Construction and performance characteristics of polymeric membrane electrode and coated graphite electrode for the selective determination of Fe³⁺ ion.

Science.gov (United States)

Bandi, Koteswara Rao; Singh, Ashok K; Upadhyay, Anjali

2014-03-01

Novel Fe(3+) ion-selective polymeric membrane electrodes (PMEs) were prepared using three different ionophores N-(4-(dimethylamino)benzylidene)thiazol-2-amine [L1], 5-((3-methylthiophene-2yl) methyleneamino)-1,3,4-thiadiazole-2-thiol [L2] and N-((3-methylthiophene-2yl)methylene)thiazol-2-amine [L3] and their potentiometric characteristics were discussed. Effect of various plasticizers and anion excluders was also studied in detail and improved performance was observed. The best performance was obtained for the membrane electrode having a composition of L2:PVC:o-NPOE:NaTPB as 3:38.5:56:2.5 (w/w; mg). A coated graphite electrode (CGE) was also prepared with the same composition and compared. CGE is found to perform better as it shows a wider working concentration range of 8.3×10(-8)-1.0×10(-1)molL(-1), a lower detection limit of 2.3×10(-8)molL(-1), and a near Nernstian slope of 19.5 ± 0.4 mVdecade(-1) of activity with a response time of 10s. The CGE shows a shelf life of 6 weeks and in view of high selectivity, it can be used to quantify Fe(3+) ion in water, soil, vegetable and medicinal plants. It can also be used as an indicator electrode in potentiometric titration of EDTA with Fe(3+) ion. Copyright © 2013. Published by Elsevier B.V.

All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for Determination of Donepezil Hydrochloride in Pharmaceutical Formulation.

Science.gov (United States)

Khamees, Nesreen; Mohamed, Tagreed Abdel-Fattah; Derar, Abeer Rashad; Aziz, Azza

2017-09-01

All-solid-state, polyvinyl chloride (PVC) membrane, and carbon paste potentiometric ion-selective electrodes (ISEs) were proposed for the determination of donepezil hydrochloride (DON) in the drug substance and a pharmaceutical formulation. The potentiometric response toward DON was based on the existence of donepezil-tetraphenyl borate (DON-TPB) in a PVC membrane or a carbon paste in the presence of dioctylphthalate. In contrast, the solid-state electrode was prepared by direct incorporation of DON-TPB into a commercial nail varnish without external additives. The electrodes exhibited Nernstian slopes of 55.0, 57.0, and 53.0 mV/decade over the concentration ranges of 1 × 10-5 to 1 × 10-3, 1 × 10-4 to 10-2, and 1 × 10-4 to 5 × 10-3 for the solid-state, PVC membrane, and carbon paste electrodes, respectively. The response of the electrodes is independent of pH in the range of 2-≤8. The electrodes showed good selectivity for DON with respect to a number of inorganic cations and amino acids. The electrodes were used for the determination of DON in pure solution and in pharmaceutical tablets with high accuracy (±2%) and precision (RSD ≤2%). The solid-state electrode is simple, economical, and rapid when compared to the PVC membrane and carbon paste electrodes.

Picomolar detection limits with current-polarized Pb2+ ion-selective membranes.

Science.gov (United States)

Pergel, E; Gyurcsányi, R E; Tóth, K; Lindner, E

2001-09-01

Minor ion fluxes across ion-selective membranes bias submicromolar activity measurements with conventional ion-selective electrodes. When ion fluxes are balanced, the lower limit of detection is expected to be dramatically improved. As proof of principle, the flux of lead ions across an ETH 5435 ionophore-based lead-selective membrane was gradually compensated by applying a few nanoamperes of galvanostatic current. When the opposite ion fluxes were matched, and the undesirable leaching of primary ions was eliminated, Nernstian response down to 3 x 10(-12) M was achieved.

Influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb(II) ion-selective electrode

DEFF Research Database (Denmark)

Joon, Narender Kumar; He, Ning; Wagner, Michal

2017-01-01

In this work, the influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb2+-selective electrode (Pb2+-ISE) was studied. The effects of bovine serum albumin (BSA) adsorption at the surface of the ion-selective membrane combined...... ions studied (Cu2+, Cd2+). Conditioning of the Pb2+-ISE in 0.01 mol dm–3 PBS resulted in a super-Nernstian response which was related to fixation/extraction of Pb2+ in the ion-selective membrane via precipitation of Pb3(PO4)2 by PO43– anions present in PBS. By conditioning of the Pb2+-ISE in 0.01 mol...

Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

Energy Technology Data Exchange (ETDEWEB)

Ghanei-Motlagh, Masoud [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Taher, Mohammad Ali, E-mail: ma_taher@yahoo.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ahmadi, Kyoumars [AJA University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sheikhshoaie, Iran [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2011-12-01

A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I{sup -} ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 {+-} 0.5 (CPtE) and 60.3 {+-} 0.4 (PME) mV decade{sup -1} in I{sup -} ion over a wide concentration range from 7.9 x 10{sup -7} to 1.0 x 10{sup -1} M for CPtE and 9.1 x 10{sup -6} to 1.0 x 10{sup -1} M I{sup -} for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time (< 10 s). The process of transfer of iodide across the membrane interface was investigated by use of the AC impedance technique. The proposed sensors were successfully applied to direct determination of iodide in samples containing interfering anions, waste water and as indicator electrodes in precipitation titrations. Highlights: {yields} We study new selective membrane electrodes for iodide ions. {yields} To the best of our knowledge this is the first coated platinum disk electrode of I{sup -}. {yields} The sensors have a wide concentration range with a fast response time. {yields} Efforts have been made to improve the selectivity with the use of CPtE.

A calixarene-based ion-selective electrode for thallium(I) detection

International Nuclear Information System (INIS)

Chester, Ryan; Sohail, Manzar; Ogden, Mark I.; Mocerino, Mauro; Pretsch, Ernö; De Marco, Roland

2014-01-01

Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl + ionophores have been utilized in Tl + ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10 −2 –10 −6 M TlNO 3 with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β IL ) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn 2+ , Ca 2+ , Ba 2+ , Cu 2+ , Cd 2+ and Al 3+ with moderate selectivity against Pb 2+ , Li + , Na + , H + , K + , NH 4 + and Cs + , noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade −1 and a lower detection limit of 30.2 nM. Due to the presence of an undesirable

Determination of Cd2+ in aqueous solution using polyindole-Ce(IV) vanadophosphate conductive nanocomposite ion-selective membrane electrode

Science.gov (United States)

Khan, Asif Ali; Quasim Khan, Mohd; Hussain, Rizwan

2017-09-01

In the present study an organic-inorganic nanocomposite ion exchanger Polyindole-Ce(IV) vanadophosphate (PIn-CVP) was synthesized via sol-gel process showing excellent ion exchange capacity (IEC‒1.90 meqg-1). The material was characterized by SEM, TEM, XRD, FTIR, and TGA. A heterogeneous ion exchange membrane of PIn-CVP (IEC‒0.90 meqg-1) was also prepared by solution casting method. PIn-CVP shows high electrical conductivity (5.5  ×  10-2 S cm-1) and it is stable up to 120 °C under ambient conditions. Cd2+ selective membrane electrode was fabricated and its linear working range (3.98  ×  10-7 M to 1.0  ×  10-1 M), response time (25 s), Nerstian slope 25.00 mV dec-1 and working pH range (4-7) were calculated. It was employed as an indicator electrode in the potentiometric titration of Cd2+.

Optimization of polymeric triiodide membrane electrode based on clozapine-triiodide ion-pair using experimental design.

Science.gov (United States)

Farhadi, Khalil; Bahram, Morteza; Shokatynia, Donya; Salehiyan, Floria

2008-07-15

Central composite design (CCD) and response surface methodology (RSM) were developed as experimental strategies for modeling and optimization of the influence of some variables on the performance of a new PVC membrane triiodide ion-selective electrode. This triiodide sensor is based on triiodide-clozapine ion-pair complexation. PVC, plasticizers, ion-pair amounts and pH were investigated as four variables to build a model to achieve the best Nernstian slope (59.9 mV) as response. The electrode is prepared by incorporating the ion-exchanger in PVC matrix plasticized with 2-nitrophenyl octal ether, which is directly coated on the surface of a graphite electrode. The influence of foreign ions on the electrode performance was also investigated. The optimized membranes demonstrate Nernstian response for triiodide ions over a wide linear range from 5.0 x 10(-6) to 1.0 x 10(-2)mol L(-1) with a limit of detection 2.0 x 10(-6) mol L(-1) at 25 degrees C. The electrodes could be used over a wide pH range 4-8, and have the advantages of easy to prepare, good selectivity and fast response time, long lifetime (over 3 months) and small interferences from hydrogen ion. The proposed electrode was successfully used as indicator electrode in potentiometric titration of triiodide ions and ascorbic acid.

Crown bridged thiacalix[4]arenes as cesium-selective ionophores in solvent polymeric membrane electrodes

International Nuclear Information System (INIS)

Bereczki, Robert; Csokai, Viktor; Gruen, Alajos; Bitter, Istvan; Toth, Klara

2006-01-01

Novel 1,3-alternate thiacalix[4]mono- and biscrown-6 ethers were studied as ionophores in poly(vinyl chloride) membrane electrodes. Their selectivity behavior was characterized with respect to large number of cations, including potential interferents in environmental samples, and the membrane composition was optimized for cesium ion response. Among the ionophores, 1,3-alternate thiacalix[4]mono(crown-6) ether showed, especially high selectivity for cesium over other alkali-metal ions. Transition and heavy metal ions did not interfere seriously with the electrode response, which indicates that the bridging sulfur atoms do not take part in the ion recognition process. The potentiometric cesium responses of all electrodes involved in this study were found close to Nernstian and the detection limits were lower than 10 -7 M. The Cs + /Na + selectivity of the different ionophore-based sensors and the solvent extraction ability of the ligands were interpreted based on the respective constants of complex formation

New Signal Readout Principle for Solid-Contact Ion-Selective Electrodes.

Science.gov (United States)

Vanamo, Ulriika; Hupa, Elisa; Yrjänä, Ville; Bobacka, Johan

2016-04-19

A novel approach to signal transduction concerning solid-contact ion-selective electrodes (SC-ISE) with a conducting polymer (CP) as the solid contact is investigated. The method presented here is based on constant potential coulometry, where the potential of the SC-ISE vs the reference electrode is kept constant using a potentiostat. The change in the potential at the interface between the ion-selective membrane (ISM) and the sample solution, due to the change in the activity of the primary ion, is compensated with a corresponding but opposite change in the potential of the CP solid contact. This enforced change in the potential of the solid contact results in a transient reducing/oxidizing current flow through the SC-ISE. By measuring and integrating the current needed to transfer the CP to a new state of equilibrium, the total cumulated charge that is linearly proportional to the change of the logarithm of the primary ion activity is obtained. In this work, different thicknesses of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) were used as solid contact. Also, coated wire electrodes (CWEs) were included in the study to show the general validity of the new approach. The ISM employed was selective for K(+) ions, and the selectivity of the membrane under implementation of the presented transduction mechanism was confirmed by measurements performed with a constant background concentration of Na(+) ions. A unique feature of this signal readout principle is that it allows amplification of the analytical signal by increasing the capacitance (film thickness) of the solid contact of the SC-ISE.

Cyanex based uranyl sensitive polymeric membrane electrodes.

Science.gov (United States)

Badr, Ibrahim H A; Zidan, W I; Akl, Z F

2014-01-01

Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods. © 2013 Published by Elsevier B.V.

Preparation and characterization of electrically conducting polypyrrole Sn(IV phosphate cation-exchanger and its application as Mn(II ion selective membrane electrode

Directory of Open Access Journals (Sweden)

A.A. Khan

2011-10-01

Full Text Available Polypyrrole Sn(IV phosphate, an organic–inorganic composite cation-exchanger was synthesized via sol-gel mixing of an organic polymer, polypyrrole, into the matrices of the inorganic precipitate of Sn(IV phosphate. The physico-chemical properties of the material were determined using Atomic Absorption Spectrometry (AAS, CHN elemental analysis (inductively coupled plasma mass spectrometry, ICP-MS, UV–VIS spectrophotometry, FTIR (Fourier Transform Infra-Red, SEM (Scanning Electron Microscopy, TGA–DTA (Thermogravimetric Analysis–Differential Thermal Analysis, and XRD (X-ray diffraction. Ion-exchange behavior was observed to characterize the material. On the basis of distribution studies, the material was found to be highly selective for toxic heavy metal ion Mn2+. Due to its selective nature, the material was used as an electroactive component for the construction of an ion-selective membrane electrode. The proposed electrode shows fairly good discrimination of mercury ion over several other inorganic ions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations for Mn(II in water.

A calixarene-based ion-selective electrode for thallium(I) detection

Energy Technology Data Exchange (ETDEWEB)

Chester, Ryan [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Sohail, Manzar [Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia); Ogden, Mark I.; Mocerino, Mauro [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Pretsch, Ernö [ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics (IBP), Universitätstrasse 16, CH-8092, Zürich (Switzerland); De Marco, Roland, E-mail: rdemarc1@usc.edu.au [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia)

2014-12-03

Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl{sup +} ionophores have been utilized in Tl{sup +} ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10{sup −2}–10{sup −6} M TlNO{sub 3} with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β{sub IL}) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn{sup 2+}, Ca{sup 2+}, Ba{sup 2+}, Cu{sup 2+}, Cd{sup 2+} and Al{sup 3+} with moderate selectivity against Pb{sup 2+}, Li{sup +}, Na{sup +}, H{sup +}, K{sup +}, NH{sub 4}{sup +} and Cs{sup +}, noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade

Recovery of fluoride ion selective electrode

International Nuclear Information System (INIS)

Monteiro, R.P.G.

1988-01-01

A recovery procedure of fluoride ion selective electrode based upon the body radiography of inactive electrode and introduction of suitable internal regeneration solution, is developed. The recovered electrode was tested in standard solutions of fluoride ions (10 sup5) to 10 -1M showing as good performance as the new one. The fluor determination by potentiometric measurements with selective electrode is used in nuclear fuel cycle for quality control of thorium and uranium mixed oxide pellets and pellets of uranium dioxides. (author) [pt

Quaternary alkylammonium and alkylphosphonium pertechnetates. Application to pertechnetate ion-selective electrodes

International Nuclear Information System (INIS)

German, K.E.; Dorokhov, A.V.; Tarasov, A.V.; Baulin, V.E.; Peretroukhine, V.; Tsivadze, A.Yu.; Kopytin, A.V.; Politov, Yu.; Pyatova, E.N.

2005-01-01

Pertechnetate ion-selective PVC membrane electrodes based on quaternary alkylammonium and phosphonium salts (bromides and pertechnetates) were examined. The most favorable ionophore was tetradecyltrimethylammonium bromide. The response function was linear within the concentration range 10 -2 -10 -6 mol/L and the slope was 52 mV/pTcO 4 . The detection limit remained at 5x10 -7 mol/L. The selectivity and response time of the electrodes was studied and it was found that the electrodes exhibited high selectivity to TcO 4 - -anion against the main inorganic components of radioactive waste solutions and environmental waters (nitrate, sulfate, chloride and others). The electrodes response was stable over a wide pH range. (author)

A copper ion-selective electrode with high selectivity prepared by sol-gel and coated wire techniques.

Science.gov (United States)

Mazloum Ardakani, M; Salavati-Niasari, M; Khayat Kashani, M; Ghoreishi, S M

2004-03-01

A sol-gel electrode and a coated wire ion-selective poly(vinyl chloride) membrane, based on thiosemicarbazone as a neutral carrier, were successfully developed for the detection of Cu (II) in aqueous solutions. The sol-gel electrode and coated electrode exhibited linear response with Nernstian slopes of 29.2 and 28.1 mV per decade respectively, within the copper ion concentration ranges 1.0 x 10(-5) - 1.0 x 10(-1) M and 6.0 x 10(-6) - 1.0 x 10(-1) M for coated and sol-gel sensors. The coated and sol-gel electrodes show detection limits of 3.0 x 10(-6) and 6.0 x 10(-6) M respectively. The electrodes exhibited good selectivities for a number of alkali, alkaline earth, transition and heavy metal ions. The proposed electrodes have response times ranging from 10-50 s to achieve a 95% steady potential for Cu2+ concentration. The electrodes are suitable for use in aqueous solutions over a wide pH range (4-7.5). Applications of these electrodes for the determination of copper in real samples, and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA, are reported. The lifetimes of the electrodes were tested over a period of six months to investigate their stability. No significant change in the performance of the sol-gel electrode was observed over this period, but after two months the coated wire copper-selective electrode exhibited a gradual decrease in the slope. The selectivity of the sol-gel electrode was found to be better than that of the coated wire copper-selective electrode. Based on these results, a novel sol-gel copper-selective electrode is proposed for the determination of copper, and applied to real sample assays.

PVC membrane, coated-wire, and carbon-paste ion-selective electrodes for potentiometric determination of galantamine hydrobromide in physiological fluids.

Science.gov (United States)

Abdel-Haleem, Fatehy M; Saad, Mohamed; Barhoum, Ahmed; Bechelany, Mikhael; Rizk, Mahmoud S

2018-08-01

We report on highly-sensitive ion-selective electrodes (ISEs) for potentiometric determining of galantamine hydrobromide (GB) in physiological fluids. Galantamine hydrobromide (GB) was selected for this study due to its previous medical importance for treating Alzheimer's disease. Three different types of ISEs were investigated: PVC membrane electrode (PVCE), carbon-paste electrode (CPE), and coated-wire electrode (CWE). In the construction of these electrodes, galantaminium-reineckate (GR) ion-pair was used as a sensing species for GB in solutions. The modified carbon-paste electrode (MCPE) was prepared using graphene oxide (MCPE-GO) and sodium tetrakis (trifluoromethyl) phenyl borate (MCPE-STFPB) as ion-exchanger. The potentiometric modified CPEs (MCPE-GO and MCPE-STFPB) show an improved performance in term of Nernstian slope, selectivity, response time, and response stability compared to the unmodified CPE. The prepared electrodes PVCE, CWE, CPE, MCPE-GO and MCPE-STFPB show Nernstian slopes of 59.9, 59.5, 58.1, 58.3 and 57.0 mV/conc. decade, and detection limits of 5.0 × 10 -6 , 6.3 × 10 -6 , 8.0 × 10 -6 , 6.0 × 10 -6 and 8.0 × 10 -6  mol L -1 , respectively. The prepared ISEs also show high selectivity against cations (i.e. Na + , K + , NH 4 + , Ca 2+ , Al 3+ , Fe 3+ ), amino acids (i.e. glycine, L-alanine alanine), and sugars (i.e. fructose, glucose, maltose, lactose). The prepared ISEs are applicable for determining GB in spiked serums, urines, and pharmaceutical preparations, using a standard addition and a direct potentiometric method. The fast response time (<10 s), long lifetime (1-5 weeks), reversibility and stability of the measured signals facilitate the application of these sensors for routine analysis of the real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Monitoring Ion Activities In and Around Cells Using Ion-Selective Liquid-Membrane Microelectrodes

Directory of Open Access Journals (Sweden)

Mark D. Parker

2013-01-01

Full Text Available Determining the effective concentration (i.e., activity of ions in and around living cells is important to our understanding of the contribution of those ions to cellular function. Moreover, monitoring changes in ion activities in and around cells is informative about the actions of the transporters and/or channels operating in the cell membrane. The activity of an ion can be measured using a glass microelectrode that includes in its tip a liquid-membrane doped with an ion-selective ionophore. Because these electrodes can be fabricated with tip diameters that are less than 1 μm, they can be used to impale single cells in order to monitor the activities of intracellular ions. This review summarizes the history, theory, and practice of ion-selective microelectrode use and brings together a number of classic and recent examples of their usefulness in the realm of physiological study.

Development of a ceramic membrane from a lithian spinel, Li1+xMyMn2-yO4 (M=trivalent or tetravalent cations) for a Li ion-selective electrode

Science.gov (United States)

Yoon, H.; Venugopal, N.; Rim, T.; Yang, B.; Chung, K.; Ko, T.

2010-12-01

Recently a few lithium containing ceramics are reported as promising cathodes for application in lithium batteries. Among them, a spinel-type lithium manganate (LM) exhibits an exceptionally high ion selectivity at room temperature. Thus, LM could have a great potential as an ion selective membrane material for screening interfering ions from lithium ion for the determination of lithium ion in salt solution. In this study, we developed an ion-selective electrode based on LM as a membrane material and investigated its lithium ion selectivity by varying the content of M in composition. A sol-gel process was successfully applied for preparing LM films without resorting to calcination at a high temperature. The LM thin film-type membranes exhibit a high selectivity for Li ion over other cations, a wide operation detection range of 10-5 ~ 10-2 M, and a fast response time less than 60 s. Furthermore, our result demonstrates a linear potentiometric response over a wide range of lithium concentration, which is compared to that of a lithium ion-selective electrode based on an ionophore. Acknowledgements: This research was supported by a grant from the Development of Technology for Extraction of Resources Dissolved in Sea Water Program funded by Ministry of Land Transport and Maritime Affairs in Korean Government (2010).

Tetraazacyclohexadeca Macrocyclic Ligand as a Neutral Carrier in a Cr Ion-selective Electrode

Directory of Open Access Journals (Sweden)

Puja Saxena

2004-12-01

Full Text Available Abstract: A polystyrene-based membrane of 2,10-dimethyl-4,12-diphenyl-1,5,9,13-tetraazacyclohexadeca-1,4,9,12-tetraene macrocyclic ionophore was prepared and investigated as Cr(III-selective electrode. The best performance was observed with the membrane having the polystyrene-ligand-dibutylphthalate-sodiumtetraphenyl borate composition 1:4:1:1 with a Nernstian slope of 19.0 mV per decade of concentration between pH 3.0 and 6.5. This electrode has been found to be chemically inert and of adequate stability with a response time of 20 s and was used over a period of 100 d with good reproducibility (S= 0.3 mV. The membrane works satisfactorily in a partially non-aqueous medium up to a maximum 30% (v/v content of methanol and ethanol. The potentiometric selectivity coefficient values indicate that the membrane sensor is highly selective for Cr(III ions over a number of monovalent, divalent and trivalent cations. The membrane electrode has also been successfully used to determine Cr3+ in various food materials.

Direct evidence of ionic fluxes across ion-selective membranes: a scanning electrochemical microscopic and potentiometric study.

Science.gov (United States)

Gyurcsányi, R E; Pergel, E; Nagy, R; Kapui, I; Lan, B T; Tóth, K; Bitter, I; Lindner, E

2001-05-01

Scanning electrochemical microscopy (SECM) supplemented with potentiometric measurements was used to follow the time-dependent buildup of a steady-state diffusion layer at the aqueous-phase boundary of lead ion-selective electrodes (ISEs). Differential pulse voltammetry is adapted to SECM for probing the local concentration profiles at the sample side of solvent polymeric membranes. Major factors affecting the membrane transport-related surface concentrations were identified from SECM data and the potentiometric transients obtained under different experimental conditions (inner filling solution composition, membrane thickness, surface pretreatment). The amperometrically determined surface concentrations correlated well with the lower detection limits of the lead ion-selective electrodes.

Poly (Vinyl Chloride Based Ion Selective Electrode for Determination of Zr (IV Ions Based on 2, 6-Dibenzylidenecyclohexanone

Directory of Open Access Journals (Sweden)

Syed A. Nabi

2008-08-01

Full Text Available A selective poly (vinyl chloride-based membrane sensor using 2,6-Dibenzylidenecyclohexanone as an ionophore have been prepared and explored as Zr (IV selective electrode. The sensitivity, working range and response time shows a significant dependence on the concentration of ionophore. The electrode prepared with 100 mg of PVC, 10 mg of ionophore and 5 ml of dibutylthylate shows the best performance. The electrode works well in the concentration range of 1×10-1-5×10-5 with a nerstian slope 55±2 eV and response time of 18 seconds. The sensor works well over the pH range 3-6. The sensor can be used for the period of over 1 month with out deviation in response characteristics. The selectivity of the electrode was studied and it was found that the electrode exhibited good selectivity for zirconium (IV over some alkaline earth metal ions. The electrode was also used as indicator electrode for potentiometeric titration of Zr (IV ions against EDTA solution.

Highly selective direct determination of chlorate ions by using a newly developed potentiometric electrode based on modified smectite.

Science.gov (United States)

Topcu, Cihan

2016-12-01

A novel polyvinyl chloride membrane chlorate (ClO 3 - ) selective electrode based on modified smectite was developed for the direct determination of chlorate ions and the potentiometric performance characteristics of its were examined. The best selectivity and sensitivity for chlorate ions were obtained for the electrode membrane containing ionophore/polyvinylchloride/o-nitrophenyloctylether in composition of 12/28/60 (w/w%). The proposed electrode showed a Nernstian response toward chlorate ions at pH=7 in the concentration range of 1×10 -7 -1×10 -1 M and the limit of detection was calculated as 9×10 -8 M from the constructed response plot. The linear slope of the electrode was -61±1mVdecade -1 for chlorate activity in the mentioned linear working range. The selectivity coefficients were calculated according to both the matched potential method and the separate solution method. The calculated selectivity coefficients showed that the electrode performed excellent selectivity for chlorate ions. The potentiometric response of electrode toward chlorate ions was found to be highly reproducible. The electrode potential was stable between pH=4-10 and it had a dynamic response time of <5s. The potentiometric behavior of the electrode in partial non-aqueous medium was also investigated and the obtained results (up to 5% (v/v) alcohol) were satisfactory. The proposed electrode was used during 15 weeks without any significant change in its potential response. Additionally, the electrode was very useful in water analysis studies such as dam water, river water, tap water, and swimming pool water where the direct determination of chlorate ions was required. Copyright © 2016 Elsevier B.V. All rights reserved.

Improving the Response of Copper(II) Selective PVC Membrane Electrode by Modification of N2S2 Donor Ligand.

Science.gov (United States)

Brinić, Slobodan; Buzuk, Marijo; Generalić, Eni; Bralić, Marija

2010-06-01

S,S'-bis(2-aminophenyl)ethanebis(thioate), (APhET), is reported as N2S2 ligand which form chelate with copper of high stability as compared to the other metals. Two modification of APhET, simpler 1,2-di-(o-aminophenylthio)ethane (DAPhTE), and the complex one 1,2-di-(o-salicylaldiminophenylthio)ethane (SAPhTE), were examined as the active material for copper(II) ion selective PVC membrane electrodes, and observed results are correlated. The obtained results with DAPhTE based electrodes show that only coordination abilities of ligand are insufficient for preparing the efficient membrane material. On the other hand, the results that are achieved with electrodes based on SAPhTE actuate interaction of ligand with polymer membrane matrix and necessity of ionophore immobilization in membrane. Optimized SAPhTE based membrane electrode has a linear range down to 10-6 mol L-1, with slope of 27.0 mV per decade, very rapid response time (under 5 seconds) and detection limit of 5.1 × 10-7 mol L-1. Such electrode is suitable for determination of copper(II) in analytical measurements by direct potentiometry and in potentiometric titrations, within pH between 2 and 7. The electrode is selective for copper(II) ions over a large number of metal ions, with the exception on Hg2+ ion when is present in concentrations above 2 × 10-5 mol L-1.

Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

International Nuclear Information System (INIS)

Ghanei-Motlagh, Masoud; Taher, Mohammad Ali; Ahmadi, Kyoumars; Sheikhshoaie, Iran

2011-01-01

A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I - ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 ± 0.5 (CPtE) and 60.3 ± 0.4 (PME) mV decade -1 in I - ion over a wide concentration range from 7.9 x 10 -7 to 1.0 x 10 -1 M for CPtE and 9.1 x 10 -6 to 1.0 x 10 -1 M I - for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time ( - . → The sensors have a wide concentration range with a fast response time. → Efforts have been made to improve the selectivity with the use of CPtE.

A calixarene-based ion-selective electrode for thallium(I) detection.

Science.gov (United States)

Chester, Ryan; Sohail, Manzar; Ogden, Mark I; Mocerino, Mauro; Pretsch, Ernö; De Marco, Roland

2014-12-03

Three new calixarene Tl(+) ionophores have been utilized in Tl(+) ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10(-2)-10(-6)M TlNO3 with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (logβIL) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn(2+), Ca(2+), Ba(2+), Cu(2+), Cd(2+) and Al(3+) with moderate selectivity against Pb(2+), Li(+), Na(+), H(+), K(+), NH4(+) and Cs(+), noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)-poly(decyl methacrylate) (PMMA-PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4mVdecade(-1) and a lower detection limit of 30.2nM. Due to the presence of an undesirable water layer and/or leaching of redox mediator from the graphite redox buffered SC, a coated wire electrode on gold and graphite redox buffered SC yielded grossly inferior detection limits against the polypyrrole/PVC SC and POT/PMMA-PDMA SC ISEs that did not display signs of a water layer or leaching of SC ingredients into the membrane. Copyright © 2014 Elsevier B.V. All rights reserved.

Trace analysis of cyanide by ion-selective electrode indicator technique

International Nuclear Information System (INIS)

Tom, R.L.; Kapauan, P.A.

1977-01-01

Due to the toxicity of cyanide, its analysis in water is important. The use of ion-selective electrodes for its determination was studied. The known addition method using a silver sulfide membrane electrode was studied. This involved using a silver indicator solution to determine the cyanide content of a sample. Known amounts of a standard cyanide solution were added and the potentials noted. The results were plotted and the original concentration of cyanide extrapolated. The results of the experiment indicated the method to be practical for analysis of industrial waste waters, even in the presence of metal ions. The metal ions were masked using an EDTA solution while possible sulfides were precipitated out using a Pb (N0 3 ) 2 solution. The method was tested on four actual samples and the results indicated the applicability of the method

Comparative Study of PVC-Free All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for the Determination of Dapoxetine Hydrochloride in Pharmaceutical Formulation.

Science.gov (United States)

Aziz, Azza; Khamees, Nesrin; Mohamed, Tagreed Abdel-Fattah; Derar, Abeer Rashad

2016-11-01

The potentiometric response characteristics and analytical applications of a poly(vinyl chloride) (PVC)-free all-solid-state ion-selective electrode for dapoxetine hydrochloride (DAP) are examined. The Nernstian response of the electrode was evaluated by comparison with PVC-based liquid membrane and carbon paste electrodes. The PVC-free electrode is prepared by direct incorporation of dapoxetine-tetraphenyl borate (DAP-TPB) as a sensing element into a commercial nail varnish containing cellulose acetate propionate. The composite was applied onto a 3 mm diameter graphite disk electrode. The electrode exhibited a Nernstian slope of 56.0 mV/decade in the concentration range of 1 × 10-4 to 1 × 10-2 mol/L with an LOD of 2 × 10-5 mol/L. The electrode is independent of pH in the range of 2 to 6 and showed good selectivity for DAP with respect to a large number of inorganic cations and amino acids. Comparable Nernstian slope, sensitivity, pH range, and selectivity pattern were obtained with a PVC membrane and a carbon paste incorporating DAP-TPB as a sensing element and dioctylphthalate as a solvent mediator. The electrodes were used for the determination of DAP in pure solution and in tablets without extraction with high accuracy and precision (RSD ≤ 2%). The nail varnish solid-state electrode is simple, economical, and rapid when compared with PVC membrane and carbon paste electrodes.

Helium Ion Microscopy of proton exchange membrane fuel cell electrode structures

DEFF Research Database (Denmark)

Chiriaev, Serguei; Dam Madsen, Nis; Rubahn, Horst-Günter

2017-01-01

electrode interface structure dependence on ionomer content, systematically studied by Helium Ion Microscopy (HIM). A special focus was on acquiring high resolution images of the electrode structure and avoiding interface damage from irradiation and tedious sample preparation. HIM demonstrated its....... In the hot-pressed electrodes, we found more closed contact between the electrode components, reduced particle size, polymer coalescence and formation of nano-sized polymer fiber architecture between the particles. Keywords: proton exchange membrane fuel cells (PEMFCs); Helium Ion Microscopy (HIM...

A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

International Nuclear Information System (INIS)

Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Yusof, Noor Azah; Tee, Tan Wee; Abdullah, Abd Halim; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Heng, Lee Yook

2011-01-01

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl + cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 x 10 -8 to 1.0 x 10 -1 M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu 2+ Ni 2+ and Pb 2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl + cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl + cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 x 10 -8 to 1.0 x 10 -1 M is linear with a Nernstian slope of 57.27 mV.

A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

Science.gov (United States)

Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Azah Yusof, Noor; Tee, Tan Wee; Yook Heng, Lee; Halim Abdullah, Abd

2011-02-01

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl+ cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 × 10-8 to 1.0 × 10-1M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu2+ Ni2+ and Pb2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl+ cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl+ cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 × 10-8 to 1.0 × 10-1M is linear with a Nernstian slope of 57.27 mV.

Determination of zirconium by fluoride ion selective electrode

International Nuclear Information System (INIS)

Mahanty, B.N.; Sonar, V.R.; Gaikwad, R.; Raul, S.; Das, D.K.; Prakash, A.; Afzal, Md.; Panakkal, J.P.

2010-01-01

Full text: Zirconium is used in a wide range of applications including nuclear clad, catalytic converters, surgical appliances, metallurgical furnaces, superconductors, ceramics, lamp filaments, anti corrosive alloys and photographical purposes. Irradiation testing of U-Zr and U-Pu-Zr fuel pins has also demonstrated their feasibility as fuel in liquid metal reactors. Different methods that are employed for the determination of zirconium are spectrophotometry, potentiometry, neutron activation analysis and mass spectrometry. Ion-selective electrode (ISE), selective to zirconium ion has been studied for the direct potentiometric measurements of zirconium ions in various samples. In the present work, an indirect method has been employed for the determination of zirconium in zirconium nitrate sample using fluoride ion selective electrode. This method is based on the addition of known excess amount of fluoride ion to react with the zirconium ion to produce zirconium tetra fluoride at about pH 2-3, followed by determination of residual fluoride ion selective electrode. The residual fluoride ion concentrations were determined from the electrode potential data using calibration plot. Subsequently, zirconium ion concentrations were determined from the concentration of consumed fluoride ions. A precision of about 2% (RSD) with the mean recovery of more than 94% has been achieved for the determination of zirconium at the concentration of 4.40 X 10 -3 moles lit -1

Rapid determination of trace level copper in tea infusion samples by solid contact ion selective electrode

Directory of Open Access Journals (Sweden)

Aysenur Birinci

2016-07-01

Full Text Available A new solid contact copper selective electrode with a poly (vinyl chloride (PVC membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds and near-Nernstian response to Cu2+ activity from 10−1 to 10−6 mol/L at the pH range of 4.0–6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS.

A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

Energy Technology Data Exchange (ETDEWEB)

Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Yusof, Noor Azah; Tee, Tan Wee; Abdullah, Abd Halim [Department of Chemistry Faculty of Science, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Rounaghi, Gholamhossein; Mohajeri, Masoomeh [Department of Chemistry, Factuality of Sciences, Islamic Azad University of Mashhad, Mashhad (Iran, Islamic Republic of); Heng, Lee Yook, E-mail: anuar@science.upm.edu.my [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E. (Malaysia)

2011-02-15

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl{sup +} cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 x 10{sup -8} to 1.0 x 10{sup -1}M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu{sup 2+} Ni{sup 2+} and Pb{sup 2+} cations, but the electrode has a wider dynamic range and a lower detection limit to Tl{sup +} cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl{sup +} cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 x 10{sup -8} to 1.0 x 10{sup -1}M is linear with a Nernstian slope of 57.27 mV.

Silver-coated ion exchange membrane electrode applied to electrochemical reduction of carbon dioxide

International Nuclear Information System (INIS)

Hori, Y.; Ito, H.; Okano, K.; Nagasu, K.; Sato, S.

2003-01-01

Silver-coated ion exchange membrane electrodes (solid polymer electrolyte, SPE) were prepared by electroless deposition of silver onto ion exchange membranes. The SPE electrodes were used for carbon dioxide (CO 2 ) reduction with 0.2 M K 2 SO 4 as the electrolyte with a platinum plate (Pt) for the counterelectrode. In an SPE electrode system prepared from a cation exchange membrane (CEM), the surface of the SPE was partly ruptured during CO 2 reduction, and the reaction was rapidly suppressed. SPE electrodes made of an anion exchange membrane (SPE/AEM) sustained reduction of CO 2 to CO for more than 2 h, whereas, the electrode potential shifted negatively during the electrolysis. The reaction is controlled by the diffusion of CO 2 through the metal layer of the SPE electrode at high current density. Ultrasonic radiation, applied to the preparation of SPE/AEM, was effective to improve the electrode properties, enhancing the electrolysis current of CO 2 reduction. Observation by a scanning electron microscope (SEM) showed that the electrode metal layer became more porous by the ultrasonic radiation treatment. The partial current density of CO 2 reduction by SPE/AEM amounted to 60 mA cm -2 , i.e. three times the upper limit of the conventional electrolysis by a plate electrode. Application of SPE device may contribute to an advancement of CO 2 fixation at ambient temperature and pressure

A Hydrogen Ion-Selective Sensor Based on Non-Plasticised Methacrylic-acrylic Membranes

Directory of Open Access Journals (Sweden)

Musa Ahmad

2002-08-01

Full Text Available A methacrylic-acrylic polymer was synthesised for use as a non-plasticised membrane for hydrogen ion-selective sensor incorporating tridodecylamine as an ionophore. The copolymer consisted of methyl methacrylate and n-butyl acrylate monomers in a ratio of 2:8. Characterisation of the copolymer using FTNMR demonstrated that the amount of each monomer incorporated during solution polymerisation was found to be similar to the amount used in the feed before polymerisation. The glass transition temperature of the copolymer determined by differential scanning calorimetry was -30.9 ºC. Potentiometric measurements conducted showed a linear pH response range of 4.3 – 9.6 with the response slope of 56.7 mV/decade. The selectivity of the sensors towards hydrogen ions was similar to other plasticiser based membrane electrodes and the logarithmic selectivity coefficients for discrimination against interference cations is close to –9.7. However, the incorporation of a lipophilic anion as membrane additive is essential in ensuring optimum performance of the hydrogen ion sensor.

Metalophthalocyanine complexes as ion-carriers in membrane-selective electrodes for detection of thiosalicylic acid

International Nuclear Information System (INIS)

Shahrokhian, Saeed; Souri, Ali

2004-01-01

The potentiometric response properties of several PVC-based membrane electrodes using phthalocyanine complexes of aluminum (AlPc), nickel (NiPc) and copper (CuPc) as anion carriers, toward thiosalicylic acid (TSA) were investigated. The influences of lipophilic ionic additives (cationic and anionic) and the pH of the buffered solutions were used for the interpretation of the mechanism of the potentiometric response of sensors. The sensitivity, linear range, detection limit, and potentiometric selectivity of the membrane sensors show a considerable dependence on the nature of central metal of the ionophore. The membrane electrodes based on AlPc demonstrate sub-Nernstian responses toward TSA over the range of 0.01 to 1x10 -5 M. In the case of NiPc and CuPc as ionophores and in the presence of trioctylmethyl ammonium (TOMA + ) as a cationic additive, a Nernstian response could be established in a range of 4 orders of magnitudes of TSA concentration (0.01 to 1x10 -6 M). The results of potentiometric investigations revealed that from thermodynamic point of view, the axial coordination of thiosalicylate with the central metal of NiPc and CuPc is more efficient with respect to AlPc. This preference in response to TSA was discussed on the basis of the softness nature of NiPc and CuPc and more affinity for coordination with the thiolate group of thiosalicylate as a soft anion. These potentiometric sensors manifest prominent advantages of high selectivity for TSA over the various inorganic and organic anions, fast response times and micromolar detection limits and can be used over a wide pH range of 4.0-8.0. The prepared electrodes based on NiPc and CuPc were successfully applied in the potentiometric titration of sub-milimolar quantities of Hg 2+ in aqueous solutions and very good recovery results were obtained in these measurements. The results of complexometric studies between Hg 2+ and TSA using electrodes based on NiPc and CuPc as indicator electrodes were compared with

Potentiometric flow injection system for determination of reductants using a polymeric membrane permanganate ion-selective electrode based on current-controlled reagent delivery.

Science.gov (United States)

Song, Wenjing; Ding, Jiawang; Liang, Rongning; Qin, Wei

2011-10-17

A polymeric membrane permanganate-selective electrode has been developed as a current-controlled reagent release system for potentiometric detection of reductants in flow injection analysis. By applying an external current, diffusion of permanganate ions across the polymeric membrane can be controlled precisely. The permanganate ions released at the sample-membrane interface from the inner filling solution of the electrode are consumed by reaction with a reductant in the sample solution thus changing the measured membrane potential, by which the reductant can be sensed potentiometrically. Ascorbate, dopamine and norepinephrine have been employed as the model reductants. Under the optimized conditions, the potential peak heights are proportional to the reductant concentrations in the ranges of 1.0×10(-5) to 2.5×10(-7)M for ascorbate, of 1.0×10(-5) to 5.0×10(-7)M for dopamine, and of 1.0×10(-5) to 5.0×10(-7)M for norepinephrine, respectively with the corresponding detection limits of 7.8×10(-8), 1.0×10(-7) and 1.0×10(-7)M. The proposed system has been successfully applied to the determination of reductants in pharmaceutical preparations and vegetables, and the results agree well with those of iodimetric analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of cerium ion by polymeric membrane and coated graphite electrode based on novel pendant armed macrocycle.

Science.gov (United States)

Singh, Ashok K; Singh, Prerna

2010-08-24

Plasticized membranes using 2,3,4:12,13,14-dipyridine-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L(1)) and 2,3,4:12,13,14-dipyridine-1,5,8,11,15,18-hexamethylacrylate-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L(2)) have been prepared and explored as Ce(III) selective sensors. Effect of various plasticizers viz. dibutylphthalate (DBP), tri-n-butylphthalate (TBP), o-nitrophenyloctylether (o-NPOE), dioctylphthalate (DOP), benzylacetate (BA) and anion excluders, sodium tetraphenylborate (NaTPB) and potassium tetrakis p-(chlorophenyl) borate was studied in detail and improved performance was observed. Optimum performance was observed for the membrane sensor having a composition of L(2):PVC:o-NPOE:KTpClPB in the ratio of 6:34:58:2 (w/w, mg). The performance of the membrane based on L(2) was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Ce(III) ions with limits of detection of 8.3x10(-8) mol L(-1) for PME and 7.7x10(-9) mol L(-1) for CGE. The response time for PME and CGE was found to be 12 s and 10 s respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.5-7.5 for PME and 2.5-8.5 for CGE. The CGE could be used for a period of 5 months. The practical utility of the CGE has been demonstrated by its usage as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce(III) solution. The proposed electrode was also successfully applied to the determination of fluoride ions in mouthwash solution and oxalate ions in real samples. 2010 Elsevier B.V. All rights reserved.

Determination of cerium ion by polymeric membrane and coated graphite electrode based on novel pendant armed macrocycle

Energy Technology Data Exchange (ETDEWEB)

Singh, Ashok K., E-mail: akscyfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India); Singh, Prerna [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India)

2010-08-24

Plasticized membranes using 2,3,4:12,13,14-dipyridine-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L{sub 1}) and 2,3,4:12,13,14-dipyridine-1,5,8,11,15,18-hexamethylacrylate- 1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L{sub 2}) have been prepared and explored as Ce(III) selective sensors. Effect of various plasticizers viz. dibutylphthalate (DBP), tri-n-butylphthalate (TBP), o-nitrophenyloctylether (o-NPOE), dioctylphthalate (DOP), benzylacetate (BA) and anion excluders, sodium tetraphenylborate (NaTPB) and potassium tetrakis p-(chlorophenyl) borate was studied in detail and improved performance was observed. Optimum performance was observed for the membrane sensor having a composition of L{sub 2}:PVC:o-NPOE:KTpClPB in the ratio of 6:34:58:2 (w/w, mg). The performance of the membrane based on L{sub 2} was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Ce(III) ions with limits of detection of 8.3 x 10{sup -8} mol L{sup -1} for PME and 7.7 x 10{sup -9} mol L{sup -1} for CGE. The response time for PME and CGE was found to be 12 s and 10 s respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.5-7.5 for PME and 2.5-8.5 for CGE. The CGE could be used for a period of 5 months. The practical utility of the CGE has been demonstrated by its usage as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce(III) solution. The proposed electrode was also successfully applied to the determination of fluoride ions in mouthwash solution and oxalate ions in real samples.

