An apparatus based on collinear tandem time-of-flight mass spectrometer has been designed for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase.The ions from a pulsed la...An apparatus based on collinear tandem time-of-flight mass spectrometer has been designed for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase.The ions from a pulsed laser vaporization supersonic ion source are skimmed and mass separated by a Wiley-McLaren time-of-flight mass spectrometer.The ion of interest is mass selected,decelerated and dissociated by a tunable IR laser.The fragment and parent ions are reaccelerated and mass analyzed by the second time-of-flight mass spectrometer.A simple new assembly integrated with mass gate,deceleration and reacceleration ion optics was designed,which allows us to measure the infrared spectra of mass selected ions with high sensitivity and easy timing synchronization.展开更多
To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-s...To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.展开更多
A new tetraphenylethylene-cyclodextrin (TPE-CD) conjugate with a linkage composed of long triethylene glycol chain and triazole ring on the CD rim has been designed and synthesized. The TPE-CD conjugate exists in a st...A new tetraphenylethylene-cyclodextrin (TPE-CD) conjugate with a linkage composed of long triethylene glycol chain and triazole ring on the CD rim has been designed and synthesized. The TPE-CD conjugate exists in a stretched form in DMSO and enhances its fluorescence after addition of a small amount of water due to aggregation-induced emission (AIE) effect. However, in the presence of a large amount of water, the TPE unit will enter the cyclodextrin cavity to form a folded self-inclusion compound. In the self-inclusion compound, not only nitrogen-containing pseudo-crown ether is formed but also arouses photo-induced electron transfer (PET) process from nitrogen atoms of triazole ring to TPE unit and quenches the fluorescence although more aggregation occurs in more water. This is the first finding that TPE-macrocycle conjugate can form pseudo-crown ether and has both the AIE phenomenon and the PET effect. Interestingly, only mercury ion arouses the fluorescence recover of the self-inclusion compound by entering the pseudo-crown ether cavity and blocking the PET process by binding to the nitrogen atoms, while other tested metal ions almost have no effect on the fluorescence. Therefore, the TPE-CD conjugate can be used for the highly selective fluorescence "Turn-On" detection of Hg^(2+).展开更多
Seawater electrolysis is promising for green hydrogen production, while its application is inhibited by sluggish anodic oxygen evolution reaction (OER) and rapid chloride corrosion‐induced electrode deactivation. Her...Seawater electrolysis is promising for green hydrogen production, while its application is inhibited by sluggish anodic oxygen evolution reaction (OER) and rapid chloride corrosion‐induced electrode deactivation. Herein, we report a conductive and ion‐ selective OER electrocatalyst with a CoFe alloy core and microporous metal‐doped carbon shell. Co/Fe‐N_(4)‐C active sites in the shell optimize the adsorption strength of intermediates and synergize with the metal core to endow the catalyst with high OER activity and selectivity, while the rich ultra‐micropores in the shell demonstrate a significant sieving effect to hinder Cl− transfer, thus protecting the inner Co/Fe‐N_(4)‐C active sites and metal core from Cl− corrosion. The catalyst is assembled in an alkaline seawater electrolyzer with an electrode geometric area of 254 cm^(2) and delivers a current density of 3000 A m^(-2) at 1.85 V for 330 h. Such catalysts can be synthesized in a large batch (100 g), providing sound opportunities for industrial seawater splitting.展开更多
Hyperoside is one of the major components of Hypericum perforatum L. and also present in many plant species such as Abelmoschus manihot （L.） Medik., Ribes nigrum L. and Rosa agrestis Savi （Rosaceae）. Because hyper...Hyperoside is one of the major components of Hypericum perforatum L. and also present in many plant species such as Abelmoschus manihot （L.） Medik., Ribes nigrum L. and Rosa agrestis Savi （Rosaceae）. Because hyperoside exhibits many biological activities, the pharmacokinetics profile of hyperoside needs to be studied for further elucidating its mechanism of action. A simple method for the determination of hyperoside in rat plasma was developed by using ultra-high performance liquid chromatography coupled with mass spectrometry （UPLC-MS）. Only 50 ~tL plasma samples were required for sample preparation. The quantitative detection of hyperoside was accomplished by selected ion monitoring （SIM） in negative ion mode. Hyperoside was analyzed in less than 10 rain. Good linearity was obtained （r2〉0.999） and the intra- and inter-day precision of the method were lower than 15%. Lower limit of quantification （LLOQ） was 4 ng/mL for hyperoside in rat plasma. Our method showed advantage in the lower LLOQ compared with the reported method; furthermore, smaller amount of plasma was needed. The method was successfully applied for the pharmacokinetics study of hyperoside in rat after intravenous administration of hyperoside.展开更多
