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
Introduction Peptides made up of alternating L- and D- amino acids can form β-helices as in gramicidin A or cyclic peptides that aggregate to form tubes In both cases the structures are hollow with all the side chai...Introduction Peptides made up of alternating L- and D- amino acids can form β-helices as in gramicidin A or cyclic peptides that aggregate to form tubes In both cases the structures are hollow with all the side chains projecting outwards. Kennedy et al. postulated that. peptides having the (LLLD)n configuration could form helices with every fourth side chain projecting inward. It is a fact that synthetic N-formyl- (LeuSerLeuGly) 6- OH, when added to a lipid bilayer, dimerizes, to form ion channels having conductances greater than that of gramicidin.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
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
Porous graphene has a high mechanical strength and an atomic-layer thickness that makes it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous so...Porous graphene has a high mechanical strength and an atomic-layer thickness that makes it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous solutions are a type of strong long-range interaction that may greatly influence fluid transport through nanopores. In this study, molecular dynamic simulations were conducted to investigate ion and water transport through 1.05-nm diameter monolayer graphene nanopores, with their edges charge-modified. Our results indicated that these nanopores are selective to counterions when they are charged. As the charge amount increases, the total ionic currents show an increase-decrease profile while the coion currents monotonically decrease. The co-ion rejection can reach 76.5% and 90.2% when the nanopores are negatively and positively charged, respectively. The Cl-ion current increases and reaches a plateau, and the Na+current decreases as the charge amount increases in systems in which Na+ions act as counterions. In addition, charge modification can enhance water transport through nanopores. This is mainly due to the ion selectivity of the nanopores. Notably, positive charges on the pore edges facilitate water transport much more strongly than negative charges.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
A novel fibroin modified electrode with ion recognition was reported. The membranewith isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. ThepH-responsive ion recognition of the modifie...A novel fibroin modified electrode with ion recognition was reported. The membranewith isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. ThepH-responsive ion recognition of the modified electrode was investigated by use of someneurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination.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 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
Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadoli...Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadolinium ion selective electrode besides the effects of their structures.1.Effect of preparation process of the grafted polymers on the properties ofgadolinium ion selective electrodesThe electrode membranes which consist of functional polymers as active materials were prepared by re-action of gadolinium chloride with the radiation grafted clmer of acrlic acid and polystyrene of which展开更多
In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- ti...In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.展开更多
In this paper is reported a new method of determining serum albumin with potentiometry. The silver ion selective electrode was used as working electrode and S. C. E as reference electrode. By controlling the ionic s...In this paper is reported a new method of determining serum albumin with potentiometry. The silver ion selective electrode was used as working electrode and S. C. E as reference electrode. By controlling the ionic strength, PH and temperature constant, a good linear relationship was obtained between the cell potential and albumin concentration. This method .possessed characters-of operating simplicity, rapidity and directness. The samples could be detected directly and the results were in accordance with the values detected by classic K method.展开更多
Fluoride is widespread in the environment, water, air, vegetation and Earth’s crust which can entre ground and surface water by natural process. Fluoride in minute quantities is essential component for human health a...Fluoride is widespread in the environment, water, air, vegetation and Earth’s crust which can entre ground and surface water by natural process. Fluoride in minute quantities is essential component for human health and help in normal mineralization of bone and formation of dental enamel. The determination of fluoride in some species was performed by using fluoride ion-selective electrode by direct measurement and standard addition method. The concentration of fluoride ion was determined in drinking water (from different place at Kathmandu), toothpaste, various brand of tea and coffees. The range of fluoride concentration in water sample was 0.16 to 0.39 mg/l, tea and coffee samples were 0.011 to 0.084 mg/l and its value of toothpaste was 0.026 to 0.75 mg/l. The concentration of fluoride ion obtain from different sample was compared with the legitimate value given by the world health organization.展开更多
