Partitioning performance of molybdenum in poly (ethylene glycol) + sodium sulfate + water aqueous two-phase systems

Wang, Ping; Zhang, Fan; Li, Pan; Sun, Tingting; Pan, Yajing; Zhang, Yongqiang

doi:10.1016/j.molliq.2018.03.053

Cited by 20 publications

(13 citation statements)

References 30 publications

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“…There are also many studies on the application of this technology to extraction and separation of metal ions, for example the separation of Hg(II), Zn(II) and Co(II) by Dehghani [25], the separation of Ca(II), Mg(II) and Ni(II) by Rodrigues [26] and the extraction of Bi(III) subsalicylate by Sen [27]. The extraction and separation performance and the extraction mechanism of molybdenum and tungsten with the aqueous twophase system were reported by our early research work [28,29], and we also used the same system to investigate the extraction and separation of vanadium. It was found that for the extraction of alone vanadium and molybdenum, molybdenum is more easily extracted into the PEG-rich phase, while vanadium is difficult to extract into the PEG-rich phase without the addition of a charge modifier under the acidic conditions [30].…”

Section: Introductionmentioning

confidence: 91%

Separation of vanadium and molybdenum from aqueous solution using PEG2000 + sodium sulfate + water aqueous two-phase system

2019

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The separation of vanadium (V) and molybdenum (VI) was studied by co-extraction with an aqueous two-phase system formed by PEG2000 + sodium sulfate + water and by selective stripping with another aqueous two-phase system formed by ammonium sulfate solution and PEG2000 phase loaded vanadium and molybdenum. The effect of aqueous pH, concentration of vanadium and molybdenum, temperature on the co-extraction and concentration of ammonium sulfate, temperature and phase ratio on selective stripping separation of vanadium and molybdenum was investigated. The experimental results on co-extraction of vanadium and molybdenum indicated that the co-extraction rate of both metals is sensitive to aqueous pH, and their extraction rate can achieve above 97.54% and 99.49%, respectively, when the pH value of aqueous solution is at 2.0, the molar ratio of vanadium to molybdenum is about 1.5, the concentration of PEG2000 is 20%, and the temperature is 313.15 K, respectively. The co-extraction rate of both metals decreases slightly with an increase in temperature from 313.15 to 343.15 K. The extraction isotherm and McCabe-Thiele method showed that two theoretical stages are needed when concentration of vanadium and molybdenum decreases from initial 12 g/L and 10 g/L to 0.1 g/L under the optimal conditions. The results on selective stripping of both metals from loaded PEG2000 phase to aqueous phase indicated that the stripping rate and precipitation rate of vanadium are evidently impacted by aqueous pH within 8.0 ~ 11.0 and then a little influenced by other parameters. The stripping rate of molybdenum is relatively lower than that of vanadium and is influenced by all kinds of stripping conditions. The stripping rate and precipitation rate of vanadium achieve 99.88% and 98.84%, respectively, and stripping rate of molybdenum achieves 81.99% under the optimal stripping conditions of O/A = 2:1, stripping temperature 343.15 K, (NH 4 ) 2 SO 4 (w/w) 40% and the pH of aqueous solution at 10.0.

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Section: Introductionmentioning

confidence: 91%

Separation of vanadium and molybdenum from aqueous solution using PEG2000 + sodium sulfate + water aqueous two-phase system

2019

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“…Among all of the components of aqueous two-phase systems (ATPS) including, e.g., polymers, ionic liquids, alcohols, salts, surfactants, sugars, among others, polymer–salt-based ATPSs are one of the most well-known components due to their simplicity, compatibility, and wide varieties. − Most reported research works on polymer–salt-based ATPSs are related to poly(ethylene glycol) (PEG) and inorganic salts such as sulfate, − phosphate, , carbonate, , nitrate, or chloride . Poly(ethylene glycol) possesses superior properties such as low toxicity, neutrality, excellent biocompatibility, and solubility in both aqueous and organic solutions. ,, The information for the phase behavior of the polymer/salt aqueous two-phase systems, therefore, has substantial significance in the applications for much biological and environmental process design. Besides, the well-known features of the kosmotropic sulfate salts, , in particular the Hofmeister series, provide significant insights into the protein stability in the extraction process as well as purification of biomolecules from other compounds. , …”

Section: Introductionmentioning

confidence: 99%

“…Considering the wide applications of ATPS composed of polymer and salt, the current study aims at obtaining the phase equilibrium of PEG + zinc sulfate/ammonium sulfate + water by measuring the phase composition at three different pH values, i.e., at 3.00, 4.70, and 5.21. It is known that the sulfate anion in the presence of PEG gives a greater separation below pH 6.00. − To provide insights into the interaction and phase behavior of polymer–salt-based ATPS, in the present work, liquid–liquid equilibrium (LLE) measurements were conducted at different temperatures (298.15, 303.15, and 308.15 K). PEGs of different molecular weights, namely, PEG 2000, PEG 3000, and PEG 8000, were selected to assess their effect on the formation of ATPS.…”

