Huizhou Liu

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (207)473.01 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, a method combined low-field magnetic separation (MS) with flotation, named as gas-assisted magnetic separation (GAMS), was applied for the removal of cadmium from wastewater. With bubbles’ assistance, the speed of magnetic separation can be greatly improved and the limitation of magnetic force on the capture distance can be overcome. Thus, GAMS is much more efficient and easily scalable than MS. In this work, ethanediamine-modified magnetic poly-(glycidyl methacrylate) microspheres (EMPs) were synthesized as the adsorbent for cadmium. And GAMS was used to separate the EMPs and Cd-loaded EMPs. The effects of pH, gas flow rate, concentration of Cd-loaded EMPs, loading volume, and ionic strength on GAMS were investigated. The results indicated that the EMPs and Cd-loaded EMPs could be rapidly and remotely removed from the solution with GAMS. And the separation time decreased with the increase of gas flow rate and NaCl concentration, but grew with the rise of pH value, loading volume, and concentration of the EMPs. This work showed the great potential of GAMS in the area of water treatment.
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    ABSTRACT: Rapid and sensitive detection of thrombin has very important significance in clinical diagnosis. In this work, bare magnetic iron oxide nanoparticles (magnetic nanoparticles) without any modification were used as fluorescence quenchers. In the absence of thrombin, a fluorescent dye (CY3) labeled thrombin aptamer (named CY3-aptamer) was adsorbed on the surface of magnetic nanoparticles through interaction between a phosphate backbone of the CY3-aptamer and hydroxyl groups on the bare magnetic nanoparticles in binding solution, leading to fluorescence quenching. Once thrombin was introduced, the CY3-aptamer formed a G-quartet structure and combined with thrombin, which resulted in the CY3-aptamer being separated from the magnetic nanoparticles and restoration of fluorescence. This proposed assay took advantage of binding affinity between the CY3-aptamer and thrombin for specificity, and bare magnetic nanoparticles for fluorescence quenching. The fluorescence signal had a good linear relationship with thrombin concentration in the range of 1-60 nM, and the limit of detection for thrombin was estimated as low as 0.5 nM. Furthermore, this method could be applied for other target detection using the corresponding fluorescence labeled aptamer.
    The Analyst 04/2015; 140(12). DOI:10.1039/c5an00519a · 3.91 Impact Factor
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    ABSTRACT: Phase separation dynamic processes in Three-Liquid-Phase System (TLPS), composed of organic oil (P507 extractant), water-soluble polymer (PEG2000), ammonium sulfate and water, with the change of mass composition of phase-forming components were investigated. It was found that dynamic separation of three-layered liquid phases in TLPS is in fact a course of dispersive polymer and organic oil droplets aggregated and separated out respectively from continuous salt aqueous bottom phase. Formation rate of organic oil phase was controlled mainly by coalescence rate of dispersed oil droplets, however rate-determining process for formation of polymer middle phase may change from drop sedimentation to coalescence or co-determined by both, when mass composition of the TLPS changed along different operation lines. With the formation of organic oil phase, it becomes another continuous phase, from which dispersive polymer droplets separated out and aggregated into a bulk phase gradually. Phase separation equilibrating time of TLPS, tE, depends on formation rate of the polymer middle phase and its equilibrium volume. A quantitative correlation of phase separation rate of TLPS with its physic-chemical properties was given. The present work promotes further understanding about influence from change in mass composition of phase-forming components in TLPS on three-phase separation dynamic processes.
