ANALYST
·
2012
·Vol. 138
·期 4
·1091-1097
·
IF 4.23
Na Zhou,Jinhua Li,Hao Chen,Chunyang Liao,Lingxin Chen
A simple and sensitive electrochemical assay strategy of stripping voltammetry for mercury ions (Hg2+) detection is described based on the synergistic effect between ionic liquid functionalized graphene oxide (GO-IL) and gold nanoparticles (AuNPs). The AuNPs–GO-IL modified onto glassy carbon electrode (GCE) resulted in highly enhanced electron conductive nanostructured membrane and large electroactive surface area, which was excellently examined by scanning electron microscopy and cyclic voltammetry. After accumulating Hg2+, anodic stripping voltammetry (ASV) was performed, and differential pulse voltammetry (DPV) was employed for signal recording of Hg2+. Several main experimental parameters were optimized, i.e., deposition potential and time of AuNPs were −0.2 V and 180 s, respectively, and accumulation potential and time of Hg2+ were −0.3 V and 660 s, respectively. Under the optimal conditions, this AuNPs–GO-IL–GCE sensor attained a good linearity in a wide range of 0.1–100 nM (R = 0.9808) between the concentration of the Hg2+ standard and peak current. The limit of detection was estimated to be 0.03 nM at a signal-to-noise ratio of 3σ. A variety of common coexistent ions in water samples were investigated, showing no obvious interferences on the Hg2+ detection. The practical application of the proposed sensor has been carried out and demonstrated as feasible for determination of trace levels of Hg2+ in drinking and environmental water samples.
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AICHE JOURNAL
·
2012
·Vol. 59
·期 5
·1657-1667
·
IF 2.261
Qiwei Yang,Huabin Xing,Baogen Su,Zongbi Bao,Jun Wang,Yiwen Yang,Qilong Ren
Separating phenols or even their homologs is an important process in environmental conservation and biomass utilization, and it has become one fascinating application of ionic liquids (ILs). Nevertheless, its underlying mechanism still needs to be elucidated at the molecular level. This work conducted a theoretical study on the interaction between ILs and phenols by quantum chemical calculations, using tocopherols as model compounds. Calculation results from geometry, electrostatic potential, natural bond orbital, atoms in molecules and energy analyses and their accordance with extraction experiments indicated the essential role of hydrogen-bonding interaction in extracting tocopherols and distinguishing the homologs by IL. The polarizable continuum model and conductor-like screening model for real solvents studies showed that the mechanism still holds when considering the solvation effect. Furthermore, with the aid of theoretical calculation, more efficient extractants, 1-ethyl-3-methylimidazolikum glycinate ([emim]Gly) and 1-ethyl-3-methylimidazolikum alaninate ([emim]Ala), were developed for the separation of tocopherol homologs. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1657–1667, 2013
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Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 23
·12367-12376
·
IF 7.443
Ying Tang,Beibei Tang,Peiyi Wu
In this work, we report a novel method to prepare a positively charged nanofiltration (NF) membrane by rapid counter-ion exchange of a poly(ionic liquid) (PIL) in aqueous solution, which transforms from being hydrophilic to hydrophobic. A thin PIL layer is deposited on the supporting membrane via a phase separation process induced by an ion exchange reaction along with a self-inhibiting effect, and a series of positively charged NF membranes are obtained. The membrane formation process is mainly dominated by the concentration of the hydrophilic PIL and its counter-ions. In brief, the density of the top layer is predominated both by the PIL and its aqueous counter-ion, and the thickness of the surface layer is mainly determined by the aqueous counter-ion. A streaming potential measurement confirmed that the resultant membrane is positively charged when the pH range is below 11. The pure water flux (PWF) was up to 45.3 L m−2 h−1 under the operating pressure of 0.6 MPa. The rejection to MgCl2 of the membrane reached 84% and decreased in the order of MgCl2, NaCl, MgSO4, and Na2SO4. It also shows a high rejection of about 90% to heavy metallic salts such as CuCl2, NiCl2 and CoCl2. The method based on the hydrophilic–hydrophobic transformation of the PIL provides an alternative way to prepare a charged membrane with high performance.
