Co-reporter:Hui Tong, Yanliang Wang, Wuping Liao, Deqian Li
Separation and Purification Technology 2013 Volume 118() pp:487-491
Publication Date(Web):30 October 2013
DOI:10.1016/j.seppur.2013.07.039
•Synergistic effects of mixtures of Cyanex 923 and organophosphoric acids are compared.•Extraction of Ce(IV) and Th(IV) shows synergistic and antagonistic effect, respectively.•The separation factor for Ce(IV)/Th(IV) reaches 36.8 with the Cyanex 923–P507 system.•High purity cerium products were obtained in the fractional extraction process.The synergistic effect of mixtures of Cyanex 923 and organophosphorus acids including P204, P507 and Cyanex 272 in extraction of Ce(IV) and Th(IV) from sulfuric acid solutions has been investigated. Under the experimental conditions, the extraction of Ce(IV) presented an significant synergistic effect with the mixed extraction systems of Cyanex 923–P204, Cyanex 923–P507 and Cyanex 923–Cyanex 272. On the contrary, the extraction of Th(IV) showed significant antagonistic effects in the mixed systems. The separation factor for Ce(IV)/Th(IV) reached as 36.8 at a mole fraction of 70% Cyanex 923 in the Cyanex 923–P507 system. It is shown that the mixed extraction systems not only enhance the extraction efficiency of Ce(IV) but also improve the selectivity of Ce(IV) over Th(IV). Furthermore, a fractional extraction process (including 4 stages of extraction, 2 stages of scrubbing and 2 stages of stripping) with the mixed Cyanex 923–P507 to separate Ce(IV) from the bastnasite leach solution has been designed. Cerium solution of Ce2(SO4)3 and CeF3 nanoparticle were obtained with 99.8% and 99.9% purity, respectively.
Co-reporter:Yanliang Wang, Wuping Liao, Deqian Li
Separation and Purification Technology 2011 Volume 82() pp:197-201
Publication Date(Web):27 October 2011
DOI:10.1016/j.seppur.2011.09.018
Solvent extraction and separation of yttrium from other rare earths in chloride medium using the mixture of sec-octylphenoxy acetic acid (CA12, HA) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272, HB) has been investigated. Tri-n-butyl phosphate (TBP) was used as the phase modifier to achieve fast phase separation and to improve the stability of the organic phase. The separation coefficients (β) between yttrium and heavy rare earths (HRE) are more significant in the double solvent (HAB) extraction system than the CA12-TBP extraction system. In a laboratory scale test with a fractional extraction process including 15 stages of extraction section and 10 stages of scrubbing section, yttrium was separated from all the other rare earths with a yield of 95% and an yttrium oxide product with 99.94% purity was obtained.Highlights► We developed HAB extraction system for Y separation using double solvent. ► Cyanex272 as co-extractant can enhance separation coefficients between Y and HRE. ► High purity Y2O3 can be obtained from IATRE ores by HAB extraction process. ► Organic phase composed of CA12, Cyanex272 and TBP is stable in extraction practice.
Co-reporter:Hui Zhang, Hongfei Li, Wei Li, Shulan Meng, Deqian Li
Journal of Colloid and Interface Science 2009 Volume 333(Issue 2) pp:764-770
Publication Date(Web):15 May 2009
DOI:10.1016/j.jcis.2009.02.012
In this paper, a novel template of carbon foam is used in building hierarchical structures of TiO2, CeO2, and ZrO2. They had multiscale morphologies, from nanowalls, nanoparticles to layer nanostructures. On a hundred-micron scale, the product was a sponge-like material constructed by nanowalls. On a hundred-nanometer scale, the electron microscope images showed that the nanowalls were porous and assembled by polycrystalline nanoparticles. Meanwhile, on one nanometer scale, many nanoparticles exhibited layer nanostructures with about 1.1 nm of thickness and spacing. In mechanism section, the process analysis and characterizations suggested that the hierarchical structures were the combined result of two templates in a “one-pot” reaction. The mesoporous nanowalls were derived from carbon foams, while the layer nanostructures were the replicas of graphite sheets. The method has potential utilizations in preparation of various adsorbent and catalyst.In this paper, hierarchical metal oxides were prepared in a “one-pot” reaction. The structure had multiscale morphologies, from nanowalls, nanoparticles to layer nanostructures. The forming mechanism was discussed.
Co-reporter:Yong Zuo;Yu Liu;Ji Chen
Journal of Chemical Technology and Biotechnology 2009 Volume 84( Issue 7) pp:949-956
Publication Date(Web):
DOI:10.1002/jctb.2116
Abstract
BACKGROUND: Ionic liquids (ILs) as environmentally benign solvents have been widely studied in the application of solvent extraction. However, few applications have been successfully industrialized because of the difficult stripping of metal ions or the loss of components of the ILs. More work needs to be done to investigate the extraction behaviour of IL-based extraction systems. In this work, the extraction behaviour of Ce(IV), Th(IV) and some trivalent rare earth (RE) nitrates by di(2-ethylhexyl) 2-ethylhexylphosphonate (DEHEHP) in the IL, 1-methyl-3-octylimidazolium hexafluorophosphate ([C8mim]PF6), was investigated and compared with that in the n-heptane system. In particular, the effect of F(I) on the extraction mechanism for Ce(IV) and its separation from Th(IV) was investigated. Otherwise, the recovery efficiency of Ce(IV) and F(I) from a practical bastnasite leach liquor was examined using IL based extraction.
