Na0.44MnO2 nanorods have been prepared by a hydrothermal method.The experimental parameters have been systematically investigated and optimized.The results show that Na0.44MnO2 nanorods obtained via the hydrothermal t...Na0.44MnO2 nanorods have been prepared by a hydrothermal method.The experimental parameters have been systematically investigated and optimized.The results show that Na0.44MnO2 nanorods obtained via the hydrothermal treatment at 200℃for 16 h show the best electrochemical properties,which deliver the high initial discharge capacity of 110.7 mA·h/g at 50 mA/g in potential window 2.0-4.0 V.To further improve their electrochemical properties,a ball milling process with graphene has been carried out to obtain Na0.44MnO2/graphene composite.The initial discharge capacity of Na0.44MnO2/graphene composite is 106.9 mA·h/g at a current density of 50 mA/g.After 100 cycles,the residual discharge capacity is 91.8 mA·h/g and the capacity retention rate is 85.9%,which is much higher than that of pristine Na0.44MnO2 nanorods(74.7%)at the same condition.What is more,when the current density reaches 500 and 1000 mA/g,the corresponding discharge capacities of Na0.44MnO2/graphene composite are about 89 and 78 mA·h/g,respectively,indicating outstanding rate capability.展开更多
We have prepared polyion complex (PIC) hydrogel consisting of poly(3-(methacryloylami no)propyl-trimethylamonium chloride) and poly(sodium p-styrenesulfonate) polyelectrolytes via a two-step polymerization pro...We have prepared polyion complex (PIC) hydrogel consisting of poly(3-(methacryloylami no)propyl-trimethylamonium chloride) and poly(sodium p-styrenesulfonate) polyelectrolytes via a two-step polymerization procedure and have investigated specific ion effects on the self- healing of the PIC hydrogel. Our study demonstrates that the mechanical properties of the PIC hydrogel are strongly dependent on the type of the ions doped in the hydrogel. The ion-specific effects can be used to modulate the self-healing efficiency of the PIC hydrogel. As the doped anions change from kosmotrops to chaotropes, the self-healing efficiency of the PIC hydrogel increases. A more chaotropic anion has a stronger ability to break the ionic bonds formed within the hydrogel, leading to a higher efficiency during the healing.展开更多
Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate...Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate (CAN) as initiator. The flocculation ability of the resulting polymer (PCAD) was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD's flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan's content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD's flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD's dosage was 8mg-Lk Compared with cationic polymer (the copolymer of AM and DMC, PAD), PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.展开更多
Molecular interactions of the ternary mixtures of 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl)-water-2,6-dimethoxyphenol (2,6-DMP, a phenolic monomer lignin model compound) were investigated in comparison wit...Molecular interactions of the ternary mixtures of 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl)-water-2,6-dimethoxyphenol (2,6-DMP, a phenolic monomer lignin model compound) were investigated in comparison with the [C4C1im]Cl-water binary systems through attenuated total reflection infrared spectroscopy. Results indicated that the microstructures of water and [C4C1im]Cl changed with varying mole fraction of [C4C1im]Cl (xIL) from 0.01 to 1.0. This change was mainly attributed to the interactions of [C4C1im]Cl-water and the self-aggregation of [C4C1im]Cl through hydrogen bonding. The band shifts of C-H on imidazolium ring and the functional groups in 2,6-DMP indicated that the occurrence of intermolecular interactions by different mechanisms (i.e., hydrogen bonding or π-π stacking) resulted in 2,6-DMP dissolution. In the case of xIL=0.12, the slightly hydrogen-bonded water was fully destroyed and [C4C1im]Cl existed in the form of hydrated ion pairs. Interestingly, the maximum 2,6-DMP solubility (238.5 g/100 g) was achieved in this case. The interactions and microstructures of [C4C1im]Cl-water mixtures influenced the dissolution behavior of 2,6-DMP.展开更多
