirring speed 1200?rpm, extractant concentration and type 0.5?mol/L ARTIL5, phase ratio 2.0 and stripping reagent type, and concentration 2.0?mol/L NH3. In optimum conditions, decyl substituted ARTIL was best in extraction process about 99.7% of extraction rate, whereas moderately hydrophobic pentyl substituted ARTIL was best in stripping process about 70.0% of stripping rate. Also, the optimized process was found as so selective toward Cr(VI) in the presence of the other metal ions with an environmental-friendly liquid–liquid–based SX method. 相似文献
7.
M. Kyrš K. Svoboda P. Lhoták J. Alexová 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(3):497-509
Solvent extraction of several long-lived fission products from diluted nitric acid in pronounced synergistic systems involving dicarbollide and conformers of a specific thiacalix[n]arene were investigated using mainly chlorobenzene as the diluent. The following factors were experimentally investigated: molar ratio of the two extractants, total extractants concentration, aqueous acidity, nature of the mineral acid used, relative phase volumes, repeated extractions and metal concentration. Data are given on the rather slow kinetics of extraction and stripping, limited chemical stability of the extractants, selectivity and interference of foreign metals. The three different conformers of the basic compound with identical chemical composition exhibit very differing extraction properties. The plots of distribution ratios of all metals tested versus the varying concentration of one extractant keeping the concentration of the other extractant constant invariably exhibit maxima, interpreted as the result of an existence of several extracted species in the extract. Suggestions are given concerning possible practical applications of two of the conformers studied. 相似文献
8.
C. S. Kedari S. S. Pandit A. Ramanujam 《Journal of Radioanalytical and Nuclear Chemistry》1997,222(1-2):141-147
The process of in situ electro-oxidation of Ce(III) to Ce(IV) followed by its extraction into the organic phase has been investigated for its applicability in the separation of Ce from nitrate medium. Solvent extraction of cerium from nitric acid after its electro-oxidation to fourth valency state was carried out using tributyl phosphate (TBP) and 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC-88A). The efficiency of the extractants at different aqueous phase nitric acid concentrations and different electrode potentials were determined. Various reducing agents such as hydroxylamine hydrochloride, sodium nitrite, ferrous sulphate as well as complexing agents like EDTA, oxalic acid etc, were studied as strippants for the back extraction of cerium from the loaded organic phase. The method developed for the extraction of cerium was further extended to the partitioning of cerium from Ce-Am mixture obtained during the KSM-17 based extraction chromatographic elemental fractionation of PUREX High Activity Waste (HAW) solutions. Recovery of Ce obtained in the extraction experiments by batch as well as by continuous flow organic phase was >95% with good radiochemical purity. 相似文献
9.
Manpreet Singh Arijit Sengupta Sk. Jayabun Tejaswi Ippili 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(1):195-208
The extraction efficiency for thorium followed the trend: Cyanex-923 > Cyanex-272 > DHOA > TBP. In case of TBP and DHOA the extraction proceeded via ‘solvation mechanism’ through Th(NO3)4·2L, while for Cyanex-923 and Cyanex-272 it proceeded via ‘ion exchange’ mechanism through (Th(NO3)2·2L)2+. The extraction process followed slower kinetics while change in Gibb’s energy revealed the spontaneity of the process. These ionic liquid based systems were found to be radiolytically stable, highly efficient and selective for Th. Oxalic acid was found to be suitable for almost quantitative stripping of Th from extracted ionic liquid phase. 相似文献
10.
Sujoy Biswas D. K. Singh K. N. Hareendran J. N. Sharma S. B. Roy 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):201-205
Solvent extraction of U(VI) with di-isodecyl phosphoric acid (DIDPA)/dodecane from nitric acid medium has been investigated
for a wide range of experimental conditions. Effect of various parameters including nitric acid concentration, DIDPA concentration,
temperature, stripping agents, and other impurities like rear earths, transition metal ion, boron, aluminum ion on U(VI) extraction
has been studied. The species extracted in the organic phase is found to be UO2(NO3)(HA2)·H2A2 at lower acidity (<3.0 M HNO3). Increase in temperature lead to the decrease in extraction with the enthalpy change by ∆H = −16.27 kJ/mol. Enhancement in extraction of U(VI) from nitric acid medium was observed with the mixture of DIDPA and tri
butyl phosphate (TBP). The stripping of U(VI) from organic phase (DIDPA–U(VI)/dodecane) with various reagents followed the
order: 4 M H2SO4 > 5% (NH4)2CO3 > 8 M HCl > 8 M HNO3 > Water. High separation factors between U(VI) and impurities suggested that the use of DIDPA for purification of uranium
from multi elements bearing solution. 相似文献
11.