RESULTS: Similar selectivity (Ce(IV) > Th(IV) ≫ RE(III)) was observed in both the IL and n-heptane systems. The existence of F(I) had a large negative impact on the extraction and separation of Ce(IV). An identical process for the extraction of Ce(NO3)4 containing F(I) by DEHEHP in both IL and n-heptane was achieved under appropriate conditions. The Ce(IV) in the IL phase may be quantitatively back extracted and may be recovered as part of high purity CeF3 and cerium sulfate.
CONCLUSION: It is possible for IL to act as an environmentally benign solvent for the recovery of Ce(IV) and F(I) from bastnasite in rare earth hydrometallurgy. Copyright © 2009 Society of Chemical Industry
Co-reporter:Xianglan Wang;Wei Li;Weiwei Wang;Shulan Meng;Deqian Li
Journal of Chemical Technology and Biotechnology 2009 Volume 84( Issue 2) pp:269-274
Publication Date(Web):
DOI:10.1002/jctb.2034
Abstract
BACKGROUND: Introducing an adduct into an extractant system is an effective method of improving extraction performance. The effect of additives upon extraction is very important, especially in the case of interfacial behaviour. In most work published in the literature, there is little data on the interfacial behaviour of extractants and modifiers. As the mass transfer must pass through an interface, the influence of isooctanol on the interfacial activity and mass transfer of ytterbium(III) using 2-ethylhexylphosphonic acid mono-2-ethlhexyl ester has been investigated.
RESULTS: With increasing amounts of isooctanol, the interfacial tension and surface excess (Γmax) of the 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester(HEHEHP)–isooctanol system decreased, and the area of the absorbed HEHEHP molecule (Amin) increased. The interfacial activity of the HEHEHP–isooctanol system varied significantly depending on ionic strength and temperature and the mass transfer flux decreased with increasing isooctanol content.
CONCLUSION: Isooctanol has a strong influence on the interfacial activity of the HEHEHP system. The influence of isooctanol on the mass transfer rate of ytterbium extraction has been discussed qualitatively. Copyright © 2008 Society of Chemical Industry
Co-reporter:Fuqiang Guo, Hongfei Li, Zhifeng Zhang, Shulan Meng, Deqian Li
Materials Research Bulletin 2009 44(7) pp: 1565-1568
Publication Date(Web):
DOI:10.1016/j.materresbull.2009.02.001
Co-reporter:Fuqiang Guo, Hongfei Li, Zhifeng Zhang, Shulan Meng, Deqian Li
Materials Science and Engineering: B 2009 Volume 163(Issue 2) pp:134-137
Publication Date(Web):15 July 2009
DOI:10.1016/j.mseb.2009.05.008
Mesoporous YF3 nanoflowers were successfully prepared via solvent extraction route. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that these nanoflowers with uneven porous architectures had a spherical shape and were consisted of many YF3 nanosheets with a thickness of about 15 nm. Energy-dispersive spectroscopy (EDS) analysis was used to check the chemical composition and purity of the products. YF3 nanoflowers had bimodal mesoporous distribution and Brunauer–Emmett–Teller (BET) surface area of 116 m2/g.
Co-reporter:Fuqiang Guo, Hongfei Li, Zhifeng Zhang, Shulan Meng, Deqian Li
Journal of Colloid and Interface Science 2008 Volume 322(Issue 2) pp:605-610
Publication Date(Web):15 June 2008
DOI:10.1016/j.jcis.2008.03.011
The formation of reversed micelles and the roles of extractant and extracted complexes were investigated in the Cyanex923/n-heptane/H2SO4 system. Interfacial tension (γ), electrical conductivity (κ), and water content measurements showed that Cyanex923 had a tendency to self-assemble, forming reversed micelles. The changes in electrical conductivity with concentration of H2SO4 in the organic phase (CH2SO4,o) exhibited an S-type curve: a correlation was found between the change in electrical conductivity and the water content as a function of CH2SO4,o. The changes of electrical conductivity were mainly induced by the components and microstructure in the organic phase, while the conversion of extracted complex also resulted in the changes of components and microstructure in the organic phase. Fourier transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS) were used to characterize the organic phases and sizes of the reversed micelles, respectively. The extractant and extracted complexes, such as Cyanex923⋅H2SO4, were involved in the formation of reversed micelles.