A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Or3+, and the relevant purifying mechanism was also addressed. ...A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Or3+, and the relevant purifying mechanism was also addressed. In detail, organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes. However, for heavy metal ions (Cu2+, Cr3+), part was removed by electrodeposition, and some was adsorbed on biofilm. In order to compare with the combined process of micro electrolysis and biofilm, the experimental data of micro electrolysis process (intermittent) or biofilm process (continuous) were provided, and the kinetic data of C6H12O6 (glucose) biodegradation by cultured microbes or acclimated microbes were also obtained. These experimental results indicated that for wastewater initially consisted of CeH12O6 (500mg-L-1), Cu2+ and Cr3+ (10mg-L-1), after treatment, its concentrations of C6H12O6, Cu2+ and Cr3+ were lowered to the level of 55-65mg.L^1, and less than 1mg-L-1, respectively. And the industrial reused water standards could be met by treated wastewater.展开更多
Recently ionic liquids(ILs) are introduced as novel dual function gas hydrate inhibitors. However, no desired gas hydrate inhibition has been reported due to poor IL selection and/or tuning method. Trial & error a...Recently ionic liquids(ILs) are introduced as novel dual function gas hydrate inhibitors. However, no desired gas hydrate inhibition has been reported due to poor IL selection and/or tuning method. Trial & error as well as selection based on existing literature are the methods currently employed for selecting and/or tuning ILs. These methods are probabilistic, time consuming, expensive and may not result in selecting high performance ILs for gas hydrate mitigation. In this work, COSMO-RS is considered as a prescreening tool of ILs for gas hydrate mitigation by predicting the hydrogen bonding energies(E_(HB)) of studied IL inhibitors and comparing the predicted E_(HB) to the depression temperature(?) and induction time. Results show that, predicted EHBand chain length of ILs strongly relate and significantly affect the gas hydrate inhibition depression temperature but correlate moderately(R = 0.70) with average induction time in literature. It is deduced from the results that, ? increases with increasing IL EHBand/or decreases with increasing chain length. However, the cation–anion pairing of ILs also affects IL gas hydrate inhibition performance. Furthermore, a visual and better understanding of IL/water behavior for gas hydrate inhibition in terms of hydrogen bond donor and acceptor interaction analysis is also presented by determining the sigma profile and sigma potential of studied IL cations and anions used for gas hydrate mitigation for easy IL selection.展开更多
Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration m...Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux (J) and tungsten rejection coefficient (R) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mg·L-1 . The decomplexation percentage of tungsten (Ⅵ)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (Ⅵ) can be extracted effectively by using 50 mg·L-1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (Ⅵ) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.展开更多
Sodium bis[N-2-oxyphenyl-5-substituted-salicylideneiminato-ONO]ruthenate(Ⅲ) hemitriethylamine compounds of general formula Na[Ru(N-R-5-X-salim)2]'0.5Et3N, where, R = C6H40, X = El, Br, NO2, salim = salicylidenei...Sodium bis[N-2-oxyphenyl-5-substituted-salicylideneiminato-ONO]ruthenate(Ⅲ) hemitriethylamine compounds of general formula Na[Ru(N-R-5-X-salim)2]'0.5Et3N, where, R = C6H40, X = El, Br, NO2, salim = salicylideneiminato, Et3N triethylamine, were synthesized and characterized on the basis of elemental analysis, MALDI-TOF (matrix-assisted laser desorption/ionization/time-of-flight) mass spectra, IH NMR (nuclear magnetic resonance), electronic spectra and cyclic voltammograms. Ru(Ⅲ) is chelated with two O2N anionic tridentate Schiff bases derived from 5-X-salicyladehyde and 2-aminophenol. Spectroscopic titrations of the Ru(Ⅲ) compounds with CT DNA (calf thymus DNA) in the LMCT (ligand metal charge transfer) region have shown moderate intercalation properties of compounds with binding constants KD = 2.06-3.85 × 104 Ml. Electrochemical evidence of intercalative mode of binding is based on the decrease of current and shift of anodic and cathodic peaks towards higher values of potential with IxL-increment of CT DNA in Ru(Ⅲ) compound solution.展开更多