    Industrial & Engineering Chemistry Research 04/2015; 54(15):150407110931007. DOI:10.1021/acs.iecr.5b00066 · 2.24 Impact Factor
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    ABSTRACT: Room temperature sodium-ion batteries with much lower cost relative to lithium-ion batteries have attracted particular interest for large-scale electrical energy storage in the fields of renewable energies and smart grid. However, most reported cathode materials were synthesized through a conventional high-temperature solid-state method. In order to further save energy and reduce cost, here we show that a series of high-performance cathode materials, sodium vanadium polyanionic compounds, Na3(VO1-xPO4)2F1+2x (x = 0, 0.5 and 1), can been synthesized by a phase-transfer assisted solvo-thermal strategy at a rather low temperature (80 - 140 oC) in one simple step, where an acid-base-coupled extractant was used to attain the phase-transfer of phosphoric acid. More importantly, the used extractant in this route can be recycled. The as-synthesized materials (Na3(VPO4)2F3 and Na3(VOPO4)2F) exhibit a high Na storage capacity of ca. 120 mAh/g which is close to the theoretical capacity and excellent cycling performance. This study makes a significant step to extend this strategy in the synthesis of functional materials from simple binary to complex multicomponent compounds.
    Chemical Communications 03/2015; 51(33). DOI:10.1039/C5CC01504A · 6.72 Impact Factor
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    ABSTRACT: In this work, a novel IL-based synergistic extraction system utilizing the ionic liquid tricaprylmethylammonium nitrate ([A336][NO3]) and the commercial extractant Di(2-ethylhexyl) 2-ethylhexyl phosphonate (DEHEHP) was developed for the extraction of rare earth (RE) nitrates. Pr(III) was used as a model RE and the effects of key factors, i.e. the ratio of [A336][NO3] to DEHEHP, the acidity of feed solutions, and the concentration of a salting-out reagent, were systematically studied. Our results demonstrate that the mixture of [A336][NO3] and DEHEHP had an obviously synergistic extraction effect for the extraction of Pr(III). The maximum synergistic enhancement coefficient of 3.44 was attained at XA = 0.4 (v%). Alternatively, mixture of [A336][Cl] and DEHEHP hardly extracted Pr(III) from chloride media. Moreover, we investigated the Pr(III) extraction mechanism and demonstrated that Pr(III) can be extracted as the neutral complexation species Pr(NO3)3﹒xDEHEHP and the ion-type species [A336]y﹒Pr(NO3)3+y. These extraction processes can effectively hamper the release of organic cation-ligands into the aqueous phase. The synergistic extraction effect is mainly derived from the enhanced solubility of the extracted species in the ionic liquid phase. The extraction behaviors of Pr(III) could be properly described by Langmuir and pseudo-second-order rate equations. Increased temperature was unfavorable for the extraction reaction but greatly improved the extraction rate. Interestingly, the mixed IL extraction system has an obviously synergistic extraction effect for light REs (LREs, La - Eu), but an anti-synergistic effect for heavy REs (HREs, Gd - Lu, Y), thus, indicating that our synergistic extraction system is helpful for the separation of LREs from HREs. In addition, the high selectivity between REs and non-REs suggested that the recovery of REs from a complicated high-salt leachate could be highly possible. It demonstrates that the IL-based synergistic extraction strategy developed in this work is promising and sustainable, and as a result, the development of an IL-based synergistic extraction process for the recovery of REs is straightforwardly envisaged.
    Green Chemistry 03/2015; 17(5). DOI:10.1039/C5GC00360A · 6.85 Impact Factor
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    ABSTRACT: Ionic liquid (IL)-based extraction is a promising and environmentally benign separation technology. To develop sustainable extraction technologies, quaternary ammonium-based IL extraction strategy is attractable. In this work, the separation of vanadium(V) from chromium(VI) by pure tricaprylmethylammonium nitrate ([A336][NO3]) and organic acidified primary amine N1923 ([RNH3][NO3]) was systematically investigated. The optimal proportion of [A336][NO3] and [RNH3][NO3] was studied and results showed that the mixed [A336][NO3] and [RNH3][NO3] exhibited an obvious synergistic-effect for V(V). The extraction of V(V) was strongly dependent on the acidity of the aqueous phase and reaches maximum at pH 2.5-3, while the maximum separation coefficient (βV/Cr) was located at about pH 9.0. Moreover, βV/Cr could be improved through adjusting the molar concentration ratio of V/Cr. The interference of coexisting anions (nitrates, chlorides, sulfate and phosphate) on the extraction of V(V) was examined and the results showed that PO43−, NO3− and Cl− had negative effects at various degrees except for SO42−. The V(V) extraction behaviors could be properly described by Langmuir and pseudo-second-order rate equations. The maximum extraction capacity for V(V) was estimated as 1.877 mmol/g at 303 K. Increased temperature had little effect on the extraction capacity, but greatly improved the extraction rate. The typical anion exchange mechanism between NO3− and V4O124− (or V3O93−) was proposed for the current extraction system. The IL phase could be renewed through stripping the loaded vanadium by a 0.5 M NaNO3 solution. This work demonstrated that quaternary ammonium IL containing a commercial organic extractant is an efficient and sustainable IL-based extraction strategy for the separation of vanadium from chromium, and as a result, the development of an IL-based extraction process is straightforwardly envisaged.