The percent ammonia nitrogen was determined in Passaic River waste water using Ion-Selective Electrode EPA Method 350.3. The intelligent ammonia sensor integrates ammonia electrode, pH electrode and Ammonia Ion electr...The percent ammonia nitrogen was determined in Passaic River waste water using Ion-Selective Electrode EPA Method 350.3. The intelligent ammonia sensor integrates ammonia electrode, pH electrode and Ammonia Ion electrode together to realize the in situ detection of ammonia. The test results have shown that the sensor is easy operation, low cost and no pollution. The ammonia is determined potentiometrically using an ammonia ion selective electrode and a pH/mV meter, having an expanded millivolt scale. The ammonia selective electrode uses a hydrophobic gas-permeable membrane to separate the sample solution from an electrode internal solution of ammonium chloride. Dissolved ammonia is converted to NH<sub>3</sub> gas by raising the pH to above 11.0 with a strong base. NH<sub>3</sub> gas diffuses the membrane and changes the internal solution pH that is sensed by the electrode. In single laboratory test results have been found 1.001 NH<sub>3</sub>-/L and 0.897 mg NH<sub>3</sub>-N/L, recoveries were 77.3% and 83.1%, respectively.展开更多
Harvesting clean energy from water evaporation has been extensively investigated due to its sustainability.To achieve high efficiency,energy conversion materials should contain multiple features which are difficult to...Harvesting clean energy from water evaporation has been extensively investigated due to its sustainability.To achieve high efficiency,energy conversion materials should contain multiple features which are difficult to be simultaneously obtained from single-component materials.Here we use composite laminar membranes assembled by nanosheets of graphene oxide and mica,and find a sustained power density induced by water evaporation that is two orders of magnitude larger than that from membranes made by either of the components.The power output is attributed to selective proton transport driven by water evaporation through the interlayer nanochannels in the membranes.This process relies on the synergistic effects from negatively charged and hydrophilic mica surfaces that are important for proton selectivity and water transport,and the tunable electrical conductivity of graphene oxide that provides optimized internal resistance.The demonstrated composite membranes offer a strategy of enhancing power generation by combining the advantages from each of their components.展开更多
Plant high-affinity K^(+) transporters(HKTs)mediate Na^(+) and K^(+) uptake,maintain Na^(+)/K^(+) homeostasis,and therefore play crucial roles in plant salt tolerance.In this study,we present cryoelectron microscopy s...Plant high-affinity K^(+) transporters(HKTs)mediate Na^(+) and K^(+) uptake,maintain Na^(+)/K^(+) homeostasis,and therefore play crucial roles in plant salt tolerance.In this study,we present cryoelectron microscopy structures of HKTs from two classes,classI HKT1;1 from Arabidopsis thaliana(AtHKT1;1)and class II HKT2;1 from Triticum aestivum(TaHKT2;1),in both Na^(+) -and K^(+) -bound states at 2.6-to 3.0-A resolutions.BothAtHKT1;1and TaHKT2;1function ashomodimers.Each HKT subunit consists of four tan-dem domain units(D1-D4)with a repeated K^(+) -channel-like M-P-M topology.In each subunit,D1-D4 assemble into an ion conduction pore with a pseudo-four-fold symmetry.Although both TaHKT2;1and AtHKT1;1 have only one putative Na^(+) ion bound in the selectivity filter with a similar coordination pattern,the two HKTs display different K^(+) binding modes in the filter.TaHKT2;1 has three K^(+) ions bound in the selec-tivity filter,but AtHKT1;1 has only two K^(+) ions bound in the filter,which has a narrowed external entrance due to the presence of a Ser residue in the first filter motif.These structures,along with compu-tational,mutational,and electrophysiological analyses,enable us to pinpoint key residues that are critical for the ion selectivity of HKTs.The findings provide new insights into the ion selectivity and ion transport mechanisms of plant HKTs and improve our understanding about how HKTs mediate plant salt tolerance and enhance crop growth.展开更多
Volatilomics is essential for understanding the biological functions and fragrance contributions of plant volatiles.However,the annotation coverage achieved using current untargeted and widely targeted volatomics(WTV)...Volatilomics is essential for understanding the biological functions and fragrance contributions of plant volatiles.However,the annotation coverage achieved using current untargeted and widely targeted volatomics(WTV)methods has been limited by low sensitivity and/or low acquisition coverage.Here,we introduce WTV 2.0,which enabled the construction of a high-coverage library containing 2111 plant volatiles,and report the development of a comprehensive selective ion monitoring(cSIM)acquisition method,including the selection of characteristic qualitative ions with the minimal ion number for each compound and an optimized segmentation method,that can acquire the smallest but sufficient number of ions for most plant volatiles,as well as the automatic qualitative and semi-quantitative analysis of cSIM data.Importantly,the library and acquisition method we developed can be self-expanded by incorporating compounds not present in the library,utilizing the obtained cSIM data.We showed that WTV 2.0 increases the median signal-to-noise ratio by 7.6-fold compared with the untargeted method,doubled the annotation coverage compared with the untargeted and WTV 1.0 methods in tomato fruit,and led to the discovery of menthofuran as a novel flavor compound in passion fruit.WTV 2.0 is a Python library with a user-friendly interface and is applicable to profiling of volatiles and primary metabolites in any species.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