AC impedance spectroscopy in pure room temperature ionic liquids (RTILs) and RTIL-water mixture was measured at the temperature of range from 30 ℃ down to -30 ℃. The cations of RTILs are N,N-diethyl-N-methyl-N-(2...AC impedance spectroscopy in pure room temperature ionic liquids (RTILs) and RTIL-water mixture was measured at the temperature of range from 30 ℃ down to -30 ℃. The cations of RTILs are N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium ([DEME]), 1-ethyl-3-methylimidazolium ([C2mim]) and l-butyl-3-methylimidazolium ([Camim]), the anions are tetrafluoroborate ([BF4]) and bis(trifluoromethanesulfonyl)imide ([TFSI]). In all pure RTILs, there are two kinds of local minima in real part of the AC impedance Zreal. By adding water to [DEME][BF4] (0 mol% 〈 x 〈 94 mol%) at room temperature, the local minimum value at higher frequency decreased remarkably at the fixed frequency with increasing water concentration. Above 94 mol% H20, a quite different profile of the AC impedance spectroscopy was obtained. In addition to Zreal. temperature dependence of an imaginary part of the impedance Zimag had an isosbestic point below 94 mol%. The isosbestic point disappeared above 94 mol%. The isosbestic point in Zing reveals an interaction between [DEME][BFa] and H2O.展开更多
We report on the fabrication of fluorescent and multicolor probes for Zn^2+ ions and temperature from a mixture of three types of fluorophore-labeled responsive block copolymers in aqueous media. Quinoline-based Zn^2...We report on the fabrication of fluorescent and multicolor probes for Zn^2+ ions and temperature from a mixture of three types of fluorophore-labeled responsive block copolymers in aqueous media. Quinoline-based Zn^2+-recognizing fluorescent mono- mer ZQMA, red-emitting rhodamine B-based monomer RhBEA, and blue-emitting coumarin derivative Coum-OH, were syn- thesized first. A ZQMA-labeled well-defined double hydrophilic block copolymer (DHBC), PEG-b-P(MEO2MA-co-ZQMA), was synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEOzMA) and ZQMA by utilizing a PEG-based macroRAFT agent. Following similar procedures, PEG-b-P(St-co-RhBEA) amphiphilic diblock copolymer and PEG-b-P(MEOzMA-co-Coum) DHBC were also synthesized, where P(St-co-RhBEA) was a RhBEA-labeled polystyrene (PS) block. At room temperature in aqueous solution, almost non- fluorescent PEG-b-P(MEOzMA-co-ZQMA) can effectively bind Zn2+ ions, leading to prominent green fluorescence enhance- ment due to the coordination of ZQMA with Zn^2+ ions. However, by mixing red-emitting PEG-b-P(St-co-RhBEA) and blue-emitting PEG-b-P(MEO2MA-co-Coum) with PEG-b-P(MEO2MA-co-ZQMA) at an appropriate ratio, three color transitions could be observed. In the absence of Zn^2+ ions, a mixed pink fluorescent originating from Coum and RhBEA was ob- served; upon the addition of a certain amount of Zn^2+ ions, the green fluorescence enhanced dramatically, leading to a white fluorescence readout. By further increasing the amount of Zn2+ ions, the green fluorescence further enhanced and overwhelmed the blue and red emissions, leading to a green-dominant mixed-fluorescence emission. In addition, upon increasing the temperature, the fluorescence of Coum decreased considerably due to the fluorescence-resonance energy transfer (FRET) between Coum and ZQMA moieties. In this way, a ratiometric fluorescent thermometer can be constructed.展开更多
Reported here is a water-soluble ligand, N-(sulfoethyl)-iminodiacetic acid (H3SEIDA), used for the complexation of uranyl ions. A coordination compound composed of uranyl cation and N-(sulfonatoethyl)-ammoniodia...Reported here is a water-soluble ligand, N-(sulfoethyl)-iminodiacetic acid (H3SEIDA), used for the complexation of uranyl ions. A coordination compound composed of uranyl cation and N-(sulfonatoethyl)-ammoniodiacetate (SEADA2-) zwitterion was synthesized from an acidic aqueous solution. This compound features a 2D undulating fes (4.82) coordination layer that is stacked and linked by hydrogen-bonding interaction to form a 3D supramolecular framework with a 1D larger-cycle channel. Thermal analysis demonstrates the relatively weak bonding between uranyl cation and SEADA2 zwitterion. The monomeric uranyl-based fluorescence emission is red-shifted by about thermal synthesis of this uranyl compound was successfully 5 nm compared to that of uranyl nitrate hexahydrate. The hydro- applied to the sequestration of uranyl ions.展开更多
Palladium nanoparticles immobilized on a cross-linked imidazolium-containing polymer were evaluated as a catalyst for Suzuki carbon-carbon cross-coupling reactions using water as the solvent. The nanocatalysts show go...Palladium nanoparticles immobilized on a cross-linked imidazolium-containing polymer were evaluated as a catalyst for Suzuki carbon-carbon cross-coupling reactions using water as the solvent. The nanocatalysts show good catalytic activities for aryl iodides and aryl bromides and moderate activity with aryl chloride substrates. Coupling of sterically hindered substrates could also be achieved in reasonable yields. The heterogeneous catalyst is stable, can be stored without precautions to exclude air or moisture, and can be easily recycled and reused.展开更多