Determination of cerium ion by polymeric membrane and coated graphite electrode based on novel pendant armed macrocycle

International Nuclear Information System (INIS)

Singh, Ashok K.; Singh, Prerna

2010-01-01

Plasticized membranes using 2,3,4:12,13,14-dipyridine-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L 1 ) and 2,3,4:12,13,14-dipyridine-1,5,8,11,15,18-hexamethylacrylate- 1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L 2 ) have been prepared and explored as Ce(III) selective sensors. Effect of various plasticizers viz. dibutylphthalate (DBP), tri-n-butylphthalate (TBP), o-nitrophenyloctylether (o-NPOE), dioctylphthalate (DOP), benzylacetate (BA) and anion excluders, sodium tetraphenylborate (NaTPB) and potassium tetrakis p-(chlorophenyl) borate was studied in detail and improved performance was observed. Optimum performance was observed for the membrane sensor having a composition of L 2 :PVC:o-NPOE:KTpClPB in the ratio of 6:34:58:2 (w/w, mg). The performance of the membrane based on L 2 was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Ce(III) ions with limits of detection of 8.3 x 10 -8 mol L -1 for PME and 7.7 x 10 -9 mol L -1 for CGE. The response time for PME and CGE was found to be 12 s and 10 s respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.5-7.5 for PME and 2.5-8.5 for CGE. The CGE could be used for a period of 5 months. The practical utility of the CGE has been demonstrated by its usage as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce(III) solution. The proposed electrode was also successfully applied to the determination of fluoride ions in mouthwash solution and oxalate ions in real samples.

Mixed complex combinations with a new schiff base used as membranes ion-selective for copper and nickel ions, analytical applications)

International Nuclear Information System (INIS)

Mitu, L.; Tigae, C.

2009-01-01

Four electrodes with liquid membrane, Cu/sup 2+/ -selective and Ni/sup 2+/ -selective, not previously described in the literature, were prepared and characterized. Electrodes 1 and 2 are based on mixed complexes of Cu(II) and Ni(II) with isonicotinoylhydrazone-2-aldehyde pyrrole (INH2AP= HL/sup 1/) as ligand and electrodes 3 and 4 are based on the mixed complexes with isonicotinoyl- hydrazone-2-hydroxy-l-naphthaldehyde (INH2HNA = H/sub 2/L/sup 2/ ) Cu/sup 2+/. selective and Ni/sup 2+/ -selective electrodes have been used to determine the copper and nickel ions in aqueous solutions, by both direct potentiometric and potentiometric titration with EDTA. They have also been used for determining the Cu/sup 2+/ and Ni/sup 2+/ ions in industrial waters by direct potentiometry. The analytical results obtained have been checked by the standard addition method and by comparison with determinations through atomic absorption spectrometry. (author)

Solid-contact pH-selective electrode using multi-walled carbon nanotubes.

Science.gov (United States)

Crespo, Gastón A; Gugsa, Derese; Macho, Santiago; Rius, F Xavier

2009-12-01

Multi-walled carbon nanotubes (MWCNT) are shown to be efficient transducers of the ionic-to-electronic current. This enables the development of a new solid-contact pH-selective electrode that is based on the deposition of a 35-microm thick layer of MWCNT between the acrylic ion-selective membrane and the glassy carbon rod used as the electrical conductor. The ion-selective membrane was prepared by incorporating tridodecylamine as the ionophore, potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as the lipophilic additive in a polymerized methylmethacrylate and an n-butyl acrylate matrix. The potentiometric response shows Nernstian behaviour and a linear dynamic range between 2.89 and 9.90 pH values. The response time for this electrode was less than 10 s throughout the whole working range. The electrode shows a high selectivity towards interfering ions. Electrochemical impedance spectroscopy and chronopotentiometry techniques were used to characterise the electrochemical behaviour and the stability of the carbon-nanotube-based ion-selective electrodes.

Cerium(III-Selective Membrane Electrode Based on Dibenzo-24-crown-8 as a Neutral Carrier

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Susheel K. Mittal

2010-01-01

Full Text Available Cerium(III-selective membrane electrodes have been prepared using dibenzo-24-crown-8 (DB24C8 as an electroactive material. A membrane having a composition: DB24C8 (4.5%, plasticizer (NPOE, 62.5% and PVC (33% gives the best performance. It works well over a wide Ce(III ion-concentration range of 1x10-5 M to 1x10-1 M with a Nernstian slope of 19.0 mV/decade and a detection limit of 3x10-5 M. It has a fast response time of 20 seconds and has an average lifetime of four months. The internal solution concentration does not have a significant effect on the response of the electrode except for a change in intercept of the calibration curves. The working pH range for Ce(III solutions (1x10-2 M and 1x10-3 M is 3.5-8.0. The proposed sensor shows a good selectivity for cerium(III with respect to alkali, alkaline earth, some transition and rare earth metal ions that are normally present along with cerium in its ores. The proposed sensor was investigated in partially non-aqueous media using acetone, methanol and DMSO mixtures with water. The electrode was further used as an indicator electrode for the potentiometric titration of Ce(III solution against oxalic acid solution.

Ion-Selective Electrode for the Determination of Iron(III in Vitamin Formulations

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Teixeira Marcos Fernando de S.

1998-01-01

Full Text Available A coated graphite-epoxy ion-selective electrode for iron(III, based on the ion-pair formed between [Fe(citrate2]3- and the tricaprylylmethylammonium cation (Aliquat 336 in a poly(vinylchloride (PVC matrix has been constructed. A thin membrane film of this ion-pair, dibutylphthalate (DBPh in PVC was deposited directly onto a Perspex® tube, which contained a graphite-epoxy conductor substrate. The coating solution was prepared by dissolving 30% (w/w of PVC in 10 mL of tetrahydrofuran following addition of 65% (w/w DBPh and 5% (w/w of the ionic pair. The effect of pH, citrate concentration and some cations on the electrode response has been investigated. The E(mV vs. log [Fe(citrate2]3- electrode response was linear for iron(III concentration from 1.0 x 10-3 mol/L to 1.0 x 10-1 mol/L in 1.0 mol/L citrate medium, with a slope of 19.3 ± 0.5 mV/decade and a useful lifetime of at least six months (more than 800 determinations for each polymeric membrane used. The detection limit was 7.5 x 10-4 mol/L and the relative standard deviation was less than 3% for a solution containing 5.0 x 10-3 mol/L of iron(III (n = 10. The application of this electrode for iron(III determination in samples of vitamin formulations is described. The results obtained with this procedure are in close agreement with those obtained using AA spectrophotometry (r = 0.9999.

A solid-contact Pb2+-selective electrode using poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) as ion-to-electron transducer

International Nuclear Information System (INIS)

Yu Shunyang; Li Fuhai; Yin Tanji; Liu Yongming; Pan, Dawei; Qin Wei

2011-01-01

Highlights: → All reagents used for the electrodes preparation were commercially available. → The lower detection limit of the proposed electrode reached subnanomolar levels. → No water film was observed with conventional commercially available PVC ion-sensing membranes. → This research provides an excellent strategy for fabrication of robust polymeric ion sensors. - Abstract: In this work, a novel all-solid-state polymeric membrane Pb 2+ -selective electrode was developed by using for the first time poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) as solid contact. To demonstrate the ion-to-electron transducing ability of MEH-PPV, chronopotentiometry and electrochemical impedance spectroscopy measurements were carried out. The proposed electrodes showed a Nernstian response of 29.1 mV decade -1 and a lower detection limit of subnanomolar level. No water film was observed with the conventional plasticized PVC membrane. This work demonstrates a new strategy for the fabrication of robust potentiometric ion sensors.

Potentiometric Determination of Ketotifen Fumarate in Pharmaceutical Preparations and Urine Using Carbon Paste and PVC Membrane Selective Electrodes

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Eman Y. Z. Frag

2011-01-01

Full Text Available This study compares between unmodified carbon paste (CPE; the paste has no ion pair and polyvinyl chloride (PVC membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF, where sodium tetraphenylborate (NaTPB was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10−7 to 10−2 mol L−1. The electrodes show Nernstian slope value of 52.51±0.20 and 51.51±0.25 mV decade−1 for CPE and PVC membrane electrodes at 30∘C, respectively. The potential is nearly stable over the pH range 3.0–6.0 and 2.0–7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets, and biological fluid (urine. The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97±0.53 and 98.62±0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.

Potentiometric determination of ketotifen fumarate in pharmaceutical preparations and urine using carbon paste and PVC membrane selective electrodes.

Science.gov (United States)

Frag, Eman Y Z; Mohamed, Gehad G; Khalil, Mohamed M; Hwehy, Mohammad M A

2011-01-01

This study compares between unmodified carbon paste (CPE; the paste has no ion pair) and polyvinyl chloride (PVC) membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF), where sodium tetraphenylborate (NaTPB) was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10(-7) to 10(-2) mol L(-1). The electrodes show Nernstian slope value of 52.51 ± 0.20 and 51.51 ± 0.25 mV decade(-1) for CPE and PVC membrane electrodes at 30°C, respectively. The potential is nearly stable over the pH range 3.0-6.0 and 2.0-7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets), and biological fluid (urine). The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97 ± 0.53 and 98.62 ± 0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.

Lanthanum(IlI) PVC membrane electrodes based on 1,3,5-trithiacyclohexane.

Science.gov (United States)

Shamsipur, Mojtaba; Yousefi, Mohammad; Hosseini, Morteza; Ganjali, Mohammad Reza

2002-11-01

Novel plasticized polymeric membrane (PPME) and membrane-coated graphite (MCGE) electrodes based on 1,3,5-trithiacyclohexane for highly selective determination of La3+ ion have been developed. The electrodes exhibit Nernstian responses over very wide concentration ranges (8.0 x 10(-6)-5.0 x 10(-2) M for PPME and 4.0 x 10(-8)-1.0 x 10(-2) M for MCGE). The limit of detections were 5.0 x 10(-6) and 2.0 x 10(-8) M for PPME and MCGE, respectively. The electrodes possess a fast response time of approximately 10 s and can be used for at least 6 months without observing any deviation. The proposed electrodes revealed excellent selectivities for La3+ over a wide variety of alkali, alkaline earth, transition, and heavy metal ions and could be used in a pH range of 5.0-8.0. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of La3+ ions with EDTA and in determination of F- in some mouthwash preparations.

Determination of uranyl ion by potentiometric titration using an uranyl-selective electrode

International Nuclear Information System (INIS)

Nassory, N.S.

1990-01-01

A potentiometric titration of uranyl ion is described using an uranyl selective electrode based on a membrane containing a complex of UO 2 -bis[di-4-(1,1,3,3-tetramethylbutyl)phenyl phosphate] as an ion-exchanger and tritolyl phosphate as a solvent mediator. The titrations were carried out with various titrants: Sodium hydroxide, potassium fluoride and sodium salts of acetate, oxalate and citrate. The equivalence points were determined by Gran's method. Good results were obtained by using sodium oxalate as a titrant for the determination of uranium in several samples of ammonium diuranate. The results were quite comparable with those obtained by X-ray fluorescence spectrometry. (orig.)

Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

International Nuclear Information System (INIS)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha

2007-01-01

The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S 1 ) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S 1 ) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10 -8 to 1.0 x 10 -1 M Cd 2+ with limit of detection 5.0 x 10 -8 M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

Energy Technology Data Exchange (ETDEWEB)

Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

2007-02-05

The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

A solid-contact Pb{sup 2+}-selective electrode using poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) as ion-to-electron transducer

Energy Technology Data Exchange (ETDEWEB)

Yu Shunyang [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Li Fuhai [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Chemistry and Chemical Engineering College, Yantai University, Yantai 264005 (China); Yin Tanji [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Liu Yongming [Chemistry and Chemical Engineering College, Yantai University, Yantai 264005 (China); Pan, Dawei [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Qin Wei, E-mail: wqin@yic.ac.cn [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

2011-09-30

Highlights: {yields} All reagents used for the electrodes preparation were commercially available. {yields} The lower detection limit of the proposed electrode reached subnanomolar levels. {yields} No water film was observed with conventional commercially available PVC ion-sensing membranes. {yields} This research provides an excellent strategy for fabrication of robust polymeric ion sensors. - Abstract: In this work, a novel all-solid-state polymeric membrane Pb{sup 2+}-selective electrode was developed by using for the first time poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) as solid contact. To demonstrate the ion-to-electron transducing ability of MEH-PPV, chronopotentiometry and electrochemical impedance spectroscopy measurements were carried out. The proposed electrodes showed a Nernstian response of 29.1 mV decade{sup -1} and a lower detection limit of subnanomolar level. No water film was observed with the conventional plasticized PVC membrane. This work demonstrates a new strategy for the fabrication of robust potentiometric ion sensors.

Ion-selective field-effect transitors. A sensor for lithium and calcium

International Nuclear Information System (INIS)

Kharitonov, A.B.; Petrukhin, O.M.; Nad', V.Yh.; Ypivakov, B.Ya.; Myasoedov, B.F.; Otmakhova, O.A.; Tal'roze, R.V.; Plateh, N.A.

1997-01-01

An Li-sensitive sensor based on a field-effect transistor with a tantalum pentoxide gate and a poly(vinyl chloride) membrane based on diethylene glycol bis-o-2-diphenylphosphinylmethyl phenyl ether is developed. THis sensor exhibits analytical characteristics close to those of a lithium-selective electrode analogous in membrane composition; it is insensitive to the concentration of hydrogen ions in the pH range 4.5-8.5. The service life of the sensor is no shorter than four months, which is comparable to the service life of the corresponding ion-selective electrode. A bifunctional sensor for Ca and Li is prepared based on membranes used for preparing the corresponding monofunctional ion-selective field-effect transistors; this sensor exhibits analytical characteristics close to those of ion-selective electrodes and monofunctional sensors. 12 refs., 6 figs., 2 tabs

Microfluidic systems with ion-selective membranes.

Science.gov (United States)

Slouka, Zdenek; Senapati, Satyajyoti; Chang, Hsueh-Chia

2014-01-01

When integrated into microfluidic chips, ion-selective nanoporous polymer and solid-state membranes can be used for on-chip pumping, pH actuation, analyte concentration, molecular separation, reactive mixing, and molecular sensing. They offer numerous functionalities and are hence superior to paper-based devices for point-of-care biochips, with only slightly more investment in fabrication and material costs required. In this review, we first discuss the fundamentals of several nonequilibrium ion current phenomena associated with ion-selective membranes, many of them revealed by studies with fabricated single nanochannels/nanopores. We then focus on how the plethora of phenomena has been applied for transport, separation, concentration, and detection of biomolecules on biochips.

Studies on the matched potential method for determining the selectivity coefficients of ion-selective electrodes based on neutral ionophores: experimental and theoretical verification.

Science.gov (United States)

Tohda, K; Dragoe, D; Shibata, M; Umezawa, Y

2001-06-01

A theory is presented that describes the matched potential method (MPM) for the determination of the potentiometric selectivity coefficients (KA,Bpot) of ion-selective electrodes for two ions with any charge. This MPM theory is based on electrical diffuse layers on both the membrane and the aqueous side of the interface, and is therefore independent of the Nicolsky-Eisenman equation. Instead, the Poisson equation is used and a Boltzmann distribution is assumed with respect to all charged species, including primary, interfering and background electrolyte ions located at the diffuse double layers. In this model, the MPM-selectivity coefficients of ions with equal charge (ZA = ZB) are expressed as the ratio of the concentrations of the primary and interfering ions in aqueous solutions at which the same amounts of the primary and interfering ions permselectively extracted into the membrane surface. For ions with unequal charge (ZA not equal to ZB), the selectivity coefficients are expressed as a function not only of the amounts of the primary and interfering ions permeated into the membrane surface, but also of the primary ion concentration in the initial reference solution and the delta EMF value. Using the measured complexation stability constants and single ion distribution coefficients for the relevant systems, the corresponding MPM selectivity coefficients can be calculated from the developed MPM theory. It was found that this MPM theory is capable of accurately and precisely predicting the MPM selectivity coefficients for a series of ion-selective electrodes (ISEs) with representative ionophore systems, which are generally in complete agreement with independently determined MPM selectivity values from the potentiometric measurements. These results also conclude that the assumption for the Boltzmann distribution was in fact valid in the theory. The recent critical papers on MPM have pointed out that because the MPM selectivity coefficients are highly concentration

All-Solid-State Sodium-Selective Electrode with a Solid Contact of Chitosan/Prussian Blue Nanocomposite

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Tanushree Ghosh

2017-11-01

Full Text Available Conventional ion-selective electrodes with a liquid junction have the disadvantage of potential drift. All-solid-state ion-selective electrodes with solid contact in between the metal electrode and the ion-selective membrane offer high capacitance or conductance to enhance potential stability. Solution-casted chitosan/Prussian blue nanocomposite (ChPBN was employed as the solid contact layer for an all-solid-state sodium ion-selective electrode in a potentiometric sodium ion sensor. Morphological and chemical analyses confirmed that the ChPBN is a macroporous network of chitosan that contains abundant Prussian blue nanoparticles. Situated between a screen-printed carbon electrode and a sodium-ionophore-filled polyvinylchloride ion-selective membrane, the ChPBN layer exhibited high redox capacitance and fast charge transfer capability, which significantly enhanced the performance of the sodium ion-selective electrode. A good Nernstian response with a slope of 52.4 mV/decade in the linear range from 10−4–1 M of NaCl was observed. The stability of the electrical potential of the new solid contact was tested by chronopotentiometry, and the capacitance of the electrode was 154 ± 4 µF. The response stability in terms of potential drift was excellent (1.3 µV/h for 20 h of continuous measurement. The ChPBN proved to be an efficient solid contact to enhance the potential stability of the all-solid-state ion-selective electrode.

Nanomolar determination of Pb (II ions by selective templated electrode

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Mazloum-Ardakani Mohammad

2012-01-01

Full Text Available Polypyrrole modified electrode, prepared by electropolymerization of pyrrole in the presence of methyl red as a dopant, was templated with respect to Pb2+ ion and applied for potentiometric and voltammetric detection of this ion. The templating process improved the analytical response characteristics of the electrode, specially their selectivity, with respect to Pb2+ ion. The improvement depends on both the incorporated ligand (dopant and the templating process, with the latter being more vital. The potentiometric response of the electrode was linear within the Pb2+ concentration range of 2.0×10-6 to 5.0×10-2 M with a near-Nernstian slope of 28.6 mV decade-1 and a detection limit of 7.0 ×10-7 M. The electrode was also used for preconcentration differential pulse anodic stripping voltammetry (DPASV and results showed that peak currents for the incorporated lead species were dependent on the metal ion concentration in the range of 1.0×10-8 to 1.0×10-3 M. The detection limit of DPASV method was 3.5 ×10-9 M. The selectivity of the electrode with respect to some transition metal ions was investigated. The modified-templated electrode was used for the successful assay of lead in two standard reference material samples.

Flow Injection Potentiometric Determination of Cd2+ Ions Using a Coated Graphite Plasticized PVC-Membrane Electrode Based on 1, 3-Bis(2-cyanobenzene)triazene.

Science.gov (United States)

Shamsipur, Mojtaba; Sahari, Shokat; Payehghadr, Mahmood; Alizadeh, Kamal

2011-09-01

1, 3-Bis(2-cyanobenzene)triazene, L, was used as a suitable ionophore for the fabrication of a new PVC-based polymeric membrane coated graphite electrode for selective sensing of Cd2+ ion. The electrode exhibited a selective linear Nernstian response to Cd2+ ion at an optimal pH range of 6-9 with a limit of detection of 8.0 × 10-6 M and a fast response time of about 2 s. The electrode was used as a proper detection system in flow-injection potentiometry of cadmium ion and resulted in well defined peaks for cadmium ions with stable baseline, excellent reproducibility and high sampling rates of over 100 injections per hour. It showed good stability, reproducibility and fast response time. The practical utility of the proposed system has also been reported.

Synthesis of nano-sized arsenic-imprinted polymer and its use as As3+ selective ionophore in a potentiometric membrane electrode: Part 1

International Nuclear Information System (INIS)

Alizadeh, Taher; Rashedi, Mariyam

2014-01-01

Highlights: • The first arsenic cation-selective membrane electrode was introduced. • A novel procedure was introduced for the preparation of As-imprinted polymer. • It was found that arsenic is recognized by the IIP as As 3+ species. • Nernstian response of 20.4 mV decade −1 and DL of 0.5 μM was obtained. - Abstract: In this study, a new strategy was proposed for the preparation of As (III)-imprinted polymer by using arsenic (methacrylate) 3 as template. Precipitation polymerization was utilized to synthesize nano-sized As (III)-imprinted polymer. Methacrylic acid and ethylene glycol dimethacrylate were used as the functional monomer and cross-linking agent, respectively. In order to assembly functional monomers around As (III) ion, sodium arsenite and methacrylic acid were heated in the presence of hydroquinone, leading to arsenic (methacrylate) 3 . The nano-sized As (III) selective polymer was characterized by FT-IR and scanning electron microscopy techniques (SEM). It was demonstrated that arsenic was recognized as As 3+ by the selective cavities of the synthesized IIP. Based on the prepared polymer, the first arsenic cation selective membrane electrode was introduced. Membrane electrode was constructed by dispersion of As (III)-imprinted polymer nanoparticles in poly(vinyl chloride), plasticized with di-nonylphthalate. The IIP-modified electrode exhibited a Nernstian response (20.4 ± 0.5 mV decade −1 ) to arsenic ion over a wide concentration range (7.0 × 10 −7 to 1.0 × 10 −1 mol L −1 ) with a lower detection limit of 5.0 × 10 −7 mol L −1 . Unlike this, the non-imprinted polymer (NIP)-based membrane electrode was not sensitive to arsenic in aqueous solution. The selectivity of the developed sensor to As (III) was shown to be satisfactory. The sensor was used for arsenic determination in some real samples

Tris(2-ethylhexyl)phosphine oxide as an effective solvent mediator for constructing a serotonin-selective membrane electrode

International Nuclear Information System (INIS)

Ueda, Keisuke; Yonemoto, Rei; Komagoe, Keiko; Masuda, Kazufumi; Hanioka, Nobumitsu; Narimatsu, Shizuo; Katsu, Takashi

2006-01-01

A series of solvent mediators containing a phosphoryl (P=O) group, such as tris(2-ethylhexyl)phosphate, bis(2-ethylhexyl) 2-ethylhexylphosphonate, 2-ethylhexyl bis(2-ethylhexyl)phosphinate, and tris(2-ethylhexyl)phosphine oxide, were used to construct serotonin-selective membrane electrodes. We found that replacing the alkoxy groups attached to phosphorus atoms in P=O groups with alkyl groups strengthened the response of the electrode to serotonin, suppressing remarkably interference from inorganic cations, such as Na + . Thus, an electrode combining tris(2-ethylhexyl)phosphine oxide with an ion-exchanger, sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate, gave a detection limit of 9 x 10 -6 M with a slope of 55.2 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM NaH 2 PO 4 /Na 2 HPO 4 (pH 7.4). This is the best detection limit of any serotonin-selective electrode developed to date. The selectivity of this electrode for serotonin was over 10 3 times that for inorganic cations, such as Na + and K + , and lipophilic quaternary ammonium ions, such as acetylcholine and (C 2 H 5 ) 4 N + . Using the electrode, we measured the amount of serotonin released from platelets and found that the results agreed well with those obtained by a conventional fluorimetric assay of serotonin

Construction of Eu3+ Ion-Selective Electrode Based on 1,2-Diaminopropane-N,N,N',N'-tetraacetic acid

Directory of Open Access Journals (Sweden)

Mohammad Reza Abedi

2011-01-01

Full Text Available A new Eu3+ PVC membrane electrode based on 1,2-diaminopropane-N, N,N',N'-tetraacetic acid (DAPTA as a suitable ionophore has been prepared and studied. The electrode shows a good selectivity for Eu(III ion with respect to most common cations including alkali, alkaline earth, transition and heavy metal ions. This electrode has a wide linear dynamic range from 1.0×10-6 to 1.0×10-2 M with a Nernstian slope of 19.7±0.5 mV per decade and a low detection limit of 7.2×10-7 M in the pH range of 2.5–9.1, while the response time was rapid (<10 s. The practical utility of the electrodes has been demonstratedby their use as indicator electrodes in the potentiometric titration of Eu3+ ions with EDTA and for the determination of Eu3+ in some water sample solutions.

Ytterbium-selective polymeric membrane electrode based on substituted urea and thiourea as a suitable carrier

International Nuclear Information System (INIS)

Singh, A.K.; Jain, A.K.; Mehtab, Sameena

2007-01-01

Plasticized membranes using 1-phenyl-3-(2-thiazolyl)-2-thiourea (PTT) and 1-phenyl-3-(2-thiazolyl)-2-urea (PTU) have been prepared and explored as ytterbium ion-selective sensors. Effect of various plasticizers, viz. chloronaphthalene (CN), o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), dioctylsebacate (DOS) and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied and improved membrane performance was observed. Optimum performance was noted with membrane of PTT having composition of PTT (3.5):PVC (80):DOS (160):NaTPB (1.5) in mg. The sensor works satisfactorily in the concentration range 1.2 x 10 -7 to 1.0 x 10 -2 M (detection limit 5.5 x 10 -8 M) with a Nernstian slope of 19.7 mV decade -1 of activity. Wide pH range (3.0-8.0), fast response time (10 s), non-aqueous tolerance (up to 20%) and adequate shelf life (12 weeks) indicate the vital utility of the proposed sensor. The proposed electrode comparatively shows good selectivity for Yb 3+ ion with respect to alkali, alkaline earth, transition and rare earth metals ions and can be used for its determination in binary mixtures and sulfite determination in white and red wine samples

Ytterbium-selective polymeric membrane electrode based on substituted urea and thiourea as a suitable carrier.

Science.gov (United States)

Singh, A K; Jain, A K; Mehtab, Sameena

2007-08-06

Plasticized membranes using 1-phenyl-3-(2-thiazolyl)-2-thiourea (PTT) and 1-phenyl-3-(2-thiazolyl)-2-urea (PTU) have been prepared and explored as ytterbium ion-selective sensors. Effect of various plasticizers, viz. chloronaphthalene (CN), o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), dioctylsebacate (DOS) and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied and improved membrane performance was observed. Optimum performance was noted with membrane of PTT having composition of PTT (3.5):PVC (80):DOS (160):NaTPB (1.5) in mg. The sensor works satisfactorily in the concentration range 1.2x10(-7) to 1.0x10(-2) M (detection limit 5.5x10(-8) M) with a Nernstian slope of 19.7 mV decade(-1) of activity. Wide pH range (3.0-8.0), fast response time (10 s), non-aqueous tolerance (up to 20%) and adequate shelf life (12 weeks) indicate the vital utility of the proposed sensor. The proposed electrode comparatively shows good selectivity for Yb3+ ion with respect to alkali, alkaline earth, transition and rare earth metals ions and can be used for its determination in binary mixtures and sulfite determination in white and red wine samples.

Ytterbium-selective polymeric membrane electrode based on substituted urea and thiourea as a suitable carrier

Energy Technology Data Exchange (ETDEWEB)

Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)], E-mail: akscyfcy@iitr.ernet.in; Jain, A.K.; Mehtab, Sameena [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

2007-08-10

Plasticized membranes using 1-phenyl-3-(2-thiazolyl)-2-thiourea (PTT) and 1-phenyl-3-(2-thiazolyl)-2-urea (PTU) have been prepared and explored as ytterbium ion-selective sensors. Effect of various plasticizers, viz. chloronaphthalene (CN), o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), dioctylsebacate (DOS) and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied and improved membrane performance was observed. Optimum performance was noted with membrane of PTT having composition of PTT (3.5):PVC (80):DOS (160):NaTPB (1.5) in mg. The sensor works satisfactorily in the concentration range 1.2 x 10{sup -7} to 1.0 x 10{sup -2} M (detection limit 5.5 x 10{sup -8} M) with a Nernstian slope of 19.7 mV decade{sup -1} of activity. Wide pH range (3.0-8.0), fast response time (10 s), non-aqueous tolerance (up to 20%) and adequate shelf life (12 weeks) indicate the vital utility of the proposed sensor. The proposed electrode comparatively shows good selectivity for Yb{sup 3+} ion with respect to alkali, alkaline earth, transition and rare earth metals ions and can be used for its determination in binary mixtures and sulfite determination in white and red wine samples.

The Role of Ion Exchange Membranes in Membrane Capacitive Deionisation.

Science.gov (United States)

Hassanvand, Armineh; Wei, Kajia; Talebi, Sahar; Chen, George Q; Kentish, Sandra E

2017-09-14

Ion-exchange membranes (IEMs) are unique in combining the electrochemical properties of ion exchange resins and the permeability of a membrane. They are being used widely to treat industrial effluents, and in seawater and brackish water desalination. Membrane Capacitive Deionisation (MCDI) is an emerging, energy efficient technology for brackish water desalination in which these ion-exchange membranes act as selective gates allowing the transport of counter-ions toward carbon electrodes. This article provides a summary of recent developments in the preparation, characterization, and performance of ion exchange membranes in the MCDI field. In some parts of this review, the most relevant literature in the area of electrodialysis (ED) is also discussed to better elucidate the role of the ion exchange membranes. We conclude that more work is required to better define the desalination performance of the proposed novel materials and cell designs for MCDI in treating a wide range of feed waters. The extent of fouling, the development of cleaning strategies, and further techno-economic studies, will add value to this emerging technique.

Synthesis and characterization of poly-o-anisidine Sn(IV tungstate: A new and novel ‘organic–inorganic’ nano-composite material and its electro-analytical applications as Hg(II ion-selective membrane electrode

Directory of Open Access Journals (Sweden)

Asif A. Khan

2012-07-01

Full Text Available An organic–inorganic nano-composite poly-o-anisidine Sn(IV tungstate was chemically synthesized by sol–gel mixing of the incorporation of organic polymer o-anisidine into the matrices of inorganic ppt of Sn(IV tungstate in different mixing volume ratios. This composite material has been characterized using various analytical techniques like XRD (X-ray diffraction, FTIR (Fourier transform infrared, SEM (Scanning electron microscopy, TEM (Transmission electron microscopy and simultaneous TGA (Thermogravimetric analysis studies. On the basis of distribution studies, the material was found to be highly selective for Hg(II. Using this nano-composite cation exchanger as electro-active material, a new heterogeneous precipitate based on ion-sensitive membrane electrode was developed for the determination of Hg(II ions in solutions. The membrane electrode was mechanically stable, with a quick response time, and can be operated within a wide pH range. The electrode was also found to be satisfactory in electrometric titrations.

Junction Potentials Bias Measurements of Ion Exchange Membrane Permselectivity.

Science.gov (United States)

Kingsbury, Ryan S; Flotron, Sophie; Zhu, Shan; Call, Douglas F; Coronell, Orlando

2018-04-17

Ion exchange membranes (IEMs) are versatile materials relevant to a variety of water and waste treatment, energy production, and industrial separation processes. The defining characteristic of IEMs is their ability to selectively allow positive or negative ions to permeate, which is referred to as permselectivity. Measured values of permselectivity that equal unity (corresponding to a perfectly selective membrane) or exceed unity (theoretically impossible) have been reported for cation exchange membranes (CEMs). Such nonphysical results call into question our ability to correctly measure this crucial membrane property. Because weighing errors, temperature, and measurement uncertainty have been shown to not explain these anomalous permselectivity results, we hypothesized that a possible explanation are junction potentials that occur at the tips of reference electrodes. In this work, we tested this hypothesis by comparing permselectivity values obtained from bare Ag/AgCl wire electrodes (which have no junction) to values obtained from single-junction reference electrodes containing two different electrolytes. We show that permselectivity values obtained using reference electrodes with junctions were greater than unity for CEMs. In contrast, electrodes without junctions always produced permselectivities lower than unity. Electrodes with junctions also resulted in artificially low permselectivity values for AEMs compared to electrodes without junctions. Thus, we conclude that junctions in reference electrodes introduce two biases into results in the IEM literature: (i) permselectivity values larger than unity for CEMs and (ii) lower permselectivity values for AEMs compared to those for CEMs. These biases can be avoided by using electrodes without a junction.

Dysprosium selective potentiometric membrane sensor

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Faridbod, Farnoush; Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

2013-03-01

A novel Dy(III) ion-selective PVC membrane sensor was made using a new synthesized organic compound, 3,4-diamino-N Prime -((pyridin-2-yl)methylene)benzohydrazide (L) as an excellent sensing element. The electrode showed a Nernstian slope of 19.8 {+-} 0.6 mV per decade in a wide concentration range of 1.0 Multiplication-Sign 10{sup -6}-1.0 Multiplication-Sign 10{sup -2} mol L{sup -1}, a detection limit of 5.5 Multiplication-Sign 10{sup -7} mol L{sup -1}, a short conditioning time, a fast response time (< 10 s), and high selectivity towards Dy(III) ion in contrast to other cations. The proposed sensor was successfully used as an indicator electrode in the potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also applied to the F{sup -} ion indirect determination of some mouth washing solutions and to the Dy{sup 3+} determination in binary mixtures. Highlights: Black-Right-Pointing-Pointer The novelty of this work is based on the high affinity of the ionophore toward the Dy{sup 3+} ions. Black-Right-Pointing-Pointer This technique is very simple, fast and inexpensive and it is not necessary to use sophisticated equipment. Black-Right-Pointing-Pointer The newly developed sensor is superior to the formerly reported Dy{sup 3+} sensors in terms of selectivity.

A new ion selective electrode for cesium (I) based on calix[4]arene-crown-6 compounds.

Science.gov (United States)

Ramanjaneyulu, P S; Kumar, Abha Naveen; Sayi, Y S; Ramakumar, K L; Nayak, S K; Chattopadhyay, S

2012-02-29

A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium has been developed. 25,27-Dihydroxycalix[4]arene-crown-6 (L1), 5,11,17,23-tetra-tert-butyl-25,27-dimethoxycalix[4]arene-crown-6 (L2) and 25,27-bis(1-octyloxy)calix[4]arene-crown-6 (L3) were investigated for their use as ionophores. The cation exchange resin DOWEX-50W was used to maintain low activity Cs+ in inner filling solution to improve the performance. The best response for cesium was observed with L3 along with optimized membrane constituents and composition. Excellent Nernstian response (56.6 mV/decade of Cs(I)) over the concentration range 10(-7) to 10(-2)M of Cs(I) was obtained with a fast response time of less than 10s. Detection limit for Cs(I) using the present ISE is 8.48×10(-8) M Cs(I). Separate solution method (SSM) was applied to ascertain the selectivity for Cs(I) over alkali, alkaline earth and transition metal ions. The response of ISE for Cs(I) was fairly constant over the pH range of 4-11. The lifetime of the electrode is 10 months which is the highest life for any membrane based Cs-ISE so far developed. The concentration of cesium ion in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing AAS. Copyright © 2011 Elsevier B.V. All rights reserved.

Ion selective electrode for cesium based on 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene.

Science.gov (United States)

Ramanjaneyulu, P S; Singh, Parminder; Sayi, Y S; Chawla, H M; Ramakumar, K L

2010-03-15

A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium was fabricated with 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene as ionophore. Different membrane constituents were investigated to realise optimum performance of the ISE developed. Of the four plasticizers and two ion additives studied, the best response was observed with membrane having 2-nitro phenyl octyl ether (oNPOE) as plasticizer and potassium tetrakis (perchloro phenyl) borate (KTpClPB) as ion additive. Linear response over concentration range of 10(-5)-10(-1)M CsCl was obtained. The Nernstian slope of the response was 56 mV per decade for Cs with a response time less than 20s. Matched potential method has been applied to find out the selectivity for Cs over several ions like Rb(+), K(+), Na(+), NH(4)(+), Sr(2+), Ba(2+), Ca(2+), Mg(2+), Cu(2+), Pb(2+), Zn(2+), Ni(2+) and Ce(3+). The response of ISE for Cs(+) was fairly constant over the pH range of 3-11. The lifetime of the electrode is 9 months which is the longest life for any membrane-based Cs-ISE so far developed. The concentration of cesium in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing atomic absorption spectrometry. (c) 2009 Elsevier B.V. All rights reserved.

Potentiometric measurement of polymer-membrane electrodes based on lanthanum

Energy Technology Data Exchange (ETDEWEB)

Saefurohman, Asep, E-mail: saefurohman.asep78@Gmail.com; Buchari,, E-mail: saefurohman.asep78@Gmail.com; Noviandri, Indra, E-mail: saefurohman.asep78@Gmail.com [Department of Chemistry, Bandung Institute of Technology (Indonesia); Syoni [Department of Metallurgy Engineering, Bandung Institute of Technology (Indonesia)

2014-03-24

Quantitative analysis of rare earth elements which are considered as the standard method that has a high accuracy, and detection limits achieved by the order of ppm is inductively coupled plasma atomic emission spectroscopy (ICPAES). But these tools are expensive and valuable analysis of the high cost of implementation. In this study be made and characterized selective electrode for the determination of rare earth ions is potentiometric. Membrane manufacturing techniques studied is based on immersion (liquid impregnated membrane) in PTFE 0.5 pore size. As ionophores to be used tri butyl phosphate (TBP) and bis(2-etylhexyl) hydrogen phosphate. There is no report previously that TBP used as ionophore in polymeric membrane based lanthanum. Some parameters that affect the performance of membrane electrode such as membrane composition, membrane thickness, and types of membrane materials studied in this research. Manufacturing of Ion Selective Electrodes (ISE) Lanthanum (La) by means of impregnation La membrane in TBP in kerosene solution has been done and showed performance for ISE-La. FTIR spectrum results for PTFE 0.5 pore size which impregnated in TBP and PTFE blank showed difference of spectra in the top 1257 cm{sup −1}, 1031 cm{sup −1} and 794.7 cm{sup −1} for P=O stretching and stretching POC from group −OP =O. The result showed shift wave number for P =O stretching of the cluster (−OP=O) in PTFE-TBP mixture that is at the peak of 1230 cm{sup −1} indicated that no interaction bond between hydroxyl group of molecules with molecular clusters fosforil of TBP or R{sub 3}P = O. The membrane had stable responses in pH range between 1 and 9. Good responses were obtained using 10{sup −3} M La(III) internal solution, which produced relatively high potential. ISE-La showed relatively good performances. The electrode had a response time of 29±4.5 second and could be use for 50 days. The linear range was between 10{sup −5} and 10{sup −1} M.

Use of marker ion and cationic surfactant plastic membrane electrode for potentiometric titration of cationic polyelectrolytes.

Science.gov (United States)

Masadome, Takashi; Imato, Toshihiko

2003-07-04

A plasticized poly (vinyl chloride) (PVC) membrane electrode sensitive to stearyltrimethylammonium (STA) ion is applied to the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by potentiometric titration, using a potassium poly (vinyl sulfate) (PVSK) solution as a titrant. The end-point of the titration is detected as the potential change of the plasticized PVC membrane electrode caused by decrease in the concentration of STA ion added to the sample solution as a marker ion due to the ion association reaction between the STA ion and PVSK. The effects of the concentration of STA ion, coexisting electrolytes in the sample solution and pH of the sample on the degree of the potential change at the end-point were examined. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 2x10(-5) to 4x10(-4) N for Cat-floc, glycol chitosan, and methylglycol chitosan.

Time-dependent ion selectivity in capacitive charging of porous electrodes

NARCIS (Netherlands)

Zhao, R.; Soestbergen, M.; Rijnaarts, H.H.M.; Wal, van der A.F.; Bazant, M.Z.; Biesheuvel, P.M.

2012-01-01

In a combined experimental and theoretical study, we show that capacitive charging of porous electrodes in multicomponent electrolytes may lead to the phenomenon of time-dependent ion selectivity of the electrical double layers (EDLs) in the electrodes. This effect is found in experiments on

Platinum porphyrins as ionophores in polymeric membrane electrodes

DEFF Research Database (Denmark)

Lvova, Larisa; Verrelli, Giorgio; Nardis, Sara

2011-01-01

A comparative study of Pt(II)- and Pt(IV)-porphyrins as novel ionophores for anion-selective polymeric membrane electrodes is performed. Polymeric membranes of different compositions, prepared by varying plasticizers, cationic and anionic additives and Pt porphyrins, have been examined...... within the electrode membranes, while those based on Pt(IV)TPPCl2 operate via a mixed mode carrier mechanism, evidencing also a partial reduction of the starting ionophore to Pt(II)TPP. Spectrophotometric measurements of thin polymeric films indicate that no spontaneous formation of hydroxide ion bridged...... porphyrin dimers occurs in the membrane plasticized both with high or low dielectric constant plasticizer, due to a low oxophilicity of central Pt. The computational study of various anion–Pt(IV)TPPCl2 complex formation by means of semi-empirical and density functional theory (DFT) methods revealed a good...

Use of ion selective electrodes for potentiometric analysis of solutions containing cadmium and cyanide ions

International Nuclear Information System (INIS)

Aleksandrov, V.V.; Glazkova, E.N.; Izmajlova, G.A.

1988-01-01

Technique for cadmium potentiometric determination in the cadmium-plating cyanide electrolyte, which countains Cd(CN) n 2-n (n=1,2,3,4) complexes, is developed. Reactions of cadmium precipitation in the form of diethyldithiocarbamate serve as the ground for determination technique. Polycrystalline membrane electrodes with hard contact are used as indicator electrodes. Pd, Ni, Cu, Ag do not interfere with cadmium determination, Fe, Zn, Bi may coprecipitate with cadmium. Determination limit of cadmium ions is 5x10 -3 M

Synthesis of nano-sized arsenic-imprinted polymer and its use as As{sup 3+} selective ionophore in a potentiometric membrane electrode: Part 1

Energy Technology Data Exchange (ETDEWEB)

Alizadeh, Taher, E-mail: Alizadeh@uma.ac.ir; Rashedi, Mariyam

2014-09-16

Highlights: • The first arsenic cation-selective membrane electrode was introduced. • A novel procedure was introduced for the preparation of As-imprinted polymer. • It was found that arsenic is recognized by the IIP as As{sup 3+} species. • Nernstian response of 20.4 mV decade{sup −1} and DL of 0.5 μM was obtained. - Abstract: In this study, a new strategy was proposed for the preparation of As (III)-imprinted polymer by using arsenic (methacrylate){sub 3} as template. Precipitation polymerization was utilized to synthesize nano-sized As (III)-imprinted polymer. Methacrylic acid and ethylene glycol dimethacrylate were used as the functional monomer and cross-linking agent, respectively. In order to assembly functional monomers around As (III) ion, sodium arsenite and methacrylic acid were heated in the presence of hydroquinone, leading to arsenic (methacrylate){sub 3}. The nano-sized As (III) selective polymer was characterized by FT-IR and scanning electron microscopy techniques (SEM). It was demonstrated that arsenic was recognized as As{sup 3+} by the selective cavities of the synthesized IIP. Based on the prepared polymer, the first arsenic cation selective membrane electrode was introduced. Membrane electrode was constructed by dispersion of As (III)-imprinted polymer nanoparticles in poly(vinyl chloride), plasticized with di-nonylphthalate. The IIP-modified electrode exhibited a Nernstian response (20.4 ± 0.5 mV decade{sup −1}) to arsenic ion over a wide concentration range (7.0 × 10{sup −7} to 1.0 × 10{sup −1} mol L{sup −1}) with a lower detection limit of 5.0 × 10{sup −7} mol L{sup −1}. Unlike this, the non-imprinted polymer (NIP)-based membrane electrode was not sensitive to arsenic in aqueous solution. The selectivity of the developed sensor to As (III) was shown to be satisfactory. The sensor was used for arsenic determination in some real samples.