Determination of hexachlorobenzene (HCB) in the solvent red 135 by solvent extraction GC-MS with selected ion monitoring mode.The result showed that the detection limit is 0.05 mg/kg.The relative standard deviation is...Determination of hexachlorobenzene (HCB) in the solvent red 135 by solvent extraction GC-MS with selected ion monitoring mode.The result showed that the detection limit is 0.05 mg/kg.The relative standard deviation is 3.3%.This method is suitable for the analysis of the HCB in the solvent red 135.展开更多
The ion selectivity of electrodeposited nickel hexacyanoferrate （NiHCF） thin films was investigated using electrochemical impedance spectroscopy （EIS） and cyclic voltammetry （CV）. NiHCF thin films were prepared ...The ion selectivity of electrodeposited nickel hexacyanoferrate （NiHCF） thin films was investigated using electrochemical impedance spectroscopy （EIS） and cyclic voltammetry （CV）. NiHCF thin films were prepared by cathodic deposition on Pt and Al substrates. EIS and CV curves were determined in 1 mol/L （KNO3＋C5NO3） and 1 mol/L （NaNO3＋CsNO3） mixture solutions, which were sensitive to the concentration of Cs^＋ in the electrolytes. Experimental results show that all Nyquist impedance plots show depressed semicircles in the high-frequency range changing over into straight lines at lower frequencies. With increasing amounts of Cs^＋, the redox potentials in CV curves shift toward more positive values and the redox peaks broaden; the semicircle radius in corresponding EIS curves and the charge transfer resistance also increase. EIS combining CV is able to provide valuable insights into the ion selectivity of NiHCF thin films. 2008 University of Science and Technology Beijing. All rights reserved.展开更多
Vanadium redox flow battery(VRB),as the most promising large-scale electrical energy storage units,has attracted extensive attention.Amphoteric ion exchange membrane(AIEM),as the core part of VRB,separates electrolyte...Vanadium redox flow battery(VRB),as the most promising large-scale electrical energy storage units,has attracted extensive attention.Amphoteric ion exchange membrane(AIEM),as the core part of VRB,separates electrolyte on both sides of electrolytic tank and conducts H+.The AIEM with cation and anion groups possesses excellent performances,such as high ion conductivity(σ),low vanadium ion permeability(Pvn+),relative stability and low cost.However,the performance of AIEM directly depends on the chemical structure of polymers.In addition to ensuring foundational physical performance,ion selectivity of AIEM is significant since the crossover of vanadium ion with various valences may reduce the battery capacity.In this paper,AIEMs for VRB and their chemical structures as well as synthesis approaches to realize all kinds of high-performing AIEMs are reviewed.The current trend and future direction of prospective materials for the VRB separators are documented in detail as well.展开更多
The textile industry spreads globally with the challenges of its wastewater treatment,especially dyes,which are difficult to degrade.To improve coagulation-flocculation process in dye wastewater treatment,an intercala...The textile industry spreads globally with the challenges of its wastewater treatment,especially dyes,which are difficult to degrade.To improve coagulation-flocculation process in dye wastewater treatment,an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride(LiBH_(4)_FeOCl) in this study.The layered crystal pristine iron oxychloride(FeOCl) material was prepared by chemical gas phase migration.LiBH4 was introduced into the layers of two dimensional(2 D) FeOCl nanosheets by a simple method of liquid phase insertion.The samples were characterized by a field emitting scanning electron microscopy(SEM),a rotating anode X-ray powder diffractometer(XRD),etc.The cationic dye was employed as the simulated pollutant.A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH_(4)_FeOCl.It is found that the intercalation modified LiBH_(4)_FeOCl exhibits the characteristics of crystal structure,and the layered structure of FeOCl is preserved.LiBH_(4)_FeOCl,as an insoluble inorganic solid coagulant,performs well for dye pollutants of methyl red,basic yellow 1,methylene blue,rhodamine B,ethyl violet and Janus green B.The reaction rate is significantly 68% higher than the current commercial coagulants of Al_(2)(SO_(4))_(3).The mechanism analysis reveals that LiBH_(4)_FeOCl breaks and disperses rapidly in the water environment.Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action.The above collaborative actions of breaking,dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH_(4)_FeOCl.The solid inorganic coagulant of LiBH4FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.展开更多