Solid polymer electrolytes(SPEs)by in situ polymerization are attractive due to their good interfacial contact with electrodes.Previously reported in situ polymerized SPEs,however,suffer from the low polymerization de...Solid polymer electrolytes(SPEs)by in situ polymerization are attractive due to their good interfacial contact with electrodes.Previously reported in situ polymerized SPEs,however,suffer from the low polymerization degree that causes poor mechanical strength,Li dendrite penetration,and performance decay in Li-metal batteries.Although highly polymerized SPEs are more stable than lowly polymerized ones,they are restricted by their sluggish long-chain mobility and poor ionic conductivity.In this work,a three-dimensional fibrous membrane with ion selectivity was prepared and used as a functional filler for the in situ formed SPE.The obtained SPE has high stability due to its high polymerization degree after the long-term heating process.The fibrous membrane plays a vital role in improving the SPE’s properties.The rich anion-adsorption sites on the fibrous membrane can alleviate the polarization effect and benefit a uniform current distribution at the interface.The fibrous nanostructure can efficiently interact with the polymeric matrix,providing rich hopping sites for fast Li+migration.Consequently,the obtained SPE enables a uniform Li deposition and long-term cycling performance in Li-metal batteries.This work reported an in situ formed SPE with both high polymerization degree and ionic conductivity,paving the way for designing high-performance SPEs with good comprehensive properties.展开更多
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.
文摘Introduction Peptides made up of alternating L- and D- amino acids can form β-helices as in gramicidin A or cyclic peptides that aggregate to form tubes In both cases the structures are hollow with all the side chains projecting outwards. Kennedy et al. postulated that. peptides having the (LLLD)n configuration could form helices with every fourth side chain projecting inward. It is a fact that synthetic N-formyl- (LeuSerLeuGly) 6- OH, when added to a lipid bilayer, dimerizes, to form ion channels having conductances greater than that of gramicidin.
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.
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Project supported by the National Basic Research Program of China(Grant Nos.2011CB707601 and 2011CB707605)the National Natural Science Foundation of China(Grant No.50925519)+2 种基金the Fundamental Research Funds for the Central UniversitiesFunding of Jiangsu Provincial Innovation Program for Graduate Education,China(Grant No.CXZZ13 0087)the Scientific Research Foundation of Graduate School of Southeast University(Grant No.YBJJ 1322)
文摘Porous graphene has a high mechanical strength and an atomic-layer thickness that makes it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous solutions are a type of strong long-range interaction that may greatly influence fluid transport through nanopores. In this study, molecular dynamic simulations were conducted to investigate ion and water transport through 1.05-nm diameter monolayer graphene nanopores, with their edges charge-modified. Our results indicated that these nanopores are selective to counterions when they are charged. As the charge amount increases, the total ionic currents show an increase-decrease profile while the coion currents monotonically decrease. The co-ion rejection can reach 76.5% and 90.2% when the nanopores are negatively and positively charged, respectively. The Cl-ion current increases and reaches a plateau, and the Na+current decreases as the charge amount increases in systems in which Na+ions act as counterions. In addition, charge modification can enhance water transport through nanopores. This is mainly due to the ion selectivity of the nanopores. Notably, positive charges on the pore edges facilitate water transport much more strongly than negative charges.
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.
文摘A novel fibroin modified electrode with ion recognition was reported. The membranewith isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. ThepH-responsive ion recognition of the modified electrode was investigated by use of someneurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination.
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.
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Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadolinium ion selective electrode besides the effects of their structures.1.Effect of preparation process of the grafted polymers on the properties ofgadolinium ion selective electrodesThe electrode membranes which consist of functional polymers as active materials were prepared by re-action of gadolinium chloride with the radiation grafted clmer of acrlic acid and polystyrene of which
文摘In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.