Amodiaquine polymeric membrane electrode.

Science.gov (United States)

Malongo, T Kimbeni; Blankert, B; Kambu, O; Amighi, K; Nsangu, J; Kauffmann, J-M

2006-04-11

The construction and electrochemical response characteristics of two types of poly(vinyl chloride) (PVC) membrane sensors for the determination of amodiaquine hydrochloride (ADQ.2HCl) are described. The sensing membrane comprised an ion-pair formed between the cationic drug and sodium tetraphenyl borate (NaTPB) or potassium tetrakis(4-chlorophenyl) borate (KTCPB) in a plasticized PVC matrix. Eight PVC membrane ion-selective electrodes were fabricated and studied. Several plasticizers were studied namely, dioctyl phthalate (DOP), 2-nitrophenyl octyl ether (NPOE), dioctyl phenylphosphonate (DOPP) and bis(2-ethylhexyl)adipate (EHA). The sensors display a fast, stable and near-Nernstian response over a relative wide ADQ concentration range (3.2 x 10(-6) to 2.0 x 10(-2) M), with slopes comprised between 28.5 and 31.4 mV dec(-1) in a pH range comprised between pH 3.7 and 5.5. The assay of amodiaquine hydrochloride in pharmaceutical dosage forms using one of the proposed sensors gave average recoveries of 104.3 and 99.9 with R.S.D. of 0.3 and 0.6% for tablets (Malaritab) and a reconstituted powder containing ADQ.2HCl, respectively. The sensor was also used for dissolution profile studies of two drug formulations. The sensor proved to have a good selectivity for ADQ.2HCl over some inorganic and organic compounds, however, berberine chloride interfered significantly. The results were validated by comparison with a spectrophotometric assay according to the USP pharmacopoeia.

Review of progresses on clinical applications of ion selective electrodes for electrolytic ion tests: from conventional ISEs to graphene-based ISEs

Directory of Open Access Journals (Sweden)

Rongguo Yan

2016-10-01

Full Text Available There exist several positively and negatively charged electrolytes or ions in human blood, urine, and other body fluids. Tests that measure the concentration of these ions in clinics are performed using a more affordable, portable, and disposable potentiometric sensing method with few sample volumes, which requires the use of ion-selective electrodes (ISEs and reference electrodes. This review summarily descriptively presents progressive developments and applications of ion selective electrodes in medical laboratory electrolytic ion tests, from conventional ISEs, solid-contact ISEs, carbon nanotube based ISEs, to graphene-based ISEs.

All-solid-state potassium-selective electrode using graphene as the solid contact

DEFF Research Database (Denmark)

Li, Fenghua; Ye, Junjin; Zhou, Min

2012-01-01

Graphene sheets are used for the first time to fabricate a new type of solid-contact ion-selective electrode (SC-ISE) as the intermediate layer between an ionophore-doped solvent polymeric membrane and a glassy carbon electrode. The new transducing layer was characterized by transmission electron...

PVC membrane based potentiometric sensor for uranyl ion using thenoyl trifluoro acetone as ionophore

International Nuclear Information System (INIS)

Nanda, D.; Chouhan, H.P.S.; Maiti, B.

2004-01-01

Uranyl ion selective electrode based on thenoyl trifluoro acetone (TTA) incorporated into a polyvinyl chloride (PVC) membrane has been developed where dibutyl phthalate and sodium tetraphenyl borate have been used as plasticizer and anion excluder respectively. The PVC membrane containing the active ionophore, TTA, and the other ingredients has been directly cast a graphite electrode. The electrode shows near Nernstian response to UO 2 2+ in the concentration range of 10 -1 to 10 -6 mol. L -1 an average slope of 30 mV/decade. Alkali and alkaline earth ions do not interfere with the determination of uranyl ion. Interference of transition metal ions and Th (IV) is eliminated using EDTA. (author)

Monitoring of fluoride and iodide levels in drinking water using ion selective electrodes

International Nuclear Information System (INIS)

Ahmed, R.; Viqar-Un-Nisa; Hussain, M.; Tanwir, R.; Qureshi, S.A.

2004-01-01

Fluoride and iodide, the most important constituents of drinking water are essential as well as toxic depending on their levels. For their analysis in water mostly ion-selective electrodes, spectrophotometry, titrimetry and coulometry etc; have been used and literature has been briefly reviewed. Ion-selective electrodes offer an efficient method for the measurement of the two halides and were mostly used during this work. Fabrication of these electrodes is briefly described. Comparison of results obtained by ion selective electrode and coulometry is given. Recoveries of the added fluoride ions from the samples were good. A large number of water samples from Rawalpindi-Islamabad area were analyzed for fluoride and iodide. Levels of fluoride and iodide from two main water reservoirs of Rawalpindi and Islamabad are reported before and after treatment. Both surface and ground water samples were analyzed and results are compared and discussed. Some samples from northern areas were also analyzed for iodide and fluoride and compared. Intake of fluoride and iodide from water of different areas is also compared. Water samples, which caused bone deformation in certain areas in Punjab due to excess fluoride, were also analyzed for fluoride and results are presented. (author)

Eletrodo íon-seletivo para determinação potenciométrica de alumínio(III em meio de fluoreto Ion-selective electrode for potentiometric determination of aluminium(III in fluoride medium

Directory of Open Access Journals (Sweden)

Evandro Piccin

2004-12-01

Full Text Available The construction and analytical evaluation of a coated graphite Al(III ion-selective electrode, based on the ionic pair formed between the Al(Fn3-n anion and tricaprylylmethylammonium cation (Aliquat 336S incorporated on a poly(vinylchloride (PVC matrix membrane are described. A thin membrane film of this ionic pair and dibutylphthalate (DBPh in PVC was deposited directly on a cylindric graphite rod (2 cm length x 0.5 cm diameter attached to the end of a glass tube using epoxy resin. The membrane solution was prepared by dissolving 40% (m/m of PVC in 10 mL of tetrahydrofuran following addition of 45% (m/m of DBPh and 15% (m/m of the ionic pair. The effect of membrane composition, fluoride concentration, and several concomitants as potential interferences on the electrode response were investigated. The aluminium(III ion-selective electrode showed a linear response ranging from 1.4 x 10-4 to 1.0 x 10-2 mol L-1, a detection limit of 4.0 x 10-5 mol L-1, aslope of -54.3±0.2mV dec-1 and a lifetime of more than 1 year (over 3000 determinations for each membrane. The slope indicates that the ion-selective electrode responds preferentially to the Al(F4- species. Application of this electrode for the aluminium(III determination in stomach anti-acid samples is reported.

Increasing selectivity of a heterogeneous ion-exchange membrane

Czech Academy of Sciences Publication Activity Database

Křivčík, J.; Neděla, D.; Hadrava, J.; Brožová, Libuše

2015-01-01

Roč. 56, č. 12 (2015), s. 3160-3166 ISSN 1944-3994. [International Conference on Membrane and Electromembrane Processes - MELPRO 2014. Prague, 18.05.2014-21.05.2014] Institutional support: RVO:61389013 Keywords : ion-exchange membrane * selectivity * permselectivity Subject RIV: JP - Industrial Processing Impact factor: 1.272, year: 2015

Behaviour of polycrystalline fluoride-selective membrane electrode in aqueous-organic media

International Nuclear Information System (INIS)

Manakova, L.I.; Bausova, N.V.; Moiseev, V.E.; Bamburov, V.G.; Sivoplyas, A.P.

1978-01-01

The behaviour of polycrystalline fluoride membrane electrode (RFME) in aqueous-organic media has been studied when the content of the organic component (methanol, ethanol, acetone, dioxane) has been changed from 20 to 80 mass%. Since LaF 3 is the base of the membrane, its solubility has been studied depending on the organic component content in the solution. It has been established that LaF 3 solubility decreases with increasing content of of the organic component. This explains the effect of the composition of an aqueous-organic solvent on the electrode sensitivity. The electrode sensitivity rises with increasing content of the organic component in an aqueous-organic solvent. A greater decrease of LaF 3 solubility in aqueous-organic solvents as compared with that of LaCl 3 , La(NO 3 ) 3 , and La 2 (SO 4 ) 3 causes a higher selectivity of RFME with respect to the anions under study

A selective iodide ion sensor electrode based on functionalized ZnO nanotubes.

Science.gov (United States)

Ibupoto, Zafar Hussain; Khun, Kimleang; Willander, Magnus

2013-02-04

In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF) was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10-6 to 1 × 10-1 M) and excellent sensitivity of -62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10-7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

A Selective Iodide Ion Sensor Electrode Based on Functionalized ZnO Nanotubes

Directory of Open Access Journals (Sweden)

Magnus Willander

2013-02-01

Full Text Available In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10−6 to 1 × 10−1 M and excellent sensitivity of –62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10−7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

Determination of arsenate in water by anion selective membrane electrode using polyurethane–silica gel fibrous anion exchanger composite

Energy Technology Data Exchange (ETDEWEB)

Khan, Asif Ali, E-mail: asifkhan42003@yahoo.com; Shaheen, Shakeeba, E-mail: shakeebashaheen@ymail.com

2014-01-15

Highlights: • PU–Si gel is new anion exchanger material synthesized and characterized. • This material used as anion exchange membrane is applied for electroanalytical studies. • The method for detection and determination of AsO{sub 4}{sup 3−} in traces amounts discussed. • The results are also verified from arsenic analyzer. -- Abstract: Polyurethane (PU)–silica (Si gel) based fibrous anion exchanger composites were prepared by solid–gel polymerization of polyurethane in the presence of different amounts of silica gel. The formation of PU–Si gel fibrous anion exchanger composite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM) and elemental analysis. The membrane having a composition of 5:3 (PU:Si gel) shows best results for water content, porosity, thickness and swelling. Our studies show that the present ion selective membrane electrode is selective for arsenic, having detection limit (1 × 10{sup −8} M to 1 × 10{sup −1} M), response time (45 s) and working pH range (5–8). The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO{sub 4}{sup 3−}) over interfering anions. The accuracy of the detection limit results was compared by PCA-Arsenomat.

Samarium (III Selective Membrane Sensor Based on Tin (IV Boratophosphate

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Ashok S. K. Kumar

2004-08-01

Full Text Available Abstract: A number of Sm (III selective membranes of varying compositions using tin (IV boratophosphate as electroactive material were prepared. Polyvinyl chloride, polystyrene and epoxy resin were used as binding materials. Membrane having composition of 40% exchanger and 60% epoxy resin exhibited best performance. This membrane worked well over a wide concentration range of 1x10-5M to 1x10-1 M of samarium ions with a Super-Nernstian slope of 40 mV/decade. It has a fast response time of less than 10 seconds and can be used for at least six months without any considerable divergence in potentials. The proposed sensor revealed good selectivities with respect to alkali, alkaline earth, some transition and rare earth metal ions and can be used in the pH range of 4.0-10.0. It was used as an indicator electrode in the potentiometric titration of Sm (III ions against EDTA. Effect of internal solution was studied and the electrode was successfully used in non-aqueous media, too.

Polymer membrane electrodes for sensitive potentiometric determination of beta-blockers.

Science.gov (United States)

Wassil, Anwar A; Farag, Abd El-Ftaah Bastawy; Moukdad, Fatma A

2007-01-01

The construction of PVC matrix-type beta-blockers (sotalol, carvedilol, and betaxolol) ion selective electrodes and their use for direct potentiometry of their respective species are described. The proposed sensors are based on the complex ion associates of beta-blockers with tungstophosphate (TP) and Ammonium Reineckate (Rein) ionophoris in poly vinyl chloride membrane (PVC) with Dioctylphthalate (DOP) plasticizer. The four electrodes (Beta-TP), (Sota-TP), (Carve-TP), and (Cave-Rein) show stable potential response with near Nernstian slope of 50.8, 33.7, 32.35, and 33 mv per decade, range of concentration 10-2-10-7 M beta-blockers. Selectivity coefficients data obtained for 11 different organic and inorganic ions are presented. The electrodes have fast response time (30 and 40 s) and were used over wide range of pH 4.5-8.5. Validation of the method according to the quality assurance standers shows suitability of proposed sensors for use in the quality control assessment of these drugs. The results obtained for the determination of beta-blockers with the proposed electrodes show average recoveries of 100.78% and a mean standard deviation of +/-1.2. The nominal are obtained. The data agree well with those obtained by standard methods.

Selective observation of charge storing ions in supercapacitor electrode materials.

Science.gov (United States)

Forse, Alexander C; Griffin, John M; Grey, Clare P

2018-02-01

Nuclear magnetic resonance (NMR) spectroscopy has emerged as a useful technique for probing the structure and dynamics of the electrode-electrolyte interface in supercapacitors, as ions inside the pores of the carbon electrodes can be studied separately from bulk electrolyte. However, in some cases spectral resolution can limit the information that can be obtained. In this study we address this issue by showing how cross polarisation (CP) NMR experiments can be used to selectively observe the in-pore ions in supercapacitor electrode materials. We do this by transferring magnetisation from 13 C nuclei in porous carbons to nearby nuclei in the cations ( 1 H) or anions ( 19 F) of an ionic liquid. Two-dimensional NMR experiments and CP kinetics measurements confirm that in-pore ions are located within Ångströms of sp 2 -hybridised carbon surfaces. Multinuclear NMR experiments hold promise for future NMR studies of supercapacitor systems where spectral resolution is limited. Copyright © 2017 University of Cambridge. Published by Elsevier Inc. All rights reserved.

Helium Ion Microscopy of proton exchange membrane fuel cell electrode structures

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Serguei Chiriaev

2017-12-01

Full Text Available Characterization of composite materials with microscopy techniques is an essential route to understanding their properties and degradation mechanisms, though the observation with a suitable type of microscopy is not always possible. In this work, we present proton exchange membrane fuel cell electrode interface structure dependence on ionomer content, systematically studied by Helium Ion Microscopy (HIM. A special focus was on acquiring high resolution images of the electrode structure and avoiding interface damage from irradiation and tedious sample preparation. HIM demonstrated its advantages in surface imaging, which is paramount in studies of the interface morphology of ionomer covered or absorbed catalyst structures in a combination with electrochemical characterization and accelerated stress test. The electrode porosity was found to depend on the ionomer content. The stressed electrodes demonstrated higher porosity in comparison to the unstressed ones on the condition of no external mechanical pressure. Moreover, formation of additional small grains was observed for the electrodes with the low ionomer content, indicating Pt redeposition through Ostwald ripening. Polymer nanofiber structures were found in the crack regions of the catalyst layer, which appear due to the internal stress originated from the solvent evaporation. These fibers have fairly uniform diameters of a few tens of nanometers, and their density increases with the increasing ionomer content in the electrodes. In the hot-pressed electrodes, we found more closed contact between the electrode components, reduced particle size, polymer coalescence and formation of nano-sized polymer fiber architecture between the particles.

Application of Photocured Polymer Ion Selective Membranes for Solid-State Chemical Sensors

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Natalia Abramova

2015-06-01

Full Text Available Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized conductive layer and sensitive membrane is presented and the proof of concept is confirmed by two examples of solid-contact electrodes for Ca ions and pH.

Ultrathin and Ion-Selective Janus Membranes for High-Performance Osmotic Energy Conversion.

Science.gov (United States)

Zhang, Zhen; Sui, Xin; Li, Pei; Xie, Ganhua; Kong, Xiang-Yu; Xiao, Kai; Gao, Longcheng; Wen, Liping; Jiang, Lei

2017-07-05

The osmotic energy existing in fluids is recognized as a promising "blue" energy source that can help solve the global issues of energy shortage and environmental pollution. Recently, nanofluidic channels have shown great potential for capturing this worldwide energy because of their novel transport properties contributed by nanoconfinement. However, with respect to membrane-scale porous systems, high resistance and undesirable ion selectivity remain bottlenecks, impeding their applications. The development of thinner, low-resistance membranes, meanwhile promoting their ion selectivity, is a necessity. Here, we engineered ultrathin and ion-selective Janus membranes prepared via the phase separation of two block copolymers, which enable osmotic energy conversion with power densities of approximately 2.04 W/m 2 by mixing natural seawater and river water. Both experiments and continuum simulation help us to understand the mechanism for how membrane thickness and channel structure dominate the ion transport process and overall device performance, which can serve as a general guiding principle for the future design of nanochannel membranes for high-energy concentration cells.

Tetracaine – selective electrodes with polymer membranes and their application in pharmaceutical formulation control

Directory of Open Access Journals (Sweden)

Ahmed Khudhair Hassan

2017-02-01

Full Text Available The construction and electrochemical response characteristics of poly(vinyl chloride (PVC membrane electrodes for tetracaine hydrochloride (TCH are described. The sensing membranes incorporating ion-association complexes of tetracaine cation with phosphotungstic acid (PTA or phosphomolybdic acid (PMA or Sodium tetraphenyl borate (NaTPB as electroactive materials and di-n-butyl phthalate (DBPH or tri-n-butyl phosphate (TBP as a plasticizer in PVC matrixes were evaluated. The results obtained show the electrodes based on PTA or PMA as electroactive compounds and DBPH as plasticizer with a fast, stable and near-Nernstian response over a wide concentration range (1 × 10−5–5 × 10−2 M, with cationic slopes of 55.02 and 52.05 mV decade−1 over a pH range of (2.5–6.5. The electrodes show good discrimination of tetracaine from several inorganic cations and sugars. The electrodes were successfully applied for the determination of tetracaine in pharmaceutical formulations.

A fast response hafnium selective polymeric membrane electrode based on N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

International Nuclear Information System (INIS)

Rezaei, B.; Meghdadi, S.; Zarandi, R. Fazel

2008-01-01

In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf 4+ (Hafnium(IV)) over a wide concentration range (2.0 x 10 -7 to 1.0 x 10 -1 M) with the determination coefficient of 0.9966 and slope of 15.1 ± 0.1 mV decades -1 . The limit of detection is 1.9 x 10 -7 M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf 4+ ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf 4+ in solutions by standard addition method for real sample analysis

Construction and performance characterization of ion-selective electrodes for potentiometric determination of pseudoephedrine hydrochloride applying batch and flow injection analysis techniques.

Science.gov (United States)

Zayed, Sayed I M; Issa, Yousry M; Hussein, Ahmed

2006-01-01

New pseudoephedrine selective electrodes have been constructed of the conventional polymer membrane type by incorporation of pseudoephedrine-phosphotungstate (PE-PT) or pseudoephedrine-silicotungstate (PE-SiT) ion-associates in a poly vinyl chloride (PVC) membrane plasticized with dibutyl phthalate (DBP). The electrodes were fully characterized in terms of the membrane composition, temperature, and pH. The electrodes exhibited mean slopes of calibration graphs of 57.09 and 56.10 mV concentration decade(-1) of PECl at 25 degrees C for (PE-PT) and (PE-SiT) electrodes, respectively. The electrodes showed fast, stable, and near-Nernstian response over the concentration ranges 6.31 x 10(-6)-1.00 x 10(-2) and 5.00 x 10(-5)-1.00x10(-2) M in the case of PE-PT applying batch and flow injection (FI) analysis, respectively, and 1.00 x 10(-5)-1.00 x 10(-2) and 5.00 x 10(-5)-1.00x10(-2) M in the case of PE-SiT for batch and FI analysis system, respectively. Detection limit was 5.01x 10(-6) M for PE-PT electrode and 6.31x10(-6) M for PE-SiT electrode. The electrodes were successfully applied for the potentiometric determination of pseudoephedrine hydrochloride (PECl) in pharmaceutical preparations with mean recovery 101.13 +/- 0.85% and 100.77+0.79% in case of PE-PT applying batch and flow injection systems, respectively, and 100.75+0.85% and 100.79 +/- 0.77% in case of PE-SiT for batch and flow injection systems, respectively. The electrodes exhibited good selectivity for PECl with respect to a large number of inorganic cations, sugars and amino acids.

Polystyrene Based Silver Selective Electrodes

Directory of Open Access Journals (Sweden)

Shiva Agarwal

2002-06-01

Full Text Available Silver(I selective sensors have been fabricated from polystyrene matrix membranes containing macrocycle, Me6(14 diene.2HClO4 as ionophore. Best performance was exhibited by the membrane having a composition macrocycle : Polystyrene in the ratio 15:1. This membrane worked well over a wide concentration range 5.0×10-6–1.0×10-1M of Ag+ with a near-Nernstian slope of 53.0 ± 1.0 mV per decade of Ag+ activity. The response time of the sensor is <15 s and the membrane can be used over a period of four months with good reproducibility. The proposed electrode works well in a wide pH range 2.5-9.0 and demonstrates good discriminating power over a number of mono-, di-, and trivalent cations. The sensor has also been used as an indicator electrode in the potentiometric titration of silver(II ions against NaCl solution. The sensor can also be used in non-aqueous medium with no significant change in the value of slope or working concentration range for the estimation of Ag+ in solution having up to 25% (v/v nonaqueous fraction.

In-line monitoring of an oxide ion in LiCl molten salt using a YSZ based oxide ion selective electrode

International Nuclear Information System (INIS)

Cho, Young Hwan; Jeon, Jong Seon; Yeon, Jei Won; Choi, In Kyu; Kim, Won Ho

2004-01-01

The electrode potential characteristics of a YSZ based membrane metal oxide electrode have been studied in molten LiCl at 700 .deg. C by the potentiometric method. The electrode exhibited a good potential response to log[O 2 ] and data reproducibility. The calibration plot (potential vs. log[O 2 ] was found to be linear, obeying the nernst equation. The electrode potential showed a good reversibility corresponding to increase/decrease of the oxide ion present in the molten LiCl. The physical and chemical durability appeared to be sound after several repeated uses, resulting in reproducible results. However, 'the proposed electrode' failed when metallic Li was present in the melt

Fabrication of novel coated pyrolytic graphite electrodes for the selective nano-level monitoring of Cd²⁺ ions in biological and environmental samples using polymeric membrane of newly synthesized macrocycle.

Science.gov (United States)

Sahani, Manoj Kumar; Singh, A K; Jain, A K; Upadhyay, Anjali; Kumar, Amit; Singh, Udai P; Narang, Shikha

2015-02-20

Novel 5-amino-1,3,4-thiadiazole-2-thiol unit based macrocyclic ionophore 5,11,17-trithia-1,3,7,9,13,15,19,20,21-nonaazatetracyclo[14.2.1.1(4,7).1(10,13)]henicosa-4(20),10(21),16(19)-triene-6,12,18-trithione (M1), was synthesized and characterized. Preliminary studies on M1 have showed that it has more the affinity toward Cd(2+) ion. Thus, the macrocyclic ionophore (M1) was used as electroactive material in the fabrication of PVC-membrane electrodes such as polymeric membrane electrode (PME), coated graphite electrode (CGE) and coated pyrolytic graphite electrode (CPGE) were prepared and its performance characteristic were compared with. The electroanalytical studies performed on PME, CGE and CPGE revealed that CPGE having membrane composition M1:PVC:1-CN:NaTPB in the ratio of 7:37:54:2 exhibits the best potentiometric characteristics in terms of detection limit of 7.58×10(-9) mol L(-1), Nernstian slope of 29.6 mV decade(-1) of activity. The sensor was found to be independent of pH in the range 2.5-8.5. The sensor showed a fast response time of 10s and could be used over a period of 4 months without any significant divergence in its potentiometric characteristics. The sensor has been employed for monitoring of the Cd(2+) ion in real samples and also used as an indicator electrode in the potentiometric titration of Cd(2+) ion with EDTA. Copyright © 2014. Published by Elsevier B.V.

Study of the ion-channel behavior on glassy carbon electrode supported bilayer lipid membranes stimulated by perchlorate anion

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhiquan; Shi, Jun; Huang, Weimin, E-mail: huangwm@jlu.edu.cn

2015-10-01

In this paper, a kind of didodecyldimethylammonium bromide (DDAB) layer membranes was supported on a glassy carbon electrode (GCE). We studied the ion channel behavior of the supported bilayer lipid membrane by scanning electrochemical microscopy (SCEM) in tris(2,2′-bipyridine) ruthenium(II) solution. Perchlorate anion was used as a presence of stimulus and ruthenium(II) complex cations as the probing ions for the measurement of SECM, the lipid membrane channel was opened and exhibited the behavior of distinct SECM positive feedback curve. The channel was in a closed state in the absence of perchlorate anions while reflected the behavior of SECM negative feedback curve. The rates of electron transfer reaction in the lipid membranes surface were detected and it was dependant on the potential of SECM. - Highlights: • The rates of electron transfer reaction in the lipid membranes surface were detected. • Dynamic investigations of ion-channel behavior of supported bilayer lipid membranes by scanning electrochemical microscopy • A novel way to explore the interaction between molecules and supported bilayer lipid membranes.

High Antifouling Property of Ion-Selective Membrane: toward In Vivo Monitoring of pH Change in Live Brain of Rats with Membrane-Coated Carbon Fiber Electrodes.

Science.gov (United States)

Hao, Jie; Xiao, Tongfang; Wu, Fei; Yu, Ping; Mao, Lanqun

2016-11-15

In vivo monitoring of pH in live brain remains very essential to understanding acid-base chemistry in various physiological processes. This study demonstrates a potentiometric method for in vivo monitoring of pH in the central nervous system with carbon fiber-based proton-selective electrodes (CF-H + ISEs) with high antifouling property. The CF-H + ISEs are prepared by formation of a H + -selective membrane (H + ISM) with polyvinyl chloride polymeric matrixes containing plasticizer bis(2-ethylhexyl)sebacate, H + ionophore tridodecylamine, and ion exchanger potassium tetrakis(4-chlorophenyl)borate onto carbon fiber electrodes (CFEs). Both in vitro and in vivo studies demonstrate that the H + ISM exhibits strong antifouling property against proteins, which enables the CF-H + ISEs to well maintain the sensitivity and reversibility for pH sensing after in vivo measurements. Moreover, the CF-H + ISEs exhibit a good response to pH changes within a narrow physiological pH range from 6.0 to 8.0 in quick response time with high reversibility and selectivity against species endogenously existing in the central nervous system. The applicability of the CF-H + ISEs is illustrated by real-time monitoring of pH changes during acid-base disturbances, in which the brain acidosis is induced by CO 2 inhalation and brain alkalosis is induced by bicarbonate injections. The results demonstrate that brain pH value rapidly decreases in the amygdaloid nucleus by ca. 0.14 ± 0.01 (n = 5) when the rats breath in pure CO 2 gas, while increases in the cortex by about 0.77 ± 0.12 (n = 3) following intraperitoneal injection of 5 mmol/kg NaHCO 3 . This study demonstrates a new potentiometric method for in vivo measurement of pH change in the live brain of rats with high reliability.

Fabrication of copper-selective PVC membrane electrode based on newly synthesized copper complex of Schiff base as carrier

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Sulekh Chandra

2016-09-01

Full Text Available The newly synthesized copper(II complex of Schiff base p-hydroxyacetophenone semicarbazone was explored as neutral ionophore for the fabrication of poly(vinylchloride (PVC based membrane electrode selective to Cu(II ions. The electrode shows a Nernstian slope of 29.8 ± 0.3 mV/decade with improved linear range of 1.8 × 10−7 to 1.0 × 10−1 M, comparatively lower detection limit 5.7 × 10−8 M between pH range of 2.0–8.0, giving a relatively fast response within 5s and can be used for at least 16 weeks without any divergence in potential. The selectivity coefficient was calculated using the fixed interference method (FIM. The electrode can also be used in partially non-aqueous media having up to 25% (v/v methanol, ethanol or acetone content with no significant change in the value of slope or working concentration range. It was successfully applied for the direct determination of copper content in water and tea samples with satisfactory results. The electrode has been used in the potentiometric titration of Cu2+ with EDTA.

Laboratory Evaluation of Ion-Selective Electrodes for Simultaneous Analysis of Macronutrients in Hydroponic Solution

Science.gov (United States)

Automated sensing of macronutrients in hydroponic solution would allow more efficient management of nutrients for crop growth in closed hydroponic systems. Ion-selective microelectrode technology requires an ion-selective membrane or a solid metal material that responds selectively to one analyte in...

Determination of extractable fluoride in contaminated soils with ion-selective electrode

OpenAIRE

Mirlean, Nicolai; Baraj, Besnik; Garcia, Marina Reback Domingues; Niencheski, Luis Felipe Hax; Baisch, Paulo Roberto Martins; Casartelli, Maria Regina de Oliveira; Robinson, Daniel

2003-01-01

In a factorial design study involving the determination of F- by ion-selective electrodes, a significant interference was demonstrated for Fe, with an even more pronounced interference for Al. The fluoride leaching procedure from polluted soil showed more reliable results using 0.5 M citric acid

The Novel SCN''- Ion-selective Electrode Based on the 1-Benzyl-3-(4-nitrophenyl) thio-urea Ionophore

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Mi; Kang, Dong Hyeon; Choe, Ju Eun; You, Jung Min; Go, Min Jeong; Lee, Jung Seong; Jeon, Seung Won [Chungnam National University, Daejeon (Korea, Republic of)

2014-09-15

A potentiometric sensor based on the 1-benzyl-3-(4-nitrophenyl) thio-urea was synthesized and tested as an ionophore in PVC based membrane sensor towards SCN - ions. This membrane exhibits a linear stable response over a wide concentration range (1.0 × 10''-5 to 1.0 × 10''-2 M) with a slope of -59.2 mV/dec., a detection limit of log[SCN''- ] = -5.05, and a selectivity coefficient for thiocyanate against perchlorate anion of logK{sub s}cn''pot = -0.133. The selectivity series of the membrane is as follows: SCN''- > ClO{sub 4}''- > I''- >NO{sub 3}''- >HSO{sub 3}''- > Cl''-HSO{sub '}'-''4 > F''- > CH{sub 3}COO''- > HCO''-''3 > Br''- > H{sub 2}PO{sub 4}''- > SO{sub 3}''-''2 > SO{sub 4}''-''2 > CO{sub 3}''-''2. The proposed electrode showed good selectivity and a good response for the SCN''- ion over a wide variety of other anions in pH 6.0 buffer solutions and has a fast response time of about < 5s.. The influences of the membrane by pH, ionophore, and plasticizer were studied.

Ion-selective electrodes in organic elemental and functional group analysis: a review

Energy Technology Data Exchange (ETDEWEB)

Selig, W.

1977-11-08

The literature on the use of ion-selective electrodes in organic elemental and functional group analysis is surveyed in some detail. The survey is complete through Chemical Abstracts, Vol. 83 (1975). 40 figures, 52 tables, 236 references.

Ion-selective electrodes in organic elemental and functional group analysis: a review

International Nuclear Information System (INIS)

Selig, W.

1977-01-01

The literature on the use of ion-selective electrodes in organic elemental and functional group analysis is surveyed in some detail. The survey is complete through Chemical Abstracts, Vol. 83 (1975). 40 figures, 52 tables, 236 references

Determination of total mercury in seafood by ion-selective electrodes based on a thiol functionalized ionic liquid

Directory of Open Access Journals (Sweden)

Juan Miao

2018-04-01

Full Text Available A mercury(II ion-selective electrode with an ionic liquid (IL, 1-methyl-2-butylthioimidazolium bis(trifluoromethanesulphonylimide ([C1C4Sim]NTf2 as active material was constructed. Parameters affecting the performance of the electrodes such as the dosages of the IL and carbon nanotubes and the aqueous pH values were investigated. Experimental results indicated that the optimal composition of the electrode filling material was 47.6% [C1C4Sim]NTf2, 47.6% tetrabutylphosphonium bis(trifluoromethanesulphonylimide (TBPNTf2 and 4.8% carboxylic multi-walled carbon nanotubes (MWCNTs-COOH. Under the selected conditions, the proposed electrodes showed a good linear response in the concentration range of 10−10–10−5 mol L−1 and had a detection limit of 4.1 × 10−11 mol L−1. No great interference from common metal ions was found. The proposed electrodes were applied to determine Hg2+ in seafood samples; the results were comparable to those of the direct mercury analyzer. Keywords: Ionic liquids (ILs, Mercury, Ion-selective electrodes, Carbon nanotubes, Seafood

New membrane materials for potassium-selective ion-sensitive field-effect transistors

NARCIS (Netherlands)

van der Wal, P.D.; van der Wal, Peter D.; Skowronska-Ptasinska, Maria; van den Berg, Albert; Bergveld, Piet; Sudholter, Ernst; Sudholter, Ernst J.R.; Reinhoudt, David

1990-01-01

Several polymeric materials were studied as membrane materials for potassium-selective ion-sensitive field-effect transistors (ISFETs) to overcome the problems related with the use of conventional plasticized poly(vinyl chloride) membranes casted on ISFET gate surfaces. Several acrylate materials,

A fast response hafnium selective polymeric membrane electrode based on N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

Energy Technology Data Exchange (ETDEWEB)

Rezaei, B. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Meghdadi, S.; Zarandi, R. Fazel [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2008-08-30

In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf{sup 4+} (Hafnium(IV)) over a wide concentration range (2.0 x 10{sup -7} to 1.0 x 10{sup -1} M) with the determination coefficient of 0.9966 and slope of 15.1 {+-} 0.1 mV decades{sup -1}. The limit of detection is 1.9 x 10{sup -7} M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf{sup 4+} ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf{sup 4+} in solutions by standard addition method for real sample analysis.

Construction and evaluation of As(V) selective electrodes based on iron oxyhydroxide embedded in silica gel membrane

International Nuclear Information System (INIS)

Rodriguez, J.A.; Barrado, E.; Vega, M.; Prieto, F.; Lima, J.L.F.C.

2005-01-01

Two As(V) selective electrodes (with and without inner reference solution) have been developed using selective membranes based on iron oxyhydroxide embedded on silica gel mixed with ultrapure graphite at a 2/98 (w/w) ratio. The active component of the membrane was synthesised by means of the sol-gel technique and characterized by X-ray and FTIR spectroscopy. This compound shows a great affinity towards As(V) ions adsorbing 408 mg g -1 . Using 1 mol l -1 phosphate buffer (at a 1/1, v/v ratio) to adjust the pH and the ionic strength to 7 and 0.5 mol l -1 , respectively, the calibration curve is linear from 1.0 x 10 -1 to 1.0 x 10 -6 mol l -1 As(V), with a practical detection limit of 4 x 10 -7 mol l -1 (0.03 mg l -1 ) and a slope close to 30 mV decade -1 . The effect of potentially interfering ions was investigated. The accuracy and precision of the procedure have been tested on arsenic-free drinking water samples spiked with known amounts of arsenic and on groundwater samples containing high levels of arsenic. Total arsenic in these samples was determined after oxidation of As(III) with iodine at pH 7. The results of total As were comparable to those generated by ET-AAS

Mixed ion-exchanger chemically modified carbon paste ion-selective electrodes for determination of triprolidine hydrochloride

Directory of Open Access Journals (Sweden)

Yousry M. Issa

2010-01-01

Full Text Available Triprolidine hydrochloride (TpCl ion-selective carbon paste electrodes were constructed using Tp-TPB/Tp-CoN and Tp-TPB/Tp-PTA as ion-exchangers. The two electrodes revealed Nernstian responses with slopes of 58.4 and 58.1 mV decade−1 at 25 °C in the ranges 6 × 10−6–1 × 10−2 and 2 × 10−5–1 × 10−2 M for Tp-TPB/Tp-CoN and Tp-TPB/Tp-PTA, respectively. The potentials of these electrodes were independent of pH in the ranges of 2.5–7.0 and 4.5–7.0, and detection limits were 6 × 10−6 and 1 × 10−5 M for Tp-TPB/Tp-CoN and Tp-TPB/Tp-PTA, respectively. The electrodes showed a very good selectivity for TpCl with respect to a large number of inorganic cations and compounds. The standard addition, potentiometric titration methods and FIA were applied to the determination of TpCl in pure solutions and pharmaceutical preparations. The results obtained were in close agreement with those found by the official method. The mean recovery values were 100.91% and 97.92% with low coefficient of variation values of 0.94%, and 0.56% in pure solutions, 99.82% and 98.53% with coefficient of variation values of 2.20%, and 0.73% for Actifed tablet and Actifed syrup, respectively, using the Tp-TPB/Tp-CoN electrode, and 98.85%, and 99.18% with coefficient of variation values of 0.48% and 0.85% for Actifed tablet and Actifed syrup, respectively, using the Tp-TPB/Tp-PTA electrode.

Potentiometric polymeric membrane electrodes for mercury detection using calixarene ionophores.

Science.gov (United States)

Tyagi, Sonika; Agarwal, Himanshu; Ikram, Saiqa

2010-01-01

It is here established that potentiometric polymeric membrane electrodes based on electrically neutral ionophores are a useful analytical tool for the detection of heavy metal ions from environmental and industrial waste water. PVC based membrane containing p-tert-butyl-calix[4]arenethioether derivative as active material along with sodiumtetraphenylborate (NaTPB) as solvent mediator and dibutylphthalate as a plasticizer in the ratio 45:9:460:310 (w/w%) (I:NaTPB:DBP:PVC) exhibits good properties with a Nernstian response of 29.50+/-1.0 mV per decade of activity and a working concentration range of 7.2 x 10(-8)-1.0 x 10(-1) M. The electrode gave more stable potential readings when used around pH 2.5-6.8 and exhibits fast response time of 14 s. The sensors were found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of acetone, methanol or ethanol and could be used over a period of 7-9 months. Excellent selectivity for Hg(2+) ions is indicated by match potential method and fixed interference method. The sensors could be used successfully in the estimation of mercury in different sample.

All-solid-state carbonate-selective electrode based on screen-printed carbon paste electrode

International Nuclear Information System (INIS)

Li, Guang; Lyu, Xiaofeng; Wang, Zhan; Rong, Yuanzhen; Hu, Ruifen; Wang, You; Luo, Zhiyuan

2017-01-01

A novel disposable all-solid-state carbonate-selective electrode based on a screen-printed carbon paste electrode using poly(3-octylthiophene-2,5-diyl) (POT) as an ion-to-electron transducer has been developed. The POT was dropped onto the reaction area of the carbon paste electrode covered by the poly(vinyl chloride) (PVC) membrane, which contains N,N-Dioctyl-3 α ,12 α -bis(4-trifluoroacetylbenzoyloxy)-5 β -cholan-24-amide as a carbonate ionophore. The electrode showed a near-Nernstian slope of  −27.5 mV/decade with a detection limit of 3.6 * 10 −5 mol l −1 . Generally, the detection time was 30 s. Because these electrodes are fast, convenient and low in cost, they have the potential to be mass produced and used in on-site testing as disposable sensors. Furthermore, the repeatability, reproducibility and stability have been studied to evaluate the properties of the electrodes. Measurement of the carbonate was also conducted in a human blood solution and achieved good performance. (paper)

Determination of chloride in MOX samples using chloride ion selective electrode

Energy Technology Data Exchange (ETDEWEB)

Govindan, R; Das, D K; Mallik, G K; Sumathi, A; Patil, Sangeeta; Raul, Seema; Bhargava, V K; Kamath, H S [Bhabha Atomic Research Centre, Tarapur (India). Advanced Fuel Fabrication Facility

1997-09-01

The chloride present in the MOX fuel is separated from the matrix by pyrohydrolysis at a temperature of 950 {+-} 50 degC and is then analyzed by chloride ion selective electrode (Cl-ISE). The range covered is 0.4-4 ppm with a precision of better than {+-}5% R.S.D. (author). 4 refs., 1 tab.

Determining fluoride ions in ammonium desulfurization slurry using an ion selective electrode method

Science.gov (United States)

Luo, Zhengwei; Guo, Mulin; Chen, Huihui; Lian, Zhouyang; Wei, Wuji

2018-02-01

Determining fluoride ions in ammonia desulphurization slurry using a fluoride ion selective electrode (ISE) is investigated. The influence of pH was studied and the appropriate total ionic strength adjustment buffer and its dosage were optimized. The impact of Fe3+ concentration on the detection results was analyzed under preferable conditions, and the error analysis of the ISE method’s accuracy and precision for measuring fluoride ion concentration in the range of 0.5-2000 mg/L was conducted. The quantitative recovery of F- in ammonium sulfate slurry was assessed. The results showed that when pH ranged from 5.5˜6 and the Fe3+ concentration was less than 750 mg/L, the accuracy and precision test results with quantitative recovery rates of 92.0%-104.2% were obtained.

Determination of the ion-exchange capacity of anion-selective membranes

Czech Academy of Sciences Publication Activity Database

Karas, F.; Hnát, J.; Paidar, M.; Schauer, Jan; Bouzek, K.

2014-01-01

Roč. 39, č. 10 (2014), s. 5054-5062 ISSN 0360-3199 Institutional support: RVO:61389013 Keywords : ion-exchange capacity * anion-selective membranes * titration Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.313, year: 2014

Determination of cobalt ions at nano-level based on newly synthesized pendant armed macrocycle by polymeric membrane and coated graphite electrode.

Science.gov (United States)

Singh, Ashok K; Singh, Prerna; Bhattacharjee, G

2009-12-15

Poly(vinylchloride) (PVC) based membranes of macrocycles 2,3,4:9,10,11-dipyridine-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L(1)) and 2,3,4:9,10,11-dipyridine-1,5,8,12-tetramethylacrylate-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L(2)) with NaTPB and KTpClPB as anion excluders and dibutylphthalate (DBP), benzyl acetate (BA), dioctylphthalate (DOP), o-nitrophenyloctyl ether (o-NPOE) and tri-n-butylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as Co(2+) selective electrodes. The best performance was observed with the membranes having the composition L(2):PVC:TBP:NaTPB in the ratio of 6:39:53:2 (w/w; mg). The performance of the membrane based on L(2) was compared with polymeric membrane electrode (PME) and coated graphite electrode (CGE). The PME exhibits detection limit of 4.7x10(-8)M with a Nernstian slope of 29.7 mV decade(-1) of activity between pH 2.5 and 8.5 whereas CGE exhibits the detection limit of 6.8x10(-9)M with a Nernstian slope of 29.5 mV decade(-1) of activity between pH 2.0 and 9.0. The response time for PME and CGE was found to be 11 and 8s, respectively. The CGE has been found to work satisfactorily in partially non-aqueous media up to 35% (v/v) content of methanol, ethanol and 25% (v/v) content of acetonitrile and could be used for a period of 4 months. The CGE was successfully applied for the determination of Co(2+) in real and pharmaceutical samples and as an indicator electrode in potentiometric titration of cobalt ion.

Highly selective potentiometric and colorimetric determinations of cobalt (II) ion using thiazole based ligands.

Science.gov (United States)

Singhal, Divya; Singh, Ashok Kumar; Upadhyay, Anjali

2014-12-01

New PVC-membrane electrodes were prepared by using 2-((thiazol-2-ylimino)methyl)phenol (L1) and 2-((thiazol-2-ylamino)methyl)phenol (L2) and explored as Co(II) selective electrodes. The effect of various plasticizers and anion excluder was studied in detail and improved performance was observed. It was found that the electrode based on L1 shows better response characteristics in comparison to L2. Optimum performance was observed for the membrane electrode having a composition of L1:NaTPB:DBP:PVC≡2:8:78:62 (w/w, mg). The performance of PME based on L1 was compared with that of CGE. The electrodes exhibit Nernstian slope for Co(II) ions with a limit of detection of 6.91×10(-7) mol L(-1) for PME and 7.94×10(-8) mol L(-1) for CGE. The response time for PME and CGE was found to be 15s and 12 s respectively. The potentiometric responses are independent in the pH range 3.0-9.0 for CGE. The CGE could be used for a period of 90 days. The CGE was used as an indicator electrode in potentiometric titration of EDTA with Co(2+) ion. Further the selectivity of the L1 and L2 was also confirmed by the UV-vis and colorimetric studies and found that L1 is more selective for Co(II) ion. Copyright © 2014 Elsevier B.V. All rights reserved.

Unique battery with a multi-functional, physicochemically active membrane separator/electrolyte-electrode monolith and a method making the same

Science.gov (United States)

Gerald II, Rex E.; Ruscic, Katarina J.; Sears, Devin N.; Smith, Luis J.; Klingler, Robert J.; Rathke, Jerome W.