Section: Introductionmentioning

confidence: 99%

Phase Equilibria of Aqueous Two-Phase Systems of PEG with Sulfate Salt: Effects of pH, Temperature, Type of Cation, and Polymer Molecular Weight

et al. 2021

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The present work reports the liquid–liquid equilibrium (LLE) measurements and the construction of binodal curves for polyethylene glycols (PEG) + zinc sulfate/ammonium sulfate + water at three different temperatures (298.15, 303.15, and 308.15 K) and pH values (3.00, 4.70, and 5.21). PEGs with different molecular weights of 2000 g·mol–1 (PEG 2000), 3000 g·mol–1 (PEG 3000), and 8000 g·mol–1 (PEG 8000) were chosen for this study. The phase composition was obtained by measuring the refractive index (n D) and density (ρ) and was further used to obtain the tie-line length (TLL) and the slope of tie-line (STL). The tie-lines are reported at different polymer lengths, pH values, and temperatures. The values of the effective excluded volume (EEV) were employed to analyze the effect of the parameters on the binodal curves. Moreover, the impact of those parameters on the TLL and STL and plait point are discussed and compared with the results of the literature. Furthermore, the binodal curves data and the tie-lines’ ends were fitted using some semiempirical equations with satisfactory results. Finally, the UNIFAC is used to calculate the LLE data of the above system and the adjusted binary group interaction parameters of the model were reported.

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“…Metals can be extracted into the polymer phase in ATPS only as anions such as MoO 4 2– or VO 3 – . , If the metal does not form oxyanions, some inorganic or organic ligands forming anionic complexes should be added. The efficiency of such a process is determined by the stability of the extracted complex and degree of ion hydratation .…”

Section: Introductionmentioning

confidence: 99%

“…Besides the nature of the extracted compounds, the extraction ability of ATPS depends on such factors as molecular weight of the polymer, the nature of phase-forming salt, ,, and the ratio of components in the polymer–salt–water system. , The interphase distribution of metals depends also on pH, since the acidity changes both composition of extracted metal compounds ,,, and the width of heterogeneous region in ATPS. , The effects of the addition of various ions and of the acidity on phase equilibria in ATPS were studied in refs − . Both increase of concentration of inorganic and organic salts , and increase of pH − expanded the heterogeneous region in the ATPS.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sodium Chloride and pH on the Composition of the Equilibrium Phases and the Partition of Palladium(II) in the Aqueous Two-Phase System PEG1500–Na₂SO₄–Water

et al. 2021

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Binodal curves for aqueous two-phase systems (ATPS) polyethylene glycol 1500 (PEG1500)−sodium sulfate− water with additions of sodium chloride and hydrochloric or sulfuric acids were determined by turbidimetric titration and analysis of coexisting phases. The results are compared with published data for the ATPS PEG1500−sodium sulfate−water without additions, and the influence of additions on the width of the two-phase field, tielines length, and slopes was traced. The influence of initial concentration of palladium, time of phase contact, pH, concentration of sodium chloride and sodium sulfate on the extraction of palladium(II) was studied. The coefficients of distribution of palladium(II) between the phases of ATPS were measured as a function of the concentrations of sodium chloride (0.1, 1.0, and 2.0 mol•L −1 ) and pH values. At lower concentrations of Cl − ions Pd(II) is extracted as a mixture of ions [Pd(H 2 O)Cl 3 ] − and [PdCl 4 ] 2− , whereas the growth of C(Cl − ) leads to prevalence of the latter, which has poorer extraction properties. Maximal values of the distribution coefficient D Pd of about 9.5 ± 0.75 were achieved in the ATPS PEG1500−Na 2 SO 4 −0.1 M HCl and PEG1500− Na 2 SO 4 −(0.05 M H 2 SO 4 + 0.1 M NaCl).

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Partitioning performance of molybdenum in poly (ethylene glycol) + sodium sulfate + water aqueous two-phase systems

Cited by 20 publications

References 30 publications

Separation of vanadium and molybdenum from aqueous solution using PEG2000 + sodium sulfate + water aqueous two-phase system

Separation of vanadium and molybdenum from aqueous solution using PEG2000 + sodium sulfate + water aqueous two-phase system

Phase Equilibria of Aqueous Two-Phase Systems of PEG with Sulfate Salt: Effects of pH, Temperature, Type of Cation, and Polymer Molecular Weight

Effect of Sodium Chloride and pH on the Composition of the Equilibrium Phases and the Partition of Palladium(II) in the Aqueous Two-Phase System PEG1500–Na₂SO₄–Water

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Partitioning performance of molybdenum in poly (ethylene glycol) + sodium sulfate + water aqueous two-phase systems

Cited by 20 publications

References 30 publications

Separation of vanadium and molybdenum from aqueous solution using PEG2000 + sodium sulfate + water aqueous two-phase system

Separation of vanadium and molybdenum from aqueous solution using PEG2000 + sodium sulfate + water aqueous two-phase system

Phase Equilibria of Aqueous Two-Phase Systems of PEG with Sulfate Salt: Effects of pH, Temperature, Type of Cation, and Polymer Molecular Weight

Effect of Sodium Chloride and pH on the Composition of the Equilibrium Phases and the Partition of Palladium(II) in the Aqueous Two-Phase System PEG1500–Na2SO4–Water

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Effect of Sodium Chloride and pH on the Composition of the Equilibrium Phases and the Partition of Palladium(II) in the Aqueous Two-Phase System PEG1500–Na₂SO₄–Water