Co-reporter:Zhifeng Zhang, Hongfei Li, Fuqiang Guo, Shulan Meng, Deqian Li
Separation and Purification Technology 2008 Volume 63(Issue 2) pp:348-352
Publication Date(Web):22 October 2008
DOI:10.1016/j.seppur.2008.05.023
Synergistic extraction and recovery of Cerium(IV) (Ce(IV)) and Fluorin (F) from sulfuric solutions using mixture of Cyanex 923 and di-2-ethylhexyl phosphoric acid (D2EHPA) in n-heptane have been carried out. In order to investigate the synergistic extraction of Cyanex 923 + D2EHPA, extraction Ce(IV), F, Ce(III) and Ce–F mixture solution using D2EHPA or Cyanex 923 as extractant alone were studied firstly, and then Synergistic extraction of Ce(IV), F and Ce(IV)–F mixture solution with D2EHPA + Cyanex 923 were carried out. The largest synergistic coefficient of Ce(IV) is obtained at the mole fraction XCyanex 923 = 0.8. The synergistic enhancement coefficients (Rmax) obtained for Ce(IV) are 23.12 in Ce(IV) solution, and in Ce–F mixed solution Rmax for Ce(IV) and F are 2.24 and 3.25 respectively. Furthermore, the beta values at XCyanex 923 = 0.8 were Ce(IV)/Ce(III) = 1321.18, CeF22+/Ce(III) = 36.35, which means that Ce(IV), CeF22+ can be effectively separated from Ce(III). Ce(IV) and CeF22+ would form the new complexes as Ce(HSO4)2A21.5B and CeF2(HSO4)A2B in the mixture system, respectively. However Ce(III) could not be extracted by the mixture system at the experimental conditions. The potential application of the mixture system to separate Ce(IV) and F from bastnasite has also been discussed.
Co-reporter:Wenwei He, Wuping Liao, Chunji Niu, Deqian Li
Separation and Purification Technology 2008 Volume 62(Issue 3) pp:674-680
Publication Date(Web):22 September 2008
DOI:10.1016/j.seppur.2008.03.022
Synergistic effect in the extraction of rare earth (RE) metals by the acid–base coupling (ABC) extractants of calix[4]arene carboxyl derivative tBu[4]CH2COOH (H4A) and primary amine N1923 (RNH2) has been investigated. The extraction of RE was enhanced by the addition of sodium cations into the aqueous phase not only in the extraction system of tBu[4]CH2COOH alone but also in the mixture of tBu[4]CH2COOH and N1923. The separation factors (SFs) indicating the extraction selectivity of adjacent RE elements became higher in the mixture system. The synergistic extracted species and reaction mechanism were deduced for the mixture system by continuous variation and slope analysis methods. The plot of synergistic enhancement coefficient Rvs. the increasing atomic number showed a “double peak effect”. The equilibrium constants and thermodynamic parameters (ΔG, ΔH and ΔS) were calculated by theoretical formula. The stripping of RE can be achieved by changing the acidity of the aqueous solution.
Co-reporter:Yong Zuo, Ji Chen, Deqian Li
Separation and Purification Technology 2008 Volume 63(Issue 3) pp:684-690
Publication Date(Web):3 November 2008
DOI:10.1016/j.seppur.2008.07.014
The extraction behavior of thorium(IV) sulfate by primary amine N1923 in imidazolium-based ionic liquid (IL) namely 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim]PF6) was systematically studied in this paper. Results showed that the extraction behavior was quite different from that using conventional solvent as diluent. A reversed micellar solubilization extraction mechanism was proposed for the extraction of thorium(IV) by N1923/[C8mim]PF6 via slope analysis method and polarized optical microscopy (POM)/transmission electron microscopy (TEM) observation. The salt-out agent, Na2SO4, was demonstrated to prompt this extraction mechanism. The extraction of several rare earths(III) (La, Ce, Nd, Gd, Er) by N1923/[C8mim]PF6 was investigated to evaluate the separation coefficients between Th(IV) and rare earth(III) (RE(III)). On this basis, we made a preliminary assessment for the possibility of using ionic liquid as diluent for the separation of Th(IV) from RE(III) in clean process.
Co-reporter:Wenwei He;Wuping Liao;Weiwei Wang;Deqian Li;Chunji Niu
Journal of Chemical Technology and Biotechnology 2008 Volume 83( Issue 9) pp:1314-1320
Publication Date(Web):
DOI:10.1002/jctb.1950
Abstract
BACKGROUND: Thermodynamics and kinetics data are both important to explain the extraction property. In order to develop a novel separation technology superior to current extraction systems, many promising extractants have been developed including calixarene carboxylic acids. The extraction thermodynamics behavior of calix[4]arene carboxylic acids has been reported extensively. In this study, the mass transfer kinetics of neodymium(III) and the interfacial behavior of calix[4]arene carboxylic acid were investigated.
RESULTS: The rate constant (Kao) becomes constant when the stirring speed was controlled between 250 rpm and 400 rpm. The activation energy (Ea) was calculated to be 21·41 kJ mol−1 or 88·17 kJ mol−1 (dependent on temperature) from the slope of log Kao against 1000/T. The linear relationship between the specific area and the extraction rate is the characteristic of an interfacial reaction control. The minimum bulk concentration of the extractant necessary to saturate the interface (Cmin) is lower than 4·19 × 10−4 mol L−1.