    Chemical Engineering Journal 03/2015; 264:487-496. DOI:10.1016/j.cej.2014.11.071 · 4.32 Impact Factor
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    ABSTRACT: A novel adsorbent, polyethylenimine-functionalized poly(vinyl alcohol) (PVA-PEI) magnetic microspheres, was prepared by a process involving: (1) synthesis of magnetic poly(vinyl acetate) microspheres (PVAc) using modified suspension polymerization, (2) preparation of PVA magnetic microspheres by methanolysis of PVAc and (3) two-step reaction with epichlorohydrin and polyethylenimine to yield amino groups. Magnetic measurement illustrated that the PVA-PEI microspheres were superparamagnetic, with a high saturated magnetization of 36.7 emu/g. Once generated, the PVA-PEI microspheres were used as adsorbent to remove Cr(VI) from an aqueous solution. The results demonstrated that the optimized pH value was observed at 2.0. The adsorption rate was extremely fast and the equilibrium was reached within 8 min. The adsorption isotherms of the adsorbent were preferably fitted to the Langmuir model, with the maximum adsorption capacity of 88.4 mg/g at 25 °C. Thermodynamic parameters indicated the spontaneous and exothermic nature of adsorption. In addition, the Cr(VI) ions were successfully eluted by a 0.1 mol/L NaOH solution, with the desorption efficiency of over 99%, and the adsorbent exhibited a good reusability. These results implied that the PVA-PEI microspheres should be considered as a potential adsorbent to remove Cr(VI) from wastewater.
    Chemical Engineering Journal 02/2015; 262:101–108. DOI:10.1016/j.cej.2014.09.045 · 4.32 Impact Factor
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    ABSTRACT: Hydrothermal carbon spherules (HCSs) can be loaded with a variety of metal nanoparticles for various applications. In this work, three types of HCSs were prepared from saccharides (mono-, di- and poly-saccharides) by a modified hydrothermal method taking glucose, sucrose and starch as sources, respectively. The deposition of Au nanoparticles onto them can be realized through a regular adsorption process. For comparison, HCSs made from mono-saccharides glucose (HCSs-M) has a higher adsorption capacity for Au(III) from aqueous acidic chloride media. The adsorption behaviors for AuCl4- by HCSs-M were investigated systematically. It shows a high selectivity for Au(III) towards Pd(II), Pt(VI), Rh(III) and some relevant base metals Fe(III), Co(II), Cu(II) and Ni(II). An extra reductant glycine can not only significantly improve the adsorption capacities and selectivity, but also accelerate the adsorption rate. Langmuir isotherm model and the 2nd-order kinetics model can properly describe the adsorption behaviors of AuCl4-. The adsorption mechanism of Au(III) by HCSs was confirmed by XPS, XRD, TG, FTIR, SEM and TEM techniques. It demonstrates that AuCl4- has been reduced to Au0 deposited onto HCSs. On the basis of this, a reduction-deposition coupled mechanism was proposed. The current research illustrates a prospect for HCSs to be used as effective adsorbents for selective adsorption separation of Au(III) from chloride media. It also demonstrates a possibility to integrate the selective recovery of gold from a complex industrial waste stream and the fabrication of functional carbon materials through loading with gold nanoparticles.