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ChemCatChem
·
2014
·Vol. 7
·期 3
·441-449
·
IF 5.044
Hui Wan,Chong Chen,Zuowang Wu,Yigen Que,Yu Feng,Wei Wang,Lei Wang,Guofeng Guan,Xiaoqin Liu
Graphical Be more active: A new strategy is proposed to construct the ionic liquid, polyoxometalate (POM), and metal–organic framework (MOF) composite. POM bridges the gap between the ionic liquid and the carrier (MOF); thus, the heteropolyanion-based ionic liquid can be encapsulated within the cages of MIL-100 (MIL=Materials of Institut Lavoisier) through anion exchange. The POM–ionic-liquid-functionalized MOF demonstrates high catalytic activity for the esterification of oleic acid with ethanol and is stable in the liquid-phase reaction, with no obvious leaching of the active component. A new strategy was proposed to construct the ionic liquid, polyoxometalate (POM), and metal–organic framework (MOF) composite. The POM-based MOF was synthesized by using the direct hydrothermal method. The sulfonic acid group-functionalized ionic liquid was used for further modification of the hybrid material to realize the encapsulation of the heteropolyanion-based ionic liquid within the cages of the MOF. The catalysts were characterized by using XRD, N 2 adsorption–desorption, FTIR, SEM, TEM, elemental analysis, and TGA. The results indicated that the heteropolyanion-based ionic liquid had been successfully encapsulated within the cages and the structure of MIL-100 (MIL=Materials of Institut Lavoisier) remained intact. The POM–ionic-liquid-functionalized MOF, with high content of the active component, had both Lewis and Brønsted acid sites, which led to high catalytic activity for the esterification of oleic acid with ethanol. The esterification reaction conditions were optimized by using response surface methodology (RSM), and the corresponding conversion of oleic acid reached 94.6 %. The catalyst could be easily recovered and reused six times without significant loss of activity.
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CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Wenjing Ding,Wenshuai Zhu,Jun Xiong,Lei Yang,Aimin Wei,Ming Zhang,Huaming Li
A novel catalyst, based on iron-based redox ionic liquid modified mesoporous SBA-15 material was successfully prepared and applied to the removal of sulfur compounds in model oil. Sample structures were extensively studied by XRD, N 2 adsorption–desorption, TEM, FTIR, DRS, and XPS analysis. This strategy provided a catalyst system with high surface area, high accessibility for substrate and oxidant. In the process of extractive catalytic oxidative desulfurization (ECODS) of model oil, [Omim]BF 4 served as not only the extractant and the reaction media but also co-catalyst. Under the optimal conditions, the sulfur removal could reach 94.3%. The mechanism of the ECODS system was also proposed.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2014
·
IF 3.552
X. Ge,C.D. Gu,X.L. Wang,J.P. Tu
Manganese oxides with desired structure are controllably obtained through annealing MnCO 3 precursors with required structures. The structures of MnCO 3 precursors are determined by a “mesocrystal formation” process in an ionic liquid system of a choline chloride/urea (CU) mixture. Without addition of surfactants, only CU solvent and manganese chloride are needed in the reaction system, in which the CU acts as reaction medium as well as control agent for particle growth. A shape transformation of MnCO 3 particles from well-defined rhombohedral mesocrystals to ellipsoidal polycrystal ensembles, and to nanoparticulate aggregates is observed when heating the reaction system for 4 h at 120, 150, and 180 °C, respectively. With a longer aging time at 120 °C, etching and disassembly of MnCO 3 mesocrystals happened. The correlation between the microstructure and the underlying formation mechanism is highlighted. Porous and nanowire-like MnO x nanostructures are obtained through a facile thermal conversion process from the diverse MnCO 3 precursors, which are demonstrated as effective and efficient adsorbents to remove organic waste (e.g. Congo red) from water. Significantly, the nanowire-like MnO x nanostructures obtained by annealing the MnCO 3 mesocrystals at 300 °C for 4 h can remove about 95% Congo red in waste water at room temperature in only one minute, which is superior to the reported hierarchical hollow nanostructured MnO 2 .
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2014
·
IF 2.726
Yinyan Li,Shiqing Xu
We introduce an ionic liquid-based method for the synthesis of uniform lanthanide fluoride microcrystals with the assistance of a sonication-accelerated reaction system. It is a fast, simple and mild process to get uniform monodisperse spherical lanthanide fluoride microcrystals in large scale. Homogeneous precipitation in a biphasic system of ethanol solution of lanthanide nitrates and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [C 4 mim][PF 6 ] led to the uniform LnF 3 microcrystals. The method was applied to the preparation of pure LnF 3 (Ln = La, Ce, Pr, Nd) and Eu 3+ -doped LaF 3 , Tb 3+ -doped CeF 3 . SEM images indicated highly uniform cotton-like spherical microcrystals were obtained. HRTEM image indicated that the microcrystals were aggregated by nanocrystals of 6–10 nm due to agglomeration effect of the ionic liquid. The uniformity and dispersility of LaF 3 decreased with the increasing of the molar ratio of [C 4 mim][PF 6 ] to La(NO 3 ) 3 ·6H 2 O. Diameter of the microcrystal decreased from La to Nd. Photoluminescence properties of Eu 3+ -doped LaF 3 and Tb 3+ -doped CeF 3 were also studied.