2012-07-24

The invention relates to a unique battery having a physicochemically active membrane separator/electrolyte-electrode monolith and method of making the same. The Applicant's invented battery employs a physicochemically active membrane separator/electrolyte-electrode that acts as a separator, electrolyte, and electrode, within the same monolithic structure. The chemical composition, physical arrangement of molecules, and physical geometry of the pores play a role in the sequestration and conduction of ions. In one preferred embodiment, ions are transported via the ion-hoping mechanism where the oxygens of the Al2O3 wall are available for positive ion coordination (i.e. Li+). This active membrane-electrode composite can be adjusted to a desired level of ion conductivity by manipulating the chemical composition and structure of the pore wall to either increase or decrease ion conduction.

Construction of a new selective coated disk electrode for Ag (I) based on modified polypyrrole-carbon nanotubes composite with new lariat ether.

Science.gov (United States)

Abbaspour, A; Tashkhourian, J; Ahmadpour, S; Mirahmadi, E; Sharghi, H; Khalifeh, R; Shahriyari, M R

2014-01-01

A poly (vinyl chloride) (PVC) matrix membrane ion-selective electrode for silver (I) ion is fabricated based on modified polypyrrole - multiwalled carbon nanotubes composite with new lariat ether. This sensor has a Nernstian slope of 59.4±0.5mV/decade over a wide linear concentration range of 1.0×10(-7) to 1.0×10(-1)molL(-1) for silver (I) ion. It has a short response time of about 8.0s and can be used for at least 50days. The detection limit is 9.3×10(-8)molL(-1) for silver (I) ion, and the electrode was applicable in the wide pH range of 1.6 -7.7. The electrode shows good selectivity for silver ion against many cations such as Hg (II), which usually imposes serious interference in the determination of silver ion concentration. The use of multiwalled carbon nanotubes (MWCNTs) in a polymer matrix improves the linear range and sensitivity of the electrode. In addition by coating the solid contact with a layer of the polypyrrole (Ppy) before coating the membrane on it, not only did it reduce the drift in potential, but a shorter response time was also resulted. The proposed electrode was used as an indicator electrode for potentiometric titration of silver ions with chloride anions and in the titration of mixed halides. This electrode was successfully applied for the determination of silver ions in silver sulphadiazine as a burning cream. © 2013.

Carbon Nanotube-Based Ion Selective Sensors for Wearable Applications.

Science.gov (United States)

Roy, Soumyendu; David-Pur, Moshe; Hanein, Yael

2017-10-11

Wearable electronics offer new opportunities in a wide range of applications, especially sweat analysis using skin sensors. A fundamental challenge in these applications is the formation of sensitive and stable electrodes. In this article we report the development of a wearable sensor based on carbon nanotube (CNT) electrode arrays for sweat sensing. Solid-state ion selective electrodes (ISEs), sensitive to Na + ions, were prepared by drop coating plasticized poly(vinyl chloride) (PVC) doped with ionophore and ion exchanger on CNT electrodes. The ion selective membrane (ISM) filled the intertubular spaces of the highly porous CNT film and formed an attachment that was stronger than that achieved with flat Au, Pt, or carbon electrodes. Concentration of the ISM solution used influenced the attachment to the CNT film, the ISM surface morphology, and the overall performance of the sensor. Sensitivity of 56 ± 3 mV/decade to Na + ions was achieved. Optimized solid-state reference electrodes (REs), suitable for wearable applications, were prepared by coating CNT electrodes with colloidal dispersion of Ag/AgCl, agarose hydrogel with 0.5 M NaCl, and a passivation layer of PVC doped with NaCl. The CNT-based REs had low sensitivity (-1.7 ± 1.2 mV/decade) toward the NaCl solution and high repeatability and were superior to bare Ag/AgCl, metals, carbon, and CNT films, reported previously as REs. CNT-based ISEs were calibrated against CNT-based REs, and the short-term stability of the system was tested. We demonstrate that CNT-based devices implemented on a flexible support are a very attractive platform for future wearable technology devices.

Construction of Tb3+ PVC-MembraneElectrode Based on N,N’-Bis(pyrrolylmethylene-2-aminobenzylamine

Directory of Open Access Journals (Sweden)

Hassan Ali Zamani

2011-01-01

Full Text Available In this work, we report as new Tb3+-PVC membrane sensor based on N,N’-bis(pyrrolylmethylene- 2-aminobenzylamine (PMA as a suitable ion carrier. Poly vinylchloride (PVC-based membrane composed of PMA with oleic acid (OA as anionic additives and acetophenone (AP as plasticizing solvent mediators. The Tb3+ sensor exhibits a Nernstian slope of 19.7±0.4 mV per decade over the concentration range of 1.0×10-5 to 1.0×10-2 M and a detection limit of 4.6×10-6 M of Tb3+ ions. The potentiometric response of the sensor is independent of the solution pH in the range of 2.9–8.1. It has a very short response time, in the whole concentration range (∼5 s. The recommended sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Tb(III ions with EDTA. The electrode was also employed for the determination of the fluoride ion in two mouth wash preparations and the determination of Tb3+ ions concentration in mixtures of three different ions.

Electrochemical evidences and consequences of significant differences in ions diffusion rate in polyacrylate-based ion-selective membranes.

Science.gov (United States)

Woźnica, Emilia; Mieczkowski, Józef; Michalska, Agata

2011-11-21

The origin and effect of surface accumulation of primary ions within the ion-selective poly(n-butyl acrylate)-based membrane, obtained by thermal polymerization, is discussed. Using a new method, based on the relation between the shape of a potentiometric plot and preconditioning time, the diffusion of copper ions in the membrane was found to be slow (the diffusion coefficient estimated to be close to 10(-11) cm(2) s(-1)), especially when compared to ion-exchanger counter ions--sodium cations diffusion (a diffusion coefficient above 10(-9) cm(2) s(-1)). The higher mobility of sodium ions than those of the copper-ionophore complex results in exposed ion-exchanger role leading to undesirably exposed sensitivity to sodium or potassium ions.

Single-ion polymer electrolyte membranes enable lithium-ion batteries with a broad operating temperature range.

Science.gov (United States)

Cai, Weiwei; Zhang, Yunfeng; Li, Jing; Sun, Yubao; Cheng, Hansong

2014-04-01

Conductive processes involving lithium ions are analyzed in detail from a mechanistic perspective, and demonstrate that single ion polymeric electrolyte (SIPE) membranes can be used in lithium-ion batteries with a wide operating temperature range (25-80 °C) through systematic optimization of electrodes and electrode/electrolyte interfaces, in sharp contrast to other batteries equipped with SIPE membranes that display appreciable operability only at elevated temperatures (>60 °C). The performance is comparable to that of batteries using liquid electrolyte of inorganic salt, and the batteries exhibit excellent cycle life and rate performance. This significant widening of battery operation temperatures coupled with the inherent flexibility and robustness of the SIPE membranes makes it possible to develop thin and flexible Li-ion batteries for a broad range of applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a pH sensing membrane electrode based on a new calix[4]arene derivative.

Science.gov (United States)

Kormalı Ertürün, H Elif; Demirel Özel, Ayça; Sayın, Serkan; Yılmaz, Mustafa; Kılıç, Esma

2015-01-01

A new pH sensing poly(vinyl chloride) (PVC) membrane electrode was developed by using recently synthesized 5,17-bis(4-benzylpiperidine-1-yl)methyl-25,26,27,28-tetrahydroxy calix[4]arene as an ionophore. The effects of membrane composition, inner filling solution and conditioning solution on the potential response of the proposed pH sensing membrane electrode were investigated. An optimum membrane composition of 3% ionophore, 67% o-nitrophenyl octyl ether (o-NPOE) as plasticizer, 30% PVC was found. The electrode exhibited a near-Nernstian slope of 58.7±1.1 mV pH(-1) in the pH range 1.9-12.7 at 20±1 °C. It showed good selectivity for H(+) ions in the presence of some cations and anions and a longer lifetime of at least 12 months when compared with the other PVC membrane pH electrodes reported in the literature. Having a wide working pH range, it was not only applied as a potentiometric indicator electrode in various acid-base titrations, but also successfully employed in different real samples. It has good reproducibility and repeatability with a response time of 6-7s. Compared to traditional glass pH electrode, it exhibited excellent potentiometric response after being used in fluoride-containing media. Copyright © 2014 Elsevier B.V. All rights reserved.

A highly sensitive PVC membrane iodide electrode based on complexes of mercury(II) as neutral carrier.

Science.gov (United States)

Chai, Y-Q; Yuan, R; Xu, L; Xu, W-J; Dai, J-Y; Jiang, F

2004-09-01

A novel solvent polymeric membrane electrode based on bis(1,3,4-thiadiazole) complexes of Hg(II) is described which has excellent selectivity and sensitivity toward iodide ion. The electrode, containing 1,4-bis(5-methyl-1,3,4-thiadiazole-2-yl-thio)butanemercury(II) [Hg(II)BMTB(NO3)4], has a Nernstian potentiometric response from 2.0 x 10(-8) to 2.0 x 10(-2) mol L(-1) with a detection limit of 8.0 x 10(-9) mol L(-1) and a slope of -59.0+/-0.5 mV/decade in 0.01 mol L(-1) phosphate buffer solution (pH 3.0, 20 degrees C). The selectivity sequence observed is iodide>bromide>thiocyanate>nitrite>nitrate>chloride>perchlorate>acetate>sulfate. The selectivity behavior is discussed in terms of the UV-Vis spectrum, and the process of transfer of iodide across the membrane interface is investigated by use of the AC impedance technique. The electrode was successfully applied to the determination of iodide in Jialing River and Spring in Jinyun Mountains, with satisfactory results.

Selective electrochemical sensor for copper (II) ion based on chelating ionophores

International Nuclear Information System (INIS)

Singh, Ashok Kumar; Mehtab, Sameena; Jain, Ajay Kumar

2006-01-01

Plasticized membranes using 3-(2-pyridinyl)-2H-pyrido[1,2,-a]-1,3,5-triazine-2,4(3H)-dithione (L 1 ) and acetoacetanilide (L 2 ) have been prepared and explored as Cu 2+ -selective sensors. Effect of various plasticizers, viz. chloronaphthalene (China), benzyl acetate (BA), o-nitrophenyloctyl ether (o-NPOE), and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied in detail and improved performance was observed at several instances. Optimum performance was observed with dithione derivative (L 1 ) having a membrane composition of L 1 (5):PVC (120):o-NPOE (240):OA (10). The sensor works satisfactorily in the concentration range 5.0 x 10 -8 to 1.0 x 10 -2 M (detection limit 4.0 x 10 -8 M) with a Nernstian slope of 29.5 mV decade -1 of activity. Wide pH range (3.0-9.5), fast response time (12 s), non-aqueous tolerance (up to 20%) and adequate shelf life (4 months) indicate the vital utility of the proposed sensor. The potentiometric selectivity coefficient values as determined by match potential method (MPM) indicate good response for Cu 2+ in presence of interfering ions. The proposed electrode comparatively shows good selectivity with respect to alkali, alkaline earth, transition and some rare earth metals ions. The electrode was used for the determination of copper in different milk powder, water samples and as indicator electrode in potentiometric titration of copper ion with EDTA

Development of a new all solid contact Cs"+ ion selective electrode

International Nuclear Information System (INIS)

Ramanjaneyulu, P.S.; Abha Naveen Kumar; Sharma, M.K.

2017-01-01

Studies were carried out to develop all solid contact cesium ion selective electrode with 25,27-bis(1-octyloxy)calix[4]arene-crown-6 as an ionophore. Polyaniline (PANI), deposited on Pt electrode by electrochemical method, was used as a transducer. Three different types of electrodes were made with variation in thickness of PANI film and gold nanoparticles doped PANI as transducers. The best response was observed with ISE having Au nanoparticles doped PANI as a transducer. The optimised ISE gave Nernstian response in the range 10"-"7 to 10"-"2 M with the slope of 55.0 ± 0.6 mV/decade of Cs"+. The response of ISE for Cs"+ is fairly constant above the pH 4. The developed ISE was successfully employed to determine Cs"+ in simulated high level nuclear waste solutions and CsCl spiked tap water samples. (author)

Schiff Base modified on CPE electrode and PCB gold electrode for selective determination of silver ion

Science.gov (United States)

Leepheng, Piyawan; Suramitr, Songwut; Phromyothin, Darinee

2017-09-01

The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag+. The determination of silver ions using the modified electrodes depended linearly on Ag+ concentration in the range 1×10-10 M to 1×10-7 M, with cyclic voltammetry sensitivity were 2.51×108 μAM-1 and 1.88×108 μAM-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10-9 M and 1.99×10-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag+ in real samples.

Miniaturized, Planar Ion-selective Electrodes Fabricated by Means of Thick-film Technology

Directory of Open Access Journals (Sweden)

Robert Koncki

2006-04-01

Full Text Available Various planar technologies are employed for developing solid-state sensorshaving low cost, small size and high reproducibility; thin- and thick-film technologies aremost suitable for such productions. Screen-printing is especially suitable due to itssimplicity, low-cost, high reproducibility and efficiency in large-scale production. Thistechnology enables the deposition of a thick layer and allows precise pattern control.Moreover, this is a highly economic technology, saving large amounts of the used inks. Inthe course of repetitions of the film-deposition procedure there is no waste of material dueto additivity of this thick-film technology. Finally, the thick films can be easily and quicklydeposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodesbased on ionophores as well as crystalline ion-selective materials dedicated forpotentiometric measurements are demonstrated. Analytical parameters of these sensors arecomparable with those reported for conventional potentiometric electrodes. All mentionedthick-film strip electrodes have been totally fabricated in only one, fully automated thick-film technology, without any additional manual, chemical or electrochemical steps. In allcases simple, inexpensive, commercially available materials, i.e. flexible, plastic substratesand easily cured polymer-based pastes were used.

Tailored ion energy distributions on plasma electrodes

International Nuclear Information System (INIS)

Economou, Demetre J.

2013-01-01

As microelectronic device features continue to shrink approaching atomic dimensions, control of the ion energy distribution on the substrate during plasma etching and deposition becomes increasingly critical. The ion energy should be high enough to drive ion-assisted etching, but not too high to cause substrate damage or loss of selectivity. In many cases, a nearly monoenergetic ion energy distribution (IED) is desired to achieve highly selective etching. In this work, the author briefly reviews: (1) the fundamentals of development of the ion energy distribution in the sheath and (2) methods to control the IED on plasma electrodes. Such methods include the application of “tailored” voltage waveforms on an electrode in continuous wave plasmas, or the application of synchronous bias on a “boundary electrode” during a specified time window in the afterglow of pulsed plasmas

Tuning the Solid Electrolyte Interphase for Selective Li- and Na-Ion Storage in Hard Carbon

Energy Technology Data Exchange (ETDEWEB)

Soto, Fernando A. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Yan, Pengfei [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Marzouk, Asma [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Wang, Chongmin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Xu, Guiliang [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Chen, Zonghai [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Liu, Jun [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Sprenkle, Vincent L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; El-Mellouhi, Fedwa [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Balbuena, Perla B. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Li, Xiaolin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA

2017-03-07

Solid-electrolyte interphase (SEI) films with controllable properties are highly desirable for improving battery performance. In this paper, a combined experimental and theoretical approach is used to study SEI films formed on hard carbon in Li- and Na-ion batteries. It is shown that a stable SEI layer can be designed by precycling an electrode in a desired Li- or Na-based electrolyte, and that ionic transport can be kinetically controlled. Selective Li- and Na-based SEI membranes are produced using Li- or Na-based electrolytes, respectively. The Na-based SEI allows easy transport of Li ions, while the Li-based SEI shuts off Na-ion transport. Na-ion storage can be manipulated by tuning the SEI layer with film-forming electrolyte additives, or by preforming an SEI layer on the electrode surface. The Na specific capacity can be controlled to < 25 mAh g(-1); approximate to 1/10 of the normal capacity (250 mAh g(-1)). Unusual selective/ preferential transport of Li ions is demonstrated by preforming an SEI layer on the electrode surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion-selective conductors using electrochemical approaches.

Method for routine determination of fluoride in urine by selective ion- electrode

International Nuclear Information System (INIS)

Pires, M.A.F.; Bellintani, S.A.

1985-01-01

A simple, fast and sensitive method is outlined for determining fluoride in urine of workers who handle fluoride compounds. The determination is based on the measurement of fluoride by ion selective electrode. Cationic interferents like Ca ++ , Mg ++ , Fe +++ and Al +++ are complexed by EDTA and citric acid. Common anions present in urine, such as Cl - , PO --- 4 and SO -- 4 do not interfere in the method. (Author) [pt

Biomimetic supercontainers for size-selective electrochemical sensing of molecular ions

Science.gov (United States)

Netzer, Nathan L.; Must, Indrek; Qiao, Yupu; Zhang, Shi-Li; Wang, Zhenqiang; Zhang, Zhen

2017-04-01

New ionophores are essential for advancing the art of selective ion sensing. Metal-organic supercontainers (MOSCs), a new family of biomimetic coordination capsules designed using sulfonylcalix[4]arenes as container precursors, are known for their tunable molecular recognition capabilities towards an array of guests. Herein, we demonstrate the use of MOSCs as a new class of size-selective ionophores dedicated to electrochemical sensing of molecular ions. Specifically, a MOSC molecule with its cavities matching the size of methylene blue (MB+), a versatile organic molecule used for bio-recognition, was incorporated into a polymeric mixed-matrix membrane and used as an ion-selective electrode. This MOSC-incorporated electrode showed a near-Nernstian potentiometric response to MB+ in the nano- to micro-molar range. The exceptional size-selectivity was also evident through contrast studies. To demonstrate the practical utility of our approach, a simulated wastewater experiment was conducted using water from the Fyris River (Sweden). It not only showed a near-Nernstian response to MB+ but also revealed a possible method for potentiometric titration of the redox indicator. Our study thus represents a new paradigm for the rational design of ionophores that can rapidly and precisely monitor molecular ions relevant to environmental, biomedical, and other related areas.

Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

Directory of Open Access Journals (Sweden)

Johanna K. Dombrovskis

2014-12-01

Full Text Available Transition metal ion-chelating ordered mesoporous carbon (TM-OMC materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

Method for fluoride routine determination in urine of personnel exposed, by ion selective electrode

International Nuclear Information System (INIS)

Pires, M.A.F.; Bellintani, S.A.

1986-01-01

A simple, fast and sensible method is outlined for the determination of fluoride in urine of workers that handle fluorine compounds. The determination is based on the measurement of fluoride by ion selective electrode. Cationic interference like Ca ++ , Mg ++ , Fe +++ and Al +++ are complexed by EDTA and citric acid. (Author) [pt

Graphene-based integrated electrodes for flexible lithium ion batteries

International Nuclear Information System (INIS)

Shi, Ying; Wen, Lei; Zhou, Guangmin; Chen, Jing; Pei, Songfeng; Huang, Kun; Cheng, Hui-Ming; Li, Feng

2015-01-01

We have prepared flexible free-standing electrodes with anode and cathode active materials deposited on a highly conductive graphene membrane by a two-step filtration method. Compared with conventional electrodes using metal as current collectors, these electrodes have displayed stronger adhesion, superior electrochemical performance, higher energy density, and better flexibility. A full lithium ion battery assembled by adopting these graphene-based electrodes has showed high rate capability and long cyclic life. We have also assembled a thin, lightweight, and flexible lithium ion battery with poly-(dimethyl siloxane) sheets as packaging material to light a red light-emitting diode. This flexible battery can be easily bent without structural failure or performance loss and operated well under a bent state. The fabrication process of these graphene-based integrated electrodes only has two filtration steps; thus it is easy to scale up. These results suggest great potential for these graphene-based flexible batteries in lightweight, bendable, and wearable electronic devices. (paper)

Ion Transport in Organic Electrolyte Solution through the Pore Channels of Anodic Nanoporous Alumina Membranes

International Nuclear Information System (INIS)

Fukutsuka, Tomokazu; Koyamada, Kohei; Maruyama, Shohei; Miyazaki, Kohei; Abe, Takeshi

2016-01-01

Highlights: • Ion transport in organic electrolyte solution in macro- and meso-pores was focused. • Anodic nanoporous alumina membrane was used as a porous material. • The specific ion conductivities drastically decreased in macro- and meso-pores. - Abstract: For the development of high energy density lithium-ion batteries with the high rate performance, the enhancement of the ion transport in the electrolyte solutions impregnated in the porous electrodes is a key. To study the ion transport in porous electrodes, anodic nanoporous alumina (APA) self-standing membranes with macro- or meso-pores were used as model porous materials. These membranes had nearly spherical pore channels of discrete 20–68 nm in diameters. By using the geometric shape of the pores, we attempted to evaluate the specific ion conductivities of the organic electrolyte solution dissolving lithium salt simply. AC impedance spectroscopy measurement of a four-electrode cell with membranes showed one depressed semi-circle in the Nyquist plots and this semi-circle can be assigned as the ion transport resistance in the pores. The specific ion conductivities evaluated from the ion transport resistances and the geometric parameters showed very small values, even in the macro-pores, as compared with that of the bulk electrolyte solution.

Membranes in Lithium Ion Batteries

Science.gov (United States)

Yang, Min; Hou, Junbo

2012-01-01

Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed. PMID:24958286

Membranes in Lithium Ion Batteries

Directory of Open Access Journals (Sweden)

Junbo Hou

2012-07-01

Full Text Available Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed.

Gadolinium(III) ion selective sensor using a new synthesized Schiff's base as a sensing material

International Nuclear Information System (INIS)

Zamani, Hassan Ali; Mohammadhosseini, Majid; Haji-Mohammadrezazadeh, Saeed; Faridbod, Farnoush; Ganjali, Mohammad Reza; Meghdadi, Soraia; Davoodnia, Abolghasem

2012-01-01

According to a solution study which showed a selective complexation between N,N′-bis(methylsalicylidene)-2-aminobenzylamine (MSAB) and gadolinium ions, MSAB was used as a sensing element in construction of a gadolinium(III) ion selective electrode. Acetophenon (AP) was used as solvent mediator and sodium tetraphenyl borate (NaTPB) as an anion excluder. The electrode showed a good selectivity towards Gd(III) ions over a wide variety of cations tested. The constructed sensor displayed a Nernstian behavior (19.7 ± 0.3 mV/decade) in the concentration range of 1.0 × 10 −6 to 1.0 × 10 −2 mol L −1 with detection limit of 5.0 × 10 −7 mol L −1 and a short response time ( 3+ –PVC membrane sensor based on an ion carrier as sensing material is introduced. ► This technique is very simple and it's not necessary to use sophisticated equipment. ► This sensor shows good selectivity against other metal ions.

Application of membrane-selective electrodes for the determination of Tiemonium methylsulphate

Directory of Open Access Journals (Sweden)

Lobna A. Hussein

2017-06-01

Full Text Available Three ion selective electrodes were developed for the quantification of Tiemonium methylsulphate (TIM. Two of these sensors involve the construction of water insoluble ion-association complexes; namely sensor1 TIM-phosphotungstate (TIM-PT and sensor 2 TIM-Reinecke (TIM-R. Molecular recognition elements have extensive applications in electrochemical sensors with a significant potential for future development thus a third electrode utilizing molecularly imprinted polymer was constructed; sensor 3 TIM-MIP. The proposed sensors showed fast, stable Nernstian responses of 56.4, 56.1and 57.5 mV/decade for sensors 1, 2 and 3, respectively, across a relatively wide TIM concentration range (1 × 10−4 to 1 × 10−2 mol L−1 for sensors 1 and 2 and 1 × 10–5 to 1 × 10–2 mol L−1 for sensor 3 in the pH range of 2–7. Sensor 1 and sensor 2 can be used for five weeks while sensor 3 for 65 days without a significant change in sensitivity. The suggested method was used to determine TIM in dosage forms. No measurable difference was obtained when the result statistically compared with respect to accuracy and precision with reported HPLC method.

Surface-Modified Membrane as A Separator for Lithium-Ion Polymer Battery

Directory of Open Access Journals (Sweden)

Jun Young Kim

2010-04-01

Full Text Available This paper describes the fabrication of novel modified polyethylene (PE membranes using plasma technology to create high-performance and cost-effective separator membranes for practical applications in lithium-ion polymer batteries. The modified PE membrane via plasma modification process plays a critical role in improving wettability and electrolyte retention, interfacial adhesion between separators and electrodes, and cycle performance of lithium-ion polymer batteries. This paper suggests that the performance of lithium-ion polymer batteries can be greatly enhanced by the plasma modification of commercial separators with proper functional materials for targeted application.

Method and apparatus for removing ions from soil

Science.gov (United States)

Bibler, Jane P.

1993-01-01

A method and apparatus for selectively removing species of ions from an area of soil. Permeable membranes 14 and 18 impregnated with an ion exchange resin that is specific to one or more species of chemical ions are inserted into ground 12 in close proximity to, and on opposing sides of, a soil area of interest 22. An electric potential is applied across electrodes 26 and 28 to cause the migration of ions out of soil area 22 toward the membranes 14 and 18. Preferably, the resin exchanges ions of sodium or hydrogen for ions of mercury that it captures from soil area 22. Once membranes 14 and 18 become substantially saturated with mercury ions, the potential applied across electrodes 26 and 28 is discontinued and membranes 14 and 18 are preferably removed from soil 12 for storage or recovery of the ions. The membranes are also preferably impregnated with a buffer to inhibit the effect of the hydrolysis of water by current from the electrodes.

AC impedance electrochemical modeling of lithium-ion positive electrodes

International Nuclear Information System (INIS)

Dees, D.; Gunen, E.; Abraham, D.; Jansen, A.; Prakash, J.

2004-01-01

Under Department of Energy's Advanced Technology Development Program,various analytical diagnostic studies are being carried out to examine the lithium-ion battery technology for hybrid electric vehicle applications, and a series of electrochemical studies are being conducted to examine the performance of these batteries. An electrochemical model was developed to associate changes that were observed in the post-test analytical diagnostic studies with the electrochemical performance loss during testing of lithium ion batteries. While both electrodes in the lithium-ion cell have been studied using a similar electrochemical model, the discussion here is limited to modeling of the positive electrode. The positive electrode under study has a composite structure made of a layered nickel oxide (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) active material, a carbon black and graphite additive for distributing current, and a PVDF binder all on an aluminum current collector. The electrolyte is 1.2M LiPF 6 dissolved in a mixture of EC and EMC and a Celgard micro-porous membrane is used as the separator. Planar test cells (positive/separator/negative) were constructed with a special fixture and two separator membranes that allowed the placement of a micro-reference electrode between the separator membranes (1). Electrochemical studies including AC impedance spectroscopy were then conducted on the individual electrodes to examine the performance and ageing effects in the cell. The model was developed by following the work of Professor Newman at Berkeley (2). The solid electrolyte interface (SEI) region, based on post-test analytical results, was assumed to be a film on the oxide and an oxide layer at the surface of the oxide. A double layer capacity was added in parallel with the Butler-Volmer kinetic expression. The pertinent reaction, thermodynamic, and transport equations were linearized for a small sinusoidal perturbation (3). The resulting system of differential equations was solved

Gadolinium(III) ion selective sensor using a new synthesized Schiff's base as a sensing material

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Mohammadhosseini, Majid [Department of Chemistry, Faculty of Basic Sciences, Shahrood Branch, Islamic Azad University, Shahrood (Iran, Islamic Republic of); Haji-Mohammadrezazadeh, Saeed [Department of Chemistry, Payame Noor University, Ardakan (Iran, Islamic Republic of); Faridbod, Farnoush [Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Meghdadi, Soraia [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Davoodnia, Abolghasem [Department of Chemistry, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2012-05-01

According to a solution study which showed a selective complexation between N,N Prime -bis(methylsalicylidene)-2-aminobenzylamine (MSAB) and gadolinium ions, MSAB was used as a sensing element in construction of a gadolinium(III) ion selective electrode. Acetophenon (AP) was used as solvent mediator and sodium tetraphenyl borate (NaTPB) as an anion excluder. The electrode showed a good selectivity towards Gd(III) ions over a wide variety of cations tested. The constructed sensor displayed a Nernstian behavior (19.7 {+-} 0.3 mV/decade) in the concentration range of 1.0 Multiplication-Sign 10{sup -6} to 1.0 Multiplication-Sign 10{sup -2} mol L{sup -1} with detection limit of 5.0 Multiplication-Sign 10{sup -7} mol L{sup -1} and a short response time (< 10 s). The working pH range of the electrode was 3.5-10.1 and lifetime of the sensor was at least 10 weeks. Analysis of certified reference materials confirmed the accuracy of the proposed sensor. The electrode was successfully applied as an indicator electrode in gadolinium titration with EDTA. - Highlights: Black-Right-Pointing-Pointer A Gd{sup 3+}-PVC membrane sensor based on an ion carrier as sensing material is introduced. Black-Right-Pointing-Pointer This technique is very simple and it's not necessary to use sophisticated equipment. Black-Right-Pointing-Pointer This sensor shows good selectivity against other metal ions.

Nanofiber membrane-electrode-assembly and method of fabricating same

Energy Technology Data Exchange (ETDEWEB)

Pintauro, Peter N.; Ballengee, Jason; Brodt, Matthew

2018-01-23

In one aspect of the present invention, a method of fabricating a fuel cell membrane-electrode-assembly (MEA) having an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode electrode, includes fabricating each of the anode electrode, the cathode electrode, and the membrane separately by electrospinning; and placing the membrane between the anode electrode and the cathode electrode, and pressing then together to form the fuel cell MEA.

A metal ion charged mixed matrix membrane for selective adsorption of hemoglobin

NARCIS (Netherlands)

Tetala, K.K.R.; Skrzypek, K.; Levisson, M.; Stamatialis, D.F.

2013-01-01

In this work, we developed a mixed matrix membrane by incorporating 20–40 µm size iminodiacetic acid modified immobeads within porous Ethylene vinyl alcohol (EVAL) polymer matrix. The MMM were charged with copper ions for selective adsorption of bovine hemoglobin in presence of bovine serum albumin.

Functions of chalcogenide electrodes in solutions of complexing reagents and interfering ions

International Nuclear Information System (INIS)

Kiyanskij, V.V.

1990-01-01

The possibility to modify chalcogenide electrodes and their behaviour in solutions of complexing reagents for the development of new methods of potentiometric titration has been studied. It is shown that complexing reagents (EDTA, cupferron, 8-hydroxyquinoline, sodium dithiocarbaminate) and Cu(2), Hg(2) produce a strong effect on the functions of Ag, Cu, Cd, Pb - selective electrodes, which is used for titration of potential-determining and non-potential-determining ions ions (Sr 2+ , La 3+ etc.) and also for modification of sulfide-selecting electrode. A method of potentiometric titration of sulfates and chlorides with modified Cd- and Ag-selective electrodes is suggested

Functionalized Nanoporous Track Etched {beta}-PVDF Membrane Electrodes for Lead (II) Determination by Square Wave Anodic Stripping Voltammetry

Energy Technology Data Exchange (ETDEWEB)

Bessbousse, H [Laboratoire des Solides Irradies, CEA-CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Nadhakumar, I [School of Chemistry, University of Southampton, University Road, Southampton S017 1BJ (United Kingdom); Decker, M; Clochard, M -C; Wade, T L [Laboratoire des Solides Irradies, CEA-CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Barsbay, M [Hacettepe University, Department of Chemistry, Polymer Chemistry Division, 06800 Beytepe Ankara (Turkey)

2012-09-15

Track etched functionalized nanoporous {beta}-PVDF membrane electrodes, or functionalized membrane electrodes (FME), are thin-layer cells made from poly(acrylic acid) (PAA) functionalized nanoporous {beta}-poly(vinylidene fluoride) ({beta}-PVDF) membranes with thin Au films sputtered on each side as electrodes. The Au film is thin enough that the pores of the membranes are not completely covered. The PAA functionalization is specifically localised in the walls of the nanoporous {beta}-PVDF membrane by grafting. The PAA is a cation exchange polymer that adsorbs metal ions, such as Pb{sup 2+}, from aqueous solutions concentrating the ions into the membrane. After a time the FME is transferred to an electrochemical cell for analysis. A negative potential is applied to the Au film of the FME for a set time to reduce the adsorbed ions onto the Au film working electrode. The other metalized side of the FME functions as a counter electrode. Finally, square-wave anodic stripping voltammetry (SW-ASV) is performed on the FME to determine the metal ion concentrations in the original solution. The calibration curve of charge versus log concentration has a Temkin isotherm form. The FME membranes are 9 {mu}m thick and have 40 nm diameter pores with a density of 10{sup 10} pores/cm{sup 2}. This high pore density provides a large capacity for ion adsorption. Au ingress in the pores during sputtering forms a random array of nanoelectrodes. Like surface modified electrodes for adsorptive stripping voltammetry, the pre-concentration step for the FME is performed at open circuit. The zero current intercept of the calibration for Pb{sup 2+} is 0.13 ppb ({mu}g/L) and a detection limit of 0.050 ppb based on 3S/N from blank measurements. Voltammetry (CV) and chronoapmerometry (CA) were used to characterize the system. The apparent diffusion coefficient (D) for Pb{sup 2+} in the PAA functionalized pores was determined to be 2.44 x 10{sup -7} cm{sup 2}/s and the partition coefficient (p

Kinetic energy budget for electroconvective flows near ion selective membranes

Science.gov (United States)

Wang, Karen; Mani, Ali

2017-11-01

Electroconvection occurs when ions are driven from a bulk fluid through an ion-selective surface. When the driving voltage is beyond a threshold, this process undergoes a hydrodynamic instability called electroconvection, which can become chaotic due to nonlinear coupling between ion-transport, fluid flow, and electrostatic forces. Electroconvection significantly enhances ion transport and plays an important role in a wide range of electrochemical applications. We investigate this phenomenon by considering a canonical geometry consisting of a symmetric binary electrolyte between an ion-selective membrane and a reservoir using 2D direct numerical simulation (DNS). Our simulations reveal that for most practical regimes, DNS of electroconvection is expensive. Thus, a plan towards development of reduced-order models is necessary to facilitate the adoption of analysis of this phenomenon in industry. Here we use DNS to analyze the kinetic energy budget to shed light into the mechanisms sustaining flow and mixing in electroconvective flows. Our analysis reveals the relative dominance of kinetic energy sources, dissipation, and transport mechanisms sustaining electroconvection at different distances from the interface and over a wide range of input parameters. Karen Wang was supported by the National Defense Science & Engineering Graduate Fellowship (NDSEG). Ali Mani was supported by the National Science Foundation Award.

A metal ion charged mixed matrix membrane for selective adsorption of hemoglobin

NARCIS (Netherlands)

Tetala, K.K.R.; Skrzypek, Katarzyna; Levisson, M.; Stamatialis, Dimitrios

2013-01-01

In this work, we developed a mixed matrix membrane by incorporating 20–40 μm size iminodiacetic acid modified immobeads within porous Ethylene vinyl alcohol (EVAL) polymer matrix. The MMM were charged with copper ions for selective adsorption of bovine hemoglobin in presence of bovine serum albumin.

Polystyrene Sulfonate Threaded through a Metal-Organic Framework Membrane for Fast and Selective Lithium-Ion Separation.

Science.gov (United States)

Guo, Yi; Ying, Yulong; Mao, Yiyin; Peng, Xinsheng; Chen, Banglin

2016-11-21

Extraction of lithium ions from salt-lake brines is very important to produce lithium compounds. Herein, we report a new approach to construct polystyrene sulfonate (PSS) threaded HKUST-1 metal-organic framework (MOF) membranes through an in situ confinement conversion process. The resulting membrane PSS@HKUST-1-6.7, with unique anchored three-dimensional sulfonate networks, shows a very high Li + conductivity of 5.53×10 -4  S cm -1 at 25 °C, 1.89×10 -3  S cm -1 at 70 °C, and Li + flux of 6.75 mol m -2  h -1 , which are five orders higher than that of the pristine HKUST-1 membrane. Attributed to the different size sieving effects and the affinity differences of the Li + , Na + , K + , and Mg 2+ ions to the sulfonate groups, the PSS@HKUST-1-6.7 membrane exhibits ideal selectivities of 78, 99, and 10296 for Li + /Na + , Li + /K + , Li + /Mg 2+ and real binary ion selectivities of 35, 67, and 1815, respectively, the highest ever reported among ionic conductors and Li + extraction membranes. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermo- and pH-responsive poly(A-ProOMe)-graft-poly(AAc) membrane for selective separation of metal ions

International Nuclear Information System (INIS)

Hasegawa, Shin; Maekawa, Yasunari; Yoshida, Masaru; Ohashi, Hitoshi; Katakai, Ryoichi

2009-01-01

We investigated the permeation behavior of Li, Co, and Ni ions through thermo- and pH-responsive gel membranes, which were prepared by γ-ray grafting of pH-responsive poly(acrylic acid) (poly(AAc)) onto a thermo-responsive polymer gel of acryloyl-L-proline methyl ester (A-ProOMe). Using 15% AAc grafted membranes, the permeation constants of Li ions are 2.8 and 3.5 times higher than those of Co and Ni ions in a pH 6.0 buffer solution at 30degC. These ratios are two and three times higher than those of 5 and 43% grafted gel membranes, respectively. By comparison with the permeation of metal ions through the non-thermo-responsive porous polyethylene membranes grafted with AAc chains or random copolymer gel membranes (poly(A-ProOMe-co-AAc)), it is clear that the structure in which adjacent carboxyl groups of poly(AAc) are surrounded by thermo-responsive A-ProOMe matrix causes selective permeability of Li ion over Co and Ni ions. The distributions of Co and Ni ions in the microscopic structures clearly show that the structure consisting of flexible chains of the carboxyl groups grafted onto the thermo-response gel membrane plays a decisive role in the superior selective permeation of a Li ion. (author)

Theoretical voltammetric response of electrodes coated by solid polymer electrolyte membranes

International Nuclear Information System (INIS)

Gómez-Marín, Ana M.; Hernández-Ortíz, Juan P.

2014-01-01

Highlights: • Discretized model for an interface of covered electrodes. • Two limiting behaviors are capture: double-layer and conductive interfaces. • Additional phenomena are included easily: acid/base equilibrium, ion mobility. • The model provides explanations to observed phenomena that is vaguely explained in the literature. • Implications on electrodes in fuel cells are given and it opens avenues to understand and design such systems. - Abstract: A model for the differential capacitance of metal electrodes coated by solid polymer electrolyte membranes, with acid/base groups attached to the membrane backbone, and in contact with an electrolyte solution is developed. With proper model parameters, the model is able to predict a limit response, given by Mott–Schottky or Gouy–Chapman–Stern theories depending on the dissociation degree and the density of ionizable acid/base groups. The model is also valid for other ionic membranes with proton donor/acceptor molecules as membrane counterions. Results are discussed in light of the electron transfer rate at membrane-coated electrodes for electrochemical reactions that strongly depend on the double layer structure. In this sense, the model provides a tool towards the understanding of the electro-catalytic activity on modified electrodes. It is shown that local maxima and minima in the differential capacitance as a function of the electrode potential may occur as consequence of the dissociation of acid/base molecular species, in absence of specific adsorption of immobile polymer anions on the electrode surface. Although the model extends the conceptual framework for the interpretation of cyclic voltammograms for these systems and the general theory about electrified interfaces, structural features of real systems are more complex and so, presented results only are qualitatively compared with experiments

Optimization of a new polymeric chromium (III) membrane electrode based on methyl violet by using experimental design.

Science.gov (United States)

Kazemi, Sayed Yahya; Hamidi, Akram sadat; Asanjarani, Neda; Zolgharnein, Javad

2010-06-15

Plackett-Burman and Box-Behnken designs were applied as experimental design strategies to screen and optimize the influence of membrane ingredients on the electrode performance. A new poly(vinyl chloride) membrane sensor for Cr(III) based on methyl violet as an ionophore was planned. The major variables to find a model for achieving the best Nernstian slope as response were: PVC, plasticizers, methyl violet, KpClTPB, pH, conditioning time and internal solution concentration. Plackett-Burman design was used to screen the main factors and Box-Behnken response surface was led to find a model for optimizing the response. The optimized membrane electrode shows a Nernstian slope for chromium (III) ions over a wide linear range from 1.99x10(-6) to 3.16x10(-2)molL(-1) and a slope of 19.5+/-0.1mVdecade(-1) of activity. It would be successfully applied in the pH range from 3.5 to 6.5 with detection limit of 1.77x10(-6)molL(-1) (0.092mgL(-1)). The response time of the sensor is about 8s and the membrane can be used for more than 6 weeks without any deviation. The relative standard deviations (R.S.D.) for six replicate the measurements of 1.0x10(-4) and 1.0x10(-3)molL(-1) of Cr(III) were 3.2 and 3%, respectively. The electrode revealed comparatively good selectivity with respect to many cations including alkali earth, transition and heavy metal ions. The electrode was successfully used as an indicator in the potentiometric titration of Cr(III) with EDTA and was also applied to the direct determination chromium (III) content of spiked water and soil samples.

Fabrication of a new samarium(III) ion-selective electrode based on 3-{l_brace}[2-oxo-1(2h)-acenaphthylenyliden]amino{r_brace}-2-thioxo -1,3-thiazolidin-4-one

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali [Islamic Azad University, Quchan (Iran, islamic Republic of). Quchan Branch. Dept. of Chemistry]. E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). Faculty of Chemistry. Center of Excellence in Electrochemistry

2007-07-01

This paper introduces the development of an original PVC membrane electrode, based on 3-{l_brace}[2-oxo-1(2H)-acenaphthylenyliden]amino{r_brace}-2-thioxo-1,3-thiazolidin-4-one (ATTO) which has revealed to be a suitable carrier for Sm{sup 3+} ions. The resulting data illustrated that the electrode shows a Nernstian slope of 19.3 {+-} 0.6 mV per decade for Sm{sup 3+} ions over a broad working concentration range of 1.0 X 10{sup -6} to 1.0 X 10{sup -1} mol L{sup -1}. The lower detection limit was found to be equal to (5.5{+-} 0.3) X 10{sup -7} mol L{sup -}'1 in the pH range of 3.5-7.5, and the response time was very short ({approx}10 s). The potentiometric sensor displayed good selectivities for a number of cations such as alkali, alkaline earth, transition and heavy metal ions. (author)

Environment-sensitive ion-track membranes

International Nuclear Information System (INIS)

Yoshida, Masaru

1996-01-01

Development of an environment-sensitive porous membrane from ion-track membranes may realize by combining the techniques of ion beam radiation and those of molecular designing and synthesis for intelligent materials. Now, the development of such membrane is progressing with an aim at selecting some specific substances and accurately control its pore size in response to any small environmental stimulus such as temperature change. The authors have been studying the molecular design, synthesis and functional expression of intelligent materials, which are called here as environment-sensitive gels. In this report, the outlines of the apparatus for the production of such porous membrane was described. An organic polymer membrane was irradiated with an ion beam and followed by chemical etching to make ion track pores. Scanning electron microscopic observation for the cross section of the membrane showed that the pore shape varies greatly depending on the ion nuclide used. The characteristics of newly produced porous membranes consisting of CR-30/A-ProDMe and polyethylene-telephtharate were investigated in respect of pore size change responding to temperature. These studies of design, synthesis and functions of such gels would enable to substitute artificial materials for the functions of human sensors. (M.N.). 54 refs

PVC-Membrane Potentiometric Electrochemical Sensor Based on 2-(4-Oxopentan-2-ylideneaminoisoindoline-1,3-dione for Selective Determination of Holmium(III

Directory of Open Access Journals (Sweden)

Hassan Ali Zamani

2011-01-01

Full Text Available 2-(4-Oxopentan-2-ylideneamino isoindoline-1,3-dione (OID was found to be a suitable neutral ionophore in the fabrication of a highly selective Ho3+ membrane sensor. The electrode has a near-Nernstian slope of 19.6±0.5 mV per decade with a wide concentration range between 1.0×10-6 and 1.0×10-2 mol/L in the pH range of 3.5–8.8, having a fast response time (∼5 s and a detection limit of 5.8×10-7 mol/L. This electrode presented very good selectivity and sensitivity towards the Ho3+ ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The practical utility of the electrode has been demonstrated by its use as an indicator electrode for the potentiometric titration of a Ho3+ solution with EDTA and for the determination of Ho3+ ions concentration in mixtures of two and three different ions.