T. Sotobayashi T. Suzuki H. Kudo 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(1):145-152
Polyethyleneglycol (PEG) and its derivatives of high molecular weight were found to be employed as useful extractants for
the solvent extraction of uranium. The extraction behaviors of uranium and neptunium were investigated, particularly concerning
the dependence of the extractibility of uranium(VI) on the molecular weight of PEG. A dominating species of the extracted
uranium(VI) thiocyanate complexes was assumed to be NH4 UO2(SCN)3·(PEG). The extraction of protactinium was also preliminarily studied. The extraction of these actinides from an acidic thiocyanate
solution increased in the order: uranium(VI)>protactinium(V)>neptunium(V). 相似文献
12.
Qichu Xu Jianfeng Wu Lixing Zhang Yusheng Yang 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):235-245
Extraction of Am(III) and Ln(III) from NaClO4 medium with di(2-ethylhexyl)dithiophosphoric acid (DEHDTP), di(2-ethylhexyl)monothiophosphoric acid (DEHMTP), di(2-ethylhexyl)monothiophosphinic
acid (DEHMTPI), dihexyldithiophosphinic acid (DHXDTPI), diheptyldithiophosphinic acid (DHPDTPI), dioctyldithiophosphinic acids
(DODTPI), dinonyldithiophosphinic acid (DNDTPI), di(1-methylheptyl)dithiophosphinic acid (DMHDTPI) and di(2-ethylhexyl)dithiophosphinic
acid (DEHDTPI) in xylene has been investigated. The order of the extraction selectivity for Am(III) is DEHDTPI > DEHDTP >
DEHMTPI > DEHMTP, DHPDTPI > DODTPI > DHXDTPI > DNDTPI, DMHDTPI > DEHDTPI > DODTPI, for extractants with 2-ethylhexyl alkyl,
straight chain alkyl, branch chain alkyl, respectively. Using 0.1 mol/l NaClO4 solution as aqueous phase, the slope values of the logD-pH and logD-logC curves are not integers, and the slope values for Am(III) are slightly higher than those for Eu(III), for all extractants.
The relationship between the slope value and extraction conditions can be described as: logS = alg(C
HA/C
M
S/4)+b. In the presence of macro Eu(ClO4)3, the formula, logSF
Am/Ln = B-2log(C
HL-D
Ln/(D
Ln + 1)C
Eu), can well describe the relationship between separation factor and the extraction condition. A high separation factor (SF
Am/Eu = 2500) is obtained by solvent extraction with 0.5 mol/1 DEHDTPI in toluene from 1 mol/l NaNO3 solution. 相似文献
13.
Effect of binary extractants and modifier–diluents systems on equilbria of propionic acid extraction
Propionic acid is an important carboxylic acid widely used in chemical industries. The recovery from aqueous waste streams and fermentation broth is of research interest. Extraction of carboxylic acids by reactive extraction using extractant-diluent, mixed extractants in diluents and extractants in mixed diluents etc. are emerging areas of study. With this aim reactive extraction of propionic acid was carried out to study: (i) effect of binary extractants (tri-n-octylamine(TOA):tri-n-butylphosphate (TBP), TOA:Aliquat 336 and TBP:Aliquat 336), (ii) effect of modifier (1-decanol) in different diluents (kerosene, n-octane, n-heptane, petroleum ether, butyl acetate, MIBK, 2-octanol, dodecanol, hexane) and (iii) effect of phase volume. Improved extractions using binary extractants and binary diluents were observed. Since liquid–liquid extraction is dependent on effect of modifier concentration, effect of phase volume, presence of single or binary extractants and binary diluents, the study will be useful in the design of reactive extraction process for propionic acid recovery. 相似文献
14.