There is an urgent need to break through the trade-off between proton conductivity and ion selectivity of proton exchange membrane(PEM)in vanadium flow battery(VFB).Proton channels in PEM are the key to controlling th...There is an urgent need to break through the trade-off between proton conductivity and ion selectivity of proton exchange membrane(PEM)in vanadium flow battery(VFB).Proton channels in PEM are the key to controlling the ion sieving and proton conductivity in VFB.Herein,two types of proton channels are reconstructed in the hybrid membrane via introducing modified Zr-MOFs(IM-UIO-66-AS)into SPEEK matrix.Internal proton channels in IM-UIO-66-AS and interfacial proton channels between grafted imidazole groups on Zr-MOFs and SPEEK greatly improve the conductivity of the IM-UIO-66-AS/SPEEK hybrid membrane.More importantly,both reconstructed proton channels block the vanadium-ion permeation to realize enhanced ion selectivity according to the size sieving and Donnan exclusion effects,respectively.Moreover,the hybrid membrane exhibits good mechanical property and dimensional stability.Benefiting from such rational design,a VFB loading with the optimized membrane exhibits enhanced voltage efficiency of 79.9%and outstanding energy efficiency of 79.6%at 200 m A cm^(-2),and keeps a notable cycle stability for 300 cycles in the long-term cycling test.Therefore,this study provides inspiration for preparing next-generation PEMs with high ion selectivity and proton conductivity for VFB application.展开更多
Tetracycline selective electrode using molecularly imprinted polymer particles as quasi-ionophore was constructed the first time, and its performance was carefully characterized. Due to the specific recognition of tet...Tetracycline selective electrode using molecularly imprinted polymer particles as quasi-ionophore was constructed the first time, and its performance was carefully characterized. Due to the specific recognition of tetracycline by the particles, the selectivity coefficients for routine interferences were less than 10-4. Benefited from the absence of tetracycline in the sensitive membrane and the optimized composition of the inner filling solution, the limit of detection of the electrode was reduced to about 2.5 × 10^-8 mol/ L. It exhibited a good electrode slope 57.6 mV/decade near the theoretical Nernstian one, with a wide linear working range from 6.0 × 10^-8 to 1.0 × 10^-3 mol/L. The fabricated electrode should be used in pH 2--4, response time of which was less than 200 s when the concentration of tetracycline was higher than 1.0 × 10^-6 mol/L and no more than 30 min at the concentration of 1.0 × 10^-8 mol/L.展开更多
We report near-zero crossover for vanadium cross-permeation through single-layer graphene immobilized at the interface of two Nafion?polymer electrolyte membranes.Vanadium ion diffusion and migration,including proton ...We report near-zero crossover for vanadium cross-permeation through single-layer graphene immobilized at the interface of two Nafion?polymer electrolyte membranes.Vanadium ion diffusion and migration,including proton mobility through membrane composites,were studied with and without graphene under diffusion and migration conditions.Single-layer graphene was found to effectively inhibit vanadium ion diffusion and migration under specific conditions.The single-layer graphene composites also enabled remarkable ion transmission selectivity improvements over pure Nafion membranes,with proton transport being four orders of magnitude faster than vanadium ion transport.Resistivity values of 0.02±0.005Ωcm^(2) for proton and 223±4Ωcm^(2) for vanadium ion through single atomic layer graphene are reported.This high selectivity may have significant impact on flow battery applications or for other electrochemical devices where proton conductivity is required,and transport of other species is detrimental.Our results emphasize that crossover may be essentially completely eliminated in some cases,enabling for greatly improved operational viability.展开更多
The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divale...The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.展开更多
It is a problem to be solved that the experimental selectivity coefficients of ion selective electrodes (ISEs) depend on the activity. This paper studied the new method of determining selectivity coefficients. A mix...It is a problem to be solved that the experimental selectivity coefficients of ion selective electrodes (ISEs) depend on the activity. This paper studied the new method of determining selectivity coefficients. A mixed ion response equation, which was similar to Nicolsky-Eisenman (N-E) equation recommended by IUPAC, was proposed. The equation includes the practical response slope of ISEs to the primary ion and the interfering ion. The selectivity coefficient was defined by the equation instead of the N-E equation. The experimental part of the method is similar to that based on the N-E equation. The values of selectivity coefficients obtained with this method do not depend on the activity whether the electrodes exhibit the Nernst response or non-Nernst response. The feasibility of the new method is illustrated experimentally.展开更多
A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride...A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride. The simulation indicated that the permissible aluminum masked at a certain p H value was limited and hardly related to F-concentration and boric acid. It is better to control p H value below 11.5 and the aluminum concentration within 0.025 mol/L to minimize the interference of hydroxide to the fluoride ISE. The decomposition conditions of boron trifluoride by aluminum chloride were investigated. It is found that the F-detection ratio will approach 1.0 if the Al/F molar ratio is 0.3—0.7 and aluminum concentration is no more than 0.02 mol/L when heated at 80 ℃ for 10 min. In one word, hydroxide is quite fit to mask aluminum for samples which contain high content of fluoride and aluminum and the BF3 content can be successfully determined by this method.展开更多