文摘In this paper is reported a new method of determining serum albumin with potentiometry. The silver ion selective electrode was used as working electrode and S. C. E as reference electrode. By controlling the ionic strength, PH and temperature constant, a good linear relationship was obtained between the cell potential and albumin concentration. This method .possessed characters-of operating simplicity, rapidity and directness. The samples could be detected directly and the results were in accordance with the values detected by classic K method.
文摘Fluoride is widespread in the environment, water, air, vegetation and Earth’s crust which can entre ground and surface water by natural process. Fluoride in minute quantities is essential component for human health and help in normal mineralization of bone and formation of dental enamel. The determination of fluoride in some species was performed by using fluoride ion-selective electrode by direct measurement and standard addition method. The concentration of fluoride ion was determined in drinking water (from different place at Kathmandu), toothpaste, various brand of tea and coffees. The range of fluoride concentration in water sample was 0.16 to 0.39 mg/l, tea and coffee samples were 0.011 to 0.084 mg/l and its value of toothpaste was 0.026 to 0.75 mg/l. The concentration of fluoride ion obtain from different sample was compared with the legitimate value given by the world health organization.
文摘The percent ammonia nitrogen was determined in Passaic River waste water using Ion-Selective Electrode EPA Method 350.3. The intelligent ammonia sensor integrates ammonia electrode, pH electrode and Ammonia Ion electrode together to realize the in situ detection of ammonia. The test results have shown that the sensor is easy operation, low cost and no pollution. The ammonia is determined potentiometrically using an ammonia ion selective electrode and a pH/mV meter, having an expanded millivolt scale. The ammonia selective electrode uses a hydrophobic gas-permeable membrane to separate the sample solution from an electrode internal solution of ammonium chloride. Dissolved ammonia is converted to NH<sub>3</sub> gas by raising the pH to above 11.0 with a strong base. NH<sub>3</sub> gas diffuses the membrane and changes the internal solution pH that is sensed by the electrode. In single laboratory test results have been found 1.001 NH<sub>3</sub>-/L and 0.897 mg NH<sub>3</sub>-N/L, recoveries were 77.3% and 83.1%, respectively.
基金support from the National Key Research and Development Program of China(No.2019YFA0705400)the National Natural Science Foundation of China(Nos.21972121 and 22021001)the Fundamental Research Funds for the Central Universities(No.20720210017).
文摘Harvesting clean energy from water evaporation has been extensively investigated due to its sustainability.To achieve high efficiency,energy conversion materials should contain multiple features which are difficult to be simultaneously obtained from single-component materials.Here we use composite laminar membranes assembled by nanosheets of graphene oxide and mica,and find a sustained power density induced by water evaporation that is two orders of magnitude larger than that from membranes made by either of the components.The power output is attributed to selective proton transport driven by water evaporation through the interlayer nanochannels in the membranes.This process relies on the synergistic effects from negatively charged and hydrophilic mica surfaces that are important for proton selectivity and water transport,and the tunable electrical conductivity of graphene oxide that provides optimized internal resistance.The demonstrated composite membranes offer a strategy of enhancing power generation by combining the advantages from each of their components.
基金supported in part by the National Key Research and Development Program of China(2022YFA1303400 to S.J.Z.and S.Q.,2020YFA0908501 to J.G.,and 2021YFF1200404 to Y.W.)the National Natural Science Foundation of China(32371204 to J.G.,82030108 and 31872796 to W.Y.,and 32371300 to Y.W.)+2 种基金Zhejiang Provincial Natural Science Foundation(LR19C050002 to J.G.)the China Postdoctoral Science Foundation(no.74,2023M743044 to J.W.)the National Postdoctoral Researcher Program of China(GZB20230634 to J.W.).
文摘Plant high-affinity K^(+) transporters(HKTs)mediate Na^(+) and K^(+) uptake,maintain Na^(+)/K^(+) homeostasis,and therefore play crucial roles in plant salt tolerance.In this study,we present cryoelectron microscopy structures of HKTs from two classes,classI HKT1;1 from Arabidopsis thaliana(AtHKT1;1)and class II HKT2;1 from Triticum aestivum(TaHKT2;1),in both Na^(+) -and K^(+) -bound states at 2.6-to 3.0-A resolutions.BothAtHKT1;1and TaHKT2;1function ashomodimers.Each HKT subunit consists of four tan-dem domain units(D1-D4)with a repeated K^(+) -channel-like M-P-M topology.In each subunit,D1-D4 assemble into an ion conduction pore with a pseudo-four-fold symmetry.Although both TaHKT2;1and AtHKT1;1 have only one putative Na^(+) ion bound in the selectivity filter with a similar coordination pattern,the two HKTs display different K^(+) binding modes in the filter.TaHKT2;1 has three K^(+) ions bound in the selec-tivity filter,but AtHKT1;1 has only two K^(+) ions bound in the filter,which has a narrowed external entrance due to the presence of a Ser residue in the first filter motif.These structures,along with compu-tational,mutational,and electrophysiological analyses,enable us to pinpoint key residues that are critical for the ion selectivity of HKTs.The findings provide new insights into the ion selectivity and ion transport mechanisms of plant HKTs and improve our understanding about how HKTs mediate plant salt tolerance and enhance crop growth.