CONCLUSION: The effect of stirring speed, temperature, and species concentration on the extraction rate demonstrates that the extraction regime depends on the extraction conditions. The chemical reaction control governs the extraction regime at temperatures below 303 K and a mixed control regime occurs when the temperature is between 303 K and 318 K. The probable locale for the chemical reaction is at the liquid–liquid interface and the rate equation is deduced to be: − d[Nd3+](a)/dt = kf[Nd3+](a)[H4A](o)0·727[H+](a)−0·978. The rate-controlling step was suggested by the analysis of the experimental results. Copyright © 2008 Society of Chemical Industry
Co-reporter:Weiwei Wang;Xianglan Wang;Yanliang Wang;Deqian Li;Wuping Liao
Journal of Chemical Technology and Biotechnology 2008 Volume 83( Issue 7) pp:1056-1063
Publication Date(Web):
DOI:10.1002/jctb.1915
Abstract
BACKGROUND: The Cyanex® 923 (trialkylphosphine oxides, TRPO)-n-heptane/cerium(IV)-H2SO4 extraction system has been investigated focusing on the physicochemical properties, surface active species and interfacial phenomena. The effects of H2SO4 and Ce(IV) extraction on them were considered.
RESULTS: Results showed that the density and refractive index reflect the mass transfer by H2SO4 and Ce(IV) extraction and the change of refractive index was more sensitive than density. The interfacial tension decreased on extraction of H2SO4 but increased on extraction of Ce(IV). The viscosity of the equilibrium organic phase increased abruptly when the extracted H2SO4 concentration in the organic phase reached certain high values. The formation of reversed micelles, with mean diameter of about 10 nm, at high H2SO4 concentrations in the organic phase, is suggested by various measurements such as viscosity, interfacial tension and dynamic light-scattering (DLS).
CONCLUSION: It is suggested that TRPO-H2SO4 complexes are more surface-active than TRPO itself and tend to aggregate into reverse micelles by self-assembling in the organic phase but the Ce(IV)-TRPO complexes are neutral, less surface-active than TRPO and not helpful for reverse micelle formation. Copyright © 2008 Society of Chemical Industry
Co-reporter:Hui Zhang, WeiWei Wang, Honhfei Li, Shulan Meng, Deqian Li
Materials Letters 2008 Volume 62(8–9) pp:1230-1233
Publication Date(Web):31 March 2008
DOI:10.1016/j.matlet.2007.08.026
In this article, a novel strategy was applied to prepare dispersed ultrafine α-Fe2O3 nanoparticles. The initial Fe(OH)3 nanoparticles were synthesized by the reaction of NaOH and FeCl3 in alcohol. With the new-formed nanoparticles as nuclei, NaCl crystallized and encapsulated the particles into solid cages. As a result, the nanoparticles were prevented from aggregating and growing. The composite of Fe(OH)3 and NaCl was calcined and then washed by water to obtain the pure α-Fe2O3 nanoparticles. The best product was highly dispersed nanoparticles, with an average size of 2.26 nm and a narrow distribution from 1.9 nm to 2.6 nm. The cage effect was confirmed again by the control experiments.
Co-reporter:Ce Liu, Fang Luo, Wuping Liao, Deqian Li, Xiaofei Wang and Richard Dronskowski
Crystal Growth & Design 2007 Volume 7(Issue 11) pp:2282
Publication Date(Web):October 24, 2007
DOI:10.1021/cg070579d
Two copper–organic framework supramolecular assemblies of p-sulfonatocalix[4]arene and 1,10-phenanthroline Cu2[C12H8N2][C28H20S4O16][H2O]23.5 (1) and Cu3[C12H8N2]3[C28H19S4O16]Cl[H2O]17.6 (2) were obtained by pH-dependent synthesis at room temperature. Both structures show 1D water-filled channels (rectangular shape in 1 and triangular in 2) with the solvent-accessible volume occupying 30.8% (1) and 24.2% (2) of the unit-cell volume, respectively. The calixarene molecules in both structures assume analogous cone shapes of C2v symmetry instead of the conventional C4v symmetry. Their connecting to different amounts of copper/phenanthroline cations leads to the formation of different structures.
Co-reporter:Jianjun Liu;Yanliang Wang;Deqian Li;Deqian Li;Yanliang Wang;Jianjun Liu
Journal of Chemical Technology and Biotechnology 2007 Volume 82(Issue 10) pp:949-955
Publication Date(Web):3 SEP 2007
DOI:10.1002/jctb.1768
BACKGROUND: Thermodynamic studies on Ce(IV) extraction with primary amine N1923 demonstrate that primary amine N1923 is an excellent extractant for separation of Ce(IV) from Re(III). In order to clarify the mechanism of extraction and to optimize the parameters in practical extraction systems used in the rare earth industry, the extraction kinetics was investigated using a constant interfacial area cell with laminar flow in the present work.
RESULTS: The data indicate that the rate constant (kao) becomes constant when stirring speed exceeds 250 rpm. The apparent forward extraction rate is calculated to be 10−1.70. The activation energy (Ea) was calculated to be 20.5 kJ/mol from the slope of log kao against 1000/T. The minimum bulk concentration of the extractant necessary to saturate the interface (Cmin) is lower than 10−5 mol L−1.