A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) me...A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) membrane electrode containing an amide derivative of ca lixarene as the neutral carrier an d a dibutyl phthalate as the plastici zer exhibited the highest sensitivity for dibenzoyl tartaric acid. The slop e of linear portion was 27.8 mV per c oncertration decade. The electrode has a fast response and a long lifetime .展开更多
Two novel heteroatom-bridged his (benzo-12-crown-4 ether)s, i.e. his [2-nitro-4,5 (1,4,7,10-tetraoxadecamethylene) disulfide 1 and diselenide 2, have been synthesized. X ray crystallographic structure was obtained for...Two novel heteroatom-bridged his (benzo-12-crown-4 ether)s, i.e. his [2-nitro-4,5 (1,4,7,10-tetraoxadecamethylene) disulfide 1 and diselenide 2, have been synthesized. X ray crystallographic structure was obtained for 1. Ion selective electrodes (ISE) for Ag+, containing 1 and 2 in PVC membrane as neutral carriers, were prepared, and their selectivity coefficients for Ag^+ (K_(Ag.M)^(pot)) were determined against other heavy metal ions, alkali and alkaline-earth metal ions. and ammonium ion. These ISEs showed excellent Ag^+ selectivities, log K_(Ag.M)^(pot) ≤ -3.8, against most of the interfering canons examined, except for Hg^+.展开更多
Three novel amprolium HCl（AMP）-selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride（PVC）. Sensor I was fabricated using potassium tetra...Three novel amprolium HCl（AMP）-selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride（PVC）. Sensor I was fabricated using potassium tetrakis（4-chlorophenyl） borate（Tp ClPB） as a cationic exchanger without incorporation of an ionophore.Sensor Ⅱ used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor Ⅲ used p-tert-butylcalix[8]arene as an ionophore. The three proposed sensors showed Nernestian response slopes of 29.2±0.8,29.3±0.6 and 30.2±0.4 m V/decade over the concentration range from 10–6 to 10–2 mol L_（-1）,respectively. The proposed sensors displayed useful analytical characteristics for the determination of AMP in bulk powder, different pharmaceutical formulations, and chicken liver and in the presence of ethopabate. The proposed method was validated according to ICH guidelines for its linearity, accuracy,precision and robustness.展开更多
Monovalent cation perm-selective membrane(MCPMs)allow fast and selective transport of monovalent cations,and they are promisingly required for extraction of special ions,such as lithium extraction,acid recovery and se...Monovalent cation perm-selective membrane(MCPMs)allow fast and selective transport of monovalent cations,and they are promisingly required for extraction of special ions,such as lithium extraction,acid recovery and sea salt production.Herein,we report a novel strategy to design the critical functional layers of MCPMs with both space charge repulsion and cross-linked dense screenability.The in-situ depo-sition polymerization of pyrrole was carried out on the surface of sulfonated polyphenyl sulfone(SPPSU)substrate membrane followed by cross-linking quaternization of the polypyrrole(PPy)layer with diiodi-nated functional molecules,thus,the membrane obtained more excellent selective permeability and sta-ble transport properties of monovalent cations.It confirms that the designed PPy layers with charged sur-face and cross-linking structure improved the hydrophilicity,facilitated cation transport and increased ion flux.Meanwhile,for the dense PPy layer,the charged cross-linked structure endowed the functional layer with the synergistic characteristics of Donnan exclusion and pore size sieving for positively charged ions,which improved the monovalent cation perm-selectivity of the membranes.At a constant current density of 5.1 mA/cm^(2),the optimal membrane exhibited superior perm-selectivity(P^(Na)_(Mg)=2.07)and monovalent cation flux(J_(Na+)=2.80×10^(−8)mol cm^(−2)s^(−1))during electrodialysis.展开更多
基金supported by the Ministry of Science and Technology of China(2013CB834603,2012YQ220113-3,and 2011YQ06010003)the National Natural Science Foundation of China(21273045 and 20933030)the Committee of Science and Technology of Shanghai(13XD1400800)
文摘An apparatus based on collinear tandem time-of-flight mass spectrometer has been designed for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase.The ions from a pulsed laser vaporization supersonic ion source are skimmed and mass separated by a Wiley-McLaren time-of-flight mass spectrometer.The ion of interest is mass selected,decelerated and dissociated by a tunable IR laser.The fragment and parent ions are reaccelerated and mass analyzed by the second time-of-flight mass spectrometer.A simple new assembly integrated with mass gate,deceleration and reacceleration ion optics was designed,which allows us to measure the infrared spectra of mass selected ions with high sensitivity and easy timing synchronization.