Recent developments on ion-exchange membranes and electro-membrane processes.

Science.gov (United States)

Nagarale, R K; Gohil, G S; Shahi, Vinod K

2006-02-28

Rapid growth of chemical and biotechnology in diversified areas fuels the demand for the need of reliable green technologies for the down stream processes, which include separation, purification and isolation of the molecules. Ion-exchange membrane technologies are non-hazardous in nature and being widely used not only for separation and purification but their application also extended towards energy conversion devices, storage batteries and sensors etc. Now there is a quite demand for the ion-exchange membrane with better selectivities, less electrical resistance, high chemical, mechanical and thermal stability as well as good durability. A lot of work has been done for the development of these types of ion-exchange membranes during the past twenty-five years. Herein we have reviewed the preparation of various types of ion-exchange membranes, their characterization and applications for different electro-membrane processes. Primary attention has been given to the chemical route used for the membrane preparation. Several general reactions used for the preparation of ion-exchange membranes were described. Methodologies used for the characterization of these membranes and their applications were also reviewed for the benefit of readers, so that they can get all information about the ion-exchange membranes at one platform. Although there are large number of reports available regarding preparations and applications of ion-exchange membranes more emphasis were predicted for the usefulness of these membranes or processes for solving certain type of industrial or social problems. More efforts are needed to bring many products or processes to pilot scale and extent their applications.

Impedance study of the ion-to-electron transduction process for carbon cloth as solid-contact material in potentiometric ion sensors

International Nuclear Information System (INIS)

Mattinen, Ulriika; Rabiej, Sylwia; Lewenstam, Andrzej; Bobacka, Johan

2011-01-01

Carbon cloth was studied as solid-contact material in potentiometric ion sensors by using electrochemical impedance spectroscopy and potentiometry. The ion-to-electron transduction process was studied by electrochemical impedance spectroscopy by using a two-electrode symmetrical cell where a liquid electrolyte was sandwiched between two solid electrodes, including bare glassy carbon (GC), GC/carbon cloth and GC/poly(3,4-ethylenedioxythiophene). Impedance data for different electrode/electrolyte combinations were evaluated and compared. Solid-contact K + -selective electrodes were fabricated by coating the carbon cloth with a conventional plasticized PVC-based K + -selective membrane via drop casting. These K + -sensors showed proper analytical performance and acceptable long-term potential stability (potential drift ≈ 1 mV/day). Solid contact reference electrodes were fabricated in an analogous manner by coating the carbon cloth with a plasticized PVC membrane containing a moderately lipophilic salt. The results indicate that carbon cloth can be used as a solid-contact material in potentiometric ion sensors and pseudo-reference electrodes.

Potentiometer determination of sulfur using silver/sulfur ion selective electrodes; Determinacion potenciometrica de sulfuros mediante electrodo-ion-selectivo de plata/sulfuro

Energy Technology Data Exchange (ETDEWEB)

Salamanca Grosso, G. [Departamento de Quimica, Instituto de Ciencias, Universidad de Tolima, Tolima (Colombia)

1996-06-01

New devices in analytical chemistry, has been emerged, and new procedures take great interest. The use of electrodes ion selective are very important in water and wastewater control of Ag+/S= electrodes for control process in wastewater from UASE plan pilot, before check their potentiometric performance so: 28.6+- 0.4 mV/decade, optimal time 20 seconds, and pH>10, detection limit 1.8 x 10``-6. The study was made in comparative way with yodometrical method: we check quantification by addition, subtraction an GRANT`s titrimetric. (Author) 10 refs.

Evaluation study of an ion selective field effect transistor electrode for measuring quality parameters of fuel ethanol

Energy Technology Data Exchange (ETDEWEB)

Gonzaga, Fabiano B.; Sobral, Sidney P.; Ribeiro, Carla M.; Goncalves, Mary A., E-mail: fbgonzaga@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia(INMETRO), Duque de Caxias, RJ (Brazil). Div. de Metrologia Quimica

2013-01-15

An ion selective field effect transistor (ISFET) electrode was evaluated for measuring pH and acid number (AN) of fuel ethanol and compared to two glass electrodes with different reference filling solutions: KCl aqueous solution (glass-KCl electrode)and LiCl ethanolic solution (glass-LiCl electrode). pH was determined at different measurement times and AN was determined using automatic potentiometric titration. For pH, the glass-KCl electrode showed the best precision and stability, with an average repeatability about four times better when compared to the ISFET electrode for the measurement time of 30 s (as indicated in the ASTM D6423 standard). For AN, the glass-KCl and glass-LiCl electrodes showed similar repeatabilities, which were about three times better than that of the ISFET electrode. In addition, the results from a recovery study demonstrated better accuracy of the glass-LiCl electrode, with a recovery value of 100.1% (author)

Smart membranes for nitrate removal, water purification, and selective ion transportation

Science.gov (United States)

Wilson, William D [Pleasanton, CA; Schaldach, Charlene M [Pleasanton, CA; Bourcier, William L [Livermore, CA; Paul, Phillip H [Livermore, CA

2009-12-15

A computer designed nanoengineered membrane for separation of dissolved species. One embodiment provides an apparatus for treatment of a fluid that includes ions comprising a microengineered porous membrane, a system for producing an electrical charge across the membrane, and a series of nanopores extending through the membrane. The nanopores have a pore size such that when the fluid contacts the membrane, the nanopores will be in a condition of double layer overlap and allow passage only of ions opposite to the electrical charge across the membrane.

Asymmetric Membranes Containing Micron-Size Silicon for High Performance Lithium Ion Battery Anode

International Nuclear Information System (INIS)

Byrd, Ian; Wu, Ji

2016-01-01

Micron-size Si anode is notorious for having extremely poor cycle life. It is mainly caused by the large volume change (∼300%) and poor mechanical strength of the Si electrode. Satisfying methods to address this issue are seriously lacking in literature. In this study, novel single-layer, double-layer and triple-layer asymmetric membranes containing micron-size silicon have been fabricated using a simple phase inversion method to dramatically improve its cyclability. The electrochemical performance of these asymmetric membranes as lithium ion battery anodes are evaluated and compared to pure micron-size Si powders and carbonaceous asymmetric membranes. All three types of asymmetric membrane electrodes demonstrate significantly enhanced stability as compared to pure Si powders. The single-layer asymmetric membrane has the largest capacity degradation due to the loss of pulverized Si powders from the membrane surface, only 40% of whose capacity can be retained in 100 cycles. But this performance is still much better than pure micron-size silicon electrode. After being coated with nanoporous carbonaceous layers on both sides of a single-layer asymmetric membrane to make a triple-layer asymmetric membrane (sandwich structure), the capacity retention is notably increased to 88% in 100 cycles at 610 mAh g"−"1 and 0.5C. The enhanced stability is attributed to the extra nanoporous coatings that can prevent the fractured Si powders from being leached out and allow facile lithium ion diffusions. Such a novel, efficient and scalable method may provide beneficiary guidance for designing high capacity lithium ion battery anodes with large volume change issues.

Development of Voltammetric Double-Polymer-Modified Electrodes for Nanomolar Ion Detection for Environmental and Biological Applications

Science.gov (United States)

Kim, Yushin

Qualitative and quantitative electrochemical methods for trace ion analysis of organic and inorganic species with environmental and biological attention have been developed and reported during past decades. The development of fast and accurate electrochemical methods is critical for field applications with various blocking contaminants. Voltammetric method is attractive not only to analyze selective ion species due to its characteristic based on ion lipophilicity, but also to lower the limit of detection by combining with stripping analysis. In my PhD work, I have developed and studied a highly selective and sensitive electrochemical method that can be used to characterize fundamental transport dynamics and to develop electrochemical sensors at liquid/liquid interfaces based on electrochemically-controlled ion transfer and recognition. The understanding of the kinetic and thermodynamic properties of the voltammetric ion transfer through polymer-modified ion-selective electrodes leads to realize the highly selective and sensitive analytical method. The ultrathin polymer membrane is used to maximize a current response by complete exhaustion of preconcentrated ions. Therefore, nanomolar detection is achieved and confirmed by a thermodynamic mechanism that controls the detection limit. It was also demonstrated experimentally and theoretically that more lipophilic ionic species gives a significantly lower detection limit. The voltammetric method was expanded into inexpensive and disposable applications based on pencil lead modified with the thin polymer membrane. In the other hand, micropipet/nanopipet voltammetry as an artificial cell membrane was used to study the interface between two immiscible solutions for environmental and biomedical applications. It is very useful to get quantitative kinetic and thermodynamic information by studying numerical simulations of ion transfer and diffusion. Molecular recognition and transport of heparin and low

Determination of lithium in organic matrix by potentiometric titration using fluoride ion selective electrode

International Nuclear Information System (INIS)

Govindan, R.; Alamelu, D.; Shah, Raju; Aggarwal, S.K.

2008-01-01

A method has been developed for the determination of lithium (Li) present in organic matrix containing hexa methylene tetramine (HMTA) and urea used in the sol-gel process for preparing lithium titanate microspheres, using fluoride ion selective electrode and potentiometric end point. Lithium is present in the wash solutions of the Sol-Gel process employed for the preparation of lithium titanate microspheres, proposed to be used in TBM (Test Blanket Module) of International Thermonuclear Experimental Reactor (ITER) project. Methods such as ICP-AES, AAS etc. used in aqueous solutions cannot be employed directly for lithium determination in organic matrix containing hexa methylene tetramine (HMTA), urea, NH 4 NO 3 , NH 4 Cl etc. A potentiometric method using a combination fluoride ion selective electrode for end point detection was developed and has been employed for lithium determination in the process streams from sol-gel process. The method is simple and rapid and an accuracy of about 0.5 % was achieved for the determination of Li in the range of 1 to 20 mg. The method is based on the complexation of Li by adding a known excess of NH 4 F solution, followed by potentiometric end point detection using fluoride ISE

Voltammetry of ion transfer across a polarized room-temperature ionic liquid membrane facilitated by valinomycin: theoretical aspects and application.

Science.gov (United States)

Langmaier, Jan; Samec, Zdenek

2009-08-01

Cyclic voltammetry is used to investigate the transfer of alkali-metal cations, protons, and ammonium ions facilitated by the complex formation with valinomycin at the interface between an aqueous electrolyte solution and a room-temperature ionic liquid (RTIL) membrane. The membrane is made of a thin (approximately 112 microm) microporous filter impregnated with an RTIL that is composed of tridodecylmethylammonium cations and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anions. An extension of the existing theory of voltammetry of ion transfer across polarized liquid membranes makes it possible to evaluate the standard ion-transfer potentials for the hydrophilic cations studied, as well as the stability constants (K(i)) of their 1:1 complexes with valinomycin, as log K(i) = 9.0 (H(+)), 11.1 (Li(+)), 12.8 (Na(+)), 17.2 (K(+)), 15.7 (Rb(+)), 15.1 (Cs(+)), and 14.7 (NH(4)(+)). These data point to the remarkably enhanced stability of the valinomycin complexes within RTIL, and to the enhanced selectivity of valinomycin for K(+) over all other univalent ions studied, compared to the conventional K(+) ion-selective liquid-membrane electrodes. Selective complex formation allows one to resolve voltammetric responses of K(+) and Na(+) in the presence of an excess of Mg(2+) or Ca(2+), which is demonstrated by determination of K(+) and Na(+) in the table and tap water samples.

Organoboron compounds as Lewis acid receptors of fluoride ions in polymeric membranes.

Science.gov (United States)

Jańczyk, Martyna; Adamczyk-Woźniak, Agnieszka; Sporzyński, Andrzej; Wróblewski, Wojciech

2012-07-06

Newly synthesized organoboron compounds - 4-octyloxyphenylboronic acid (OPBA) and pinacol ester of 2,4,6-trifluorophenylboronic acid (PE-PBA) - were applied as Lewis acid receptors of fluoride anions. Despite enhanced selectivity, the polymer membrane electrodes containing the lipophilic receptor OPBA exhibited non-Nernstian slopes of the responses toward fluoride ions in acidic conditions. Such behavior was explained by the lability of the B-O bond in the boronic acids, and the OH(-)/F(-) exchange at higher fluoride content in the sample solution. In consequence, the stoichiometry of the OPBA-fluoride complexes in the membrane could vary during the calibration, changing the equilibrium concentration of the primary anion in membrane and providing super-Nernstian responses. The proposed mechanism was supported by (19)F NMR studies, which indicated that the fluoride complexation proceeds more effectively in acidic solution leading mainly to PhBF(3)(-) species. Finally, the performances of the membranes based on the phenylboronic acid pinacol ester, with a more stable B-O bond, were tested. As it was expected, Nernstian fluoride responses were recorded for such membranes with worsened fluoride selectivity. Copyright © 2012 Elsevier B.V. All rights reserved.

Monovalent-ion-selective membranes for reserve electrodialysis

NARCIS (Netherlands)

Güler, E.; van Baak, Willem; Saakes, Michel; Nijmeijer, Dorothea C.

2014-01-01

Reverse electrodialysis (RED) is a process that can be used to generate energy from salinity gradients. Since its application in practice requires the use of natural seawater and river water, the presence of multivalent ions is inevitable, but this currently limits RED performance. Membranes with

Simple and rapid mercury ion selective electrode based on 1-undecanethiol assembled Au substrate and its recognition mechanism

Energy Technology Data Exchange (ETDEWEB)

Li, Xian-Qing; Liang, Hai-Qing [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Cao, Zhong, E-mail: zhongcao2004@163.com [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Xiao, Qing [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Xiao, Zhong-Liang, E-mail: xiaozhongliang@163.com [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); State Key Laboratory of High Performance Complex Manufacturing, School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China); Song, Liu-Bin [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Chen, Dan [Hunan Airbluer Environmental Protection Technology Co., Ltd., Changsha 410014 (China); Wang, Fu-Liang [State Key Laboratory of High Performance Complex Manufacturing, School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China)

2017-03-01

A simple and rapid mercury ion selective electrode based on 1-undecanethiol (1-UDT) assembled Au substrate (Au/1-UDT) has been well constructed. 1-UDT was for the purpose of generating self-assembled monolayer on gold surface to recognize Hg{sup 2+} in aqueous solution, which had a working concentration range of 1.0 × 10{sup −} {sup 8}–1.0 × 10{sup −4} mol L{sup −1}, with a Nernst response slope of 28.83 ± 0.4 mV/-pC, a detection limit of 4.5 × 10{sup −9} mol L{sup −1}, and a good selectivity over the other tested cations. Also, the Au/1-UDT possessed good reproducibility, stability, and short response time. The recovery obtained for the determination of mercury ion in practical tremella samples was in the range of 99.8–103.4%. Combined electrochemical analysis and X-ray photoelectron spectroscopy (XPS) with quantum chemical computation, the probable recognition mechanism of the electrode for selective recognition of Hg{sup 2+} has been investigated. The covalent bond formed between mercury and sulfur is stronger than the one between gold and sulfur and thus prevents the adsorption of 1-UDT molecules on the gold surface. The quantum chemical computation with density functional theory further demonstrates that the strong interaction between the mercury atom and the sulfur atom on the gold surface leads to the gold sulfur bond ruptured and the gold mercury metallophilic interaction. - Highlights: • A simple and rapid mercury ion selective electrode has been well constructed. • The Au/1-UDT electrode for sensing Hg{sup 2+} has a sensitivity of 28.83 ± 0.4 mV/− pC. • The ISE method has a detection limit of Hg{sup 2+} down to 4.5 × 10{sup −9} mol L{sup −1}. • A mechanism with density functional theory for recognition of Hg{sup 2+} is developed. • The quantum chemical computation demonstrates Au-Hg metallophilic interaction.

Oxide materials as positive electrodes of lithium-ion batteries

International Nuclear Information System (INIS)

Makhonina, Elena V; Pervov, Vladislav S; Dubasova, Valeriya S

2004-01-01

The published data on oxide materials as positive electrodes for lithium-ion batteries are described systematically. The mechanisms of structural changes in cathode materials occurring during the operation of lithium-ion batteries and the problems concerned with their selection are discussed. Modern trends in optimising cathode materials and lithium-ion batteries on the whole are considered.

Determination of fluoride content in UO2F2 and ADUF solution by ion selective electrode

International Nuclear Information System (INIS)

Samanta, Papu; Kumar, Pradeep; Bagchi, A.C.

2017-01-01

During production of uranium metal powder, liquid solution UO 2 F 2 and ADUF containing high content of fluoride gets generated. Fluoride being corrosive in nature, fluorides concentration needs to determined. Ion selective electrode, LaF 3 (Eu) crystal, has been used. Uranium was found to interfere with fluoride analysis. Study was carried out to selectively remove uranium by solvent extraction employing D2EHPA+Cyanex 923 and TBP in dodecane. The TBP was found effective to remove uranium. (author)

Plasma-modified polyethylene membrane as a separator for lithium-ion polymer battery

International Nuclear Information System (INIS)

Kim, Jun Young; Lee, Yongbeom; Lim, Dae Young

2009-01-01

The surface of polyethylene (PE) membranes as a separator for lithium-ion polymer battery was modified with acrylonitrile (AN) using the plasma technology. The plasma-induced acrylonitrile coated PE (PiAN-PE) membrane was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and contact angle measurement. The electrochemical performance of the lithium-ion polymer cell fabricated with the PE and the PiAN-PE membranes were also analyzed. The surface characterization demonstrates that the enhanced adhesion of the PiAN-PE membrane resulted from the increased polar component of surface energy for the PiAN-PE membrane. The presence of the PiAN induced onto the surface of the membrane via the plasma modification plays a critical role in improving the wettability and electrolyte retention, the interfacial adhesion between the electrodes and the separator, the cycle performance of the resulting lithium-ion polymer cell assembly. The PiAN-PE membrane modified by the plasma treatment holds a great potential to be used as a high-performance and cost-effective separator for lithium-ion polymer battery.

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes.

Science.gov (United States)

Geise, Geoffrey M; Cassady, Harrison J; Paul, Donald R; Logan, Bruce E; Hickner, Michael A

2014-10-21

Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The charge density and polarizability

Negative electrodes for Na-ion batteries.

Science.gov (United States)

Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

2014-08-07

Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

Electrically driven ion separations and nanofiltration through membranes coated with polyelectrolyte multilayers

Science.gov (United States)

White, Nicholas

Polyelectrolyte multilayer (PEM) films deposited using the layer-by-layer (LBL) method are attractive for their simple deposition, tailorable nature, scalability, and charge or size-based selectivity for solutes. This dissertation explores ion separations in electrodialysis (ED) and solute removal through nanofiltration with PEMs deposited on polymer membranes. ED membranes typically exhibit modest selectivities between monovalent and divalent ions. In contrast, this work shows that K+/Mg 2+ ED selectivities reach values >1000 when using Nafion 115 cation-exchange membranes coated with multilayer poly(4-styrenesulfonate) (PSS)/protonated poly(allylamine) (PAH) films. For comparison, the corresponding K+ /Mg2+ selectivity of bare Nafion 115 is salt concentrations, the K+ transference number approaches unity and the K+/Mg2+ selectivity is >20,000, presumably because the applied current is below the limiting value for K+ and H+ transport is negligible at this high K+ concentration. The high selectivities of these membranes may enable electrodialysis applications such as purification of salts that contain divalent or trivalent ions. The high ED selectivities of (PAH/PSS)5PAH-coated Nafion membranes translate to separations with Li+/Co2+ and K +/La3+. Even with adsorption of only 3 polyelectrolyte layers, Nafion membranes exhibit a Li+/Co2+ selectivity >23. However, the resistance to monovalent-ion passage does not decrease significantly with fewer polyelectrolyte layers. At overlimiting currents, hydroxides from water splitting form insoluble metal hydroxides to foul the membrane. With 0.1 M source-phase salt concentrations, transference numbers for monovalent cations approach unity and selectivities are >5000 because the diffusion-limited K+ or Li+ currents exceed the applied current. However, ED selectivities gradually decline with time. Thus, future research should aim to increase membrane stability and limiting currents to fully exploit the remarkable selectivity

A new potentiometric electrode incorporating functionalized β-cyclodextrins for diclofenac determination.

Science.gov (United States)

Lenik, Joanna

2014-12-01

This paper reports the preparation of diclofenac-selective membrane electrodes incorporating β-cyclodextrins: (2-hydroxypropyl)-β-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, and heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin. Several plasticized poly(vinyl chloride) membranes of different compositions were tested with the best electrode being the one incorporating heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin with the membrane plasticized with 2-nitrophenyloctyl ether. The electrode is characterized by a near-Nernstian response slope of -60.0 mV decade(-1) over the linear range of 5.0×10(-5)-1.0×10(-2) mol L(-1) and a limit of detection of 1.4×10(-5) mol L(-1). The proposed electrode can easily discriminate diclofenac ions from several inorganic and organic interferents and some common drug excipients. The electrode has a response time of 10s and can be used within a pH range of 6.2-8.5 over 10 months without any considerable deterioration. The electrical properties of the membrane electrode were studied by impedance spectroscopy. The notable advantages of the diclofenac-selective electrode include its high sensitivity, selectivity, cost-effectiveness, and comfortable application in drug and urine analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Fabrication of novel coated graphite electrodes for the selective nano-level determination of Cd{sup 2+} ions in biological and environmental samples

Energy Technology Data Exchange (ETDEWEB)

Singh, Jitendra [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India); Singh, Ashok Kumar, E-mail: akscyfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India); Jain, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India)

2011-10-30

Novel cadmium selective coated graphite electrodes were prepared using three different ionophores N{sup 1}, N{sup 2}-dicyanoethyl-N{sup 1}, N{sup 2}-bis(pyridin-2-ylmethyl)benzene-1, 2-diamine [L{sub 1}], N{sup 1}, N{sup 2}-dicyanoethyl-N{sup 1}, N{sup 2}-bis(thiophen-2-ylmethyl) benzene-1, 2-diamine [L{sub 2}] and N{sup 1}, N{sup 2}-dicyanoethyl-N{sup 1}, N{sup 2}-bis(furan-2-ylmethyl)benzene-1, 2-diamine [L{sub 3}], and their potentiometric characteristics were determined. Membranes having different compositions of poly(vinylchloride) (PVC), the plasticizer o-nitrophenyloctylether (o-NPOE), sodium tetraphenylborate (NaTPB) as an anionic additive and ionophores were coated onto the graphite surface. The potential response measurements showed that the best performance was exhibited by the electrodes with membranes having the composition L{sub 1}: o-NPOE:NaTPB:PVC as 4:51:2.5:42.5 (wt.%), L{sub 2}: o-NPOE:NaTPB:PVC as 3:52.5:1.5:43 (wt.%) and L{sub 3}: o-NPOE:NaTPB:PVC as 7:49:3.5:40.5 (wt.%). These electrodes had the widest working concentration range, Nernstian slope and fast response times of 12 s, 7 s and 17 s for L{sub 1}, L{sub 2} and L{sub 3}, respectively. The selectivity studies showed that these electrodes have higher selectivity towards Cd{sup 2+} over a large number of cations and could tolerate up to 20 vol.% non-aqueous impurities. Furthermore, the electrodes generated constant potentials in the pH range 2.0-8.0, with a shelf life of approximately four to six weeks. The high selectivity of these electrodes permits their use in the detection of the Cd{sup 2+} content in some medicinal plants, soil and industrial wastewater samples. The electrodes could also be used as an indicator electrode in the potentiometric titration of Cd{sup 2+} with EDTA.

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes

KAUST Repository

Geise, Geoffrey M.

2014-08-26

© the Partner Organisations 2014. Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The

High-field modulated ion-selective field-effect-transistor (FET) sensors with sensitivity higher than the ideal Nernst sensitivity.

Science.gov (United States)

Chen, Yi-Ting; Sarangadharan, Indu; Sukesan, Revathi; Hseih, Ching-Yen; Lee, Geng-Yen; Chyi, Jen-Inn; Wang, Yu-Lin

2018-05-29

Lead ion selective membrane (Pb-ISM) coated AlGaN/GaN high electron mobility transistors (HEMT) was used to demonstrate a whole new methodology for ion-selective FET sensors, which can create ultra-high sensitivity (-36 mV/log [Pb 2+ ]) surpassing the limit of ideal sensitivity (-29.58 mV/log [Pb 2+ ]) in a typical Nernst equation for lead ion. The largely improved sensitivity has tremendously reduced the detection limit (10 -10  M) for several orders of magnitude of lead ion concentration compared to typical ion-selective electrode (ISE) (10 -7  M). The high sensitivity was obtained by creating a strong filed between the gate electrode and the HEMT channel. Systematical investigation was done by measuring different design of the sensor and gate bias, indicating ultra-high sensitivity and ultra-low detection limit obtained only in sufficiently strong field. Theoretical study in the sensitivity consistently agrees with the experimental finding and predicts the maximum and minimum sensitivity. The detection limit of our sensor is comparable to that of Inductively-Coupled-Plasma Mass Spectrum (ICP-MS), which also has detection limit near 10 -10  M.

Selective passive adsorption of nitrate with surfactant treated porous electrode and electrostatic regeneration

Science.gov (United States)

Oyarzun, Diego I.; Hemmatifar, Ali; Palko, James W.; Stadermann, Michael; Santiago, Juan G.; Stanford microfluidics lab Team; Lawrence Livermore National Lab Team

2017-11-01

Nitrate is an important pollutant in drinking water worldwide, and a number of methods exist for the removal of nitrate from water including ion exchange and reverse osmosis. However, these approaches suffer from a variety of disadvantages including the need for a regenerating brine supply and disposal of used brine for ion exchange and low water recovery ratio for reverse osmosis. We are researching and developing a form of capacitive deionization (CDI) for energy efficient desalination and selective removal of ionic toxins from water. In CDI an electrode is used to electrostatically trap ions in a pair of porous electrodes. Here, we demonstrate the use of high surface area activated carbon electrodes functionalized with ion exchange moieties for adsorption of nitrate from aqueous solution. Unlike a traditional ion exchanger, the functionalized surfaces can be repeatedly regenerated by the application of an electrostatic potential which displaces the bound NO3- while leaving an excess of electronic charge on the electrode. Trimethylammonium has an intrinsic selectivity, we are using this moiety to selectively remove nitrate over chloride. We performed adsorption/desorption cycles under several desorption voltages and ratios of concentrations.

Simultaneous determination of free calcium, magnesium, sodium and potassium ion concentrations in simulated milk ultrafiltrate and reconstituted skim milk using the Donnan Membrane Technique

NARCIS (Netherlands)

Gao, R.; Temminghoff, E.J.M.; Leeuwen, van H.P.; Valenberg, van H.J.F.; Eisner, M.D.; Boekel, van M.A.J.S.

2009-01-01

This study focused on determination of free Ca2+, Mg2+, Na+ and K+ concentrations in a series of CaCl2 solutions, simulated milk ultrafiltrate and reconstituted skim milk using a recently developed Donnan Membrane Technique (DMT). A calcium ion selective electrode was used to compare the DMT

Manual and Flow-Injection Detection/Quantification of Polyquaterniums via Fully Reversible Polyion-Sensitive Polymeric Membrane-Based Ion-Selective Electrodes.

Science.gov (United States)

Ferguson, Stephen A; Meyerhoff, Mark E

2017-10-27

The detection of four different polyquaterniums (PQs) using a fully reversible potentiometric polyion sensor in three different detection modes is described. The polyion sensing "pulstrodes" serve as the detector for direct dose-response experiments, beaker titrations, and in a flow-injection analysis (FIA) system. Direct polycation response toward PQ-2, PQ-6, PQ-10, and poly(2-methacryloxyethyltrimethylammonium) chloride (PMETAC) yields characteristic information about each PQ species (e.g., relative charge densities, etc.) via syringe pump addition of each PQ species to a background electrolyte solution. Quantitative titrations are performed using a syringe pump to deliver heparin as the polyanion titrant to quantify all four PQs at μg/mL levels. Both the direct and indirect methods incorporate the use of a three-electrode system including counter, double junction reference, and working electrodes. The working electrode possesses a plasticized poly(vinyl chloride) (PVC) membrane containing the neutral lipophilic salt of dinonylnaphthalenesulfonate (DNNS - ) tridodecylmethylammonium (TDMA + ). Further, the titration method is shown to be useful to quantify PQ-6 levels in recreational swimming pool water collected in Ann Arbor, MI. Finally, a FIA system equipped with a pulstrode detector is used to demonstrate the ability to potentially quantify PQ levels via a more streamlined and semiautomated testing platform.

Pore-Size-Tuned Graphene Oxide Frameworks as Ion-Selective and Protective Layers on Hydrocarbon Membranes for Vanadium Redox-Flow Batteries.

Science.gov (United States)

Kim, Soohyun; Choi, Junghoon; Choi, Chanyong; Heo, Jiyun; Kim, Dae Woo; Lee, Jang Yong; Hong, Young Taik; Jung, Hee-Tae; Kim, Hee-Tak

2018-05-07

The laminated structure of graphene oxide (GO) membranes provides exceptional ion-separation properties due to the regular interlayer spacing ( d) between laminate layers. However, a larger effective pore size of the laminate immersed in water (∼11.1 Å) than the hydrated diameter of vanadium ions (>6.0 Å) prevents its use in vanadium redox-flow batteries (VRFB). In this work, we report an ion-selective graphene oxide framework (GOF) with a d tuned by cross-linking the GO nanosheets. Its effective pore size (∼5.9 Å) excludes vanadium ions by size but allows proton conduction. The GOF membrane is employed as a protective layer to address the poor chemical stability of sulfonated poly(arylene ether sulfone) (SPAES) membranes against VO 2 + in VRFB. By effectively blocking vanadium ions, the GOF/SPAES membrane exhibits vanadium-ion permeability 4.2 times lower and a durability 5 times longer than that of the pristine SPAES membrane. Moreover, the VRFB with the GOF/SPAES membrane achieves an energy efficiency of 89% at 80 mA cm -2 and a capacity retention of 88% even after 400 cycles, far exceeding results for Nafion 115 and demonstrating its practical applicability for VRFB.

Fabrication and Characterisation of Membrane-Based Gold Electrodes

DEFF Research Database (Denmark)

Bakmand, Tanya; Kwasny, Dorota; Dimaki, Maria

2015-01-01

This work presents a versatile, membrane based electrochemical sensor with thin film electrodes fabricated through Ebeam evaporation directly on porous materials (membranes). Here, the fabrication of the electrodes is described along with possible methods for integration in fluidic systems...

Electrodialytic separation of alkali-element ions with the aid of ion-exchange membranes

International Nuclear Information System (INIS)

Gurskii, V.S.; Moskvin, L.N.

1988-01-01

Electrodialytic separation of ions bearing charges of the same sign with the aid of ion-exchange membranes has been examined in the literature in relation to the so-called ideal membranes, which do not exhibit selectivity with respect to one ion type in ion exchange. It has been shown that separation on such membranes is effective only for counterions differing in size of charge. A matter of greater importance from the practical standpoint is the possibility of using electrodialysis for separating ions bearing like charges and having similar properties, including ionic forms of isotopes of the same element. In this paper they report a comparative study of ion separation, with reference to the Cs-Na pair, by electrodialysis through various types of cation-exchange membranes. Changes of the solution concentration in the cathode compartment were monitored by measurement of 22 Na and 137 Cs activities

Determination of Nd3+ Ions in Solution Samples by a Coated Wire Ion-Selective Sensor

Directory of Open Access Journals (Sweden)

Hassan Ali Zamani

2012-01-01

Full Text Available A new coated wire electrode (CWE using 5-(methylsulfanyl-3-phenyl-1H-1,2,4-triazole (MPT as an ionophore has been developed as a neodymium ion-selective sensor. The sensor exhibits Nernstian response for the Nd3+ ions in the concentration range of 1.0×10−6-1.0×10−2 M with detection limit of 3.7×10−7 M. It displays a Nernstian slope of 20.2±0.2 mV/decade in the pH range of 2.7–8.1. The proposed sensor also exhibits a fast response time of ∼5 s. The sensor revealed high selectivity with respect to all common alkali, alkaline earth, transition and heavy metal ions, including members of the lanthanide family other than Nd3+. The electrode was used as an indicator electrode in the potentiometric titration of Nd(III ions with EDTA. The electrode was also employed for the determination of the Nd3+ ions concentration in water solution samples.

Improvement of interface property for membrane electrode assembly in fuel cell

International Nuclear Information System (INIS)

Fujii, K.; Sato, Y.; Kakigi, T.; Matsuura, A.; Mitani, N.; Muto, F.; Li Jingye; Miura, T.; Oshima, A.; Washio, M.

2006-01-01

Membrane electrode assembly (MEA) in polymer electrolyte fuel cells (PEFC) is consisted of proton exchange membrane (PEM), binder and Pt/C electrodes. In our previous work, partial-fluorinated sulfonic acid membranes were synthesized for PEMs using pre-EB grafting method. In the fuel cell (FC) operation, the dispersion of per-fluorinated sulfonic acid such as Nafion (DuPont de Nemours LTD.) was used for binder material. So, it is found that the trouble on conditions at three phase interface would occur at high temperature FC operation due to the differences of thermal properties. Thus, the control of interface property is important. In this study, in order to improve the interface properties, proton exchange membrane was synthesized from poly (tetrafluoroethylene-co-perfluoroalkylvinylether) (PFA), and then the obtained sulfonated PFA (s-PFA) was applied for binder material. PFA membranes were grafted in liquid styrene after EB irradiation under nitrogen atmosphere, and then sulfonated by chlorosulfonic acid solutions. The s-PFA membranes were milled to the powder in the mortar, and the average diameter was about 13 μm. S-PFA / Nafion blend dispersion was prepared by s-PFA mixed with Nafion dispersion with various ratios. MEAs were fabricated by using obtained binders, s-PFA membranes and Pt / C electrodes, followed by hot pressing at 110 degree C and at 8 MPa during 3 min. The properties of MEAs were measured by electrochemical analyses. In consequence, ion conductivities in MEA using obtained binders were about 1.3 times higher than those using Nafion dispersion. And, both power densities at 500 mA/cm 2 and maximum power densities were 1.1 times higher than those of Nafion dispersion. These are due to the improvement of the proton transfer at interface. (authors)

Spatial atomic layer deposition for coating flexible porous Li-ion battery electrodes

Energy Technology Data Exchange (ETDEWEB)

Yersak, Alexander S.; Sharma, Kashish; Wallas, Jasmine M.; Dameron, Arrelaine A.; Li, Xuemin; Yang, Yongan; Hurst, Katherine E.; Ban, Chunmei; Tenent, Robert C.; George, Steven M. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 and Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309

2018-01-01

Ultrathin atomic layer deposition (ALD) coatings on the electrodes of Li-ion batteries can enhance the capacity stability of the Li-ion batteries. To commercialize ALD for Li-ion battery production, spatial ALD is needed to decrease coating times and provide a coating process compatible with continuous roll-to-roll (R2R) processing. The porous electrodes of Li-ion batteries provide a special challenge because higher reactant exposures are needed for spatial ALD in porous substrates. This work utilized a modular rotating cylinder spatial ALD reactor operating at rotation speeds up to 200 revolutions/min (RPM) and substrate speeds up to 200 m/min. The conditions for spatial ALD were adjusted to coat flexible porous substrates. The reactor was initially used to characterize spatial Al2O3 and ZnO ALD on flat, flexible metalized polyethylene terephthalate foils. These studies showed that slower rotation speeds and spacers between the precursor module and the two adjacent pumping modules could significantly increase the reactant exposure. The modular rotating cylinder reactor was then used to coat flexible, model porous anodic aluminum oxide (AAO) membranes. The uniformity of the ZnO ALD coatings on the porous AAO membranes was dependent on the aspect ratio of the pores and the reactant exposures. Larger reactant exposures led to better uniformity in the pores with higher aspect ratios. The reactant exposures were increased by adding spacers between the precursor module and the two adjacent pumping modules. The modular rotating cylinder reactor was also employed for Al2O3 ALD on porous LiCoO2 (LCO) battery electrodes. Uniform Al coverages were obtained using spacers between the precursor module and the two adjacent pumping modules at rotation speeds of 25 and 50 RPM. The LCO electrodes had a thickness of ~49 um and pores with aspect ratios of ~12-25. Coin cells were then constructed using the ALD-coated LCO electrodes and were tested to determine their battery

An accurate and stable nitrate-selective electrode for the in situ determination of nitrate in agricultural drainage waters.

Science.gov (United States)

Le Goff, Thierry; Braven, Jim; Ebdon, Les; Chilcottt, Neil P; Scholefield, David; Wood, John W

2002-04-01

A field evaluation of a novel nitrate-ion selective electrode (ISE) was undertaken by continuous immersion over a period of 5 months in agricultural drainage weirs. The nitrate sensor N,N,N-triallyl leucine betaine was covalently attached to polystyrene-block-polybutadiene-block-polystyrene (SBS) using a free radical initiated co-polymerisation, to produce a rubbery membrane which was incorporated into a commercially available electrode body. A measurement unit was constructed comprising the nitrate-ISEs, a reference electrode and a temperature probe connected through a pre-amplifier to a data-logger and battery supply. A temperature correction algorithm was developed to accomodate the temperature changes encountered in the drainage weirs. The nitrate results obtained with the ISEs at hourly intervals compared very favourably (R2 = 0.99) with those obtained with laboratory automated chemical determinations made on contemporaneous samples of drainage in a concentration range 0.47-16 ppm nitrate-N. The ISEs did not require re-calibration and no deterioration in performance or fouling of the membrane surface was observed over four months of deployment.

Potentiometric determination of trypsin using a polymeric membrane polycation-sensitive electrode based on current-controlled reagent delivery.

Science.gov (United States)

Chen, Yan; Ding, Jiawang; Qin, Wei

2012-12-01

A potentiometric biosensor for the determination of trypsin is described based on current-controlled reagent delivery. A polymeric membrane protamine-sensitive electrode with dinonylnaphthalene sulfonate as cation exchanger is used for in situ generation of protamine. Diffusion of protamine across the polymeric membrane can be controlled precisely by applying an external current. The hydrolysis catalyzed with trypsin in sample solution decreases the concentration of free protamine released at the sample-membrane interface and facilitates the stripping of protamine out of the membrane surface via the ion-exchange process with sodium ions from the sample solution, thus decreasing the membrane potential, by which the protease can be sensed potentiometrically. The influences of anodic current amplitude, current pulse duration and protamine concentration in the inner filling solution on the membrane potential response have been studied. Under optimum conditions, the proposed protamine-sensitive electrode is useful for continuous and reversible detection of trypsin over the concentration range of 0.5-5UmL(-1) with a detection limit of 0.3UmL(-1). The proposed detection strategy provides a rapid and reagentless way for the detection of protease activities and offers great potential in the homogeneous immunoassays using proteases as labels. Copyright © 2012 Elsevier B.V. All rights reserved.

Selective transport of metal ions through cation exchange membrane in the presence of a complexing agent

Energy Technology Data Exchange (ETDEWEB)

Tingchia Huang; Jaukai Wang (National Cheng Kung Univ., Tainan (Taiwan, Province of China))

1993-01-01

Selective transport of metal ions through a cation exchange membrane was studied in stirred batch dialyzer for the systems Ni[sup 2+]-Cu[sup 2+] and Cu[sup 2+]-Fe[sup 3+]. Oxalic acid, malonic acid, citric acid, glycine, and ethylenediaminetetraacetic acid were employed as the complexing agents added in the feed solution in order to increase the permselectivity of metal ions. The experimental results show that the selective transport behavior of metal ions depends on the valence and the concentration of metal ions, the stoichiometric ratio of complexing agent to metal ions, and the pH value of the feed solution, but is independent of the concentration of counterion in the stripping phase. A theoretical approach was formulated on the basis of the Nernst-Planck equation and interface quasi-equilibrium. Theoretical solutions obtained from numerical calculation were in agreement with the experimental data.

Measuring calcium, potassium, and nitrate in plant nutrient solutions using ion-selective electrodes in hydroponic greenhouse of some vegetables.

Science.gov (United States)

Vardar, Gökay; Altıkatoğlu, Melda; Ortaç, Deniz; Cemek, Mustafa; Işıldak, İbrahim

2015-01-01

Generally, the life cycle of plants depends on the uptake of essential nutrients in a balanced manner and on toxic elements being under a certain concentration. Lack of control of nutrient levels in nutrient solution can result in reduced plant growth and undesired conditions such as blossom-end rot. In this study, sensitivity and selectivity tests for various polyvinylchloride (PVC)-based ion-selective membranes were conducted to identify those suitable for measuring typical concentration ranges of macronutrients, that is, NO(3-), K(+), and Ca(2+), in hydroponic solutions. The sensitivity and selectivity of PVC-membrane-based ion-selective sensors prepared with tetradodecylammoniumnitrate for NO(3-), valinomycin for K(+), and Ca ionophore IV for Ca(2+) were found to be satisfactory for measuring NO(3-), K(+), and Ca(2+) ions in nutrient solutions over typical ranges of hydroponic concentrations. Potassium, calcium, and nitrate levels that were utilized by cucumber and tomato seedlings in the greenhouse were different. The findings show that tomato plants consumed less amounts of nitrate than cucumber plants over the first 2 months of their growth. We also found that the potassium intake was higher than other nutritional elements tested for all plants. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Ion-Selective Electrodes for the Potentiometric Determination of Pramoxine HCl Using Different Ionophores.

Science.gov (United States)

Ramadan, Nesrin K; Merey, Hanan A

2012-12-01

Four novel pramoxine HCl (PAM) selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using sodium-tetraphenylborate (TPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl -cyclodextrin as an ionophore, while sensors 3 and 4 were constructed using 4-sulfocalix-6-arene and 4-sulfocalix-8-arene respectively as ionophores. Linear responses of PAM within the concentration ranges of 1.0 × 10-4 to 1.0 × 10-2 mol L-1 and 1.0 × 10-5 to 1.0 × 10-2 mol L-1 were obtained using sensors 1 and 2, respectively and 1.0 × 10-6 to 1.0 × 10-2 mol L-1 were obtained using sensors 3 and 4. Nernstian slopes of 50.4 ± 0.6, 54.3 ± 0.8, 56.3 ± 0.3 and 59.1 ± 0.5 mV/decade over the pH range of 3.0-6.0 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for PAM. The utility of 2-hydroxy- propylcyclodextrin (2HP-β-CD) and 4-sulfocalix [6,8] arene (SC 6, 8) as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2, 3 and 4 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of PAM in bulk powder, pharmaceutical formulation, and in biological fluid. Validation of the method showed the suitability of the proposed electrodes for the use in the quality control assessment of the drug. Furthermore, statistical comparison between the results obtained by the proposed method and the official method of the drug was performed and no significant difference was found.

Rapid fabrication of microfluidic polymer electrolyte membrane fuel cell in PDMS by surface patterning of perfluorinated ion-exchange resin

Energy Technology Data Exchange (ETDEWEB)

Song, Yong-Ak; Han, Jongyoon [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Batista, Candy [Roxbury Community College, 1234 Columbus Ave., Roxbury Crossing, MA 02120 (United States); Sarpeshkar, Rahul [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)

2008-09-01

In this paper we demonstrate a simple and rapid fabrication method for a microfluidic polymer electrolyte membrane (PEM) fuel cell using polydimethylsiloxane (PDMS), which has become the de facto standard material in BioMEMS. Instead of integrating a Nafion sheet film between two layers of a PDMS device in a traditional ''sandwich format,'' we pattern a perfluorinated ion-exchange resin such as a Nafion resin on a glass substrate using a reversibly bonded PDMS microchannel to generate an ion-selective membrane between the fuel-cell electrodes. After this patterning step, the assembly of the microfluidic fuel cell is accomplished by simple oxygen plasma bonding between the PDMS chip and the glass substrate. In an example implementation, the planar PEM microfluidic fuel cell generates an open circuit voltage of 600-800 mV and delivers a maximum current output of nearly 4 {mu}A. To enhance the power output of the fuel cell we utilize self-assembled colloidal arrays as a support matrix for the Nafion resin. Such arrays allow us to increase the thickness of the ion-selective membrane to 20 {mu}m and increase the current output by 166%. Our novel fabrication method enables rapid prototyping of microfluidic fuel cells to study various ion-exchange resins for the polymer electrolyte membrane. Our work will facilitate the development of miniature, implantable, on-chip power sources for biomedical applications. (author)

Functional polyterthiophene-appended uranyl-salophen complex: electropolymerization and ion-selective response for monohydrogen phosphate.