CONCLUSION: Studies of interfacial tension and the effects of stirring rate and specific interfacial area on the extraction rate show that the extraction rate is kinetically controlled, and a mass transfer model has been proposed. The rate equation has been obtained as: − d[Ce(IV)]/dt = 10−1.70[Ce(IV)] [(RNH3)2SO4]1.376. The rate-controlling step has been evaluated from analysis of the experimental results. Copyright © 2007 Society of Chemical Industry
Co-reporter:Jianjun Liu;Weiwei Wang;Deqian Li;Wenwei He
Journal of Chemical Technology and Biotechnology 2007 Volume 82(Issue 8) pp:705-710
Publication Date(Web):6 JUL 2007
DOI:10.1002/jctb.1712
The kinetics of ytterbium(III) extraction from sulfate medium with Cyanex 923 in heptane has been investigated with a constant interfacial cell with laminar flow, which aimed to identify the extraction regime, reaction zone and rate equations. It was found that the extraction rate of ytterbium(III) increased linearly with stirring speed and specific interfacial area. The activation energy Ea (9.56 kJ mol−1), activation enthalpy ΔH± (7.05 kJ mol−1), activation entropy ΔS±298 (−0.31 kJ mol−1) and Gibbs free energy of activation ΔG±298 (98.3 kJ mol−1) were calculated from the dependence of extraction rate on temperature. The experiential rate equations were obtained by investigating the influence of the concentration of various species on the extraction rate. A diffusion regime has been deduced from evidence of the linear dependence of extraction rate on stirring speed and the low value of the activation energy. The liquid–liquid interface is most probably the reaction zone in view of the linear dependence of extraction rate on specific interfacial area, the high interfacial activity and low water-solubility of extractant. Thus the mass transfer rate is controlled by interfacial film diffusion of species. Copyright © 2007 Society of Chemical Industry
Co-reporter:Hui Zhang;Xianglan Wang;Shulan Meng;Wei Li;Deqian Li;Xianglan Wang;Hui Zhang;Wei Li;Shulan Meng;Deqian Li
Journal of Chemical Technology and Biotechnology 2007 Volume 82(Issue 4) pp:376-381
Publication Date(Web):5 APR 2007
DOI:10.1002/jctb.1680
The extraction behavior of lanthanides and yttrium usinsg CYANEX 925 (mixture of branched chain alkylated phosphine oxides) in n-heptane from nitrate medium has been studied. The effects of aqueous phase ionic strength, CYANEX 925 concentration in the organic phase, and temperature on Sm3+, Nd3+ and Y3+ extraction have been investigated. The extractability of the lanthanides and yttrium increases with increasing nitrate concentration, as well as with increasing CYANEX 925 concentration. An extraction mechanism is proposed based on slope analysis. Furthermore, the infra-red spectra of CYANEX 925 saturated with lanthanides are employed to provide evidence of the composition of the complex. The relationship between the logarithm of the distribution ratio and lanthanide atomic number is also discussed which indicates that yttrium can be separated from light lanthanides. In addition separation of the light and heavy lanthanide groups is also possible using CYANEX 925. From the temperature dependence data, the thermodynamic parameters values (ΔH, ΔS and ΔG) are calculated. Copyright © 2007 Society of Chemical Industry
Co-reporter:Wei Li, Xianglan Wang, Shulan Meng, Deqian Li, Ying Xiong
Separation and Purification Technology 2007 Volume 54(Issue 2) pp:164-169
Publication Date(Web):1 April 2007
DOI:10.1016/j.seppur.2006.08.029
Extraction and separation of yttrium from the rare earths in chloride medium using sec-octylphenoxy acetic acid (CA-12), tri-n-butyl phosphate (TBP) as modifier, in kerosene has been investigated. The separation coefficients, β, were obtained and the extraction selectivity has been enhanced when compared with that of naphthenic acid. The experimental results indicated that CA-12–TBP system could be employed to separate yttrium from rare earths. Fractional extraction (15 stages for extraction and 10 stages for scrubbing) was studied, the raffinate of the first stage was abundant in purity yttrium of 99.5%, with a yield of >95%, percentage of yttrium in the mixture rare earths was less than 5% in the loaded organic phase of the 25th stage and loaded capability was about 0.2 mol/L.
Co-reporter:Xiaobo Sun, Jinping Wang, Deqian Li, Hongfei Li
Separation and Purification Technology 2006 Volume 50(Issue 1) pp:30-34
Publication Date(Web):June 2006
DOI:10.1016/j.seppur.2005.11.004
Synergistic extraction of trivalent rare earths (RE = Sc, Y, La, Gd, Yb) from hydrochloride medium using mixture of bis(2,4,4-trimethylpentyl)phosphinic acid (HL, Cyanex272) and Sec-nonylphenoxy acetic acid (HA, CA-100) in n-heptane has been studied. The synergistic enhancement coefficients were observed for La (1.30), Gd (1.97), Y (3.59), Yb (8.21) and Sc (14.41). The results indicated yttrium was extracted into n-heptane as YH5A4L4 mixed species instead of Y(HL2)3, Y(OH)2A(HA)3 which were extracted by Cyanex272 and CA-100, respectively. A cation exchange mechanism was proposed and further clarified by IR spectra. The equilibrium constants, formation constants and thermodynamic functions such as ΔG, ΔH and ΔS were determined. The Cyanex272 + CA-100 system not only enhanced the extraction efficiency of RE but also improved the selectivities significantly. The mutual separation factors of these ions suggested the mixture system would be of practical value in extraction and separation of rare earths.