基金The National Key Basic Research Program (973) of China (No. 2002CB410808) and CAS Research Program on Soil Biosystems andAgro-Product Safety (No. CXTD-Z2005-4-1)
文摘To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.
基金National Natural Science Foundation of China(Nos. 91856125 and 21673089)HUST Graduate Innovation Fund for financial support。
文摘A new tetraphenylethylene-cyclodextrin (TPE-CD) conjugate with a linkage composed of long triethylene glycol chain and triazole ring on the CD rim has been designed and synthesized. The TPE-CD conjugate exists in a stretched form in DMSO and enhances its fluorescence after addition of a small amount of water due to aggregation-induced emission (AIE) effect. However, in the presence of a large amount of water, the TPE unit will enter the cyclodextrin cavity to form a folded self-inclusion compound. In the self-inclusion compound, not only nitrogen-containing pseudo-crown ether is formed but also arouses photo-induced electron transfer (PET) process from nitrogen atoms of triazole ring to TPE unit and quenches the fluorescence although more aggregation occurs in more water. This is the first finding that TPE-macrocycle conjugate can form pseudo-crown ether and has both the AIE phenomenon and the PET effect. Interestingly, only mercury ion arouses the fluorescence recover of the self-inclusion compound by entering the pseudo-crown ether cavity and blocking the PET process by binding to the nitrogen atoms, while other tested metal ions almost have no effect on the fluorescence. Therefore, the TPE-CD conjugate can be used for the highly selective fluorescence "Turn-On" detection of Hg^(2+).
基金Funding provided by the National Key R&D Program of China(Grant No.2021YFB3801301)National Natural Science Foundation of China(Grant Nos.22378119,22075076,and 22208092)the Key R&D Plan for Science and Technology in Huai'an City(Industrial Category,HAG202301).
文摘Seawater electrolysis is promising for green hydrogen production, while its application is inhibited by sluggish anodic oxygen evolution reaction (OER) and rapid chloride corrosion‐induced electrode deactivation. Herein, we report a conductive and ion‐ selective OER electrocatalyst with a CoFe alloy core and microporous metal‐doped carbon shell. Co/Fe‐N_(4)‐C active sites in the shell optimize the adsorption strength of intermediates and synergize with the metal core to endow the catalyst with high OER activity and selectivity, while the rich ultra‐micropores in the shell demonstrate a significant sieving effect to hinder Cl− transfer, thus protecting the inner Co/Fe‐N_(4)‐C active sites and metal core from Cl− corrosion. The catalyst is assembled in an alkaline seawater electrolyzer with an electrode geometric area of 254 cm^(2) and delivers a current density of 3000 A m^(-2) at 1.85 V for 330 h. Such catalysts can be synthesized in a large batch (100 g), providing sound opportunities for industrial seawater splitting.
文摘Hyperoside is one of the major components of Hypericum perforatum L. and also present in many plant species such as Abelmoschus manihot （L.） Medik., Ribes nigrum L. and Rosa agrestis Savi （Rosaceae）. Because hyperoside exhibits many biological activities, the pharmacokinetics profile of hyperoside needs to be studied for further elucidating its mechanism of action. A simple method for the determination of hyperoside in rat plasma was developed by using ultra-high performance liquid chromatography coupled with mass spectrometry （UPLC-MS）. Only 50 ~tL plasma samples were required for sample preparation. The quantitative detection of hyperoside was accomplished by selected ion monitoring （SIM） in negative ion mode. Hyperoside was analyzed in less than 10 rain. Good linearity was obtained （r2〉0.999） and the intra- and inter-day precision of the method were lower than 15%. Lower limit of quantification （LLOQ） was 4 ng/mL for hyperoside in rat plasma. Our method showed advantage in the lower LLOQ compared with the reported method; furthermore, smaller amount of plasma was needed. The method was successfully applied for the pharmacokinetics study of hyperoside in rat after intravenous administration of hyperoside.