The development of economic and environmentally friendly extractants to recover cobalt metal is required due to the increasing demand for this metal.In this study,solvent extraction of Co(Ⅱ) from aqueous solution using a mixture of N,N’-carbonyl difatty amides(CDFAs) synthesised from palm oil as the extractant was carried out.The effects of various parameters such as acid,contact time,extractant concentration,metal ion concentration and stripping agent and the separation of Co(Ⅱ) from other metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ) were investigated.It was found that the extraction of Co(Ⅱ) into the organic phase involved the formation of 1:1 complexes.Co(Ⅱ) was successfully separated from commonly associated metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ).Co(Ⅱ) stripping from the loaded organic phase was studied in aqueous solution.These results are useful to recover Co(Ⅱ) from aqueous solution utilising(CDFAs) as an extractant. 相似文献
15.
Separation of Zr and Hf from strong hydrochloric acid solution by solvent extraction with TEHA 总被引:1,自引:0,他引:1
Raju Banda Hwa Young Lee Man Seung Lee 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1537-1543
In order to separate Zr(IV) and Hf(IV) from chloride solutions, TEHA (tri 2-ethyl hexyl amine) was used as an extractant. The aqueous phase consisted of 200 ppm of Zr and Hf in strong HCl solution. In our solvent extraction system, the extractability of the constituents by TEHA was found to be in the following order, HCl > Zr(IV) > Hf(IV). The highest separation factor between the two metals was obtained from 8 M HCl solution. Based on the selectivity towards Zr over Hf with TEHA, McCabe–Thiele plot was constructed and batch simulation of counter-current extraction studies has been conducted. Scrubbing results from the loaded TEHA showed that Hf was selectively scrubbed over Zr by strong HCl solution (9 M). Complete stripping of Zr was possible from the organic phase with distilled water after scrubbing of Hf. The extraction behavior of Zr and Hf by TEHA was compared with that by TiOA and TOA. Our results can be utilized in developing a solvent extraction process to separate Zr and Hf from concentrated chloride solutions by using TEHA. 相似文献
16.
The technique for and methods of separation of products of nuclear fission play a major role in many stages of the nuclear
fuel cycle. The extraction of these products from effluent solution after the processing of the burnt-up nuclear fuel is receiving
considerable attention. Trivalent lanthanoides are usualy extracted together with Am(III) and their mutual separation is rather
difficult.1–4 The extraction of lanthanoides with tertiary amines or quaternary ammonium salts involving the benzyl group as one of substituents
has been studied in order to find the influence of the alkyl chain length on the extraction selectivity and capacity.3–5 Suitable extractants for the separation of Am(III) and Ln(III) from the acidic nitrate solutions were recommended. Using
vapour phase osmometry and cryoscopy the association of these compounds was measured at 5.25 and 50°C allowing a rough estimation
of medium association degree for the formation of the aggregates. The method of apparent molar volumes, supplemented by the
spectrophotometric method, was used for identification of the chemical composition of the aqueous phase. 相似文献
17.
R. B. Gujar S. A. Ansari M. S. Murali P. K. Mohapatra V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(2):377-385
Extraction behaviour of actinides, lanthanides, fission products and structural elements has been studied with the two diglycolamide
extractants, namely N,N,N′,N′-tetra-2-ethylhexyl diglycolamide (T2EHDGA) and N,N,N′,N′-tetraoctyl diglycolamide (TODGA). The
acid extraction studies suggested that T2EHDGA (KH: 1.8) is less basic as compared to its linear homologue, TODGA (KH: 4.1). The distribution ratio of Am(III) by 0.1 M diglycolamides followed the order: TODGA > T2EHDGA. The number of ligand
molecules present in the stoichiometry of the extracted species of Am(III) was found to be three and four for T2EHDGA and
TODGA, respectively. Thermodynamics studies suggested that the extraction of Am(III) by both the extractants is exothermic
in nature. The radiolytic stability of TODGA and T2EHDGA solutions in n-dodecane has been investigated. Due to lower distribution ratio of Am by T2EHDGA, 0.2 M of its solution has been used as
compared to 0.1 M solution of TODGA. The distribution behaviour of various metal ions, viz. Am, Nd, Fe, Mo, Cr, Sr and Cs
has been studied from nitric acid as well as from simulated high level waste solution. 相似文献
18.