Co-reporter:Junmei Zhao;Shulan Meng;Deqian Li
Journal of Chemical Technology and Biotechnology 2006 Volume 81(Issue 8) pp:1384-1390
Publication Date(Web):23 JUN 2006
DOI:10.1002/jctb.1572
The synergistic effect of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP, HA) and di-(2-ethylhexyl)-2-ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y3+, and taking Yb3+ and Y3+ as examples, RE3+ is extracted as RE(OH)A2.B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change ΔG (−17.06 kJ mol−1), enthalpy change ΔH (−35.08 kJ mol−1) and entropy change ΔS (−60.47 J K−1 mol−1) for Y3+ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry
Co-reporter:Wei Li;Shulan Meng;Xianglan Wang;Deqian Li
Journal of Chemical Technology and Biotechnology 2006 Volume 81(Issue 5) pp:761-766
Publication Date(Web):23 MAR 2006
DOI:10.1002/jctb.1532
The solvent extraction of rare earths from chloride solution has been investigated using mixtures of 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (HEHEHP, P507) and organophosphorus acids [di-(2-ethylhexyl)phosphoric acid (HDEHP, P204), isopropylphosphonic acid 1-hexyl-4-ethyloctyl ester (HHEOIPP), bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272), bis(2,4,4-trimethylpentyl)monothiophosphinic acid (Cyanex 302), and bis(2,4,4-trimethypentyl)dithiophosphinic acid (Cyanex 301)]. Results show that the extractability of the selected extractants for rare earths decreases in the order: HEHEHP/HDEHP > HEHEHP/Cyanex 301 > HEHEHP/HHEOIPP > HEHEHP/Cyanex 302 > HEHEHP/Cyanex 272. A possible explanation of the different extractabilities is given based on the structure of the extractants. Furthermore, the possibilities of the separation of adjacent rare earths with these mixtures were investigated according to the extractabilities; the results show the possibility of separating the rare earths. Copyright © 2006 Society of Chemical Industry
Co-reporter:Shulan Meng;Xiaobo Sun;Deqian Li
Journal of Chemical Technology and Biotechnology 2006 Volume 81(Issue 5) pp:755-760
Publication Date(Web):12 APR 2006
DOI:10.1002/jctb.1487
The synergistic extraction of rare earths (La, Nd, Gd, Y and Yb) with a mixture of 2-ethylhexyl 2-ethylhexylphosphonate (EHEHPA) (HA) and trialkylphosphine oxide (Cyanex 923) (B) from a hydrochloride medium was investigated. The mixed system significantly enhances the extraction efficiency for lighter lanthanides and the synergistic enhancement coefficients for La (4.52), Nd (3.35), Gd (2.08), Y (1.31) and Yb (1.08) decrease with decreasing ionic radius of the rare earths. The extraction equilibrium of La, Nd and Gd indicate that La and Nd were extracted as MA3·B, whereas Gd was extracted as Gd(OH)A2(HA)2·B. The equilibrium constants, thermodynamic functions such as ΔG, ΔH and ΔS and formation constants of the extracted species were determined. The stripping properties were also studied. Copyright © 2006 Society of Chemical Industry
Co-reporter:Q. Jia, Z.H. Wang, D.Q. Li, C.J. Niu
Journal of Alloys and Compounds 2004 Volume 374(1–2) pp:434-437
Publication Date(Web):14 July 2004
DOI:10.1016/j.jallcom.2003.11.056
In the present paper, the adsorption of thulium(III) from chloride medium on an extraction resin containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (CL302, HL) has been studied. The results show that 1.5 h is enough for the adsorption equilibrium. The distribution coefficients are determined as a function of the acidity of the aqueous phase and the data are analyzed both graphically and numerically. The plots of log D versus pH give a straight line with a slope of about 3, indicating that 3 protons are released in the adsorption reaction of thulium(III). The content of Cyanex302 in the resin is determined to be 48.21%. The total amount of Tm3+ adsorbed up to resin saturation is determined to be 82.46 mg Tm3+/g resin. Therefore, the sorption reactions of Tm3+ from chloride medium with CL302 can be described as:The Freundlich’s isothermal adsorption equation is also determined as:The amounts (Q) of Tm3+ adsorbed with the resin have been studied at different temperatures (15–40 °C) at fixed concentrations of Tm3+, amounts of extraction resin, ion strength and acidities in the aqueous phase. The thermodynamic quantities, i.e., ΔG, ΔH and ΔS can thus be determined. In addition, the adsorption of gadolinium(III), terbium(III), dysprosium(III), holmium(III), erbium(III) using the extraction resin has also been investigated and compared with the result of thulium(III). The efficiency of the resin in the separation of the metal ions is provided according to the separation factors.