文摘Determination of hexachlorobenzene (HCB) in the solvent red 135 by solvent extraction GC-MS with selected ion monitoring mode.The result showed that the detection limit is 0.05 mg/kg.The relative standard deviation is 3.3%.This method is suitable for the analysis of the HCB in the solvent red 135.
基金the National Natural Science Foundation of China(No.20676089)the Scholar Council Foundation of Shanxi Province,China(No.2004-24).
文摘The ion selectivity of electrodeposited nickel hexacyanoferrate （NiHCF） thin films was investigated using electrochemical impedance spectroscopy （EIS） and cyclic voltammetry （CV）. NiHCF thin films were prepared by cathodic deposition on Pt and Al substrates. EIS and CV curves were determined in 1 mol/L （KNO3＋C5NO3） and 1 mol/L （NaNO3＋CsNO3） mixture solutions, which were sensitive to the concentration of Cs^＋ in the electrolytes. Experimental results show that all Nyquist impedance plots show depressed semicircles in the high-frequency range changing over into straight lines at lower frequencies. With increasing amounts of Cs^＋, the redox potentials in CV curves shift toward more positive values and the redox peaks broaden; the semicircle radius in corresponding EIS curves and the charge transfer resistance also increase. EIS combining CV is able to provide valuable insights into the ion selectivity of NiHCF thin films. 2008 University of Science and Technology Beijing. All rights reserved.
基金the National Natural Science Foundation of China(Nos.51503187,21504037 and 51603194)the National key R&D Project(No.2016YFE0102700)+3 种基金the Shanxi provincial foundation for science and technology research(Nos.201601D021058,201701D221050,20181101006,20181102019)Partial support is also from the NIMHD-RCMI grant number 5G12MD007595 from the National Institute of Minority HealthHealth Disparities and the NIGMS-BUILD(No.8UL1GM118967)National Science Foundation(No.1700429)。
文摘Vanadium redox flow battery(VRB),as the most promising large-scale electrical energy storage units,has attracted extensive attention.Amphoteric ion exchange membrane(AIEM),as the core part of VRB,separates electrolyte on both sides of electrolytic tank and conducts H+.The AIEM with cation and anion groups possesses excellent performances,such as high ion conductivity(σ),low vanadium ion permeability(Pvn+),relative stability and low cost.However,the performance of AIEM directly depends on the chemical structure of polymers.In addition to ensuring foundational physical performance,ion selectivity of AIEM is significant since the crossover of vanadium ion with various valences may reduce the battery capacity.In this paper,AIEMs for VRB and their chemical structures as well as synthesis approaches to realize all kinds of high-performing AIEMs are reviewed.The current trend and future direction of prospective materials for the VRB separators are documented in detail as well.
基金financial supports by the National Key Basic Research Program of China (No.2019YFC1906700)National Natural Science Foundation of China (Nos.21876049,51878643)University of Shanghai for Science and Technology (Grant Agreement No.ZR18PY01)。
文摘The textile industry spreads globally with the challenges of its wastewater treatment,especially dyes,which are difficult to degrade.To improve coagulation-flocculation process in dye wastewater treatment,an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride(LiBH_(4)_FeOCl) in this study.The layered crystal pristine iron oxychloride(FeOCl) material was prepared by chemical gas phase migration.LiBH4 was introduced into the layers of two dimensional(2 D) FeOCl nanosheets by a simple method of liquid phase insertion.The samples were characterized by a field emitting scanning electron microscopy(SEM),a rotating anode X-ray powder diffractometer(XRD),etc.The cationic dye was employed as the simulated pollutant.A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH_(4)_FeOCl.It is found that the intercalation modified LiBH_(4)_FeOCl exhibits the characteristics of crystal structure,and the layered structure of FeOCl is preserved.LiBH_(4)_FeOCl,as an insoluble inorganic solid coagulant,performs well for dye pollutants of methyl red,basic yellow 1,methylene blue,rhodamine B,ethyl violet and Janus green B.The reaction rate is significantly 68% higher than the current commercial coagulants of Al_(2)(SO_(4))_(3).The mechanism analysis reveals that LiBH_(4)_FeOCl breaks and disperses rapidly in the water environment.Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action.The above collaborative actions of breaking,dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH_(4)_FeOCl.The solid inorganic coagulant of LiBH4FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.