Science.gov (United States)

Kim, Junghwan; Kang, Dong Min; Shin, Sung Chul; Choi, Myong Yong; Kim, Jineun; Lee, Shim Sung; Kim, Jae Sang

2008-04-28

We have synthesized a bis(terthiophene)-appended uranyl-salophen complex, comprising N,N'-bis[4-(5,2':5',2''-terthiophen-3'-yl)salicylidene]-1,2-ethanediamine-uranyl complexes (TUS), and used it as a monomer for the electrochemical polymerizations (poly-TUS) on glassy carbon surfaces to prepare functionalized conducting polymer (CP) films. The poly-TUS films prepared from propylene carbonate/0.1 M tetrabutyl ammonium perchlorate (TBAP) on a glassy carbon electrode have both the functionality of ion-to-electron transducers (solid contact) and Lewis-acidic binding sites for a monohydrogen phosphate (MHP) ion-selective electrode (ISE). The CP/poly-TUS sensor showed a linear range between 1.0 x 10(-1) and 1.0 x 10(-4.5) M with a near-Nernstian behavior (-30.4 mV decade(-1)) at a pH of 8.2. The detection limit of the electrode was 10(-5.0) M and the response time was improved (polyvinyl chloride (PVC) liquid membrane with or without tridodecylmethylammonium chloride (TDMACl) as an additive was also constructed and its performance as an MHP-ISE were studied. The superior selectivity and sensitivity of the CP/poly-TUS sensor enabled the direct measurement of MHP in a wide variety of applications.

Application of 8-amino-N-(2-hydroxybenzylidene)naphthyl amine as a neutral ionophore in the construction of a lanthanum ion-selective sensor

Energy Technology Data Exchange (ETDEWEB)

Ganjali, M.R. [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)]. E-mail: ganjali@khayam.ut.ac.ir; Norouzi, P. [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Alizadeh, T. [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Adib, M. [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

2006-08-25

In this work, a novel La(III) membrane sensor based on 8-amino-N-(2-hydroxybenzylidene)naphthylamine (AIP) is presented. This electrode reveals good selectivity for La{sup 3+} over a wide variety of lanthanides metal ions. Theoretical calculations and conductance study of AIP to lanthanum and some other metal ions were carried out and confirmed selectivity toward La(III) ions. The electrode comprises 7% AIP, 30% PVC, 61% NPOE and 2% KTpClPB. The sensor displays a linear dynamic range between 1.0 x 10{sup -7} and 1.0 x 10{sup -1} M, with a nice Nernstian slope of 20.3 {+-} 0.3 mV per decade and a detection limit of 8.0 x 10{sup -8} M. The potentiometric response is independent of pH in the range of 4.0-9.0. The proposed sensor posses the advantage of short response time, and especially, very good selectivity towards a large number of cations, such as Sm(III), Ce(III, Pr(III), Yb(III) and Hg(II), low detection limit and wide linear dynamic range in comparison with former ones. The electrode can be used for at least seven weeks without any considerable divergence in the potentials. It was used as an indicator electrode in the potentiometric titration of La(III) ions with EDTA. The sensor was applied to the determination of La(III) ions concentration in binary mixtures. It was also applied for the determination of fluoride ions in mouth wash preparations.

Electrochemical activation and inhibition of neuromuscular systems through modulation of ion concentrations with ion-selective membranes

Science.gov (United States)

Song, Yong-Ak; Melik, Rohat; Rabie, Amr N.; Ibrahim, Ahmed M. S.; Moses, David; Tan, Ara; Han, Jongyoon; Lin, Samuel J.

2011-12-01

Conventional functional electrical stimulation aims to restore functional motor activity of patients with disabilities resulting from spinal cord injury or neurological disorders. However, intervention with functional electrical stimulation in neurological diseases lacks an effective implantable method that suppresses unwanted nerve signals. We have developed an electrochemical method to activate and inhibit a nerve by electrically modulating ion concentrations in situ along the nerve. Using ion-selective membranes to achieve different excitability states of the nerve, we observe either a reduction of the electrical threshold for stimulation by up to approximately 40%, or voluntary, reversible inhibition of nerve signal propagation. This low-threshold electrochemical stimulation method is applicable in current implantable neuroprosthetic devices, whereas the on-demand nerve-blocking mechanism could offer effective clinical intervention in disease states caused by uncontrolled nerve activation, such as epilepsy and chronic pain syndromes.

Membrane capacitive deionization

NARCIS (Netherlands)

Biesheuvel, P.M.; Wal, van der A.

2010-01-01

Membrane capacitive deionization (MCDI) is an ion-removal process based on applying an electrical potential difference across an aqueous solution which flows in between oppositely placed porous electrodes, in front of which ion-exchange membranes are positioned. Due to the applied potential, ions

Analytical application of solid contact ion-selective electrodes for determination of copper and nitrate in various food products and drinking water.

Science.gov (United States)

Wardak, Cecylia; Grabarczyk, Malgorzata

2016-08-02

A simple, fast and cheap method for monitoring copper and nitrate in drinking water and food products using newly developed solid contact ion-selective electrodes is proposed. Determination of copper and nitrate was performed by application of multiple standard additions technique. The reliability of the obtained results was assessed by comparing them using the anodic stripping voltammetry or spectrophotometry for the same samples. In each case, satisfactory agreement of the results was obtained, which confirms the analytical usefulness of the constructed electrodes.

Development of pvc membrane based potentiometric pH sensor using amine type neutral carrier

International Nuclear Information System (INIS)

Khan, M.F.

1999-01-01

The glass membrane-based pH-electrode has proved its utility over decades. However some limitations are associated with these type of sensors. It can not be used for measuring pH of hydrofluoric acid solution and is difficult to miniaturize for biological applications due to its high resistance and fragility. In the present investigation modified PVC-membranes have been cast by incorporating lipophilic salt tetrabutyl ammonium tetraphenylborate and sodium tetraphenylborate along with electro active compound tri-n-octylamine as neutral carrier. The performance comparison of fabricated pH-sensitive membrane electrode has been carried out regarding their Nernstian slope and life time. The performance comparison of the membrane electrodes fabricated from laboratory grade tri-n-octylamine and those prepared from highly purified ionophore was also carried out. The slopes of the modified membrane electrodes based on pure ionophore were 59 mV/decade H/sup +/ ions and commercial ionophore 54 mV/decade H/sup +/ ions. The linear range was from pH 5-11. In the range of pH 6-10 response was excellent. The measurement of selectivity coefficients for the probable, interfering ions (anions and cations) were also carried out. (author)

Ion-selective electrodes in potentiometric titrations; a new method for processing and evaluating titration data.

Science.gov (United States)

Granholm, Kim; Sokalski, Tomasz; Lewenstam, Andrzej; Ivaska, Ari

2015-08-12

A new method to convert the potential of an ion-selective electrode to concentration or activity in potentiometric titration is proposed. The advantage of this method is that the electrode standard potential and the slope of the calibration curve do not have to be known. Instead two activities on the titration curve have to be estimated e.g. the starting activity before the titration begins and the activity at the end of the titration in the presence of large excess of titrant. This new method is beneficial when the analyte is in a complexed matrix or in a harsh environment which affects the properties of the electrode and the traditional calibration procedure with standard solutions cannot be used. The new method was implemented both in a method of linearization based on the Grans's plot and in determination of the stability constant of a complex and the concentration of the complexing ligand in the sample. The new method gave accurate results when using titrations data from experiments with samples of known composition and with real industrial harsh black liquor sample. A complexometric titration model was also developed. Copyright © 2015 Elsevier B.V. All rights reserved.

Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation

Directory of Open Access Journals (Sweden)

Ricardo Couto

2015-01-01

Full Text Available In this work, a supported ionic liquid membrane (SILM was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA] ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2 and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73 for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids.

Amperometric Ion-Selective Electrode for Alkali Metal Cations Based on a Room-Temperature Ionic Liquid Membrane

Czech Academy of Sciences Publication Activity Database

Langmaier, Jan; Trojánek, Antonín; Samec, Zdeněk

2009-01-01

Roč. 21, 17-18 (2009), s. 1977-1983 ISSN 1040-0397 R&D Projects: GA MŠk ME08098; GA AV ČR IAA400400704 Institutional research plan: CEZ:AV0Z40400503 Keywords : room-temperature ionic liquid * alkali metals * Crown ether * cyclic voltammetry * amperometric ion-selective elkectrode Subject RIV: CG - Electrochemistry Impact factor: 2.630, year: 2009

Comparative studies of neodymium (III)-selective PVC membrane sensors

Energy Technology Data Exchange (ETDEWEB)

Gupta, Vinod K., E-mail: vinodfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India); Goyal, Rajendra N.; Sharma, Ram A. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

2009-08-04

Sensors based on two neutral ionophores, N,N'-bis((1H-pyrrol-2-yl)methylene)cyclohexane-1,2-diamine (L{sub 1}) and 3,3'-(cyclohexane-1,2-diylbis(azan-1-yl-1-ylidene) bis(methan-1-yl-1-ylidene)bis(5-hydroxymethyl)pyridine-2-ol) (L{sub 2}) are described for quantification of neodymium (III). Effect of various plasticizers; 2-nitrophenyloctylether (o-NPOE), dibutyl butylphosphonate (DBBP), tri-n-butyl phosphates (TBP), dioctylpthalate (DOP) and chloronapthalen (CN) and anion excluder, sodiumtetraphenylborate (NaTPB) has been studied. The membrane composition of PVC:o-NPOE:ionophore (L{sub 1}):NaTPB (w/w; mg) of 150:300:5:5 exhibited best performance. The sensor with ionophore (L{sub 1}) exhibits significantly enhanced selectivity towards neodymium (III) in the concentration range 5.0 x 10{sup -7} to 1.0 x 10{sup -2} M with a detection limit of 1.0 x 10{sup -7} M and a Nernstian compliance (19.8 {+-} 0.3 mV decade{sup -1} of activity) within pH range 4.0-8.0. The response time of sensor was found as 10 s. The influence of the membrane composition and possible interfering ions has also been investigated on the response properties of the electrode. The fast and stable response, good reproducibility and long-term stability of the sensor are observed. The sensor has been found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol or acetonitrile and could be used for a period of 3 months. The selectivity coefficients determined by using fixed interference method (FIM) indicate high selectivity for neodymium. The proposed electrode shows fairly good discrimination of neodymium (III) from other cations. The application of prepared sensor has been demonstrated in the determination of neodymium (III) in spiked water samples.

Optimized electrode coverage of membrane actuators based on epitaxial PZT thin films

International Nuclear Information System (INIS)

Nguyen, M D; Dekkers, M; Blank, D H A; Rijnders, G; Nazeer, H

2013-01-01

This research presents an optimization of piezoelectric membrane actuators by maximizing the actuator displacement. Membrane actuators based on epitaxial Pb(Zr,Ti)O 3 thin films grown on all-oxide electrodes and buffer layers using silicon technology were fabricated. Electrode coverage was found to be an important factor in the actuation displacement of the piezoelectric membranes. The optimum electrode coverage for maximum displacement was theoretically determined to be 39%, which is in good agreement with the experimental results. Dependences of membrane displacement and optimum electrode coverage on membrane diameter and PZT-film/Si-device-layer thickness ratio have also been investigated. (paper)

Electrode assembly for a lithium ion battery, process for the production of such electrode assembly, and lithium ion battery comprising such electrode assemblies

NARCIS (Netherlands)

Mulder, F.M.; Wagemaker, M.

2013-01-01

The invention provides an electrode assembly for a lithium ion battery, the electrode assembly comprising a lithium storage electrode layer on a current collector, wherein the lithium storage electrode layer is a porous layer having a porosity in the range of -35 %, with pores having pore widths in

Quantitative Determination of NTA and Other Chelating Agents in Detergents by Potentiometric Titration with Copper Ion Selective Electrode.

Science.gov (United States)

Ito, Sana; Morita, Masaki

2016-01-01

Quantitative analysis of nitrilotriacetate (NTA) in detergents by titration with Cu 2+ solution using a copper ion selective electrode was achieved. This method tolerates a wide range of pH and ingredients in detergents. In addition to NTA, other chelating agents, having relatively lower stability constants toward Cu 2+ , were also qualified with sufficient accuracy by this analytical method for model detergent formulations. The titration process was automated by automatic titrating systems available commercially.

Computational simulation of lithium ion transport through polymer nanocomposite membranes

International Nuclear Information System (INIS)

Moon, P.; Sandi, G.; Kizilel, R.; Stevens, D.

2003-01-01

We think of membranes as simple devices to facilitate filtration. In fact, membranes play a role in chemical, biological, and engineering processes such as catalysis, separation, and sensing by control of molecular transport and recognition. Critical factors that influence membrane discrimination properties include composition, pore size (as well as homogeneity), chemical functionalization, and electrical transport properties. There is increasing interest in using nanomaterials for the production of novel membranes due to the unique selectivity that can be achieved. Clay-polymer nanocomposites show particular promise due to their ease of manufacture (large sheets), their rigidity (self supporting), and their excellent mechanical properties. However, the process of lithium ion transport through the clay-polymer nanocomposite and mechanisms of pore size selection are poorly understood at the ionic and molecular level. In addition, manufacturing of clay-polymer nanocomposite membranes with desirable properties has proved challenging. We have built a general membrane-modeling tool (simulation system) to assist in developing improved membranes for selection, electromigration, and other electrochemical applications. Of particular interest are the recently formulated clay-polymer membranes. The transport mechanisms of the lithium ions membranes are not well understood and, therefore, they make an interesting test case for the model. In order to validate the model, we synthesized polymer nanocomposites membranes.

Etched ion track polymer membranes for sustained drug delivery

International Nuclear Information System (INIS)

Rao, Vijayalakshmi; Amar, J.V.; Avasthi, D.K.; Narayana Charyulu, R.

2003-01-01

The method of track etching has been successfully used for the production of polymer membranes with capillary pores. In the present paper, micropore membranes have been prepared by swift heavy ion irradiation of polycarbonate (PC). PC films were irradiated with ions of gold, silicon and oxygen of varying energies and fluence. The ion tracks thus obtained were etched chemically for various time intervals to get pores and these etched films were used as membranes for the drug release. Ciprofloxacine hydrochloride was used as model drug for the release studies. The drug content was estimated spectrophotometrically. Pore size and thus the drug release is dependent on the etching conditions, ions used, their energy and fluence. Sustained drug release has been observed in these membranes. The films can be selected for practical utilization by optimizing the irradiation and etching conditions. These films can be used as transdermal patches after medical treatment

Engineering the Membrane/Electrode Interface To Improve the Performance of Solid-State Supercapacitors.

Science.gov (United States)

Huang, Chun; Zhang, Jin; Snaith, Henry J; Grant, Patrick S

2016-08-17

This paper investigates the effect of adding a 450 nm layer based on porous TiO2 at the interface between a 4.5 μm carbon/TiO2 nanoparticle-based electrode and a polymer electrolyte membrane as a route to improve energy storage performance in solid-state supercapacitors. Electrochemical characterization showed that adding the interface layer reduced charge transfer resistance, promoted more efficient ion transfer across the interface, and significantly improved charge/discharge dynamics in a solid-state supercapacitor, resulting in an increased areal capacitance from 45.3 to 111.1 mF cm(-2) per electrode at 0.4 mA cm(-2).

A four-diode full-wave ionic current rectifier based on bipolar membranes: overcoming the limit of electrode capacity.

Science.gov (United States)

Gabrielsson, Erik O; Janson, Per; Tybrandt, Klas; Simon, Daniel T; Berggren, Magnus

2014-08-13

Full-wave rectification of ionic currents is obtained by constructing the typical four-diode bridge out of ion conducting bipolar membranes. Together with conjugated polymer electrodes addressed with alternating current, the bridge allows for generation of a controlled ionic direct current for extended periods of time without the production of toxic species or gas typically arising from electrode side-reactions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Applications of atomic emission spectrum from liquid electrode discharge to metal ion detection].

Science.gov (United States)

Mao, Xiu-Ling; Wu, Jian; Ying, Yi-Bin

2010-02-01

The fast and precise detection of metal ion is an important research project concerning studies in diverse academic fields and different kinds of detecting technologies. In the present paper, the authors review the research on atomic emission spectrum based on liquid electrode discharge and its applications in the detection of metal ion. In the first part of this paper the principles and characteristics of the methods based on electrochemistry and spectroscopy were introduced. The methods of ion-selective electrode (ISE), anodic stripping voltammetry, atomic emission spectrum and atomic absorption spectrum were included in this part and discussed comparatively. Then the principles and characteristics of liquid electrode spectra for metal ion detection were introduced. The mechanism of the plasma production and the characteristics of the plasma spectrum as well as its advantages compared with other methods were discussed. Secondly, the authors divided the discharge system into two types and named them single liquid-electrode discharge and double-liquid electrode respectively, according to the number of the liquid electrode and the configuration of the discharge system, and the development as well as the present research status of each type was illustrated. Then the characteristics and configurations of the discharge systems including ECGD, SCGD, LS-APGD and capillary discharge were discussed in detail as examples of the two types. By taking advantage of the technology of atomic emission spectrum based on liquid electrode discharge, the detecting limit of heavy metals such as copper, mercury and argent as well as active metal ions including sodium, potass and magnesium can achieve microg x L(-1). Finally, the advantages and problems of the liquid-electrode discharge applied in detection of metal ion were discussed. And the applications of the atomic emission spectrum based on liquid electrode discharge were prospected.

Tuning the Solid Electrolyte Interphase for Selective Li- and Na-Ion Storage in Hard Carbon

Energy Technology Data Exchange (ETDEWEB)

Soto, Fernando A. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Yan, Pengfei [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Marzouk, Asma [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Wang, Chongmin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Xu, Guiliang [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Chen, Zonghai [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Liu, Jun [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Sprenkle, Vincent L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; El-Mellouhi, Fedwa [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825 Doha Qatar; Balbuena, Perla B. [Department of Chemical Engineering, Texas A& M University, College Station TX 77843-3122 USA; Li, Xiaolin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA

2017-03-07

Solid-electrolyte interphase (SEI) with controllable properties are highly desirable to improve battery performance. In this paper, we use a combined experimental and simulation approach to study the SEI formation on hard carbon in Li and Na-ion batteries. We show that with proper additives, stable SEI can be formed on hard carbon by pre-cycling the electrode materials in Li or Na-ion electrolyte. Detailed mechanistic studies suggest that the ion transport in the SEI layer is kinetically controlled and can be tuned by the applied voltage. Selective Na and Li-ion SEI membranes are produced using the Na or Li-ion based electrolytes respectively. The large Na ion SEI allows easy transport of Li ions, while the small Li ion SEI shuts off the Na-ion transport. Na-ion storage can be manipulated by tuning the SEI with film-forming electrolyte additives or preforming a SEI on the electrodes’ surface. The Na specific capacity can be controlled to <25 mAh/g, ~1/10 of the normal capacity (250 mAh/g). Unusual selective/preferential transport of Li-ion is demonstrated by preforming a SEI on the electrode’s surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion selective conductors using electrochemical approaches in the future.

Polymer solution, fiber mat, and nanofiber membrane-electrode-assembly therewith, and method of fabricating same

DEFF Research Database (Denmark)

2016-01-01

of fibers. The fibers may further include particles of a catalyst. The fiber mat may be used to form an electrode or a membrane. In a further aspect, a fuel cell membrane-electrode-assembly has an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode...... electrode. Each of the anode electrode, the cathode electrode and the membrane may be formed with a fiber mat....

High Speed, Low Cost Fabrication of Gas Diffusion Electrodes for Membrane Electrode Assemblies

Energy Technology Data Exchange (ETDEWEB)

DeCastro, Emory S.; Tsou, Yu-Min; Liu, Zhenyu

2013-09-20

Fabrication of membrane electrode assemblies (MEAs) depends on creating inks or pastes of catalyst and binder, and applying this suspension to either the membrane (catalyst coated membrane) or gas diffusion media (gas diffusion electrode) and respectively laminating either gas diffusion media or gas diffusion electrodes (GDEs) to the membrane. One barrier to cost effective fabrication for either of these approaches is the development of stable and consistent suspensions. This program investigated the fundamental forces that destabilize the suspensions and developed innovative approaches to create new, highly stable formulations. These more concentrated formulations needed fewer application passes, could be coated over longer and wider substrates, and resulted in significantly lower coating defects. In March of 2012 BASF Fuel Cell released a new high temperature product based on these advances, whereby our customers received higher performing, more uniform MEAs resulting in higher stack build yields. Furthermore, these new materials resulted in an “instant” increase in capacity due to higher product yields and material throughput. Although not part of the original scope of this program, these new formulations have also led us to materials that demonstrate equivalent performance with 30% less precious metal in the anode. This program has achieved two key milestones in DOE’s Manufacturing R&D program: demonstration of processes for direct coating of electrodes and continuous in-line measurement for component fabrication.

Total cyanide mass measurement with micro-ion selective electrode for determination of specific activity of carbon-11 cyanide.

Science.gov (United States)

Shea, Colleen; Alexoff, David L; Kim, Dohyun; Hoque, Ruma; Schueller, Michael J; Fowler, Joanna S; Qu, Wenchao

2015-08-01

In this research, we aim to directly measure the specific activity (SA) of the carbon-11 cyanide ([(11)C]CN¯) produced by our in-house built automated [(11)C]HCN production system and to identify the major sources of (12)C-cyanide ((12)CN¯). The [(11)C]CN¯ is produced from [(11)C]CO2, which is generated by the (14)N(p,α)(11)C nuclear reaction using a cyclotron. Direct measurement of cyanide concentrations was accomplished using a relatively inexpensive, and easy to use ion selective electrode (ISE) which offered an appropriate range of sensitivity for detecting mass. Multiple components of the [(11)C]HCN production system were isolated in order to determine their relative contributions to (12)CN¯ mass. It was determined that the system gases were responsible for approximately 30% of the mass, and that the molecular sieve/nickel furnace unit contributed approximately 70% of the mass. Beam on target (33µA for 1 and 10min) did not contribute significantly to the mass. Additionally, we compared the SA of our [(11)C]HCN precursor determined using the ISE to the SA of our current [(11)C]CN¯ derived radiotracers determined by HPLC to assure there was no significant difference between the two methods. These results are the first reported use of an ion selective electrode to determine the SA of no-carrier-added cyanide ion, and clearly show that it is a valuable, inexpensive and readily available tool suitable for this purpose. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using ion-selective electrode for determining iodine-131 preparation specific activity

International Nuclear Information System (INIS)

Melnik, M.I.; Nazirova, T.E.

2002-01-01

A pilot facility was developed in 2000 for the production of iodine-131. The parameters of the preparation are as follows: chemical form: sodium iodide solution (NaI-131) in a carbonate-bicarbonate buffer (or in 0.001M NaOH); specific activity: carrier free (> 5 Ci/mg); solution pH: 7-10; radionuclide purity: > 99.9%; radiochemical purity: > 97%; bulk activity: 0.15 Ci/ml. The experimental results of investigation aimed at the determination of the specific activity of the I-131 preparation using a iodine-selective electrode are described. The method enables the analytical concentration of iodide ions in the carbonate-bicarbonate buffer (pH = 8-11) and NaOH solution (0.01 mol/l, pH = 8-11) to be determined. A micro-cell has been developed for the analysis of the I-131 solution allowing the sample volume to be reduced to below 0.3 ml. The relative error of determination of the analytical concentration of iodide (10 -6 to 10 -1 mol/l) does not exceed 1%

Potentiometric Sensor for Gadolinium(III Ion Based on Zirconium(IV Tungstophosphate as an Electroactive Material

Directory of Open Access Journals (Sweden)

Harish K. Sharma

2009-01-01

Full Text Available A new inorganic ion exchanger has been synthesized namely Zirconium(IV tungstophosphate [ZrWP]. The synthesized exchanger was characterized using ion exchange capacity and distribution coefficient (Kd. For further studies, exchanger with 0.35 meq/g ion-exchange capacity was selected. Electrochemical studies were carried out on the ion exchange membranes using epoxy resin as a binder. In case of ZrWP, the membrane having the composition; Zirconium(IV tugstophosphate (40% and epoxy resin (60% exhibits best performance. The membrane works well over a wide range of concentration from 1×10-5 to 1×10-1 M of Gd(III ion with an over- Nernstian slope of 30 mv/ decade. The response time of the sensor is 15 seconds. For this membrane, effect of internal solution has been studied and the electrode was successfully used in partially non-aqueous media too. Fixed interference method and matched potential method has been used for determining selectivity coefficient with respect to alkali, alkaline earth, some transition and rare earth metal ions that are normally present along with Gd(III in its ores. The electrode can be used in the pH range 4.0-10.0 for 10-1 M and 3.0-7.0 for 10-2 M concentration of target ion. These sensors have been used as indicator electrodes in the potentiometric titration of Gd(III ion against EDTA and oxalic acid.

In situ nanostructure formation of (micro-hydroxo)bis(micro-carboxylato) diruthenium units in nafion membrane and its utilization for selective reduction of nitrosonium ion in aqueous medium.

Science.gov (United States)

Kumar, Annamalai Senthil; Tanase, Tomoaki; Iida, Masayasu

2007-01-16

Nanostructured molecular film containing the (micro-hydroxo)bis(micro-carboxylato) diruthenium(III) units, [RuIII2(micro-OH)(micro-CH3COO)2(HBpz3)2]+ ({RuIII2(micro-OH)}), was prepared by an in situ conversion of its micro-oxo precursor, [RuIII2(micro-O)(micro-CH3COO)2(HBpz3)2] ({RuIII2(micro-O)}), in a Nafion membrane matrix, where HBpz3 is hydrotris(1-pyrazolyl)borate. The conversion procedure results in fine nanoparticle aggregates of the {RuIII2(micro-OH)} units in the Nafion membrane (Nf-{RuIII2(micro-OH)}), where an average particle size (4.1 +/- 2.3 nm) is close to the Nafion's cluster dimension of approximately 4 nm. Chemically modified electrodes by using the Nafion molecular membrane films (Nf-{RuIII2(micro-OH)}-MMFEs) were further developed on ITO/glass and glassy carbon electrode (GCE) surfaces, and a selective reduction of nitrosonium ion (NO+), presumably through reaction of a {RuIIRuIII(micro-OH)} mixed-valence state with HNO2, was demonstrated without interference by molecular oxygen in an acidic aqueous solution. The Nf-{RuIII2(micro-OH)}-MMFEs are stable even in a physiological condition (pH 7), where the naked {RuIII2(-OH)} complex is readily transformed into its deprotonated {RuIII2(micro-O)} form, demonstrating an unusual stabilizing effects for the {RuIII2(micro-OH)} unit by the Nafion cluster environment.

Development of Electrically Switched Ion Exchange Process for Selective Ion Separations

International Nuclear Information System (INIS)

Rassat, Scot D.; Sukamto, Johanes H.; Orth, Rick J.; Lilga, Michael A.; Hallen, Richard T.

1999-01-01

The electrically switched ion exchange (ESIX) process, being developed at Pacific Northwest National Laboratory, provides an alternative separation method to selectively remove ions from process and waste streams. In the ESIX process, in which an electroactive ion exchange film is deposited onto a high surface area electrode, uptake and elution are controlled directly by modulating the electrochemical potential of the film. This paper addresses engineering issues necessary to fully develop ESIX for specific industrial alkali cation separation challenges. The cycling and chemical stability and alkali cation selectivity of nickel hexacyanoferrate (NiHCF) electroactive films were investigated. The selectivity of NiHCF was determined using cyclic voltammetry and a quartz crystal microbalance to quantify ion uptake in the film. Separation factors indicated a high selectivity for cesium and a moderate selectivity for potassium in high sodium content solutions. A NiHCF film with improved redox cycling and chemical stability in a simulated pulp mill process stream, a targeted application for ESIX, was also prepared and tested

Ion-Exchanged SAPO-34 Membranes for Krypton-Xenon Separation: Control of Permeation Properties and Fabrication of Hollow Fiber Membranes.

Science.gov (United States)

Kwon, Yeon Hye; Min, Byunghyun; Yang, Shaowei; Koh, Dong-Yeun; Bhave, Ramesh R; Nair, Sankar

2018-02-21

Separation of radioisotope 85 Kr from 136 Xe is of importance in used nuclear fuel reprocessing. Membrane separation based on zeolite molecular sieves such as chabazite SAPO-34 is an attractive alternative to energy-intensive cryogenic distillation. We report the synthesis of SAPO-34 membranes with considerably enhanced performance via thickness reduction based upon control of a steam-assisted vapor-solid conversion technique followed by ion exchange with alkali metal cations. The reduction of membrane thickness leads to a large increase in Kr permeance from 7.5 to 26.3 gas permeation units (GPU) with ideal Kr/Xe selectivities >20 at 298 K. Cation-exchanged membranes show large (>50%) increases in selectivity at ambient or slight subambient conditions. The adsorption, diffusion, and permeation characteristics of ion-exchanged SAPO-34 materials and membranes are investigated in detail, with potassium-exchanged SAPO-34 membranes showing particularly attractive performance. We then demonstrate the fabrication of selective SAPO-34 membranes on α-alumina hollow fibers.

Selective Thallium (I Ion Sensor Based on Functionalised ZnO Nanorods

Directory of Open Access Journals (Sweden)

Z. H. Ibupoto

2012-01-01

Full Text Available Well controlled in length and highly aligned ZnO nanorods were grown on the gold-coated glass substrate by hydrothermal growth method. ZnO nanorods were functionalised with selective thallium (I ion ionophore dibenzyldiaza-18-crown-6 (DBzDA18C6. The thallium ion sensor showed wide linear potentiometric response to thallium (I ion concentrations ( M to  M with high sensitivity of 36.87 ± 1.49 mV/decade. Moreover, thallium (I ion demonstrated fast response time of less than 5 s, high selectivity, reproducibility, storage stability, and negligible response to common interferents. The proposed thallium (I ion-sensor electrode was also used as an indicator electrode in the potentiometric titration, and it has shown good stoichiometric response for the determination of thallium (I ion.

Preparation and selected properties of ion-containing reverse osmosis membranes

International Nuclear Information System (INIS)

Hegazy, E.S.A.; Dessouki, A.M.

1986-01-01

Ion-containing reverse osmosis membranes were prepared by the post radiation grafting of 4-vinylpyridine onto low density polyethylene films, followed by quaternization of the pyridine rings in the graft chains to confer ionic character to the membranes. The effect of some preparation conditions on the grafting yield was investigated. Different quaternizing agents such as methyl iodide, allyl bromide, and hydrochloric acid were used for the quaternization of the graft chains. The effect of quaternizing agent and degree of grafting on the properties of the membranes such as swelling behaviour, specific electric resistance, water flux and salt rejection, was investigated. The properties of these ionic membranes did not deteriorate with the operation time and they show a great promise for the use in the field of reverse osmosis desalination of sea water. (author)

Real-time two-dimensional imaging of potassium ion distribution using an ion semiconductor sensor with charged coupled device technology.

Science.gov (United States)

Hattori, Toshiaki; Masaki, Yoshitomo; Atsumi, Kazuya; Kato, Ryo; Sawada, Kazuaki

2010-01-01

Two-dimensional real-time observation of potassium ion distributions was achieved using an ion imaging device based on charge-coupled device (CCD) and metal-oxide semiconductor technologies, and an ion selective membrane. The CCD potassium ion image sensor was equipped with an array of 32 × 32 pixels (1024 pixels). It could record five frames per second with an area of 4.16 × 4.16 mm(2). Potassium ion images were produced instantly. The leaching of potassium ion from a 3.3 M KCl Ag/AgCl reference electrode was dynamically monitored in aqueous solution. The potassium ion selective membrane on the semiconductor consisted of plasticized poly(vinyl chloride) (PVC) with bis(benzo-15-crown-5). The addition of a polyhedral oligomeric silsesquioxane to the plasticized PVC membrane greatly improved adhesion of the membrane onto Si(3)N(4) of the semiconductor surface, and the potential response was stabilized. The potential response was linear from 10(-2) to 10(-5) M logarithmic concentration of potassium ion. The selectivity coefficients were K(K(+),Li(+))(pot) = 10(-2.85), K(K(+),Na(+))(pot) = 10(-2.30), K(K(+),Rb(+))(pot) =10(-1.16), and K(K(+),Cs(+))(pot) = 10(-2.05).

Selective capillary diffusion of equimolar H2/D2 gas mixtures through etched ion track membranes prepared from polyethylene terephthalate and polyimide

International Nuclear Information System (INIS)

Schmidt, K.; Angert, N.; Trautmann, C.

1996-01-01

The selective capillary diffusion of equimolar H 2 /D 2 gas mixtures through ion track membranes prepared from polyethylene terephthalate and polyimide was investigated at a temperature of 293 K, a primary pressure of 0.15 MPa and a secondary pressure of 10 -4 MPa. Different values of the separation factor Z(H 2 /D 2 ) between experiment and computer simulation exists in the case of polyethylene terephthalate ion track membranes because of multiple pores. Membranes for which multiple pores were reduced by varying the irradiation angle showed an increased separation factor. The separation factor is a function of the pore diameter. This is shown for polyimide ion track membranes with a pore size in the range of 0.17 and 0.5 μm. After grafting with styrene the separation factor increased, indicating grafting within the pores. (orig.)

Ion Motion Stability in Asymmetric Surface Electrode Ion Traps

Science.gov (United States)

Shaikh, Fayaz; Ozakin, Arkadas

2010-03-01

Many recently developed designs of the surface electrode ion traps for quantum information processing have asymmetry built into their geometries. The asymmetry helps rotate the trap axes to angles with respect to electrode surface that facilitate laser cooling of ions but introduces a relative angle between the RF and DC fields and invalidates the classical stability analysis of the symmetric case for which the equations of motion are decoupled. For asymmetric case the classical motion of a single ion is given by a coupled, multi-dimensional version of Mathieu's equation. In this poster we discuss the stability diagram of asymmetric surface traps by performing an approximate multiple scale perturbation analysis of the coupled Mathieu equations, and validate the results with numerical simulations. After obtaining the stability diagram for the linear fields, we simulate the motion of an ion in a given asymmetric surface trap, utilizing a method-of-moments calculation of the electrode fields. We obtain the stability diagram and compare it with the ideal case to find the region of validity. Finally, we compare the results of our stability analysis to experiments conducted on a microfabricated asymmetric surface trap.

The use of ion-selective membranes for the recovery of sulphuric acid out of contaminated solutions. Comparing electrodialysis, electro electrodialysis and diffusion dialysis

International Nuclear Information System (INIS)

Cattoir, S.

1998-02-01

The amount of waste arising from dismantled reactors is minimized by decontamination processes. These processes result in contaminated effluents, containing acid and metal salts. The quantity of final waste can be substantially reduced when the acid is extracted out of the decontamination effluents prior to neutralisation. This report discusses three membrane techniques for the displacement of acids out of mixed acid/salt solutions: electrodialysis (ED), electro electrodialysis (EED) and diffusion dialysis (DD). EED uses an electrical potential difference across an anion-selective membrane; DD uses a concentration difference across an anion-selective membrane; ED uses an electrical potential difference, across an anion- and a cation-selective membrane. EED can displace up to 90% of the sulphuric acid, the amount of metal ions in the displaced-acid solution is less than 1% of the ions in the original contaminated solution. Treatment costs are estimated to about 18 Belgian Francs per litre. In DD the purity of the displaced acid is comparable to EED. Treatment costs are about 21 Belgian Francs per litre. In ED 90% acid-displacement is easily reached, but 5% metal ions are also displaced. Treatment costs are about 6 Belgian Francs per litre. Therefore, in spite of the lower purity of the resulting acid, ED is economically speaking the best choice

Polyurethane Ionophore-Based Thin Layer Membranes for Voltammetric Ion Activity Sensing.

Science.gov (United States)

Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

2016-06-07

We report on a plasticized polyurethane ionophore-based thin film material (of hundreds of nanometer thickness) for simultaneous voltammetric multianalyte ion activity detection triggered by the oxidation/reduction of an underlying poly(3-octylthiophene) film. This material provides excellent mechanical, physical, and chemical robustness compared to other polymers. Polyurethane films did not exhibit leaching of lipophilic additives after rinsing with a direct water jet and exhibited resistance to detachment from the underlying electrode surface, resulting in a voltammetric current response with less than acrylate) ionophore-based membranes of the same thickness and composition exhibited a significant deterioration of the signal after identical treatment. While previously reported works emphasized fundamental advancement of multi-ion detection with multi-ionophore-based thin films, polyurethane thin membranes allow one to achieve real world measurements without sacrificing analytical performance. Indeed, polyurethane membranes are demonstrated to be useful for the simultaneous determination of potassium and lithium in undiluted human serum and blood with attractive precision.

Design of Smart Ion-Selective Electrode Arrays Based on Source Separation through Nonlinear Independent Component Analysis

Directory of Open Access Journals (Sweden)

Duarte L.T.

2014-03-01

Full Text Available The development of chemical sensor arrays based on Blind Source Separation (BSS provides a promising solution to overcome the interference problem associated with Ion-Selective Electrodes (ISE. The main motivation behind this new approach is to ease the time-demanding calibration stage. While the first works on this problem only considered the case in which the ions under analysis have equal valences, the present work aims at developing a BSS technique that works when the ions have different charges. In this situation, the resulting mixing model belongs to a particular class of nonlinear systems that have never been studied in the BSS literature. In order to tackle this sort of mixing process, we adopted a recurrent network as separating system. Moreover, concerning the BSS learning strategy, we develop a mutual information minimization approach based on the notion of the differential of the mutual information. The method works requires a batch operation, and, thus, can be used to perform off-line analysis. The validity of our approach is supported by experiments where the mixing model parameters were extracted from actual data.

Monitoring changes in membrane polarity, membrane integrity, and intracellular ion concentrations in Streptococcus pneumoniae using fluorescent dyes.

Science.gov (United States)

Clementi, Emily A; Marks, Laura R; Roche-Håkansson, Hazeline; Håkansson, Anders P

2014-02-17

Membrane depolarization and ion fluxes are events that have been studied extensively in biological systems due to their ability to profoundly impact cellular functions, including energetics and signal transductions. While both fluorescent and electrophysiological methods, including electrode usage and patch-clamping, have been well developed for measuring these events in eukaryotic cells, methodology for measuring similar events in microorganisms have proven more challenging to develop given their small size in combination with the more complex outer surface of bacteria shielding the membrane. During our studies of death-initiation in Streptococcus pneumoniae (pneumococcus), we wanted to elucidate the role of membrane events, including changes in polarity, integrity, and intracellular ion concentrations. Searching the literature, we found that very few studies exist. Other investigators had monitored radioisotope uptake or equilibrium to measure ion fluxes and membrane potential and a limited number of studies, mostly in Gram-negative organisms, had seen some success using carbocyanine or oxonol fluorescent dyes to measure membrane potential, or loading bacteria with cell-permeant acetoxymethyl (AM) ester versions of ion-sensitive fluorescent indicator dyes. We therefore established and optimized protocols for measuring membrane potential, rupture, and ion-transport in the Gram-positive organism S. pneumoniae. We developed protocols using the bis-oxonol dye DiBAC4(3) and the cell-impermeant dye propidium iodide to measure membrane depolarization and rupture, respectively, as well as methods to optimally load the pneumococci with the AM esters of the ratiometric dyes Fura-2, PBFI, and BCECF to detect changes in intracellular concentrations of Ca(2+), K(+), and H(+), respectively, using a fluorescence-detection plate reader. These protocols are the first of their kind for the pneumococcus and the majority of these dyes have not been used in any other bacterial

PVC Based Membrane of Ti(IV Iodovanadate for Pb(II Determination

Directory of Open Access Journals (Sweden)

Mu. Naushad

2008-08-01

Full Text Available Ti(IV iodovanadate has been synthesized by mixing a mixture of aqueous solutions of 0.1 M sodium vanadate and 0.1 M potassium iodate with 0.1 M solution of Ti(IV chloride at pH 1.0. Distribution coefficients (Kd of various metal ions were determined on the column of Ti(IV iodovanadate which showed the selectivity of Pb(II ions by this cation exchange material. So Ti(IV iodovanadate has been used as an electoactive material for the construction of Pb(II selective electrode. The main purpose of this study is to develop an inexpensive, simple and reliable ion-selective electrode for Pb(II determination. The sensor exhibit Nernstian response for Pb(II ions over a wide concentration range of 1 x 10-7 M to 1 x 10-1 M with a slope of 30±0.4 mV per decade of activity. The electrode is suitable for use in aqueous solution in a pH range of 2-7.2 with a response time of 10 second. The membrane electrode can be used at least for 4 months without any divergence in potential. The selectivity coefficients were determined by the mixed solution method and revealed that the electrode was selective for Pb(II ions in the presence of interfering cations. The sensor could be used as an indicator electrode in the potentiometric titration of Pb(II ions with EDTA. The practical applicability of the proposed sensor has been reported for Pb(II determination in a standard rock sample and water sample. The results are found to be in good agreement with those obtained by using conventional methods.

Electrically Driven Ion Separations in Permeable Membranes

Energy Technology Data Exchange (ETDEWEB)

Bruening, Merlin [Michigan State Univ., East Lansing, MI (United States)

2017-04-21

Membranes are attractive for a wide range of separations due to their low energy costs and continuous operation. To achieve practical fluxes, most membranes consist of a thin, selective skin on a highly permeable substrate that provides mechanical strength. Thus, this project focused on creating new methods for forming highly selective ultrathin skins as well as modeling transport through these coatings to better understand their unprecedented selectivities. The research explored both gas and ion separations, and the latter included transport due to concentration, pressure and electrical potential gradients. This report describes a series of highlights of the research and then provides a complete list of publications supported by the grant. These publications have been cited more than 4000 times. Perhaps the most stunning finding is the recent discovery of monovalent/divalent cation and anion selectivities around 1000 when modifying cation- and anion-exchange membranes with polyelectrolyte multilayers (PEMs). This discovery builds on many years of exciting research. (Citation numbers refer to the journal articles in the bibliography.)

Functional polyterthiophene-appended uranyl-salophen complex: Electropolymerization and ion-selective response for monohydrogen phosphate

International Nuclear Information System (INIS)

Kim, Junghwan; Kang, Dong Min; Shin, Sung Chul; Choi, Myong Yong; Kim, Jineun; Lee, Shim Sung; Kim, Jae Sang

2008-01-01

We have synthesized a bis(terthiophene)-appended uranyl-salophen complex, comprising N,N'-bis[4-(5,2':5',2''-terthiophen-3'-yl)salicylidene] -1,2-ethanediamine-uranyl complexes (TUS), and used it as a monomer for the electrochemical polymerizations (poly-TUS) on glassy carbon surfaces to prepare functionalized conducting polymer (CP) films. The poly-TUS films prepared from propylene carbonate/0.1 M tetrabutyl ammonium perchlorate (TBAP) on a glassy carbon electrode have both the functionality of ion-to-electron transducers (solid contact) and Lewis-acidic binding sites for a monohydrogen phosphate (MHP) ion-selective electrode (ISE). The CP/poly-TUS sensor showed a linear range between 1.0 x 10 -1 and 1.0 x 10 -4.5 M with a near-Nernstian behavior (-30.4 mV decade -1 ) at a pH of 8.2. The detection limit of the electrode was 10 -5.0 M and the response time was improved (<10 s) compared to that of conventional ISEs (<20 s). For comparison, a conventional ISE (with an internal aqueous solution) based on a TUS monomer/o-nitrophenyl octylether (o-NPOE)/polyvinyl chloride (PVC) liquid membrane with or without tridodecylmethylammonium chloride (TDMACl) as an additive was also constructed and its performance as an MHP-ISE were studied. The superior selectivity and sensitivity of the CP/poly-TUS sensor enabled the direct measurement of MHP in a wide variety of applications

Polyanion-Type Electrode Materials for Sodium-Ion Batteries.