    11/2014; 3(4). DOI:10.1039/C4TA05597G
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    ABSTRACT: A novel Heck reaction catalyst consisting of a palladium(II) complex of meso-tetra(p-hydroxyphenyl)porphyrin (MTP) and cross-linked chloromethylated polystyrene microspheres (PMs) was successfully prepared via covalent ether bonds between the chloride groups in the PMs and the hydroxyl groups in MTP. The catalyst was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES). This polystyrene-supported palladium-complex was an efficient heterogeneous catalyst for cross-coupling of aryl iodides with ethyl acrylate. The reaction of iodobenzene and ethyl acrylate under N2 at 100 °C and a catalyst concentration of 0.1% gave a gas chromatography product yield of 99.8%, which is much higher than that achieved using a free palladium(II) complex of MTP as the catalyst (41.3%). The catalyst was recycled up to six times without significant loss of catalytic activity. These results suggest that the immobilized palladium(II)–MTP catalyst has potential applications in synthetic and industrial chemistry.
    Particuology 11/2014; DOI:10.1016/j.partic.2014.08.003 · 1.65 Impact Factor
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    ABSTRACT: Many papers have reported that salt ions can exert a great influence on the self-assembly behavior of PEO-PPO copolymers in the aqueous solution. Whereas the mechanism through which salt ions influence the self-assembly behavior of PEO-PPO copolymers is unclear and the dispute is mainly focused on whether the salt ions have a direct interaction with PEO-PPO copolymers. In this paper, the interaction of sodium and potassium ions with PEO-PPO copolymer was investigated by using FTIR, Raman and 23Na NMR spectroscopy. Experimental results reveal that direct interactions between salt cations and PEO-PPO macromolecular chains indeed occur in appropriate conditions. The present work highlights the role of cations in the self-assembly process of PEO-PPO copolymer.
    Vibrational Spectroscopy 10/2014; 75. DOI:10.1016/j.vibspec.2014.10.001 · 1.55 Impact Factor
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    ABSTRACT: In the present work, three-liquid-phase extraction and separation of rare earths and Fe, Al, and Si by a novel mixersettlermixer three-chamber integrated extractor was investigated. Various three-liquid-phase systems (TLPSs) involving different organic extractants were employed to conduct continuous three-liquid-phase separation of rare earths and Fe, Al, and Si. In the TLPS of PC-88A/PEG 2000/(NH4)(2)SO4H2O, light, middle, and heavy rare-earth ions had different distribution behaviors selectively into the organic top phase and salt-rich bottom phase, while most of Fe, Al, and Si were enriched into the poly(ethylene glycol) (PEG)-rich middle phase. Influences from aqueous pH values, agitation speeds, and flow ratios on three-liquid-phase partition behaviors of rare earths and Fe, Al, Si were evaluated. Experimental results indicated that an increase of the aqueous pH value facilitated the extraction of rare earths into the organic top phase and enrichment of Fe, Al, and Si into the PEG-rich middle phase. An increase of the agitation speed in three-phase mixer resulted in a change in the disappearance time of the dispersion band in a three-phase settler. The agitation speeds in a two-phase mixer and flow ratios of the organic phase to an aqueous biphasic mixture resulted in a change in the phase volumes of three-layered liquid flows in a three-phase settler so as to affect the partition behaviors of rare earths and Fe, Al, and Si. On the basis of analysis of the phase-forming behaviors of TLPSs and partition behaviors of rare earths and Fe, Al, and Si, the novel mixersettlermixer extractor is recommended for future application of continuous and countercurrent TLPE processes.