Co-reporter:Q.K Shang, W Li, Q Jia, D.Q Li
Fluid Phase Equilibria 2004 Volume 219(Issue 2) pp:195-203
Publication Date(Web):28 May 2004
DOI:10.1016/j.fluid.2004.01.032
The partitioning behavior of four amino acids, cysteine, phenylalanine, methionine, and lysine in 15 aqueous two-phase systems (ATPSs) with different polyethylene glycol (PEG) molecular weights and phosphate buffers has been studied in the present paper. The phase diagrams of the systems are investigated together with the effect of the PEG molecular weight and pH of the phosphate solutions. The composition of these systems and some parameters such as density and refractive index are determined. The influences of salts in ATPSs, side chain structure of the amino acids, pH of ATPSs, and the PEG molecular weight on the distribution ratios of the amino acids have been studied. This work is useful for the purification of amino acids and the separation of some proteins whose main surface exposed amino acid residues are these four amino acids, respectively.
Co-reporter:Y.G Wang, Y Xiong, S.L Meng, D.Q Li
Talanta 2004 Volume 63(Issue 2) pp:239-243
Publication Date(Web):28 May 2004
DOI:10.1016/j.talanta.2003.09.034
The selective extraction of yttrium from heavy lanthanide by liquid–liquid extraction using CA-100 in the presence of the complexing agent, such as EDTA, DTPA, and HEDTA was investigated. The extraction of heavy lanthanide in the present of the complexing agent was suppressed when compared to that of Y because of the masking effect, but the selective extraction of Y was enhanced. All complexing agents formed 1:1 complex with rare earth elements (RE), and only free rare earth ions could take part in the extraction. The condition for separation was obtained by exploring the effects of the complexing agent concentration, the extractant concentration, pH and the equilibration time on the extraction of the heavy rare earth elements.
Co-reporter:Qiong Jia, Wuping Liao, Deqian Li, Chunji Niu
Analytica Chimica Acta 2003 Volume 477(Issue 2) pp:251-256
Publication Date(Web):3 February 2003
DOI:10.1016/S0003-2670(02)01430-7
The synergistic effect of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP) and triisobutylphosphine sulphide (TIBPS, B) is investigated in the extraction of lanthanum(III) from chloride solution. Lanthanum(III) is extracted by the mixture as LaCl2·PMBP·B0.5 instead of La(PMBP)3·(HPMBP) which is extracted by HPMBP alone. The equilibrium constants and thermodynamic functions such as ΔG, ΔH and ΔS are determined. The extraction of other rare earth ions by mixtures of HPMBP and TIBPS is also studied and the possibility of separating rare earth ions is discussed.
Co-reporter:Q.K. Shang, D.Q. Li, J.X. Qi
Journal of Solid State Chemistry 2003 Volume 171(1–2) pp:358-361
Publication Date(Web):15 February–1 March 2003
DOI:10.1016/S0022-4596(03)00002-1
Separation of scandium(III), yttrium(III) and lanthanum(III) was performed by high-performance centrifugal partition chromatography (HPCPC) employing the stationary phase of S-octyl phenyloxy acetic acid (CA-12). The liquid–liquid extraction behavior of CA-12 for Sc(III), Y(III) and La(III), the acidity of aqueous phase, and the operation conditions of HPCPC were examined. The retention volume (VR) increased with the order of Y(III), La(III) and Sc(III) accompanied with the elution of the mobile phase in different pH, which is lowered from 4.6 to 2.1.
Co-reporter:Y.G. Wang, Y.H. Zhu, D.Q. Li
Journal of Solid State Chemistry 2003 Volume 171(1–2) pp:362-366
Publication Date(Web):15 February–1 March 2003
DOI:10.1016/S0022-4596(02)00213-X
The extraction kinetics of ytterbium with sec-nonylphenoxy acetic acid (CA-100) in heptane have been investigated using a constant interfacial area cell with laminar flow. The influence of stirring speed and temperature on the rate indicated that the extraction rate was controlled by the experiment conditions. The plot of interfacial area on the rate showed a linear relationship. This fact together with the low solubility in water and strong surface activity of CA-100 at heptane–water interfaces made the interface the most probable locale for the chemical reactions. The influences of extractant concentration and hydrogen ion concentration on the extraction rate were investigated, and the forward and reverse rate equations for the ytterbium extraction with CA-100 were also obtained. Based on the experimental data, the apparent forward extraction rate constant was calculated. Interfacial reaction models were proposed that agree well with the rate equations obtained from experimental data.
Co-reporter:Wuping Liao, Jiku Wang, Deqian Li
Materials Letters 2003 Volume 57(Issue 7) pp:1309-1311
Publication Date(Web):January 2003
DOI:10.1016/S0167-577X(02)00977-1
Besides the spheres, polyhedral silver nanoclusters were prepared by the polyol process with 3-aminopropyl triethoxysilane (APTES). In the process, APTES acts as not only the stabilizer but also the template.