基金supported by the National Natural Science Foundation of China(Grant No.21975267)the Central Guidance on Local Science and Technology Development Fund of Liaoning Province(No:2022JH6/100100001)。
文摘There is an urgent need to break through the trade-off between proton conductivity and ion selectivity of proton exchange membrane(PEM)in vanadium flow battery(VFB).Proton channels in PEM are the key to controlling the ion sieving and proton conductivity in VFB.Herein,two types of proton channels are reconstructed in the hybrid membrane via introducing modified Zr-MOFs(IM-UIO-66-AS)into SPEEK matrix.Internal proton channels in IM-UIO-66-AS and interfacial proton channels between grafted imidazole groups on Zr-MOFs and SPEEK greatly improve the conductivity of the IM-UIO-66-AS/SPEEK hybrid membrane.More importantly,both reconstructed proton channels block the vanadium-ion permeation to realize enhanced ion selectivity according to the size sieving and Donnan exclusion effects,respectively.Moreover,the hybrid membrane exhibits good mechanical property and dimensional stability.Benefiting from such rational design,a VFB loading with the optimized membrane exhibits enhanced voltage efficiency of 79.9%and outstanding energy efficiency of 79.6%at 200 m A cm^(-2),and keeps a notable cycle stability for 300 cycles in the long-term cycling test.Therefore,this study provides inspiration for preparing next-generation PEMs with high ion selectivity and proton conductivity for VFB application.
基金Financial supports from Ningbo Science and Technology Bureau(No.2007C10061)Department of Education of Zhejiang Province(No.20070963)Science and Technology Department of Zhejiang Province of China(No. 2008R40G2070056) are gratefully acknowledged
文摘Tetracycline selective electrode using molecularly imprinted polymer particles as quasi-ionophore was constructed the first time, and its performance was carefully characterized. Due to the specific recognition of tetracycline by the particles, the selectivity coefficients for routine interferences were less than 10-4. Benefited from the absence of tetracycline in the sensitive membrane and the optimized composition of the inner filling solution, the limit of detection of the electrode was reduced to about 2.5 × 10^-8 mol/ L. It exhibited a good electrode slope 57.6 mV/decade near the theoretical Nernstian one, with a wide linear working range from 6.0 × 10^-8 to 1.0 × 10^-3 mol/L. The fabricated electrode should be used in pH 2--4, response time of which was less than 200 s when the concentration of tetracycline was higher than 1.0 × 10^-6 mol/L and no more than 30 min at the concentration of 1.0 × 10^-8 mol/L.
文摘We report near-zero crossover for vanadium cross-permeation through single-layer graphene immobilized at the interface of two Nafion?polymer electrolyte membranes.Vanadium ion diffusion and migration,including proton mobility through membrane composites,were studied with and without graphene under diffusion and migration conditions.Single-layer graphene was found to effectively inhibit vanadium ion diffusion and migration under specific conditions.The single-layer graphene composites also enabled remarkable ion transmission selectivity improvements over pure Nafion membranes,with proton transport being four orders of magnitude faster than vanadium ion transport.Resistivity values of 0.02±0.005Ωcm^(2) for proton and 223±4Ωcm^(2) for vanadium ion through single atomic layer graphene are reported.This high selectivity may have significant impact on flow battery applications or for other electrochemical devices where proton conductivity is required,and transport of other species is detrimental.Our results emphasize that crossover may be essentially completely eliminated in some cases,enabling for greatly improved operational viability.
基金supported by the Fundamental Research Funds for the Central Universities(WK2060000030)USTC Research Funds of the Double First Class Initiative(YD2060002022)Major Science and Technology Innovation Projects in Shandong Province(2022CXGC020415).
文摘The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.
文摘It is a problem to be solved that the experimental selectivity coefficients of ion selective electrodes (ISEs) depend on the activity. This paper studied the new method of determining selectivity coefficients. A mixed ion response equation, which was similar to Nicolsky-Eisenman (N-E) equation recommended by IUPAC, was proposed. The equation includes the practical response slope of ISEs to the primary ion and the interfering ion. The selectivity coefficient was defined by the equation instead of the N-E equation. The experimental part of the method is similar to that based on the N-E equation. The values of selectivity coefficients obtained with this method do not depend on the activity whether the electrodes exhibit the Nernst response or non-Nernst response. The feasibility of the new method is illustrated experimentally.