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JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Kun Yin,Zhengxi Zhang,Li Yang,Shin-Ichi Hirano
An imidazolium-based polymerized ionic liquid (PIL), poly(1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonylimide)) is successfully synthesized via a new three-step process comprising the direct radical polymerization of the 1-vinylimidazole monomer , and subsequent quaternization reaction followed by an anion exchange procedure. Furthermore, polymer electrolytes are prepared by blending as-obtained PIL as the polymer host with an ionic liquid and LiTFSI salt. Electrochemical measurements demonstrate that compared with polymer electrolytes containing the PIL host synthesized by the conventional route, polymer electrolytes containing the PIL host obtained by new synthetic process exhibit significantly improved capacity and cycling performance, which is due to higher ionic liquid content.
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BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Peini Zhao,Jingcheng Hao
A new analytical approach for detecting diaminopyridine derivatives has been constructed using a molecular imprinting-electrochemical sensor. Opposed to the conventional strategy of employing diaminopyridine as the functional monomer and uracil derivatives as the target analyte , in the current study, the 2,6-Diaminopyridine-imprinted core–shell nanoparticles were synthesized with 2,6-Diaminopyridine as the template molecule and 6-aminouracil as the functional monomer. Graphene and ionic liquid which can assist 2,6-Diaminopyridine-imprinted core–shell nanoparticles in electrochemical reaction kinetics by increasing conductivity have been introduced to form one of the electrode modified layers. The proposed analytical method has been applied in 2,6-Diaminopyridine detection in hair-dyes and demonstrated appropriate sensitivity and selectivity, with a linear range of 0.0500–35.0 mg kg −1 and a detection limit as low as 0.0275 mg kg −1 .
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Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 14
·5140-5148
·
IF 0
Kaisheng Yao,Weiwei Lu,Xinying Li,Jianji Wang
In this work, a facile strategy was developed for tunable synthesis and assembly of ZnS nanoparticles at ionic liquid (IL)–H2O interfaces. The assembled ZnS films at different IL–H2O interfaces were characterized and analyzed by scanning electron microscopy, X-ray diffraction, selected area electron diffraction and transmission electron microscopy. It was found that by using ILs with different anions and/or different alkyl chain lengths of the imidazolium cations, the properties of IL–H2O interfaces could be modulated, which in turn directed the formation of flexible ZnS films with various morphologies and different crystal phases. On the basis of the controlled experiments, a possible growth mechanism was suggested for the ZnS films at IL–H2O interfaces. Furthermore, water contact angle measurements showed that the as-prepared ZnS films demonstrated adjustable wetting properties from superhydrophobicity to hydrophilicity.
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RSC Advances
·
2013
·Vol. 4
·期 8
·4194-4202
·
IF 2.562
Jinzhu Chen,Guoying Zhao,Limin Chen
Direct conversion of fructose into 5-hydroxymethylfurfural (HMF) and alkyl levulinate is achieved by making use of ionic liquid-based polyoxometalate salts (IL-POMs) as solid acid catalysts. Among these solid acids, phosphotungstic acid-derived IL-POM shows the highest catalytic performance in both the HMF and ethyl levulinate (EL) formation. A study for optimizing the reaction conditions such as the reaction time and the temperature has been performed. High HMF and EL yields of up to 99% and 82%, respectively, are obtained from fructose under the investigated conditions. Moreover, the generality of the catalyst is further demonstrated by processing representative di- and polysaccharides such as sucrose and inulin with good yields to HMF (76% from inulin and 48% from sucrose) and EL (67% from inulin and 45% from sucrose), again under mild conditions, thereby eliminating the separate hydrolysis step before the dehydration reaction. The catalyst recycling experiment indicates that the adsorption and accumulation of oligomeric products on the catalyst surface results in a partial deactivation of catalyst. The mechanism research reveals that a major pathway for EL formation involves a fructose-to-HMF transformation followed by HMF etherification and rehydration of HMF-ether to give EL. The research highlights an efficient, environment-friendly and recyclable solid acid for biomass valorization.
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PHOTOCHEMISTRY AND PHOTOBIOLOGY
·
2014
·Vol. 90
·期 6
·1462-1466
·
IF 2.684
Ying Mei,Bing Yan
A special multifunctional ionic liquid compound (1-methyl-3-(2-(thiocarboxyoxy)-ethyl)-2H-imidazole-1,3-diium bromide (SHIL)) is used as the chemical bridge to link lanthanide beta-diketonates and polymer resin, which are designated as Ln(L) 4 -SHIL-WR/MR (Ln = Eu, Tb, Sm; L = thenoyltrifluoroacetonate (TTA), acetylacetonate (AA), dibenzoylmethane (DBM); WR = Wang resin, MR = Merrifield resin). Among SHIL and polymer resin are assembled to form covalently bonded system through condensation reaction. Then tetrakis lanthanide beta-diketonates are linked to SHIL through ion-exchange reaction. Physical characterization and especially the photoluminescent performance of the multicomponent hybrids are studied. The hybrid materials possess good stability and excellent luminescent property. The results provide useful path to obtain luminescent hybrids for further practical application.
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