    Industrial & Engineering Chemistry Research 10/2014; 53(41):16033-16043. DOI:10.1021/ie5025694 · 2.24 Impact Factor
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    ABSTRACT: Monodisperse orthorhombic-phase rare earth fluorides nano-/microcrystals with a special shape of disk-stacked cylinder have been synthesized via a facile phase transfer assisted solvo-thermal route, where an acid-base-coupled extractant has been employed to transfer hydrofluoric acid into an oil phase as a fluoride source. The synthetic parameters have been optimized and a possible formation mechanism has also been proposed. More importantly, the adopted acid-base-coupled extractant in this route can be recycled. Surveying all of the lanthanides from La to Lu, most of the heavy rare earths, such as Tb, Dy, Ho, Er, Tm and Yb, can form LnF3 nanocrystals with the similar morphologies. Furthermore, Ln(3+)-doped YF3 (Ln=Tb, Yb/Er) nanocrystals have also been synthesized, and their down-conversion and up-conversion (980nm) luminescent properties were examined. The current approach could be extended to synthesize other metal fluorides nanoparticles.
    Journal of Colloid and Interface Science 09/2014; 436:171–178. DOI:10.1016/j.jcis.2014.08.067 · 3.55 Impact Factor
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    ABSTRACT: SignificanceBubbles can be used to greatly improve the speed of magnetic separation and overcome the limitation of magnetic force on the capture distance, making low-field magnetic separation highly efficient and easily scalable. This novel method leads to the development of a medium-free continuous gas-assisted magnetic separator on small pilot scale using low-field permanent magnet. This separator is demonstrated highly efficient for recovery of proteins-loaded magnetic nanoparticles from large volume bio-suspension. © 2014 American Institute of Chemical Engineers AIChE J, 2014
    AIChE Journal 09/2014; 60(9). DOI:10.1002/aic.14533 · 2.58 Impact Factor
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    ABSTRACT: Polyethylenimine-grafted poly(glycidyl methacrylate) (PGMA-PEI) microspheres were prepared using the dispersion polymerization method and a two-step reaction with ethylenediamine (EDA) and polyethylenimine (PEI). The PGMA-PEI microspheres were then characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) and tested for their ability to remove hexavalent chromium (Cr(VI)) from an aqueous solution in batch tests. The results demonstrated that Cr(VI) adsorption depended significantly on pH. The optimized pH value for the Cr(VI) adsorption was 2.0. The adsorption isotherms of PGMA-PEI microspheres with Cr(VI) fit the Langmuir model. The maximum adsorption capacities were 460.83, 485.44 and 505.05 mg g(-1) for PGMA-PEI600, PGMA-PEI1800 and PGMA-PEI10,(172) microspheres, respectively. The adsorption reached equilibrium within 10min and the experimental data fit the pseudo-second-order model. The obtained thermodynamic parameters (Delta G(0), Delta H-0 and Delta S-0) showed that the adsorption of Cr(VI) was an endothermic and spontaneous process. Competition from coexisting ions of K+, Na+, Ca2+, Cu2+, Cl-, NO3-, H2PO4-, and HPO42- was insignificant except SO42-. The regeneration study revealed that PGMA-PEI microspheres could be repeatedly used with no significant loss of adsorption efficiency.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 09/2014; 457:160–168. DOI:10.1016/j.colsurfa.2014.05.061 · 2.35 Impact Factor
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    ABSTRACT: BACKGROUND Adsorption is believed to be an effective and green technology for the removal and recovery of rare earths (III) from dilute solution.RESULTSA novel hybrid gel, abbreviated as ALG-PGA, has been prepared through crosslinking calcium alginate (ALG) and γ-poly glutamic acid (PGA), and its adsorption behavior towards whole rare earths (III) has been examined. Taking Nd(III) as a representative element, the adsorption capacity, kinetics, reusability, selectivity and mechanism have been investigated. Cation exchange is proposed as a possible adsorption mechanism. Doping PGA molecules into calcium alginate beads can significantly enhance the adsorption capacity and the selectivity of rare earths from non-rare earths. The maximum adsorption capacity obtained for Nd(III) was 1.65 mmol g−1. Reutilization of ALG-PGA gel was confirmed for up to eight consecutive sorption–desorption cycles with no damage to the gel.CONCLUSION The prepared biosorbent, ALG-PGA, was biocompatible and cost effective with a good adsorption ability for Nd(III), and provides a new approach to the recovery of rare earths (III) from rare earths-containing wastewater. © 2013 Society of Chemical Industry
    Journal of Chemical Technology & Biotechnology 07/2014; 89(7). DOI:10.1002/jctb.4186 · 2.49 Impact Factor
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    ABSTRACT: We explore whether it is possible to use 2D correlation spectrum to characterize intermolecular interactions between two solutes dissolved in the same solution when one substance does not possesses any characteristic peak. We demonstrate that the interaction can be manifested by characteristic cross peaks in 2D asynchronous correlated spectrum. The above cross peaks reflect the subtle spectral variations on the characteristic peak of another solute under intermolecular interaction. On the other hand, 2D synchronous spectrum is not suitable to characterize intermolecular interaction since the cross peaks contain irremovable interfering parts. The terbium-chloride/benzamide/methanol system is used to demonstrate that this approach is applicable in the real chemical system.