基金Supported by the Independent Innovation Fund of Tianjin University(No.1307)
文摘A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride. The simulation indicated that the permissible aluminum masked at a certain p H value was limited and hardly related to F-concentration and boric acid. It is better to control p H value below 11.5 and the aluminum concentration within 0.025 mol/L to minimize the interference of hydroxide to the fluoride ISE. The decomposition conditions of boron trifluoride by aluminum chloride were investigated. It is found that the F-detection ratio will approach 1.0 if the Al/F molar ratio is 0.3—0.7 and aluminum concentration is no more than 0.02 mol/L when heated at 80 ℃ for 10 min. In one word, hydroxide is quite fit to mask aluminum for samples which contain high content of fluoride and aluminum and the BF3 content can be successfully determined by this method.
文摘A new type of di benzoyl tartaric acid selective electr ode has been developed. Three double\| arm calixarene derivatives were emp loyed as the neutral ionophores. The poly(vinyl chloride) membrane electrode containing an amide derivative of ca lixarene as the neutral carrier an d a dibutyl phthalate as the plastici zer exhibited the highest sensitivity for dibenzoyl tartaric acid. The slop e of linear portion was 27.8 mV per c oncertration decade. The electrode has a fast response and a long lifetime .
文摘Two novel heteroatom-bridged his (benzo-12-crown-4 ether)s, i.e. his [2-nitro-4,5 (1,4,7,10-tetraoxadecamethylene) disulfide 1 and diselenide 2, have been synthesized. X ray crystallographic structure was obtained for 1. Ion selective electrodes (ISE) for Ag+, containing 1 and 2 in PVC membrane as neutral carriers, were prepared, and their selectivity coefficients for Ag^+ (K_(Ag.M)^(pot)) were determined against other heavy metal ions, alkali and alkaline-earth metal ions. and ammonium ion. These ISEs showed excellent Ag^+ selectivities, log K_(Ag.M)^(pot) ≤ -3.8, against most of the interfering canons examined, except for Hg^+.
文摘Three novel amprolium HCl（AMP）-selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride（PVC）. Sensor I was fabricated using potassium tetrakis（4-chlorophenyl） borate（Tp ClPB） as a cationic exchanger without incorporation of an ionophore.Sensor Ⅱ used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor Ⅲ used p-tert-butylcalix[8]arene as an ionophore. The three proposed sensors showed Nernestian response slopes of 29.2±0.8,29.3±0.6 and 30.2±0.4 m V/decade over the concentration range from 10–6 to 10–2 mol L_（-1）,respectively. The proposed sensors displayed useful analytical characteristics for the determination of AMP in bulk powder, different pharmaceutical formulations, and chicken liver and in the presence of ethopabate. The proposed method was validated according to ICH guidelines for its linearity, accuracy,precision and robustness.
基金supported by the Public Welfare Project of the Science and Technology Committee of Zhejiang Province(No.LGF20B060002)the China Postdoctoral Science Foundation funded project(No.2016M601964)+1 种基金Provincial Key R&D Program of Zhe-jiang Province(No.2019C03094)the National Natural Science Foundation of China(Nos.22075246 and 21776253).
文摘Monovalent cation perm-selective membrane(MCPMs)allow fast and selective transport of monovalent cations,and they are promisingly required for extraction of special ions,such as lithium extraction,acid recovery and sea salt production.Herein,we report a novel strategy to design the critical functional layers of MCPMs with both space charge repulsion and cross-linked dense screenability.The in-situ depo-sition polymerization of pyrrole was carried out on the surface of sulfonated polyphenyl sulfone(SPPSU)substrate membrane followed by cross-linking quaternization of the polypyrrole(PPy)layer with diiodi-nated functional molecules,thus,the membrane obtained more excellent selective permeability and sta-ble transport properties of monovalent cations.It confirms that the designed PPy layers with charged sur-face and cross-linking structure improved the hydrophilicity,facilitated cation transport and increased ion flux.Meanwhile,for the dense PPy layer,the charged cross-linked structure endowed the functional layer with the synergistic characteristics of Donnan exclusion and pore size sieving for positively charged ions,which improved the monovalent cation perm-selectivity of the membranes.At a constant current density of 5.1 mA/cm^(2),the optimal membrane exhibited superior perm-selectivity(P^(Na)_(Mg)=2.07)and monovalent cation flux(J_(Na+)=2.80×10^(−8)mol cm^(−2)s^(−1))during electrodialysis.