Mao Jia-Jun Jia Wei-Jie Shao Xing-Zhi Chen Yu-De 《Journal of Radioanalytical and Nuclear Chemistry》1991,147(2):287-295
The synergistic extraction of uranium(VI) from hydrochloric acid solution with five chelating agents: 1-phenyl-3-methyl-4-benzoylpyrazolone-5 (PMBP), 1-phenyl-3-methyl-4-acetylpyrazolone-5 (PMAP), 1-phenyl-3-methyl-4-(2-chlorobenzoyl)pyrazolone-5 (PMCBP), 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone-5 (PMNBP) and 1-phenyl-3-methyl-4-trifluoroacetylpyrazolone-5 (PMTFP) plus the neutral extractants tributylphosphate (TBP), dioctyl sulfoxide (DOSO) and trioctylphosphine oxide (TOPO) in chloroform has been investigated. The extraction coefficients have been found to be greater for such mixtures than the individual component. The formulas of the extracted species have been determined to be UO2A2B (where HA = chelating agent, B = neutral extractant). Extraction power of these chelating agents increases as follows: PMCBP>PMNBP>PMTFP=PMBP>PMAP. Synergistic extraction power of the neutral extractants increases as follows: TOPO>DOSO>TBP. The extraction equilibrium constants have been calculated. The mechanism of the synergistic extraction and possible structure of the extracted species are discussed. 相似文献
19.
Melisa Lalikoglu 《印度化学会志》2022,99(1):100303
The fermentation of biomass and organic waste streams is the primary source of formic acid production. Formic acid is the hydrogen energy carrier and is used as a hydrogen storage medium in fuel cells. Sustainable production of formic acid makes the hydrogen-fuel cell entirely environmentally friendly and ensures the long-term storage of renewable energy. Therefore, green, economic, and sustainable production and recovery of formic acid are highly demanded. In this study, it was aimed to use a new generation, green, easily prepared, and designer hydrophobic deep eutectic solvents (HDES) for the removal of formic acid via reactive extraction. HDESs obtained by preparing binary mixtures of nonanoic acid, decanoic acid, dodecanoic acid (HBD), and menthol (HBA) were used as diluents; tri-n-octylamine (TOA) and Amberlite LA-2 (Amb.LA-2) were acted as extractants. Experiments were performed to investigate the effect of extractant type and concentration, initial acid concentration, and volume of the organic phase on extraction. Experimental data were presented by calculating the extraction efficiency (E%), distribution coefficient (D), and loading factor (Z). Results demonstrated that the extraction efficiency remained between 10 and 13% when performing physical extraction using M-NA, M-DA, and M-DDA, while TOA was diluted with the same HDESs reached around 90% and with Amb.LA-2 85%. The highest distribution coefficient was obtained that the organic phase consisting of TOA and M-DDA mixture was used. The efficiency of utilized HDESs was in the following order: M-DDA ?> ?M-DA ?> ?M-NA. 相似文献
20.
Kwanghyun No Jong Seung Kim Seyoung Kim Duong Tuan Quang In-Chul Hwang Jacques Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(3-4):353-360
A series of tetrahomodiazacalix[4]arenes (1–8) with different substituents (or substituted) at the upper rim and/or N-side arm has been synthesized with acceptable yields. The compounds were characterized by elemental analysis, IR, MS and
NMR methods. In particular, 5 was shown by X-ray crystallography to adopt the cone conformation in the solid state. Two-phase picrate extraction showed
that 2 and 6, bearing N-2-picolyl arms, are the best extractants. Of the cations tested, Ag(I) is the best extracted by almost all ligands and the
extraction efficiency follows the order 2-picolyl > 3-picolyl > 4-picolyl. 相似文献