Science.gov (United States)

Ni, Qiao; Bai, Ying; Wu, Feng; Wu, Chuan

2017-03-01

Sodium-ion batteries, representative members of the post-lithium-battery club, are very attractive and promising for large-scale energy storage applications. The increasing technological improvements in sodium-ion batteries (Na-ion batteries) are being driven by the demand for Na-based electrode materials that are resource-abundant, cost-effective, and long lasting. Polyanion-type compounds are among the most promising electrode materials for Na-ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion-type electrode materials are Na 3 V 2 (PO 4 ) 3 and NaTi 2 (PO 4 ) 3 for Na-based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na-ion batteries. Carbonophosphate Na 3 MnCO 3 PO 4 and amorphous FePO 4 have also recently emerged and are contributing to further developing the research scope of polyanion-type Na-ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion-type electrode materials for Na-ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems.

Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

Science.gov (United States)

Ni, Qiao; Wu, Feng

2017-01-01

Sodium‐ion batteries, representative members of the post‐lithium‐battery club, are very attractive and promising for large‐scale energy storage applications. The increasing technological improvements in sodium‐ion batteries (Na‐ion batteries) are being driven by the demand for Na‐based electrode materials that are resource‐abundant, cost‐effective, and long lasting. Polyanion‐type compounds are among the most promising electrode materials for Na‐ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion‐type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na‐based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na‐ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion‐type Na‐ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion‐type electrode materials for Na‐ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems. PMID:28331782

Application of N-Quinoline-2-carboxamido-8-aminoquinoline in Fabrication of a Ho(III-PVC Membrane Sensor

Directory of Open Access Journals (Sweden)

Hassan Ali Zamani

2011-01-01

Full Text Available The N-quinoline-2-carboxamido-8-aminoquinoline (QCA was used as a suitable ion carrier in the construction of a Ho(III PVC-based membrane sensor. This sensor demonstrated good selectivity and sensitivity towards the holmium ion for a broad variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The proposed electrode exhibits a linear dynamic range between 1.0×10-6 and 1.0×10-2 M, with a near Nernstian slope of 20.4±0.3 mV per decade and a detection limit of 4.2×10-7 M. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride, 56% nitrobenzene, 2% sodium tetraphenyl borate, 10% oleic acid and 2% QCA. The potentiometric response of the constructed electrode is pH independent in the range of 2.4-7.4. The sensor possesses the advantages of short conditioning time, fast response time (∼ 5 s and especially, good selectivity towards transition and heavy metal and some mono, di and trivalent cations. The Ho3+ sensor was successfully applied as an indicator electrode in the potentiometric titration of Ho(III ions with EDTA. The electrode was also used for the determination of Ho3+ ions in mixtures of different ions and the determination of the fluoride ion in mouth wash solutions.

A MEMS platform for in situ, real-time monitoring of electrochemically induced mechanical changes in lithium-ion battery electrodes

International Nuclear Information System (INIS)

Pomerantseva, Ekaterina; Jung, Hyun; Gnerlich, Markus; Baron, Sergio; Gerasopoulos, Konstantinos; Ghodssi, Reza

2013-01-01

We report the first successful demonstration of an optical microelectromechanical systems (MEMS) sensing platform for the in situ characterization of electrochemically induced reversible mechanical changes in lithium-ion battery (LIB) electrodes. The platform consists of an array of flexible membranes with a reflective surface on one side and a thin-film LIB electrode on the other side. The membranes deflect due to the active battery material volume change caused by lithium intercalation (expansion) and extraction (contraction). This deflection is monitored using the Fabry–Perot optical interferometry principle. The active material volume change causes high internal stresses and mechanical degradation of the electrodes. The stress evolution observed in a silicon thin-film electrode incorporated into this MEMS platform follows a ‘first elastic, then plastic’ deformation scheme. Understanding of the internal stresses in battery electrodes during discharge/charge is important for improving the reliability and cycle lifetime of LIBs. The developed MEMS platform presents a new method for in situ diagnostics of thin-film LIB electrodes to aid the development of new materials, optimization of electrode performance, and prevention of battery failure. (paper)

Selectivity of Direct Methanol Fuel Cell Membranes

Directory of Open Access Journals (Sweden)

Antonino S. Aricò

2015-11-01

Full Text Available Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK, new generation perfluorosulfonic acid (PFSA systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC. The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2. This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115.

Selectivity of Direct Methanol Fuel Cell Membranes.

Science.gov (United States)

Aricò, Antonino S; Sebastian, David; Schuster, Michael; Bauer, Bernd; D'Urso, Claudia; Lufrano, Francesco; Baglio, Vincenzo

2015-11-24

Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion(®) were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate-PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA) was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC). The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA) was higher than the benchmark Nafion(®) 115-based MEA (77 mW·cm(-2) vs. 64 mW·cm(-2)). This result was due to a lower methanol crossover (47 mA·cm(-2) equivalent current density for s-PEEK vs. 120 mA·cm(-2) for Nafion(®) 115 at 60 °C as recorded at OCV with 2 M methanol) and a suitable area specific resistance (0.15 Ohm cm² for s-PEEK vs. 0.22 Ohm cm² for Nafion(®) 115).

The determination of small amounts of fluoride in uranium compounds by use of an ion-selective electrode

International Nuclear Information System (INIS)

Shelton, B.M.

1975-01-01

A method is presented for the determination of fluoride in uranium metal and oxide at levels from 16 p.p.m. upwards. Uranium is separated from fluoride by extraction into a solution of di(2-ethylhexyl)-phosphoric acid (HDEHP) in carbon tetrachloride. The fluoride remaining in the aqueous phase is determined by potentiometric measurement with an ion-selective electrode. A correction is made for the fluoride lost during the dissolution or extraction step, or both, which is based on a determination of the apparent loss of fluoride on spiked samples that are taken through the whole procedure [af

Polyion selective polymeric membrane-based pulstrode as a detector in flow-injection analysis.

Science.gov (United States)

Bell-Vlasov, Andrea K; Zajda, Joanna; Eldourghamy, Ayman; Malinowska, Elzbieta; Meyerhoff, Mark E

2014-04-15

A method for the detection of polyions using fully reversible polyion selective polymeric membrane type pulstrodes as detectors in a flow-injection analysis (FIA) system is examined. The detection electrode consists of a plasticized polymeric membrane doped with 10 wt % of tridodecylmethylammonium-dinonylnaphthalene sulfonate (TDMA/DNNS) ion-exchanger salt. The pulse sequence used involves a short (1 s) galvanostatic pulse, an open-circuit pulse (0.5 s) during which the EMF of the cell is measured, and a longer (15 s) potentiostatic pulse to return the membrane to its original chemical composition. It is shown that total pulse sequence times can be optimized to yield reproducible real-time detection of injected samples of protamine and heparin at up to 20 samples/h. Further, it is shown that the same membrane detector can be employed for FIA detection of both polycations at levels ≥10 μg/mL and polyanions at levels of ≥40 μg/mL by changing the direction of the galvanostatic pulse. The methodology described may also be applicable in the detection of polyionic species at low levels in other flowing configurations, such as in liquid chromatography and capillary electrophoresis.

An Integrated Glucose Sensor with an All-Solid-State Sodium Ion-Selective Electrode for a Minimally Invasive Glucose Monitoring System

Directory of Open Access Journals (Sweden)

Junko Kojima

2015-06-01

Full Text Available We developed a minimally invasive glucose monitoring system that uses a microneedle to permeate the skin surface and a small hydrogel to accumulate interstitial fluid glucose. The measurement of glucose and sodium ion levels in the hydrogel is required for estimating glucose levels in blood; therefore, we developed a small, enzyme-fixed glucose sensor with a high-selectivity, all-solid-state, sodium ion-selective electrode (ISE integrated into its design. The glucose sensor immobilized glucose oxidase showed a good correlation between the glucose levels in the hydrogels and the reference glucose levels (r > 0.99, and exhibited a good precision (coefficient of variation = 2.9%, 0.6 mg/dL. In the design of the sodium ISEs, we used the insertion material Na0.33MnO2 as the inner contact layer and DD16C5 exhibiting high Na+/K+ selectivity as the ionophore. The developed sodium ISE exhibited high selectivity (\\( \\log \\,k^{pot}_{Na,K} = -2.8\\ and good potential stability. The sodium ISE could measure 0.4 mM (10−3.4 M sodium ion levels in the hydrogels containing 268 mM (10−0.57 M KCl. The small integrated sensor (ϕ < 10 mm detected glucose and sodium ions in hydrogels simultaneously within 1 min, and it exhibited sufficient performance for use as a minimally invasive glucose monitoring system.

Electrode-analytical properties of polyvinylchloride membranes based on triple metal-polymeric complexes

Directory of Open Access Journals (Sweden)

Katerina V. Matorina

2015-10-01

Full Text Available The influence of the nature of the electrode-active substances (EAS, the composition of the external and internal solutions on the formation of the analytical signal of polyvinylchloride (PVC membranes based on associates and triple metal-polymeric complexes (TMPC was established. Dehumidification of synthesized membranes increases with the content of polyvinylpyrrolidone (PVP. The value of the swelling degree is more than two times greater for membranes, which contain as EAS TMPC, relative to membranes based on associates. The value of water absorption of membranes is determined by the nature of EAS. They formed a series of increasing of the swelling degree such as associate < background membrane < TMPC. Swelling of the background membrane is explained by the physical sorption of water molecules on the surface of plasticized membrane. Hydration of PVP macromolecules varies with the introduction of metal ions, macromolecules unit undergoes a conformational transition. PVP macromolecules form tunnels or cavities where complex particles distributed and additional water accumulated through the second coordination layer. Constructed sensors based on TMPC have slope of electrode function equal to 25 mV/pC. Linear dependence of potential on the polymer concentration is observed in the range of 5–7 pC units. Sensors based on associates have slope of the electrode function of 20–25 mV/pC that can be varied depending on the nature of the EAS. Working range is 4–8 pC. Response time of sensor is less than 1 min. The optimal time for conditioning of the synthesized PVC membrane is 24 hours. Potentiometric sensors have been developed for the determination of residual amounts of low molecular PVP which is a food additive E 1201 commonly used for thickening, stabilizing and clarifying of food products. The content of PVP was determined in real objects (apple juice, beer, red wine and cognac with using the polyvinylpyrrolidone sensors (Sr < 0.08. The

Multilayer membranes of p-sulfonato-calix[8]arene and polyvinylamine and their use for selective enrichment of rare earth metal ions

Energy Technology Data Exchange (ETDEWEB)

Toutianoush, Ali [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany); El-Hashani, Ashraf [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany); Schnepf, Judit [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany); Tieke, Bernd [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany)]. E-mail: Tieke@Uni-Koeln.de

2005-06-30

Using alternating electrostatic layer-by-layer assembly of p-octasulfonato-calix[8]arene and polyvinylamine, multilayer assemblies were built up on porous polymer supports. The resulting composite membranes with ultrathin separation layer were studied on their permeability for various metal chloride salts in aqueous solution. The membranes were permeable for sodium chloride, but much less permeable for divalent metal chlorides such as magnesium and zinc chloride, the theoretical separation factors {alpha} (NaCl/MgCl{sub 2}) and {alpha} (NaCl/ZnCl{sub 2}) being 43 and 20. Rare earth metal chlorides LnCl{sub 3} with Ln being La, Ce, Pr and Sm and the related YCl{sub 3} were strongly rejected from the membrane, the theoretical separation factors {alpha} (NaCl/LaCl{sub 3}) and {alpha} (NaCl/YCl{sub 3}) being 138 and 160, for example. Possible origins for the selective ion transport are discussed in terms of Donnan rejection of the highly charged ions and complex formation of the rare earth metal ions with the p-sulfonato-calixarene units in the membrane.

Multilayer membranes of p-sulfonato-calix[8]arene and polyvinylamine and their use for selective enrichment of rare earth metal ions

International Nuclear Information System (INIS)

Toutianoush, Ali; El-Hashani, Ashraf; Schnepf, Judit; Tieke, Bernd

2005-01-01

Using alternating electrostatic layer-by-layer assembly of p-octasulfonato-calix[8]arene and polyvinylamine, multilayer assemblies were built up on porous polymer supports. The resulting composite membranes with ultrathin separation layer were studied on their permeability for various metal chloride salts in aqueous solution. The membranes were permeable for sodium chloride, but much less permeable for divalent metal chlorides such as magnesium and zinc chloride, the theoretical separation factors α (NaCl/MgCl 2 ) and α (NaCl/ZnCl 2 ) being 43 and 20. Rare earth metal chlorides LnCl 3 with Ln being La, Ce, Pr and Sm and the related YCl 3 were strongly rejected from the membrane, the theoretical separation factors α (NaCl/LaCl 3 ) and α (NaCl/YCl 3 ) being 138 and 160, for example. Possible origins for the selective ion transport are discussed in terms of Donnan rejection of the highly charged ions and complex formation of the rare earth metal ions with the p-sulfonato-calixarene units in the membrane

Lanthanide metal complex-based membrane electrodes for sensing of biological amino alcohols

International Nuclear Information System (INIS)

Mahajan, Rakesh Kumar; Kaur, Ravneet; Shinoda, Satoshi; Tsukube, Hiroshi

2008-01-01

Electrodes selective for amino alcohols were prepared by incorporating lanthanide tris(β-diketonates) in PVC membranes, which formed 1:1 highly coordinated complexes with amino alcohols. Several electrodes gave near-Nernstian slopes for 2-amino-3-methyl-1-butanol in the linear concentration range of 1.0 x 10 -1 to 1.0 x 10 -3 M, while the low detection limits of these electrodes were order of ∼10 -4 M. Although the observed response profiles were significantly dependent on the natures of the targeted amino alcohols, the electrodes exhibited stable potentiometric signals in the pH range of 6-12 in short time period of 20 s. The related monoalcohol, diol, and zwitterionic amino acid substrates gave no response, indicating that the present type of lanthanide tris(β-diketonates) were applicable in potentiometric sensing of amino alcohols

Solid contact potassium selective electrodes for biomedical applications – a review

NARCIS (Netherlands)

van de Velde, Lennart; d'Angremont, E.; Olthuis, Wouter

2016-01-01

Ion-selective electrodes (ISE) are used in several biomedical applications, including laboratory sensing of potassium concentration in blood and urine samples. For on-site determination of potassium concentration and usage in other applications such as determination of extracellular potassium

Cation Recognition: Novel Potentiometric PVC-Membrane Sensor based on Meso-octamethylcalix[4]pyrrole for the Determination of Trace Amounts of Titanium (III) Ions

International Nuclear Information System (INIS)

Saeid Ahmadzadeh; Anuar Kassim Majid Rezayi

2011-01-01

The present work deals with developing a novel high selective membrane electrode based on meso-octamethylcalix[4]pyrrole for accurate determination of trace amount of titanium (III) ions in real sample solutions. The amounts of ionophore (4 mg), PVC (33 mg), dioctyl phthalate (DOP) as plasticizer (62.8 mg) and sodium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate (NaTFPB) as an ionic additive (0.2 mg) were optimized in the preparation of the membrane. The electrode exhibited a linear response with a near Nernstian slope of 29.49±0.16 (mV per decade of activity) over the pH range from 1 to 3 with a satisfactory concentration range of 1.0 x 10 -6 to 1.0 x x10 -2 M. The developed sensor exhibited good reproducibility over a period of about 3 months with a fast response time of 15 seconds. (author)

Development of more efficient and cheaper MEA's for PEM fuel cells; Membrane-electrode-assembly

Energy Technology Data Exchange (ETDEWEB)

Yde Andersen, S. (IRD Fuel Cell A/S, Svendborg (Denmark)); Nilsson, M.S. (Danish Power System Aps, Charlottenlund (Denmark)); Siu, A.; Plackett, D. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Dansk Polymer Center, Roskilde (Denmark)); Li, Q. (Technical Univ. of Denmark, Dept. of Chemistry, Kgs. Lyngby (Denmark))

2008-06-15

The project covered 5 main areas: 1) polymer and membranes; 2) electrocatalysts; 3) gas diffusion electrodes; 4) MEAs; and 5) evaluation techniques. For the polymers, by purification of monomers and optimizing parameters, high molecular weight polybenzimidazoles have been synthesized in batches of 50 g with good reproducibility. Based on the polymer, two types of new membranes have been prepared. One is the cross-linked (covalently and acid-base) PBI blend membranes. The blend membranes were systematically characterized and show excellent properties such as very high acid doping levels, conductivity, mechanical strength and durability. The other type is composite membranes based on PBI and nanoclay. Using the modified nanoclay, good dispersion and transparent composite membranes have been achieved. For catalyst preparation, the carbon supports have been modified with thermal treatment. Improved corrosion resistance was achieved with little sacrificing of the catalytic activity. High Pt loading catalysts were prepared, based on which high performance gas diffusion electrodes were fabricated. The performance target of both cathode and anode was achieved, as evaluated by the PTFE half cell tests. New gas diffusion layer (GDL) materials have been developed and tested in different MEA configurations. Significant performance improvement has been achieved with also potential to reduce the cost. Techniques for applying micro porous layers and catalyst layers have been optimized, including tape casting, spraying, and catalyst-coated membrane (CCM). Using the developed membranes and gas diffusion electrodes, membrane-electrode assemblies (MEAs) were fabricated for both single cell and stack tests. Selection of sealing materials and design of integrated gaskets have been made for both low and high temperature MEAs. Parameters for hot-pressing such as temperature, pressure and duration were systematically studied. 44 MEAs with an active area of 256 cm{sup 2} have been prepared

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes

KAUST Repository

Geise, Geoffrey M.; Cassady, Harrison J.; Paul, Donald R.; Logan, Bruce E.; Hickner, Michael A.

2014-01-01

-ions also appeared to influence permselectivity leading to ion-specific effects; co-ions that are charge dense and have low polarizability tended to result in high membrane permselectivity. This journal is

Theoretical voltammetric response of electrodes coated by solid polymer electrolyte membranes.

Science.gov (United States)

Gómez-Marín, Ana M; Hernández-Ortíz, Juan P

2014-09-24

A model for the differential capacitance of metal electrodes coated by solid polymer electrolyte membranes, with acid/base groups attached to the membrane backbone, and in contact with an electrolyte solution is developed. With proper model parameters, the model is able to predict a limit response, given by Mott-Schottky or Gouy-Chapman-Stern theories depending on the dissociation degree and the density of ionizable acid/base groups. The model is also valid for other ionic membranes with proton donor/acceptor molecules as membrane counterions. Results are discussed in light of the electron transfer rate at membrane-coated electrodes for electrochemical reactions that strongly depend on the double layer structure. In this sense, the model provides a tool towards the understanding of the electro-catalytic activity on modified electrodes. It is shown that local maxima and minima in the differential capacitance as a function of the electrode potential may occur as consequence of the dissociation of acid/base molecular species, in absence of specific adsorption of immobile polymer anions on the electrode surface. Although the model extends the conceptual framework for the interpretation of cyclic voltammograms for these systems and the general theory about electrified interfaces, structural features of real systems are more complex and so, presented results only are qualitatively compared with experiments. Copyright © 2014 Elsevier B.V. All rights reserved.

Reliable reference electrodes for lithium-ion batteries

KAUST Repository

La Mantia, F.; Wessells, C.D.; Deshazer, H.D.; Cui, Yi

2013-01-01

Despite the high attention drawn to the lithium-ion batteries by the scientific and industrial community, most of the electrochemical characterization is carried out using poor reference electrodes or even no reference electrode. In this case

Selective transport and incorporation of highly charged metal and metal complex ions in self-assembled polyelectrolyte multilayer membranes

International Nuclear Information System (INIS)

Toutianoush, Ali; Tieke, Bernd

2002-01-01

The transport of aqueous salts containing mono-, di- and trivalent metal and tetravalent metal complex ions across ultrathin polyvinylammonium/polyvinylsulphate (PVA/PVS) membranes is described. The membranes were prepared by electrostatic layer-by-layer (LBL) assembly of the two polyelectrolytes. Using spectroscopic measurements and permeability studies, it is demonstrated that the transport of copper(II) chloride, lanthanum(III) chloride, barium chloride and potassium hexacyanoferrate(II) is accompanied by the permanent incorporation of the metal and metal complex ions in the membrane. Upon the uptake of copper, lanthanum and hexacyanoferrate ions, the membranes become cross-linked so that the permeation rates of other salts not taken up by the membrane, e.g. sodium chloride, potassium chloride and magnesium chloride, are decreased. The uptake of barium ions leads to a decrease of the cross-linking density of the membrane so that the permeation rate of NaCl is increased. Possible mechanisms for the ion uptake are discussed

Micropatterned Carbon-on-Quartz Electrode Chips for Photocurrent Generation from Thylakoid Membranes

DEFF Research Database (Denmark)

Bunea, Ada-Ioana; Heiskanen, Arto R.; Pankratova, Galina

2018-01-01

Harvesting the energy generated by photosynthetic organisms through light-dependent reactions is a significant step towards a sustainable future energy supply. Thylakoid membranes are the site of photosynthesis, and thus particularly suited for developing photo-bioelectrochemical cells. Novel ele......]+/2+) are used for evaluating photocurrent generation from thylakoid membranes with different electrode geometries. Current densities up to 71 µA cm-2 are measured upon illumination through the transparent electrode chip with solar simulated irradiance (1000 W m-2)....... electrode materials and geometries could potentially improve the efficiency of energy harvesting using thylakoid membranes. For commercial applications, electrodes with large surface areas are needed. Photolithographic patterning of a photoresist, followed by pyrolysis, is a flexible and fast approach...

A selective potentiometric copper (II) ion sensor based on the functionalized ZnO nanorods.

Science.gov (United States)

Khun, K; Ibupoto, Z H; Liu, X; Nur, O; Willander, M; Danielsson, B

2014-09-01

In this work, ZnO nanorods were hydrothermally grown on the gold-coated glass substrate and characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The ZnO nanorods were functionalized by two different approaches and performance of the sensor electrode was monitored. Fourier transform infrared spectroscopy (FTIR) was carried out for the confirmation of interaction between the ionophore molecules and ZnO nanorods. In addition to this, the surface of the electrode was characterized by X-ray photoelectron spectroscopy (XPS) showing the chemical and electronic state of the ionophore and ZnO nanorod components. The ionophore solution was prepared in the stabilizer, poly vinyl chloride (PVC) and additives, and then functionalized on the ZnO nanorods that have shown the Nernstian response with the slope of 31 mV/decade. However, the Cu2+ ion sensor was fabricated only by immobilizing the selective copper ion ionophore membrane without the use of PVC, plasticizers, additives and stabilizers and the sensor electrode showed a linear potentiometric response with a slope of 56.4 mV/decade within a large dynamic concentration range (from 1.0 x 10(-6) to 1.0 x 10(-1) M) of copper (II) nitrate solutions. The sensor showed excellent repeatability and reproducibility with response time of less than 10 s. The negligible response to potentially interfering metal ions such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe3+), zinc (Zn2+), and sodium (Na+) allows this sensor to be used in biological studies. It may also be used as an indicator electrode in the potentiometric titration.

Different types of pre-lithiated hard carbon as negative electrode material for lithium-ion capacitors

International Nuclear Information System (INIS)

Zhang, Jin; Liu, Xifeng; Wang, Jing; Shi, Jingli; Shi, Zhiqiang

2016-01-01

Highlights: • Two types of HC materials with different properties as negative electrode. • Lithium ion intercalation plateau of HC affects electrochemical performance of LIC. • The electrochemical performance of LIC is operated at different potential ranges. • The selection of HC and appropriate potential range of LIC have been proposed. - ABSTRACT: Lithium-ion capacitors (LICs) are assembled with activated carbon (AC) cathode and pre-lithiated hard carbon (HC) anode. Two kinds of HC materials with different physical and electrochemical behaviors have been investigated as the negative electrodes for LIC. Compared with spherical HC, the irregular HC shows a distinct lithium ion intercalation plateau in the charge–discharge process. The existence of lithium ion intercalation plateau for irregular HC greatly affects the electrochemical behavior of HC negative electrode and AC positive electrode. The effect of working potential range on the electrochemical performance of LIC-SH and LIC-IH is investigated by the galvanostatic charging–discharging, electrochemical impedance tests and cycle performance testing. The charge–discharge potential range of the irregular HC negative electrode is lower than the spherical HC electrode due to the existence of lithium ion intercalation plateau, which is conducive to the sufficient utilization of the AC positive electrode. The working potential range of LIC should be controlled to realize the optimization of electrochemical performance of LIC. LIC-IH at the working potential range of 2.0-4.0 V exhibits the optimal electrochemical performance, high energy density up to 85.7 Wh kg −1 and power density as high as 7.6 kW kg −1 (based on active material mass of two electrodes), excellent capacity retention about 96.0% after 5000 cycles.

Materials Genomics Screens for Adaptive Ion Transport Behavior by Redox-Switchable Microporous Polymer Membranes in Lithium-Sulfur Batteries.

Science.gov (United States)

Ward, Ashleigh L; Doris, Sean E; Li, Longjun; Hughes, Mark A; Qu, Xiaohui; Persson, Kristin A; Helms, Brett A

2017-05-24

Selective ion transport across membranes is critical to the performance of many electrochemical energy storage devices. While design strategies enabling ion-selective transport are well-established, enhancements in membrane selectivity are made at the expense of ionic conductivity. To design membranes with both high selectivity and high ionic conductivity, there are cues to follow from biological systems, where regulated transport of ions across membranes is achieved by transmembrane proteins. The transport functions of these proteins are sensitive to their environment: physical or chemical perturbations to that environment are met with an adaptive response. Here we advance an analogous strategy for achieving adaptive ion transport in microporous polymer membranes. Along the polymer backbone are placed redox-active switches that are activated in situ, at a prescribed electrochemical potential, by the device's active materials when they enter the membrane's pore. This transformation has little influence on the membrane's ionic conductivity; however, the active-material blocking ability of the membrane is enhanced. We show that when used in lithium-sulfur batteries, these membranes offer markedly improved capacity, efficiency, and cycle-life by sequestering polysulfides in the cathode. The origins and implications of this behavior are explored in detail and point to new opportunities for responsive membranes in battery technology development.

Method for fabricating carbon/lithium-ion electrode for rechargeable lithium cell

Science.gov (United States)

Huang, Chen-Kuo (Inventor); Surampudi, Subbarao (Inventor); Attia, Alan I. (Inventor); Halpert, Gerald (Inventor)

1995-01-01

The method includes steps for forming a carbon electrode composed of graphitic carbon particles adhered by an ethylene propylene diene monomer binder. An effective binder composition is disclosed for achieving a carbon electrode capable of subsequent intercalation by lithium ions. The method also includes steps for reacting the carbon electrode with lithium ions to incorporate lithium ions into graphitic carbon particles of the electrode. An electrical current is repeatedly applied to the carbon electrode to initially cause a surface reaction between the lithium ions and to the carbon and subsequently cause intercalation of the lithium ions into crystalline layers of the graphitic carbon particles. With repeated application of the electrical current, intercalation is achieved to near a theoretical maximum. Two differing multi-stage intercalation processes are disclosed. In the first, a fixed current is reapplied. In the second, a high current is initially applied, followed by a single subsequent lower current stage. Resulting carbon/lithium-ion electrodes are well suited for use as an anode in a reversible, ambient temperature, lithium cell.

Selective sensing of mercury(II) using PVC-based membranes incorporating recently synthesized 1,3-alternate thiacalix[4]crown ionophore.

Science.gov (United States)

Mahajan, Rakesh Kumar; Kamal, Ajar; Kumar, Naresh; Bhalla, Vandana; Kumar, Manoj

2013-05-01

The construction and electrodes characteristics of poly(vinylchloride) (PVC)-based polymeric membrane electrode (PME) and coated graphite electrode (CGE), incorporating 1,3-alternate thiacalix[4]crown as ionophore for estimation of Hg(II) ions, are reported here. The best potential response was observed for PME-1 having membrane composition of: ionophore (6.2 mg), PVC (100.0 mg), 2-nitrophenyl octyl ether (2-NPOE; 200.0 mg), and sodium tetraphenyl borate (NaTPB; 2.0 mg); for CGE-1 with the membrane composition: ionophore (3.5 mg), PVC (40.0 mg), 2-NPOE (80.0 mg), and NaTPB (2.0 mg). The electrodes exhibits Nernstian slope of 29.16 mV/decade with PME-1 and 30.39 mV/decade with CGE-1 for Hg(II) ions over wide concentration range, i.e., 1.0 × 10(-1) to 5.0 × 10(-6) M with PME-1 and 1.0 × 10(-1) to 5.0 × 10(-7) M with CGE-1. Lower detection limits were found to be 9.77 × 10(-6) M for PME-1 and 7.76 × 10(-7) M for CGE-1 with response time varying from 10 to 20 s. Also, these electrodes work within pH range of 2.0-6.0 for PME-1 and 1.5-6.5 for CGE-1. Overall, CGE-1 has been found to be better than PME-1. CGE-1 has been used as indicator electrode for the potentiometric titration of Hg(II) ions with EDTA as well as successfully applied for determination of Hg(II) content in wastewater, insecticide, dental amalgam, and ayurvedic medicines samples with very good performance (0.9974 correlation coefficient in the comparison against volumetric method).

Investigation into diffusion induced plastic deformation behavior in hollow lithium ion battery electrode revealed by analytical model and atomistic simulation

International Nuclear Information System (INIS)

Li, Jia; Fang, Qihong; Wu, Hong; Liu, Youwen; Wen, Pihua

2015-01-01

Highlights: • Diffusion induced stress is established. • Yield stress is dependent upon concentration. • Plastic deformation induced stress lowers tensile stress. • Plastic deformation suppresses crack nucleation. • Plastic deformation occurs not only at lithiated phase but also at electrode interior. - Abstract: This paper is theoretically suggested to describe diffusion induced stress in the elastoplastic hollow spherical silicon electrode for plastic deformation using both analytical model and molecular simulation. Based on the plastic deformation and the yield criterion, we develop this model accounting for the lithium-ion diffusion effect in hollow electrode, focusing on the concentration and stress distributions undergoing lithium-ion insertion. The results show that the two ways, applied compressive stress to inner surface or limited inner surface with higher concentration using biological membranes maintaining concentration difference, lead to the compressive stress induced by the lithium-ion diffusion effect. Hollow spherical electrode reduces effectively diffusion induced stress through controlling and tuning electrode parameters to obtain the reasonably low yield strength. According to MD simulations, plastic deformation phenomenon not only occurs at interface layer of lithiated phase, but also penetrates at electrode interior owning to confinement imposed by lithiated phase. These criteria that radial and hoop stresses reduce dramatically when plastic deformation occurs near the end faces of hollow electrode, may help guide development of new materials for lithium-ion batteries with enhanced mechanical durability, by means of reasonable designing yield strength to maintain mechanical stress below fracture strength, thereby increasing battery life.

A fast response cadmium-selective polymeric membrane electrode based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide as a new neutral carrier.

Science.gov (United States)

Rezaei, B; Meghdadi, S; Zarandi, R Fazel

2008-05-01

A new polyvinylchloride membrane sensor for Cd(2+) ions based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide (Mebqb) as a new and excellent neutral ionophore has been prepared. The sensor shows a Nernestian response for cadmium ions over a wide concentration range (1.0 x 10(-6) to 1.0 x 10(-1) M) with the determination coefficient of 0.9964 and slope of 29.9 +/- 0.5 mV decade(-1). The limit of detection is 8 x 10(-7) M. It has a fast response time of 3-8s and can be used for at least 8 weeks without any divergence in potential. The electrode can be used in the pH range from 4.0 to 9.0. The proposed sensor shows a very good discriminating ability towards Cd(2+) ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Cd(2+) in standard and real sample solutions.

A fast response cadmium-selective polymeric membrane electrode based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide as a new neutral carrier

International Nuclear Information System (INIS)

Rezaei, B.; Meghdadi, S.; Zarandi, R. Fazel

2008-01-01

A new polyvinylchloride membrane sensor for Cd 2+ ions based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide (Mebqb) as a new and excellent neutral ionophore has been prepared. The sensor shows a Nernestian response for cadmium ions over a wide concentration range (1.0 x 10 -6 to 1.0 x 10 -1 M) with the determination coefficient of 0.9964 and slope of 29.9 ± 0.5 mV decade -1 . The limit of detection is 8 x 10 -7 M. It has a fast response time of 3-8 s and can be used for at least 8 weeks without any divergence in potential. The electrode can be used in the pH range from 4.0 to 9.0. The proposed sensor shows a very good discriminating ability towards Cd 2+ ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Cd 2+ in standard and real sample solutions

Europium (III) PVC membrane sensor based on N-pyridine-2-carboxamido-8-aminoquinoline as a sensing material

International Nuclear Information System (INIS)

Zamani, Hassan Ali; Kamjoo, Rahman; Mohammadhosseini, Majid; Zaferoni, Mojdeh; Rafati, Zynab; Ganjali, Mohammad Reza; Faridbod, Farnoush; Meghdadi, Soraia

2012-01-01

Conductometric study in acetonitrile solution shows the selectivity of PCQ toward europium ion. Therefore, a new europium PVC membrane electrode was prepared based on N-pyridine-2-carboxamido-8-aminoquinoline (PCQ) as an ion carrier. The electrode has a wide concentration range from 1.0 × 10 −2 and 1.0 × 10 −6 mol L −1 , Nernstian slope of 19.8 ± 0.3 mV per decade and a detection limit of 6.4 × 10 −7 mol L −1 . The potentiometric response is pH independent in the range of 2.4–7.4. The proposed sensor has a relatively fast response time less than 10 s and it can be used for at least 2 months without any considerable divergence in its potentials. The proposed electrode revealed good selectivity toward europium ion in comparison with variety of other metal ions. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of Eu 3+ ions with EDTA and for determination of Eu 3+ ion concentration in mixtures of two and three different ions. - Highlights: ► A new ion carrier is introduced to preparation of a selective sensor for Eu 3+ ions. ► This technique is very simple and it's not necessary to use sophisticated equipment. ► The novelty of this work is the high affinity of the ionophore toward the Eu 3+ ions. ► The sensor is superior to the formerly reported Eu 3+ sensors in terms of selectivity.

Ion transport Modeling in a Bipolar Membrane

International Nuclear Information System (INIS)

Kim, Jung Soo; Park, Kwang Heon; Kim, Kwang Wook

2010-01-01

The COL(Carbonate-based Oxidative Leaching) process is an environmentally-friendly technique for collecting only uranium from spent fuel with oxidation leaching/ precipitation of carbonate solution. The bipolar membrane used for the electrolyte circulation of the salt used in the COL process is a special form of ion exchange membrane which combines CEM(cation exchange membrane) and AEM(anion exchange membrane). After arranging positive ion exchange layer toward negative terminal and positive ion exchange layer toward positive terminal, then supply electricity, water molecules are decomposed into protons and hydroxyl ions by a strong electric field in the transition region inside bipolar membrane.1) In this study, a theoretical approach to increase the efficiency of Na + and NO3 - ion collecting device using bipolar membrane was taken and simulating using the COMSOL program was tried. The details of results are also discussed

Recent Advances in the Fabrication of Membranes Containing “Ion Pairs” for Nanofiltration Processes

Directory of Open Access Journals (Sweden)

Yan-Li Ji

2017-12-01

Full Text Available In the face of serious environmental pollution and water scarcity problems, the membrane separation technique, especially high efficiency, low energy consumption, and environmental friendly nanofiltration, has been quickly developed. Separation membranes with high permeability, good selectivity, and strong antifouling properties are critical for water treatment and green chemical processing. In recent years, researchers have paid more and more attention to the development of high performance nanofiltration membranes containing “ion pairs”. In this review, the effects of “ion pairs” characteristics, such as the super-hydrophilicity, controllable charge character, and antifouling property, on nanofiltration performances are discussed. A systematic survey was carried out on the various approaches and multiple regulation factors in the fabrication of polyelectrolyte complex membranes, zwitterionic membranes, and charged mosaic membranes, respectively. The mass transport behavior and antifouling mechanism of the membranes with “ion pairs” are also discussed. Finally, we present a brief perspective on the future development of advanced nanofiltration membranes with “ion pairs”.

Highly selective and sensitive optical sensor for determination of Pb2+and Hg2+ ions based on the covalent immobilization of dithizone on agarose membrane

Science.gov (United States)

Zargoosh, Kiomars; Babadi, Fatemeh Farhadian

2015-02-01

A highly sensitive and selective optical membrane for determination of Hg2+ and Pb2+ was prepared by covalent immobilization of dithizone on agarose membrane. In addition to its high stability, reproducibility and relatively long lifetime, the proposed optical sensor revealed good selectivity for target ions over a large number of alkali, alkaline earth, transition, and heavy metal ions. The proposed optical membrane displays linear responses from 1.1 × 10-8 to 2.0 × 10-6 mol L-1 and 1.2 × 10-8 to 2.4 × 10-6 mol L-1 for Hg2+ and Pb2+, respectively. The limits of detection (LOD) were 2.0 × 10-9 mol L-1 and 4.0 × 10-9 mol L-1 for Hg2+ and Pb2, respectively. The prepared optical membrane was successfully applied to the determination of Hg2+ and Pb2+ in industrial wastes, spiked tap water and natural waters without any preconcentration step.

Materials Genomics Screens for Adaptive Ion Transport Behavior by Redox-Switchable Microporous Polymer Membranes in Lithium–Sulfur Batteries

Science.gov (United States)

2017-01-01

Selective ion transport across membranes is critical to the performance of many electrochemical energy storage devices. While design strategies enabling ion-selective transport are well-established, enhancements in membrane selectivity are made at the expense of ionic conductivity. To design membranes with both high selectivity and high ionic conductivity, there are cues to follow from biological systems, where regulated transport of ions across membranes is achieved by transmembrane proteins. The transport functions of these proteins are sensitive to their environment: physical or chemical perturbations to that environment are met with an adaptive response. Here we advance an analogous strategy for achieving adaptive ion transport in microporous polymer membranes. Along the polymer backbone are placed redox-active switches that are activated in situ, at a prescribed electrochemical potential, by the device’s active materials when they enter the membrane’s pore. This transformation has little influence on the membrane’s ionic conductivity; however, the active-material blocking ability of the membrane is enhanced. We show that when used in lithium–sulfur batteries, these membranes offer markedly improved capacity, efficiency, and cycle-life by sequestering polysulfides in the cathode. The origins and implications of this behavior are explored in detail and point to new opportunities for responsive membranes in battery technology development. PMID:28573201

Methods of making membrane electrode assemblies

Science.gov (United States)

Kim, Yu Seung; Lee, Kwan -Soo; Rockward, Tommy Q. T.

2015-07-28

Method of making a membrane electrode assembly comprising: providing a membrane comprising a perfluorinated sulfonic acid; providing a first transfer substrate; applying to a surface of the first transfer substrate a first ink, said first ink comprising an ionomer and a catalyst; applying to the first ink a suitable non-aqueous swelling agent; forming an assembly comprising: the membrane; and the first transfer substrate, wherein the surface of the first transfer substrate comprising the first ink and the non-aqueous swelling agent is disposed upon one surface of the membrane; and heating the assembly at a temperature of 150.degree. C. or less and at a pressure of from about 250 kPa to about 3000 kPa or less for a time suitable to allow substantially complete transfer of the first ink and the second ink to the membrane; and cooling the assembly to room temperature and removing the first transfer substrate and the second transfer substrate.

Use of a silver ion selective electrode to assess mechanisms responsible for biological effects of silver nanoparticles

International Nuclear Information System (INIS)

Koch, Marcus; Kiefer, Silke; Cavelius, Christian; Kraegeloh, Annette

2012-01-01

For a detailed analysis of the biological effects of silver nanoparticles, discrimination between effects related to the nano-scale size of the particles and effects of released silver ions is required. Silver ions are either present in the initial particle dispersion or released by the nanoparticles over time. The aim of this study is to monitor the free silver ion activity {Ag + } in the presence of silver nanoparticles using a silver ion selective electrode. Therefore, silver in the form of silver nanoparticles, 4.2 ± 1.4 nm and 2–30 nm in size, or silver nitrate was added to cell culture media in the absence or presence of A549 cells as a model for human type II alveolar epithelial cells. The free silver ion activity measured after the addition of silver nanoparticles was determined by the initial ionic silver content. The p {Ag + } values indicated that the cell culture media decrease the free silver ion activity due to binding of silver ions by constituents of the media. In the presence of A549 cells, the free silver ion activity was further reduced. The morphology of A549 cells, cultivated in DME medium containing 9.1% (v/v) FBS, was affected by adding AgNO 3 at concentrations of ≥30 μM after 24 h. In comparison, silver nanoparticles up to a concentration of 200 μM Ag did not affect cellular morphology. Our experiments indicate that the effect of silver nanoparticles is mainly mediated by silver ions. An effect of silver on cellular morphology was observed at p {Ag + } ≤ 9.2.

A new selectophore for gadolinium selective sensor

International Nuclear Information System (INIS)

Zamani, Hassan Ali; Faridbod, Farnoush; Ganjali, Mohammad Reza

2014-01-01

Based on a selective complexation of N′-(2-oxo-1,2-di(pyridin-2-yl)ethylidene)furan-2-carbohydrazide (L) with Gd(III) ions, it was used as a selectophore in construction of a Gd(III) selective PVC membrane sensor. Different compositions for the membrane were tested. The o-nitrophenyloctyl ether (NPOE) was used as suitable plasticizer, and a mixture of sodium tetraphenyl borate (NaTPB) and oleic acid (OA) as anion excluders. The proposed sensor displayed a Nernstian behavior with the slope of 19.9 ± 0.6 mV decade −1 in concentration range of 1.0 × 10 −6 to 1.0 × 10 −2 mol L −1 . Detection limit was 4.2 × 10 −7 mol L −1 and response time was ∼ 10 s. Applicable pH range of the electrode was 4.2–8.0. Lifetime of the sensor is at least 10 weeks. Analysis of certified reference materials confirmed the accuracy of the proposed electrode. - Highlights: • This work reports design of membrane sensor for monitoring of Gd3+ ions. • The novelty of this work is the high affinity of the ionophore toward the Gd3+ ions. • The sensor is superior to the formerly reported Gd3+ sensors in terms of selectivity

Application of membrane LaF3 electrode in the determination of stability constants of Uranyl Fluoride complex in solution

International Nuclear Information System (INIS)

Muzakky; Iswani GS; Mintolo

1996-01-01

A membrane electrode LaF 3 has been applied in the determination of uranyl fluoride complex stability constant in solution. The determination is based on the detection of free F ion in solution as a result of hydrolysis reaction (process) of uranyl ions into the uranyl hydroxide form at low pH. The experiment results showed that there was no effect of ammonium carbonate 2 M titran, flow rate on the electrode response. The F release is optimum at pH 1. The free F ion in solution is calculated from the standard curve at pH 1, after the fluoride concentration at the same pH has been corrected. Using the plot of average number of ligand binding (n) versus minus log of free ligand (-log F) the value of β1 = 4.4, β2 = 7.48, β3=9.73, and β4 = 11.67

Hybrid capacitive deionization with anion-exchange membranes for lithium extraction

Directory of Open Access Journals (Sweden)

Siekierka Anna

2017-01-01

Full Text Available Lithium is considered to be a critical material for various industrial fields. We present our studies on extraction lithium from diluted aqueous solution by novel hybrid system based on a membrane capacitive deionization and batteries desalination. Hybrid CDI is comprised by a lithium selective adsorbent, activated carbon electrode and anion-exchange membranes. Here, we demonstrated implication of various type of anion-exchange membranes and influence their properties on effective capacity and energy requirements in charge/discharge steps. We described a configuration with anion-exchange membrane characterized by adsorption capacity of 35 mg/g of Li+ with 0.08Wh/g and removal efficiency of 60 % of lithium ions, using novel selective desalination technique.