    Journal of Molecular Structure 07/2014; 1069:127–132. DOI:10.1016/j.molstruc.2014.01.046 · 1.60 Impact Factor
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    ABSTRACT: Gas-assisted three-liquid-phase extraction (GATE), which has the advantages of both three-liquid-phase extraction and solvent sublation, is a novel separation technique for separation and concentration of two organic compounds into different phases in one step. This highly effective and economically applicable method has been developed for separating emodin and rhein from herbal extract. In a GATE system composed of butyl acetate/PEG4000/ammonium sulphate aqueous solution, influence of various parameters including gas flow rate, flotation time, salt concentration, initial volume of PEG and butyl acetate were investigated. Within 50 min of 30 ml · min− 1 nitrogen flow, removal ratio of emodin and rhein from aqueous phase could be over 99% and 97%, respectively. Mass fraction of emodin in the BA phase and rhein in the PEG phase could reach 97% and 95%, respectively. It is demonstrated that gas bubbling is effective for partitioning of emodin and rhein into butyl acetate and PEG phase respectively, and dispersed PEG and butyl acetate could be captured in the aqueous solution. Experimental results show that GATE could be an effective and economical technology for concentration and separation of co-existed products in medicinal plants. Graphic abstract The figure is schematic diagram of gas-assisted three-liquid-phase extraction system. The flotation column is made of glass, is equipped with a G4 sintered glass sparger (pore size 3-4 μm). The inner diameter of the column is 36 mm and the length is 450 mm. There are three coexisting phases in the column, i.e. organic phase, polymer phase and aqueous phase (containing ammonium sulphate solution and simulated herbal exact). Three ports are open at different parts along the column to obtain samples of the three phases. In the process of gas bubbling, emodin and rhein initially contained in the aqueous phase are extracted into organic phase and polymer phase, respectively.
    Chinese Journal of Chemical Engineering 06/2014; 22(9). DOI:10.1016/j.cjche.2014.06.029 · 0.87 Impact Factor
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    ABSTRACT: Separations among vanadium(V) and chromium(VI) remain challenging. The extraction behaviors of V(V) along with Cr(VI) by a few of pure imidazolium-based hydrophobic ionic liquids have been investigated. Among these hydrophobic ionic liquids, [C(8)mim][PF6] exhibits a special extraction for V(V) while a weak extraction for Cr(VI). The extraction behavior of V(V) by [C(8)mim][PF6] was particularly studied. The extraction of V(V) is strongly dependent on the acidity of the aqueous phase, and the maximum separation factor between V and Cr (beta(V/Cr)) was calculated to be 100.6 in case of pH 3.5. The most probable extraction mechanism of V(V) has been proposed to be the anion exchange between the main species HV10O273- and PF6-. Furthermore, V(V) in IL phase can be quantitatively stripped by KPF6 solution under the basic condition (C-OH(-) = 1 mol/l). Recycle test indicates that the extraction capacity shows no apparent decline until the 9th continuous extraction-stripping cycle. The result also provides a new approach for the preparation of a novel ionic liquid with metal oxo-anions as counter anion.