基金Project(51672234)supported by the National Natural Science Foundation of ChinaProject(1337304)supported by the Program for Innovative Research Cultivation Team in University,Ministry of Education,China
文摘Na0.44MnO2 nanorods have been prepared by a hydrothermal method.The experimental parameters have been systematically investigated and optimized.The results show that Na0.44MnO2 nanorods obtained via the hydrothermal treatment at 200℃for 16 h show the best electrochemical properties,which deliver the high initial discharge capacity of 110.7 mA·h/g at 50 mA/g in potential window 2.0-4.0 V.To further improve their electrochemical properties,a ball milling process with graphene has been carried out to obtain Na0.44MnO2/graphene composite.The initial discharge capacity of Na0.44MnO2/graphene composite is 106.9 mA·h/g at a current density of 50 mA/g.After 100 cycles,the residual discharge capacity is 91.8 mA·h/g and the capacity retention rate is 85.9%,which is much higher than that of pristine Na0.44MnO2 nanorods(74.7%)at the same condition.What is more,when the current density reaches 500 and 1000 mA/g,the corresponding discharge capacities of Na0.44MnO2/graphene composite are about 89 and 78 mA·h/g,respectively,indicating outstanding rate capability.
文摘We have prepared polyion complex (PIC) hydrogel consisting of poly(3-(methacryloylami no)propyl-trimethylamonium chloride) and poly(sodium p-styrenesulfonate) polyelectrolytes via a two-step polymerization procedure and have investigated specific ion effects on the self- healing of the PIC hydrogel. Our study demonstrates that the mechanical properties of the PIC hydrogel are strongly dependent on the type of the ions doped in the hydrogel. The ion-specific effects can be used to modulate the self-healing efficiency of the PIC hydrogel. As the doped anions change from kosmotrops to chaotropes, the self-healing efficiency of the PIC hydrogel increases. A more chaotropic anion has a stronger ability to break the ionic bonds formed within the hydrogel, leading to a higher efficiency during the healing.
基金supported by Young Scientist Foundation (2008BS09001) from the Department of Science and Technology of Shandong Province
文摘Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC) as raw materials and ceric ammonium nitrate (CAN) as initiator. The flocculation ability of the resulting polymer (PCAD) was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD's flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan's content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD's flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD's dosage was 8mg-Lk Compared with cationic polymer (the copolymer of AM and DMC, PAD), PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.
基金This work was supported by the National Natural Science Foundation of China (No.21106011 and No.21276034) and the Program of Science and Technology of Liaoning Province (No.201602058), and China Scholarship Council.
文摘Molecular interactions of the ternary mixtures of 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl)-water-2,6-dimethoxyphenol (2,6-DMP, a phenolic monomer lignin model compound) were investigated in comparison with the [C4C1im]Cl-water binary systems through attenuated total reflection infrared spectroscopy. Results indicated that the microstructures of water and [C4C1im]Cl changed with varying mole fraction of [C4C1im]Cl (xIL) from 0.01 to 1.0. This change was mainly attributed to the interactions of [C4C1im]Cl-water and the self-aggregation of [C4C1im]Cl through hydrogen bonding. The band shifts of C-H on imidazolium ring and the functional groups in 2,6-DMP indicated that the occurrence of intermolecular interactions by different mechanisms (i.e., hydrogen bonding or π-π stacking) resulted in 2,6-DMP dissolution. In the case of xIL=0.12, the slightly hydrogen-bonded water was fully destroyed and [C4C1im]Cl existed in the form of hydrated ion pairs. Interestingly, the maximum 2,6-DMP solubility (238.5 g/100 g) was achieved in this case. The interactions and microstructures of [C4C1im]Cl-water mixtures influenced the dissolution behavior of 2,6-DMP.
基金Supported by the Natural Science Foundation of Tianjin,China(No.013802911).