基金supported by key project of regional joint fund of National Natural Science FoundationNational Natural Science Foundation of China(U22A20476)Hainan international science and technology cooperation research and development project(GHYF2023005)+3 种基金Sanya Yazhou Sci-Tech City(SYND-2022-02).)Hainan Yazhou Bay Seed Lab(Nono.B21HJ0903)“111”Project111 Project(Nono.D20024).)Hainan Provincial Natural Science Foundation of China Hainan Provincial Natural Science Foundation of China(320MS011).)‘PhD Scientific Research and Innovation Foundation of Sanya Yazhou Bay Science and Technology City(HSPHDSRF-2023-12-001).)’Basic Research Project in 2023 of Yazhouwan National Laboratory.
文摘Volatilomics is essential for understanding the biological functions and fragrance contributions of plant volatiles.However,the annotation coverage achieved using current untargeted and widely targeted volatomics(WTV)methods has been limited by low sensitivity and/or low acquisition coverage.Here,we introduce WTV 2.0,which enabled the construction of a high-coverage library containing 2111 plant volatiles,and report the development of a comprehensive selective ion monitoring(cSIM)acquisition method,including the selection of characteristic qualitative ions with the minimal ion number for each compound and an optimized segmentation method,that can acquire the smallest but sufficient number of ions for most plant volatiles,as well as the automatic qualitative and semi-quantitative analysis of cSIM data.Importantly,the library and acquisition method we developed can be self-expanded by incorporating compounds not present in the library,utilizing the obtained cSIM data.We showed that WTV 2.0 increases the median signal-to-noise ratio by 7.6-fold compared with the untargeted method,doubled the annotation coverage compared with the untargeted and WTV 1.0 methods in tomato fruit,and led to the discovery of menthofuran as a novel flavor compound in passion fruit.WTV 2.0 is a Python library with a user-friendly interface and is applicable to profiling of volatiles and primary metabolites in any species.
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.
基金The authors acknowledge the funding from the Shenzhen Science and Technology Program(No.RCBS20210609103647030)National Natural Science Foundation of China(Nos.22005134,12275119,and 52227802)+3 种基金Guangdong Grant(No.2021ZT09C064)Major Science and Technology Infrastructure Project of Material Genome Big-science Facilities Platform supported by the Municipal Development and Reform Commission of Shenzhen,Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices(No.2019B121205001)the Open Research Fund of Songshan Lake Materials Laboratory(No.2022SLABFK04)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515012403).
文摘Solid polymer electrolytes(SPEs)by in situ polymerization are attractive due to their good interfacial contact with electrodes.Previously reported in situ polymerized SPEs,however,suffer from the low polymerization degree that causes poor mechanical strength,Li dendrite penetration,and performance decay in Li-metal batteries.Although highly polymerized SPEs are more stable than lowly polymerized ones,they are restricted by their sluggish long-chain mobility and poor ionic conductivity.In this work,a three-dimensional fibrous membrane with ion selectivity was prepared and used as a functional filler for the in situ formed SPE.The obtained SPE has high stability due to its high polymerization degree after the long-term heating process.The fibrous membrane plays a vital role in improving the SPE’s properties.The rich anion-adsorption sites on the fibrous membrane can alleviate the polarization effect and benefit a uniform current distribution at the interface.The fibrous nanostructure can efficiently interact with the polymeric matrix,providing rich hopping sites for fast Li+migration.Consequently,the obtained SPE enables a uniform Li deposition and long-term cycling performance in Li-metal batteries.This work reported an in situ formed SPE with both high polymerization degree and ionic conductivity,paving the way for designing high-performance SPEs with good comprehensive properties.