    Separation and Purification Technology 06/2014; 131:94–101. DOI:10.1016/j.seppur.2014.05.003 · 3.07 Impact Factor
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    ABSTRACT: A new strategy was suggested to remove Fe, Al and Si impurities from rare-earth leach solution by controlling partitioning and selective enrichment of those impurities and rare earths in three-liquid-phase systems. Experimental results indicated that aqueous pH value and addition of water-soluble complexing agents or their mixtures into initial aqueous solution have significant influence on three-liquid-phase partitioning of Fe, Al, Si and rare earths. When only 1,10-phenanthroline was added, Fe and Si can be "filtered" into PEG-rich middle phase of three-liquid-phase system (Cyanex 272/PEG 2000/(NH4)(2)SO4-H2O) without affecting separation of heavy and light rare-earth ions in top organic and bottom salt-rich phase, respectively. Al remained in bottom phase. However, addition of EDTA and 1,10-phenanthroline promoted enrichment of Fe, Al and Si into PEG-rich middle phase, and almost all of rare earths were concentrated in salt-rich bottom phase. Those rare earths in salt-rich phase after removal of impurities can be further separated by another three-liquid-phase system of Cyanex 272/PEG 600/(NH4)(2)SO4-H2O. Heavy, middle and light rare earths, Yb, Eu and La, can be selectively enriched into different liquid phases. Therefore, separation of non-rare-earth impurities from rare earths, and then between light, middle and heavy rare earths can be achieved by two stages of three-liquid-phase partitioning. The present work highlights three-liquid-phase system can be a potential separation media for removal of Fe, Al, Si from complex rare-earth leach solution and group separation of different target metals into different liquid phases. (c) 2014 Elsevier B.V. All rights reserved.
    Separation and Purification Technology 04/2014; 127:97–106. DOI:10.1016/j.seppur.2014.02.035 · 3.07 Impact Factor
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    ABSTRACT: A novel amino-functionalized magnetic cellulose composite was prepared by a process involving: (1) synthesis of magnetic silica nanoparticles using the co-precipitation method followed by the hydrolysis of sodium silicate, (2) coating with cellulose through the regeneration of cellulose dissolved in 7 wt% NaOH/12 wt% urea aqueous solvent, (3) grafting of glycidyl methacrylate using cerium initiated polymerization and (4) ring-opening reaction of epoxy groups with ethylenediamine to yield amino groups. Once generated, the resulting composite was tested for its ability to remove Cr(VI) from an aqueous solution in batch experiments. The results demonstrated that Cr(VI) adsorption was highly pH dependent. The optimized pH value was 2.0. The adsorption isotherms of the adsorbent fit the Langmuir model, with the maximum adsorption capacity of 171.5 mg/g at 25 °C. The adsorption rate was considerably fast, and the adsorption reached equilibrium within 10 min. The obtained thermodynamic parameters showed that the adsorption of Cr(VI) onto the adsorbent was an exothermic and spontaneous process. In addition, the Cr(VI) ions could be effectively desorbed using a 0.1 mol/L NaOH solution and the adsorbent exhibited a good reusability. The composite material should be a promising adsorbent for Cr(VI) removal, with the advantages of high adsorption capacity, rapid adsorption rate and convenient recovery under magnetic field.
    Chemical Engineering Journal 04/2014; 241:175–183. DOI:10.1016/j.cej.2013.12.051 · 4.32 Impact Factor

Publication Stats

3k Citations
473.01 Total Impact Points

Institutions

  • 1999–2015
    • Chinese Academy of Sciences
      • • State Key Laboratory of Biochemical Engineering
      • • Key Laboratory of Green Process and Engineering
      • • Institute of Process Engineering
      Peping, Beijing, China
    • Academia Sinica
      T’ai-pei, Taipei, Taiwan
  • 2007
    • Beijing University of Chemical Technology
      Peping, Beijing, China
  • 2001
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China
  • 1995
    • Peking University
      • Department of Chemistry
      Beijing, Beijing Shi, China