文摘A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Or3+, and the relevant purifying mechanism was also addressed. In detail, organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes. However, for heavy metal ions (Cu2+, Cr3+), part was removed by electrodeposition, and some was adsorbed on biofilm. In order to compare with the combined process of micro electrolysis and biofilm, the experimental data of micro electrolysis process (intermittent) or biofilm process (continuous) were provided, and the kinetic data of C6H12O6 (glucose) biodegradation by cultured microbes or acclimated microbes were also obtained. These experimental results indicated that for wastewater initially consisted of CeH12O6 (500mg-L-1), Cu2+ and Cr3+ (10mg-L-1), after treatment, its concentrations of C6H12O6, Cu2+ and Cr3+ were lowered to the level of 55-65mg.L^1, and less than 1mg-L-1, respectively. And the industrial reused water standards could be met by treated wastewater.
文摘Recently ionic liquids(ILs) are introduced as novel dual function gas hydrate inhibitors. However, no desired gas hydrate inhibition has been reported due to poor IL selection and/or tuning method. Trial & error as well as selection based on existing literature are the methods currently employed for selecting and/or tuning ILs. These methods are probabilistic, time consuming, expensive and may not result in selecting high performance ILs for gas hydrate mitigation. In this work, COSMO-RS is considered as a prescreening tool of ILs for gas hydrate mitigation by predicting the hydrogen bonding energies(E_(HB)) of studied IL inhibitors and comparing the predicted E_(HB) to the depression temperature(?) and induction time. Results show that, predicted EHBand chain length of ILs strongly relate and significantly affect the gas hydrate inhibition depression temperature but correlate moderately(R = 0.70) with average induction time in literature. It is deduced from the results that, ? increases with increasing IL EHBand/or decreases with increasing chain length. However, the cation–anion pairing of ILs also affects IL gas hydrate inhibition performance. Furthermore, a visual and better understanding of IL/water behavior for gas hydrate inhibition in terms of hydrogen bond donor and acceptor interaction analysis is also presented by determining the sigma profile and sigma potential of studied IL cations and anions used for gas hydrate mitigation for easy IL selection.
基金Supported by the National Natural Science Foundation of China (20976040)Science and Technology Planning Project of Hunan Province of China (2009SK3036)
文摘Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux (J) and tungsten rejection coefficient (R) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mg·L-1 . The decomplexation percentage of tungsten (Ⅵ)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (Ⅵ) can be extracted effectively by using 50 mg·L-1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (Ⅵ) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.
文摘Sodium bis[N-2-oxyphenyl-5-substituted-salicylideneiminato-ONO]ruthenate(Ⅲ) hemitriethylamine compounds of general formula Na[Ru(N-R-5-X-salim)2]'0.5Et3N, where, R = C6H40, X = El, Br, NO2, salim = salicylideneiminato, Et3N triethylamine, were synthesized and characterized on the basis of elemental analysis, MALDI-TOF (matrix-assisted laser desorption/ionization/time-of-flight) mass spectra, IH NMR (nuclear magnetic resonance), electronic spectra and cyclic voltammograms. Ru(Ⅲ) is chelated with two O2N anionic tridentate Schiff bases derived from 5-X-salicyladehyde and 2-aminophenol. Spectroscopic titrations of the Ru(Ⅲ) compounds with CT DNA (calf thymus DNA) in the LMCT (ligand metal charge transfer) region have shown moderate intercalation properties of compounds with binding constants KD = 2.06-3.85 × 104 Ml. Electrochemical evidence of intercalative mode of binding is based on the decrease of current and shift of anodic and cathodic peaks towards higher values of potential with IxL-increment of CT DNA in Ru(Ⅲ) compound solution.
文摘AC impedance spectroscopy in pure room temperature ionic liquids (RTILs) and RTIL-water mixture was measured at the temperature of range from 30 ℃ down to -30 ℃. The cations of RTILs are N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium ([DEME]), 1-ethyl-3-methylimidazolium ([C2mim]) and l-butyl-3-methylimidazolium ([Camim]), the anions are tetrafluoroborate ([BF4]) and bis(trifluoromethanesulfonyl)imide ([TFSI]). In all pure RTILs, there are two kinds of local minima in real part of the AC impedance Zreal. By adding water to [DEME][BF4] (0 mol% 〈 x 〈 94 mol%) at room temperature, the local minimum value at higher frequency decreased remarkably at the fixed frequency with increasing water concentration. Above 94 mol% H20, a quite different profile of the AC impedance spectroscopy was obtained. In addition to Zreal. temperature dependence of an imaginary part of the impedance Zimag had an isosbestic point below 94 mol%. The isosbestic point disappeared above 94 mol%. The isosbestic point in Zing reveals an interaction between [DEME][BFa] and H2O.