Co-reporter:Shan-Tang Yue;Wu-Ping Liao;Qiang Su
Chinese Journal of Chemistry 2002 Volume 20(Issue 6) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20020200605
The kinetics of RE (La, Gd, Er, Yb and Y) extraction with sec-octylphenoxy acetic acid was investigated using a constant interfacial area cell with laminar flow at 303 K. The natures of the extracted complexes have some effect on the extraction rate which is controlled by the reaction rate of M(III) and extractant molecules at two-phase interface for Er(III), Yb(III) and Y(III), by a mixed chemical reaction-diffusion for Gd (III) and a diffusion for La(III). The extractant molecules tend to adsorb at the interface. So an interfacial extraction reaction model was derived.
Co-reporter:Wuping Liao, Qingkun Shang, Guihong Yu, Deqian Li
Talanta 2002 Volume 57(Issue 6) pp:1085-1092
Publication Date(Web):19 July 2002
DOI:10.1016/S0039-9140(02)00146-7
Phase behavior of the extraction system, Cyanex 923–heptane/H2SO4–H2O has been studied. The third phase appeared at different aqueous H2SO4 concentration with varying initial Cyanex 923 concentration and temperature affects its appearance. Almost all of H2SO4 and H2O are extracted into the middle phase. The H2SO4 concentration in the third phase increases with the increasing aqueous acid concentration (CH2SO4,b) while the water content first increases and then reaches a constant value at CH2SO4,b=11.3 mol l−1. In the region of CH2SO4,b higher than 5.2 mol l−1, the composition of the middle phase is only related to the equilibrium concentration of H2SO4 in the bottom phase. H2SO4 and H2O are transferred into the middle phase mainly by their coordination with Cyanex 923 when CH2SO4,b is less than 11.3 mol l−1. When CH2SO4,b is higher than 11.3 mol l−1, excess H2SO4 is solubilized into the polar layer of the aggregates. In the region considered, the extracted complex changes from C923 · H2SO4 to C923 · H2SO4 · H2O and then to C923 · (H2SO4)2 · H2O.
Co-reporter:Yanliang Wang, Wuping Liao, Deqian Li
Separation and Purification Technology (27 October 2011) Volume 82() pp:197-201
Publication Date(Web):27 October 2011
DOI:10.1016/j.seppur.2011.09.018
Solvent extraction and separation of yttrium from other rare earths in chloride medium using the mixture of sec-octylphenoxy acetic acid (CA12, HA) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272, HB) has been investigated. Tri-n-butyl phosphate (TBP) was used as the phase modifier to achieve fast phase separation and to improve the stability of the organic phase. The separation coefficients (β) between yttrium and heavy rare earths (HRE) are more significant in the double solvent (HAB) extraction system than the CA12-TBP extraction system. In a laboratory scale test with a fractional extraction process including 15 stages of extraction section and 10 stages of scrubbing section, yttrium was separated from all the other rare earths with a yield of 95% and an yttrium oxide product with 99.94% purity was obtained.Highlights► We developed HAB extraction system for Y separation using double solvent. ► Cyanex272 as co-extractant can enhance separation coefficients between Y and HRE. ► High purity Y2O3 can be obtained from IATRE ores by HAB extraction process. ► Organic phase composed of CA12, Cyanex272 and TBP is stable in extraction practice.
![Nonacyclo[43.3.1.13,7.19,13.115,19.121,25.127,31.133,37.139,43]hexapentaconta-1(49),3,5,7(56),9,11,13(55),15,17,19(54),21,23,25(53),27,29,31(52),33,35,37(51),39,41,43(50),45,47-tetracosaene-5,11,17,23,29,35,41,47-octasulfonic acid, 49,50,51,52,53,54,55,56-octahydroxy-](/data/chemimg/103300/137407-62-6.png)
![Nonacyclo[43.3.1.13,7.19,13.115,19.121,25.127,31.133,37.139,43]hexapentaconta-1(49),3,5,7(56),9,11,13(55),15,17,19(54),21,23,25(53),27,29,31(52),33,35,37(51),39,41,43(50),45,47-tetracosaene-5,11,17,23,29,35,41,47-octasulfonic acid, 49,50,51,52,53,54,55,56-octahydroxy-](/data/chemimg/103300/137407-62-6_b.png)
![Acetic acid, 2,2',2'',2'''-[[5,11,17,23-tetrakis(1,1-dimethylethyl)pentacyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene-25,26,27,28-tetrayl]tetrakis(oxy)]tetrakis-](/data/chemimg/2289000/113215-72-8.png)
![Acetic acid, 2,2',2'',2'''-[[5,11,17,23-tetrakis(1,1-dimethylethyl)pentacyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene-25,26,27,28-tetrayl]tetrakis(oxy)]tetrakis-](/data/chemimg/2289000/113215-72-8_b.png)
![Pentacyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene-5,11,17,23-tetrasulfonic acid, 25,26,27,28-tetrahydroxy-, sodium salt (1:4)](http://img.cochemist.com/data/images/110242-20-1.png)
![Pentacyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene-5,11,17,23-tetrasulfonic acid, 25,26,27,28-tetrahydroxy-, sodium salt (1:4)](http://img.cochemist.com/data/images/110242-20-1_b.png)