基金supported by the National Natural Science Foundation of China(21274137,51273190,91027026,and 51033005)the Specialized Research Fund for the Doctoral Program of Higher Education(20123402130010)
文摘We report on the fabrication of fluorescent and multicolor probes for Zn^2+ ions and temperature from a mixture of three types of fluorophore-labeled responsive block copolymers in aqueous media. Quinoline-based Zn^2+-recognizing fluorescent mono- mer ZQMA, red-emitting rhodamine B-based monomer RhBEA, and blue-emitting coumarin derivative Coum-OH, were syn- thesized first. A ZQMA-labeled well-defined double hydrophilic block copolymer (DHBC), PEG-b-P(MEO2MA-co-ZQMA), was synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEOzMA) and ZQMA by utilizing a PEG-based macroRAFT agent. Following similar procedures, PEG-b-P(St-co-RhBEA) amphiphilic diblock copolymer and PEG-b-P(MEOzMA-co-Coum) DHBC were also synthesized, where P(St-co-RhBEA) was a RhBEA-labeled polystyrene (PS) block. At room temperature in aqueous solution, almost non- fluorescent PEG-b-P(MEOzMA-co-ZQMA) can effectively bind Zn2+ ions, leading to prominent green fluorescence enhance- ment due to the coordination of ZQMA with Zn^2+ ions. However, by mixing red-emitting PEG-b-P(St-co-RhBEA) and blue-emitting PEG-b-P(MEO2MA-co-Coum) with PEG-b-P(MEO2MA-co-ZQMA) at an appropriate ratio, three color transitions could be observed. In the absence of Zn^2+ ions, a mixed pink fluorescent originating from Coum and RhBEA was ob- served; upon the addition of a certain amount of Zn^2+ ions, the green fluorescence enhanced dramatically, leading to a white fluorescence readout. By further increasing the amount of Zn2+ ions, the green fluorescence further enhanced and overwhelmed the blue and red emissions, leading to a green-dominant mixed-fluorescence emission. In addition, upon increasing the temperature, the fluorescence of Coum decreased considerably due to the fluorescence-resonance energy transfer (FRET) between Coum and ZQMA moieties. In this way, a ratiometric fluorescent thermometer can be constructed.
基金financially supported by the National Natural Science Foundation of China(91122007)the Specialized Research Fund for the Doctoral Program of Higher Education(20110211130002)
文摘Reported here is a water-soluble ligand, N-(sulfoethyl)-iminodiacetic acid (H3SEIDA), used for the complexation of uranyl ions. A coordination compound composed of uranyl cation and N-(sulfonatoethyl)-ammoniodiacetate (SEADA2-) zwitterion was synthesized from an acidic aqueous solution. This compound features a 2D undulating fes (4.82) coordination layer that is stacked and linked by hydrogen-bonding interaction to form a 3D supramolecular framework with a 1D larger-cycle channel. Thermal analysis demonstrates the relatively weak bonding between uranyl cation and SEADA2 zwitterion. The monomeric uranyl-based fluorescence emission is red-shifted by about thermal synthesis of this uranyl compound was successfully 5 nm compared to that of uranyl nitrate hexahydrate. The hydro- applied to the sequestration of uranyl ions.
基金supported by the Ecole Polytechnique Fédérale de Lausanne and the Iranian Ministry of Science,Research and Technology(to S.G.-E.)
文摘Palladium nanoparticles immobilized on a cross-linked imidazolium-containing polymer were evaluated as a catalyst for Suzuki carbon-carbon cross-coupling reactions using water as the solvent. The nanocatalysts show good catalytic activities for aryl iodides and aryl bromides and moderate activity with aryl chloride substrates. Coupling of sterically hindered substrates could also be achieved in reasonable yields. The heterogeneous catalyst is stable, can be stored without precautions to exclude air or moisture, and can be easily recycled and reused.