Hybrid capacitive deionization with anion-exchange membranes for lithium extraction

Science.gov (United States)

Siekierka, Anna; Bryjak, Marek

2017-11-01

Lithium is considered to be a critical material for various industrial fields. We present our studies on extraction lithium from diluted aqueous solution by novel hybrid system based on a membrane capacitive deionization and batteries desalination. Hybrid CDI is comprised by a lithium selective adsorbent, activated carbon electrode and anion-exchange membranes. Here, we demonstrated implication of various type of anion-exchange membranes and influence their properties on effective capacity and energy requirements in charge/discharge steps. We described a configuration with anion-exchange membrane characterized by adsorption capacity of 35 mg/g of Li+ with 0.08Wh/g and removal efficiency of 60 % of lithium ions, using novel selective desalination technique.

Poly(ο-methoxyaniline) modified electrode for detection of lithium ions

International Nuclear Information System (INIS)

Lindino, Cleber Antonio; Casagrande, Marcella; Peiter, Andreia; Ribeiro, Caroline

2012-01-01

This paper reports the use of an electrode modified with poly(ο-methoxyaniline) for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly(ο-methoxyaniline) was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10 -5 to 1 x 10 -4 mol L -1 . The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry). (author)

Poly({omicron}-methoxyaniline) modified electrode for detection of lithium ions

Energy Technology Data Exchange (ETDEWEB)

Lindino, Cleber Antonio; Casagrande, Marcella; Peiter, Andreia; Ribeiro, Caroline [Departamento de Quimica, Universidade Estadual do Oeste do Parana, Toledo, PR (Brazil)

2012-07-01

This paper reports the use of an electrode modified with poly({omicron}-methoxyaniline) for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly({omicron}-methoxyaniline) was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10{sup -5} to 1 x 10{sup -4} mol L{sup -1}. The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry). (author)

Poly(o-methoxyaniline modified electrode for detection of lithium ions

Directory of Open Access Journals (Sweden)

Cleber Antonio Lindino

2012-01-01

Full Text Available This paper reports the use of an electrode modified with poly(o-methoxyaniline for detecting lithium ions. These ions are present in drugs used for treating bipolar disorder and that requires periodical monitoring of the concentration of lithium in blood serum. Poly(o-methoxyaniline was obtained electrochemically by cyclic voltammetry on the surface of a gold electrode. The results showed that the electrode modified with a conducting polymer responded to lithium ions in the concentration range of 1 x 10-5 to 1 x 10-4 mol L-1 . The results also confirmed that the performance of the modified electrode was comparable to that of the standard method (atomic emission spectrophotometry.

Effects of ion implantation on the electrochemical characteristics of carbon electrodes

International Nuclear Information System (INIS)

Takahashi, Katsuo; Iwaki, Masaya

1994-01-01

Various carbon materials are important electrode materials for electrochemical field. By ion implantation, the surface layer reforming of carbon materials (mainly galssy carbon) was carried out, and the effect that it exerts to their electrode characteristics was investigated. As the results of the ion implantation of Li, N, O, K, Ti, Zn, Cd and others performed so far, it was found that mainly by the change of the surface layer to amorphous state, there were the effects of the lowering of base current and the lowering of electrode reaction rate, and it was known that the surface layers of carbon materials doped with various kinds of ions showed high chemical stability. The use of carbon materials as electrodes in electrochemistry is roughly divided into the electrodes for electrolytic industry and fuel cells for large current and those for the measurement in electrochemical reaction for small current. The structure of carbon materials and electrode characteristics, and the reforming effect by ion implantation are reported. (K.I.)

High voltage and high specific capacity dual intercalating electrode Li-ion batteries

Science.gov (United States)

West, William C. (Inventor); Blanco, Mario (Inventor)

2010-01-01

The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

Clearance of short circuited ion optics electrodes by capacitive discharge. [in ion thrusters

Science.gov (United States)

Poeschel, R. L.

1976-01-01

The ion optics electrodes of low specific impulse (3000 sec) mercury electron bombardment ion thrusters are vulnerable to short circuits by virtue of their relatively small interelectrode spacing (0.5 mm). Metallic flakes from backsputtered deposits are the most probable cause of such 'shorts' and 'typical' flakes have been simulated here using refractory wire that has a representative, but controllable, cross section. Shorting wires can be removed by capacitive discharge without significant damage to the electrodes. This paper describes an evaluation of 'short' removal versus electrode damage for several combinations of capacitor voltage, stored energy, and short circuit conditions.

Distance scaling of electric-field noise in a surface-electrode ion trap

Science.gov (United States)

Sedlacek, J. A.; Greene, A.; Stuart, J.; McConnell, R.; Bruzewicz, C. D.; Sage, J. M.; Chiaverini, J.

2018-02-01

We investigate anomalous ion-motional heating, a limitation to multiqubit quantum-logic gate fidelity in trapped-ion systems, as a function of ion-electrode separation. Using a multizone surface-electrode trap in which ions can be held at five discrete distances from the metal electrodes, we measure power-law dependencies of the electric-field noise experienced by the ion on the ion-electrode distance d . We find a scaling of approximately d-4 regardless of whether the electrodes are at room temperature or cryogenic temperature, despite the fact that the heating rates are approximately two orders of magnitude smaller in the latter case. Through auxiliary measurements using the application of noise to the electrodes, we rule out technical limitations to the measured heating rates and scalings. We also measure the frequency scaling of the inherent electric-field noise close to 1 /f at both temperatures. These measurements eliminate from consideration anomalous-heating models which do not have a d-4 distance dependence, including several microscopic models of current interest.

Phosphoric acid distribution in the membrane electrode assembly of high temperature proton exchange membrane fuel cells

International Nuclear Information System (INIS)

Kwon, Kyungjung; Park, Jung Ock; Yoo, Duck Young; Yi, Jung S.

2009-01-01

The ionomer content in electrode is one of the most important parameters for the high performance of fuel cells. The high temperature PEMFC based on phosphoric acid (PA)-doped polymer membrane with unhumidified reactant gases has a difficulty in controlling the liquid state PA ionomer content in electrode. To evaluate the PA content in electrode, the three techniques of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and acid-base titration (ABT) are carried out in situ or ex situ. The properties of membrane electrode assembly (MEA) such as electrochemical surface area (ESA), ohmic resistance, charge transfer resistance, double layer capacitance and the amount of PA in MEA components (anode, cathode and membrane) are extracted by each technique. Ex situ CV with the usage of dry gases has a limitation in assessing the reliable ESA of unhumidified PEMFC. While in situ EIS presents some informative values of resistance and capacitance for understanding the PA distribution in MEA, its sensitivity to the PA content in MEA components needs to be higher for detecting a subtle change in PA distribution. Ex situ ABT supplies a clear PA distribution in MEA at room temperature but does not seem to reflect the operating state well at high temperatures. However, it can be used as a detection tool for the loss of the initial acid content in membrane during a long-term MEA durability study.

Phosphoric acid distribution in the membrane electrode assembly of high temperature proton exchange membrane fuel cells

Energy Technology Data Exchange (ETDEWEB)

Kwon, Kyungjung [Fuel Cell Group, Energy Lab, SAIT, Samsung Electronics Co., Ltd., San 14-1, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do, 446-712 (Korea, Republic of)], E-mail: kfromberk@gmail.com; Park, Jung Ock; Yoo, Duck Young; Yi, Jung S. [Fuel Cell Group, Energy Lab, SAIT, Samsung Electronics Co., Ltd., San 14-1, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do, 446-712 (Korea, Republic of)

2009-11-01

The ionomer content in electrode is one of the most important parameters for the high performance of fuel cells. The high temperature PEMFC based on phosphoric acid (PA)-doped polymer membrane with unhumidified reactant gases has a difficulty in controlling the liquid state PA ionomer content in electrode. To evaluate the PA content in electrode, the three techniques of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and acid-base titration (ABT) are carried out in situ or ex situ. The properties of membrane electrode assembly (MEA) such as electrochemical surface area (ESA), ohmic resistance, charge transfer resistance, double layer capacitance and the amount of PA in MEA components (anode, cathode and membrane) are extracted by each technique. Ex situ CV with the usage of dry gases has a limitation in assessing the reliable ESA of unhumidified PEMFC. While in situ EIS presents some informative values of resistance and capacitance for understanding the PA distribution in MEA, its sensitivity to the PA content in MEA components needs to be higher for detecting a subtle change in PA distribution. Ex situ ABT supplies a clear PA distribution in MEA at room temperature but does not seem to reflect the operating state well at high temperatures. However, it can be used as a detection tool for the loss of the initial acid content in membrane during a long-term MEA durability study.

A fast response cadmium-selective polymeric membrane electrode based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide as a new neutral carrier

Energy Technology Data Exchange (ETDEWEB)

Rezaei, B. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-84111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Meghdadi, S.; Zarandi, R. Fazel [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-84111 (Iran, Islamic Republic of)

2008-05-01

A new polyvinylchloride membrane sensor for Cd{sup 2+} ions based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide (Mebqb) as a new and excellent neutral ionophore has been prepared. The sensor shows a Nernestian response for cadmium ions over a wide concentration range (1.0 x 10{sup -6} to 1.0 x 10{sup -1} M) with the determination coefficient of 0.9964 and slope of 29.9 {+-} 0.5 mV decade{sup -1}. The limit of detection is 8 x 10{sup -7} M. It has a fast response time of 3-8 s and can be used for at least 8 weeks without any divergence in potential. The electrode can be used in the pH range from 4.0 to 9.0. The proposed sensor shows a very good discriminating ability towards Cd{sup 2+} ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Cd{sup 2+}in standard and real sample solutions.

Phosphate Framework Electrode Materials for Sodium Ion Batteries.

Science.gov (United States)

Fang, Yongjin; Zhang, Jiexin; Xiao, Lifen; Ai, Xinping; Cao, Yuliang; Yang, Hanxi

2017-05-01

Sodium ion batteries (SIBs) have been considered as a promising alternative for the next generation of electric storage systems due to their similar electrochemistry to Li-ion batteries and the low cost of sodium resources. Exploring appropriate electrode materials with decent electrochemical performance is the key issue for development of sodium ion batteries. Due to the high structural stability, facile reaction mechanism and rich structural diversity, phosphate framework materials have attracted increasing attention as promising electrode materials for sodium ion batteries. Herein, we review the latest advances and progresses in the exploration of phosphate framework materials especially related to single-phosphates, pyrophosphates and mixed-phosphates. We provide the detailed and comprehensive understanding of structure-composition-performance relationship of materials and try to show the advantages and disadvantages of the materials for use in SIBs. In addition, some new perspectives about phosphate framework materials for SIBs are also discussed. Phosphate framework materials will be a competitive and attractive choice for use as electrodes in the next-generation of energy storage devices.

Emulsion liquid membrane for selective extraction of bismuth from nitrate medium

International Nuclear Information System (INIS)

Mokhtari, Bahram; Pourabdollah, Kobra

2013-01-01

The novelty of this work is the selective extraction of bismuth ions from nitrate medium by emulsion liquid membrane. Di(2-ethylhexyl)phosphoric acid was used as extractant of bismuth ions from nitrate medium by emulsion liquid membrane, and Triton X-100 was used as the biodegradable surfactant in n-pentanol n-pentanol bulk membrane. The extraction of bismuth ions was evaluated by the yield of extraction. The experimental parameters were evaluated and were optimized. They included the ratio of di(2-ethylhexyl)phosphoric acid concentration to the concentration of /Triton X-100 concentration (1.0 : 0.5% w/w), nature of diluents (n-pentanol), nature and concentration of the stripping solution (sulfuric acid, 0.5M), stirring speed (1,800 rpm) and equilibrium time of extraction (20min), initial feed solution of bismuth (350 ppm) and the volume ratio of the internal stripping phase to the membrane phase (14 times). The experimental parameters of kinetic extraction revealed that the bismuth ions were extracted at 100% 97%

Emulsion liquid membrane for selective extraction of bismuth from nitrate medium

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, Bahram; Pourabdollah, Kobra [Islamic Azad University, Shahreza (Iran, Islamic Republic of)

2013-07-15

The novelty of this work is the selective extraction of bismuth ions from nitrate medium by emulsion liquid membrane. Di(2-ethylhexyl)phosphoric acid was used as extractant of bismuth ions from nitrate medium by emulsion liquid membrane, and Triton X-100 was used as the biodegradable surfactant in n-pentanol n-pentanol bulk membrane. The extraction of bismuth ions was evaluated by the yield of extraction. The experimental parameters were evaluated and were optimized. They included the ratio of di(2-ethylhexyl)phosphoric acid concentration to the concentration of /Triton X-100 concentration (1.0 : 0.5% w/w), nature of diluents (n-pentanol), nature and concentration of the stripping solution (sulfuric acid, 0.5M), stirring speed (1,800 rpm) and equilibrium time of extraction (20min), initial feed solution of bismuth (350 ppm) and the volume ratio of the internal stripping phase to the membrane phase (14 times). The experimental parameters of kinetic extraction revealed that the bismuth ions were extracted at 100% 97%.

Europium (III) PVC membrane sensor based on N-pyridine-2-carboxamido-8-aminoquinoline as a sensing material

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Kamjoo, Rahman [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Mohammadhosseini, Majid [Department of Chemistry, Faculty of Basic Sciences, Shahrood Branch, Islamic Azad University, Shahrood (Iran, Islamic Republic of); Zaferoni, Mojdeh; Rafati, Zynab [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Faridbod, Farnoush [Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Meghdadi, Soraia [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2012-04-01

Conductometric study in acetonitrile solution shows the selectivity of PCQ toward europium ion. Therefore, a new europium PVC membrane electrode was prepared based on N-pyridine-2-carboxamido-8-aminoquinoline (PCQ) as an ion carrier. The electrode has a wide concentration range from 1.0 Multiplication-Sign 10{sup -2} and 1.0 Multiplication-Sign 10{sup -6} mol L{sup -1}, Nernstian slope of 19.8 {+-} 0.3 mV per decade and a detection limit of 6.4 Multiplication-Sign 10{sup -7} mol L{sup -1}. The potentiometric response is pH independent in the range of 2.4-7.4. The proposed sensor has a relatively fast response time less than 10 s and it can be used for at least 2 months without any considerable divergence in its potentials. The proposed electrode revealed good selectivity toward europium ion in comparison with variety of other metal ions. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of Eu{sup 3+} ions with EDTA and for determination of Eu{sup 3+} ion concentration in mixtures of two and three different ions. - Highlights: Black-Right-Pointing-Pointer A new ion carrier is introduced to preparation of a selective sensor for Eu{sup 3+} ions. Black-Right-Pointing-Pointer This technique is very simple and it's not necessary to use sophisticated equipment. Black-Right-Pointing-Pointer The novelty of this work is the high affinity of the ionophore toward the Eu{sup 3+} ions. Black-Right-Pointing-Pointer The sensor is superior to the formerly reported Eu{sup 3+} sensors in terms of selectivity.

Analysis of the Durability of PEM FC Membrane Electrode Assemblies in Automotive Applications through the Fundamental Understanding of Membrane and MEA Degradation Pathways

Energy Technology Data Exchange (ETDEWEB)

Perry, Randal L. [DuPont

2013-10-31

The Project focused on mitigation of degradation processes on membrane electrode assemblies. The approach was to develop a model to improve understanding of the mechanisms, and to use it to focus mitigation strategies. The detailed effects of various accelerated stress tests (ASTs) were evaluated to determine the best subset to use in model development. A combination of ASTs developed by the Fuel Cell Commercialization Conference of Japan and the Fuel Cell Tech Team were selected for use. The ASTs were compared by measuring effects on performance, running in-situ diagnostics, and performing microscopic analyses of the membrane electrode assemblies after the stress tests were complete. Nissan ran FCCJ AST protocols and performed in situ and ex-situ electrochemical testing. DuPont ran FCTT and USFCC AST protocols, performed scanning and transmission electron microscopy and ran in-situ electrochemical tests. Other ex-situ testing was performed by IIT, along with much of the data analysis and model development. These tests were then modified to generate time-dependent data of the degradation mechanisms. Three different catalyst types and four membrane variants were then used to generate data for a theoretically-based degradation model. An important part of the approach was to use commercially available materials in the electrodes and membranes made in scalable semiworks processes rather than lab-based materials. This constraint ensured all materials would be practicable for full-scale testing. The initial model for the electrode layer was tested for internal consistency and agreement with the data. A Java-based computer application was developed to analyze the time-dependent AST data using polarization curves with four different cathode gas feeds and generate model parameters. Data showed very good reproducibility and good consistency as cathode catalyst loadings were varied. At the point of termination of the project, a basic electrode model was in hand with several

Separation of chloride and fluoride from uranium compounds and their determination by ion selective electrodes

International Nuclear Information System (INIS)

Pires, M.A.F.; Abrao, A.

1982-01-01

Fluoride and chloride must be rigorously controlled in uranium compounds, especially in ceramic grade UO 2 . Their determination is very difficult without previous uranium separation, particularly when both are at a low concentration. A simple procedure is described for this separation using a strong cationic resin to retain the uranyl ion. Both anions are determined in the effluent solution. Uranium compounds of nuclear fuel cycle, especially ammonium diuranate, ammonium uranyl tricarbonate, sodium diuranate, uranium trioxide and dioxide and uranium peroxide are dissolved in nitric acid and the solutions are percolated through the resin column. Chloride and fluoride are determined in the effluent by selective electrodes, the detection limits being 0.02 μg F - /ml and 1.0 μg Cl - /ml. The dissolution of the sample, the acidity of the solution, the measurement conditions and the sensitivity of the method are discussed. (Author) [pt

Calculation of separation selectivity of aqueous electrolytic solutions with reverse osmosis membranes

International Nuclear Information System (INIS)

Ognevskij, A.V.; Fomichev, S.V.; Khvostov, V.F.; Kochergin, N.V.; AN SSSR, Moscow

1988-01-01

Viscosity and dielectric permittivity of a bound water layer in micropores of cellulose acetate membranes used for electrolyte ion separation by reverse osmosis method are calculated using the water cluster model and the proposed structural temperature parameter. Based on the model representations presented an algorithmof reverse osmosis membrane selectivity calculation in diluted aqueous solutions ofelectrolytes containing Cs + , Sr 2+ , I - and other ions is constructed

A cerium(III) selective polyvinyl chloride membrane sensor based on a Schiff base complex of N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine

International Nuclear Information System (INIS)

Gupta, Vinod Kumar; Singh, A.K.; Gupta, Barkha

2006-01-01

A polyvinyl chloride (PVC) based membrane sensor for cerium ions was prepared by employing N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine as an ionophore, oleic acid (OA) as anion excluder and o-nitrophenyloctyl ether (o-NPOE) as plasticizer. The plasticized membrane sensor exhibits a Nernstian response for Ce(III) ions over a wide concentration range (1.41 x 10 -7 to 1.0 x 10 -2 M) with a limit of detection as low as 8.91 x 10 -8 M. It has a fast response time (<10 s) and can be used for 4 months. The sensor revealed a very good selectivity with respect to common alkali, alkaline earth and heavy metal ions. The response of the proposed sensor is independent of pH between 3.0 and 8.0. It was used as an indicator electrode in potentiometric titration of fluoride, carbonate and oxalate anions and determination of cerium in simulated mixtures

Determination of contaminants in boric acid used as neutron moderator by means of ion chromatography and selective electrodes

International Nuclear Information System (INIS)

Pires, M.A.F.; Abrao, A.

1988-07-01

The boric acid used as neutron moderator in reactors must observe restrictions about the concentration of some impurities. According to Westinghouse (1) specification, the highest limits for sodium, sulphate, phosphate, fluoride, and chlorine are: Na + - 0,003%; SO 4 -2 - 0,0006%; PO 4 -3 - 0,003%; F - - 0,00002%; Cl - - 0,00004%. This paper describes the determination of ions above mentioned directly in the boric acid solution. The sample is dissolved in water or in an appropriate eluent and is injected in the ion chromatograph. Na + and F - are determined by means of selective electrodes. The determination limits found for F - (0,0002%) and Cl - (0,0002%) are not sufficiently low to attent the specifications. The determination limits found for SO 4 -2 (0,0005%), PO 4 -3 (0,0003%) and Na + (0,0005%) are good enough for nuclear pure boric acid analysis. In some samples nitrate (detection limit 0,0015%) was found as well. Boric acid from different suppliers were analysed. (author) [pt

PVC-membrane potentiometric sensors based on a recently synthesized Schiff base for Fe(III ion

Directory of Open Access Journals (Sweden)

S. Yousef Ebrahimipur

2012-12-01

Full Text Available A potentiometric iron sensor based on the use 3-(2-diethylamino-ethylimino-1,3-dihydro-indol-2-one (DEDIO as an ionophore in poly(vinyl chloride (PVC matrix, is reported. The plasticized membrane sensor exhibits a Nernstian response for Fe(III ions over a wide concentration range (2.0 × 10-6 - 5.0 × 10-2 M with a super Nernstian slope of 26(plus or minus 1 mV per decade. It has a fast response time of less than 12 s and can be used for ten weeks without any considerable divergences in its potentials the electrode can be used in the pH range 4.5-8.0. The proposed sensor shows fairly good discriminating ability towards Fe(III ion in comparison with a large number of alkali, alkaline earth, transition and heavy metal ions. The sensor was used as indicator electrode in potentiometric titration of Fe(III ions vs. EDTA.DOI: http://dx.doi.org/10.4314/bcse.v26i1.7

Freestanding eggshell membrane-based electrodes for high-performance supercapacitors and oxygen evolution reaction

Science.gov (United States)

Geng, Jing; Wu, Hao; Al-Enizi, Abdullah M.; Elzatahry, Ahmed A.; Zheng, Gengfeng

2015-08-01

A type of freestanding, light-weight eggshell membrane-based electrode is demonstrated for supercapacitors and for oxygen evolution reaction (OER) catalysis. As a widely available daily waste, eggshell membranes have unique porous three-dimensional grid-like fibrous structures with relatively high surface area and abundant macropores, allowing for effective conjugation of carbon nanotubes and growth of NiCo2O4 nanowire arrays, an effective supercapacitor material and OER catalyst. The three-dimensional fibrous eggshell membrane frameworks with carbon nanotubes offer efficient pathways for charge transport, and the macropores between adjacent fibers are fully accessible for electrolytes and bubble evolution. As a supercapacitor, the eggshell membrane/carbon nanotube/NiCo2O4 electrode shows high specific capacitances at current densities from 1 to 20 A g-1, with excellent capacitance retention (>90%) at 10 A g-1 for over 10 000 cycles. When employed as an OER catalyst, this eggshell membrane-based electrode exhibits an OER onset potential of 1.53 V vs. the reversible hydrogen electrode (RHE), and a stable catalytic current density of 20 mA cm-2 at 1.65 V vs. the RHE.A type of freestanding, light-weight eggshell membrane-based electrode is demonstrated for supercapacitors and for oxygen evolution reaction (OER) catalysis. As a widely available daily waste, eggshell membranes have unique porous three-dimensional grid-like fibrous structures with relatively high surface area and abundant macropores, allowing for effective conjugation of carbon nanotubes and growth of NiCo2O4 nanowire arrays, an effective supercapacitor material and OER catalyst. The three-dimensional fibrous eggshell membrane frameworks with carbon nanotubes offer efficient pathways for charge transport, and the macropores between adjacent fibers are fully accessible for electrolytes and bubble evolution. As a supercapacitor, the eggshell membrane/carbon nanotube/NiCo2O4 electrode shows high specific

Electrode Materials for Lithium/Sodium-Ion Batteries

DEFF Research Database (Denmark)

Shen, Yanbin

2014-01-01

The synthesis of electrode materials for lithium/sodium ion batteries and their structural stability during lithium/sodium insertion/extraction are the two essential issues that have limited battery application in the fields requiring long cycle life and high safety. During her PhD studies, Yanbin...... Shen systematically investigated the controlled synthesis of electrode materials for lithium/sodium ion batteries. She also investigated their formation mechanisms and structural evolution during the operation of batteries using in situ/operando X-ray diffraction techniques. The research findings...... provide insights into formation mechanisms of Li4Ti5O12 anode material from both hydrothermal and solid-state reaction. The results also contribute to a thorough understanding of the intercalation and decay mechanisms of O3/P2 layered sodium cathode materials in sodium ion batteries....

Wastewater treatment with ion-exchange chitin membrane

International Nuclear Information System (INIS)

Paulenova, A.; Fjeld, R. A.; Visacky, V.

2001-01-01

Chitin, poly(N-acetyl-D glucosamine) and chitosan, its deacetylated derivates have recently obtained attention as bio-sorbents, because they shown a great ability to accumulate heavy metals and other pollutants. It was found that recovery of metals is strongly affected by pH. At low acidic pH range 4-5 chitin membrane exhibits better selectivity for lead than for cadmium or zinc. Sorption preference for metals decreases in the order: Pb > Cd > Zn. For uranium, as well for strontium was observed significant increase of recovery at decrease of pH to slightly acidic, close to neutral value. It was shown that chemical behavior of chitin membrane is excellent; ion-exchange nature of chitin was not changed during chitin membrane manufacturing process. Using of chitin membrane instead of chitin flake column brings significant increasing of driving force of the separation process, limited in the case of column experimental design by diffusion coefficient, while in the case of membrane process only by mass transfer coefficient. (authors)

Recycling positive-electrode material of a lithium-ion battery

Science.gov (United States)

Sloop, Steven E.

2017-11-21

Examples are disclosed of methods to recycle positive-electrode material of a lithium-ion battery. In one example, the positive-electrode material is heated under pressure in a concentrated lithium hydroxide solution. After heating, the positive-electrode material is separated from the concentrated lithium hydroxide solution. After separating, the positive electrode material is rinsed in a basic liquid. After rinsing, the positive-electrode material is dried and sintered.

High-performance Fuel Cell with Stretched Catalyst-Coated Membrane: One-step Formation of Cracked Electrode.

Science.gov (United States)

Kim, Sang Moon; Ahn, Chi-Yeong; Cho, Yong-Hun; Kim, Sungjun; Hwang, Wonchan; Jang, Segeun; Shin, Sungsoo; Lee, Gunhee; Sung, Yung-Eun; Choi, Mansoo

2016-05-23

We have achieved performance enhancement of polymer electrolyte membrane fuel cell (PEMFC) though crack generation on its electrodes. It is the first attempt to enhance the performance of PEMFC by using cracks which are generally considered as defects. The pre-defined, cracked electrode was generated by stretching a catalyst-coated Nafion membrane. With the strain-stress property of the membrane that is unique in the aspect of plastic deformation, membrane electrolyte assembly (MEA) was successfully incorporated into the fuel cell. Cracked electrodes with the variation of strain were investigated and electrochemically evaluated. Remarkably, mechanical stretching of catalyst-coated Nafion membrane led to a decrease in membrane resistance and an improvement in mass transport, which resulted in enhanced device performance.

Amphoteric Ion-Exchange Membranes with Significantly Improved Vanadium Barrier Properties for All-Vanadium Redox Flow Batteries.

Science.gov (United States)

Nibel, Olga; Rojek, Tomasz; Schmidt, Thomas J; Gubler, Lorenz

2017-07-10

All-vanadium redox flow batteries (VRBs) have attracted considerable interest as promising energy-storage devices that can allow the efficient utilization of renewable energy sources. The membrane, which separates the porous electrodes in a redox flow cell, is one of the key components in VRBs. High rates of crossover of vanadium ions and water through the membrane impair the efficiency and capacity of a VRB. Thus, membranes with low permeation rate of vanadium species and water are required, also characterized by low resistance and stability in the VRB environment. Here, we present a new design concept for amphoteric ion-exchange membranes, based on radiation-induced grafting of vinylpyridine into an ethylene tetrafluoroethylene base film and a two-step functionalization to introduce cationic and anionic exchange sites, respectively. During long-term cycling, redox flow cells containing these membranes showed higher efficiency, less pronounced electrolyte imbalance, and significantly reduced capacity decay compared to the cells with the benchmark material Nafion 117. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance of a polymer electrolyte membrane fuel cell with thin film catalyst electrodes

Energy Technology Data Exchange (ETDEWEB)

Chun, Young Gab; Kim, Chang Soo; Peck, Dong Hyun; Shin, Dong Ryul [Korea Institute of Energy Research, Taejon (Korea, Republic of)

1998-03-15

In order to develop a kW-class polymer electrolyte membrane fuel cell (PEMFC), several electrodes have been fabricated by different catalyst layer preparation procedures and evaluated based on the cell performance. Conventional carbon paper and carbon cloth electrodes were fabricated using a ptfe-bonded Pt/C electrol catalyst by coating and rolling methods. Thin-film catalyst/ionomer composite layers were also formed on the membrane by direct coating and transfer printing techniques. The performance evaluation with catalyst layer preparation methods was carried out using a large or small electrode single cell. Conventional and thin film membrane and electrode assemblies (MEAs) with small electrode area showed a performance of 350 and 650 mA/cm{sup 2} at 0.6 V, respectively. The performance of direct coated thin film catalyst layer with 300 cm{sup 2} MEAs was higher than those of the conventional and transfer printing technique MEAs. The influence of some characteristic parameters of the thin film electrode on electrochemical performance was examined. Various other aspects of overall operation of PEMFC stacks were also discussed. (orig.)

Report on results of development of fuel cell power generation technology 1998. Research and development on polymer electrolyte fuel cell (technological development of element, research on ion exchange membrane for practicability of high performance cell); 1998 nendo seika hokokusho. Nenryo denchi hatsuden gijutsu kaihatsu, kotai kobunshigata nenryo denchi no kenkyu kaihatsu, yoso kenkyu kaihatsu (koseino denchi jitsuyoka no tame no ion kokan maku ni kansuru kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

This paper explains the results during fiscal 1998 of ion exchange membranes in the development of polymer electrolyte fuel cells. Studies were made on three kinds of standard and two kinds of experimental membranes selected among the Flemion membranes, which are perfluorosulfonic acid membranes made by Asahi Glass Co.,Ltd., and also on the Nafion membranes by Dupon as reference. As the resistance evaluation of the environmental cycle for the membranes, a temperature cycle test was carried out, with the characteristics measured such as moisture content, membrane resistance, mechanical properties, and gas permeability, so that the effects were examined of the temperature cycle on the membranes. Evaluation was also commenced on the water permeability, an important substance-moving characteristic of ion exchange membranes. In the evaluation of the characteristics of membrane-electrode assemblies, the environmental cycle test was performed by joining electrodes to membranes, with the evaluation similarly made as for the membranes alone. On the basis of a correlation between the water permeability and the cell performance, studies were made on the effect of thickness of the membranes on the cell performances. A continuous stability/durability operation of 3,500 hours was verified using Flemion R. As for membrane reinforcement, studies were continued on the cloth and fibril reinforcements as in the previous year.(NEDO)

Reliable reference electrodes for lithium-ion batteries

KAUST Repository

La Mantia, F.

2013-06-01

Despite the high attention drawn to the lithium-ion batteries by the scientific and industrial community, most of the electrochemical characterization is carried out using poor reference electrodes or even no reference electrode. In this case, the performances of the active material are inaccurate, especially at high current densities. In this work we show the error committed in neglecting the polarizability of lithium counter electrodes, and we propose two reference electrodes to use in organic electrolytes based on lithium salts, namely Li4Ti5O12 and LiFePO 4. In particular, it was observed that, the polarizability of the metallic lithium counter electrode has a relevant stochastic component, which renders measurements at high current densities (above 1 mA·cm - 2) in two electrode cells non reproducible.

Mechanics of high-capacity electrodes in lithium-ion batteries

International Nuclear Information System (INIS)

Zhu, Ting

2016-01-01

Rechargeable batteries, such as lithium-ion batteries, play an important role in the emerging sustainable energy landscape. Mechanical degradation and resulting capacity fade in high-capacity electrode materials critically hinder their use in high-performance lithium-ion batteries. This paper presents an overview of recent advances in understanding the electrochemically-induced mechanical behavior of the electrode materials in lithium-ion batteries. Particular emphasis is placed on stress generation and facture in high-capacity anode materials such as silicon. Finally, we identify several important unresolved issues for future research. (topical review)

Solvent-Free Manufacturing of Electrodes for Lithium-ion Batteries

Science.gov (United States)

Ludwig, Brandon; Zheng, Zhangfeng; Shou, Wan; Wang, Yan; Pan, Heng

2016-03-01

Lithium ion battery electrodes were manufactured using a new, completely dry powder painting process. The solvents used for conventional slurry-cast electrodes have been completely removed. Thermal activation time has been greatly reduced due to the time and resource demanding solvent evaporation process needed with slurry-cast electrode manufacturing being replaced by a hot rolling process. It has been found that thermal activation time to induce mechanical bonding of the thermoplastic polymer to the remaining active electrode particles is only a few seconds. Removing the solvent and drying process allows large-scale Li-ion battery production to be more economically viable in markets such as automotive energy storage systems. By understanding the surface energies of various powders which govern the powder mixing and binder distribution, bonding tests of the dry-deposited particles onto the current collector show that the bonding strength is greater than slurry-cast electrodes, 148.8 kPa as compared to 84.3 kPa. Electrochemical tests show that the new electrodes outperform conventional slurry processed electrodes, which is due to different binder distribution.

Nickel-Tin Electrode Materials for Nonaqueous Li-Ion Cells

Science.gov (United States)

Ehrlich, Grant M.; Durand, Christopher

2005-01-01

Experimental materials made from mixtures of nickel and tin powders have shown promise for use as the negative electrodes of rechargeable lithium-ion electrochemical power cells. During charging (or discharging) of a lithium-ion cell, lithium ions are absorbed into (or desorbed from, respectively) the negative electrode, typically through an intercalation or alloying process. The negative electrodes (for this purpose, designated as anodes) in state-of-the-art Li-ion cells are made of graphite, in which intercalation occurs. Alternatively, the anodes can be made from metals, in which alloying can occur. For reasons having to do with the electrochemical potential of intercalated lithium, metallic anode materials (especially materials containing tin) are regarded as safer than graphite ones; in addition, such metallic anode materials have been investigated in the hope of obtaining reversible charge/discharge capacities greater than those of graphite anodes. However, until now, each of the tin-containing metallic anode formulations tested has been found to be inadequate in some respect.

21 CFR 173.21 - Perfluorinated ion exchange membranes.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under the...

Titanium (III) cation selective electrode based on synthesized tris(2pyridyl) methylamine ionophore and its application in water samples

Science.gov (United States)

Rezayi, Majid; Karazhian, Reza; Abdollahi, Yadollah; Narimani, Leila; Sany, Seyedeh Belin Tavakoly; Ahmadzadeh, Saeid; Alias, Yatimah

2014-04-01

The introduction of low detection limit ion selective electrodes (ISEs) may well pave the way for the determination of trace targets of cationic compounds. This research focuses on the detection of titanium (III) cation using a new PVC-membrane sensor based on synthesized tris(2pyridyl) methylamine (tpm) ionophore. The application and validation of the proposed sensor was done using potentiometric titration, inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS). The membrane sensor exhibited a Nernstian response to the titanium (III) cation over a concentration range of 1.0 × 10-6-1.0 × 10-2 M and pH range from 1-2.5. The Nernstian slope, the lower of detection (LOD), and the response time (t95%) of the proposed sensor were 29.17 +/- 0.24 mV/dec, 7.9 × 10-7 M, and 20 s, respectively. The direct determination of 4-39 μg/ml of titanium (III) standard solution showed an average recovery of 94.60 and a mean relative standard deviation of 1.8 at 100.0 μg/ml. Finally, the utilization of the electrodes as end-point indicators for potentiometric titration with EDTA solutions for titanium (III) sensor was successfully carried out.

Development and fabrication of membrane electrode assembly for PEM fuel cell

International Nuclear Information System (INIS)

Anjum, M.A.R.; Arshad, M.; Hussain, S.; Saeed, M.M.

2011-01-01

The 10 cm x 10 cm active area membrane electrode assembly (MEA) has been fabricated by adopting two routes, i.e., catalyst-coated membrane (CCM) and catalyst-coated support (CCS). In CCM method, the catalyst is directly applied on the Nafion membrane while in CCS method, catalyst is applied on support (GDL). The catalyst layer was prepared by nano-sized platinum on carbon particle, the ionomer material of the membrane and a solvent that allows the catalyst to behave like ink. The catalyst slurry was applied on the membrane, hot-pressed the sandwich of GDL and catalyst-coated Nafion membrane to form a single unit which behaves as electrodes. The primary tests regarding the efficiency of indigenously-fabricated MEAs have been carried out successfully. The performance of MEA with respect to continuous operation for long hours from the standpoint of proper functioning was also checked. A maximum power of 13 watt was obtained. (author)

Freestanding eggshell membrane-based electrodes for high-performance supercapacitors and oxygen evolution reaction.

Science.gov (United States)

Geng, Jing; Wu, Hao; Al-Enizi, Abdullah M; Elzatahry, Ahmed A; Zheng, Gengfeng

2015-09-14

A type of freestanding, light-weight eggshell membrane-based electrode is demonstrated for supercapacitors and for oxygen evolution reaction (OER) catalysis. As a widely available daily waste, eggshell membranes have unique porous three-dimensional grid-like fibrous structures with relatively high surface area and abundant macropores, allowing for effective conjugation of carbon nanotubes and growth of NiCo2O4 nanowire arrays, an effective supercapacitor material and OER catalyst. The three-dimensional fibrous eggshell membrane frameworks with carbon nanotubes offer efficient pathways for charge transport, and the macropores between adjacent fibers are fully accessible for electrolytes and bubble evolution. As a supercapacitor, the eggshell membrane/carbon nanotube/NiCo2O4 electrode shows high specific capacitances at current densities from 1 to 20 A g(-1), with excellent capacitance retention (>90%) at 10 A g(-1) for over 10,000 cycles. When employed as an OER catalyst, this eggshell membrane-based electrode exhibits an OER onset potential of 1.53 V vs. the reversible hydrogen electrode (RHE), and a stable catalytic current density of 20 mA cm(-2) at 1.65 V vs. the RHE.

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Energy Technology Data Exchange (ETDEWEB)

Sherazi, Tauqir A. [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Guiver, Michael D.; Kingston, David; Xue, Xinzhong [Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Ahmad, Shujaat [PIEAS/PINSTECH, P O Nilore, Islamabad 45650 (Pakistan); Kashmiri, M. Akram [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Board of Intermediate and Secondary Education, Lahore 54000 (Pakistan)

2010-01-01

Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a {sup 60}Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion {sup registered} 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC. (author)

The electrochemical behavior and surface structure of titanium electrodes modified by ion beams

International Nuclear Information System (INIS)

Huang, G.F.; Xie, Z.; Huang, W.Q.; Yang, S.B.; Zhao, L.H.

2004-01-01

Industrial grade titanium modified by ion implantation and sputtering was used as electrodes. The effect of ion beam modification on the electrochemical behavior and surface structure of electrodes was investigated. Also discussed is the hydrogen evolution process of the electrode in acidic solution. Several ions such as Fe + , C + , W + , Ni + and others, were implanted into the electrode. The electrochemical tests were carried out in 1N H 2 SO 4 solution at 30±1 deg. C. The electrode potential was measured versus a saturate calomel electrode as a function of immersion time. The cathodic polarization curves were measured by the stable potential static method. The surface layer composition and the chemical state of the electrodes were also investigated by Auger electron spectrometer (AES) and X-ray photoelectron spectroscopy (XPS) technique. The results show that: (1) the stability of modified electrodes depends on the active elements introduced by ion implantation and sputtering deposition. (2) The hydrogen evolution activity of industrial grade titanium may be improved greatly by ion beam modification. (3) Ion beam modification changed the composition and the surface state of electrodes over a certain depth range and forms an activity layer having catalytic hydrogen evolution, which inhibited the absorption of hydrogen and formation of titanium hydride. Thus promoted hydrogen evolution and improved the hydrogen evolution catalytic activity in industrial grade titanium

Cadmium-sensitive electrode based on tetracetone derivatives of p-tert-butylcalix[8]arene

Energy Technology Data Exchange (ETDEWEB)

Dernane, C. [Université de Jijel, Laboratoire de Matériaux: Elaborations-Propriétés-Applications, BP 98, Ouled Aissa, 18000 Jijel (Algeria); Zazoua, A., E-mail: azazoua@yahoo.fr [Université de Jijel, Laboratoire de Matériaux: Elaborations-Propriétés-Applications, BP 98, Ouled Aissa, 18000 Jijel (Algeria); Kazane, I. [Université de Jijel, Laboratoire de Matériaux: Elaborations-Propriétés-Applications, BP 98, Ouled Aissa, 18000 Jijel (Algeria); Jaffrezic-Renault, N. [Université de Lyon, LSA-UMR 5180 CNRS, Université Claude Bernard Lyon 1, 69622 Villeurbanne cedex (France)

2013-10-15

The performance of a cadmium-sensitive electrode based on the tetracetone derivatives of p-tert butylcalix[8]arene was investigated. The ion-sensitivity of the calix[8]arene was examined via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectrometry, UV/Vis spectroscopy and FT-IR spectroscopy. The sensitive membrane containing the active ionophore was cast onto the surface of a gold electrode. The electrode exhibited a linear relationship between the charge transfer resistance (R{sub ct}) and the logarithm of the detected ion concentration. The cathodic peak at a potential of 0.56 V increased linearly as the Cd{sup 2+} ion concentration increased. The detection limit of the device reached 10{sup −7} M with high sensitivity toward cadmium. - Highlights: • The performances of cadmium-sensitive electrode were investigated. • The sensitive membrane was casted on the surface of a gold electrode. • The electrode showed a linear relationship between the R{sub ct} and the ion concentration. • The detection limit of the device was 10{sup −7} M with high sensitivity toward cadmium.

Silver ion recognition using potentiometric sensor based on recently synthesized isoquinoline-1,3-dione derivatives

Directory of Open Access Journals (Sweden)

AJAR KAMAL

2012-08-01

Full Text Available The four derivatives of isoquinoline-1,3-dione based on β-lactum (I-IV, have been explored as neutral ionophores for preparing poly(vinylchloride based polymeric membrane electrodes (PME selective to silver(I ions. The addition of sodium tetraphenylborate (NaTPB and dioctylsebacate (DOS as a plasticizer was found to improve the performance of ion selective electrodes. The best performance was obtained with PME-1 based on ionophore I having composition: ionophore (9.2 mg, PVC (100.1 mg, DOS (201.1 mg and NaTPB (1.5 mg in 5 mL tetrahydrofuran. The electrode response was linear with Nernstian slope of 58.44 mV/decade in the concentration range of 1.0 x 10-1 M to 5.0 x 10-6 M and detection limit of 5.83 x 10-6 M. It performs satisfactorily over wide pH range of 1.0-5.5. The proposed sensor can be used over a period of more than three months without any significant drift in potential and shows good selectivity to silver(I ion over a number of cations especially with no interference of mercury(II ions. Sharp end point was obtained when the sensor was used as an indicator electrode for the potentiometric titration of silver(I ions with chloride ions and therefore this electrode (PME-1 could be used for quantitative determination of silver(I ion in synthetic water, silver foil and dental amalgam samples.

Ion beam heating of thin silicon membranes

International Nuclear Information System (INIS)

Tissot, P.E.; Hart, R.R.

1993-01-01

For silicon membranes irradiated by an ion beam in a vacuum environment, such as the masks used for ion beam lithography and the membranes used for thin film self-annealing, the heat transfer modes are radiation and limited conduction through the thin membrane. The radiation component depends on the total hemispherical emissivity which varies with the thickness and temperature of the membrane. A semiempirical correlation for the absorption coefficient of high resistivity silicon was derived and the variation of the total emissivity with temperature was computed for membranes with thicknesses between 0.1 and 10 μm. Based on this result, the temperatures reached during exposure to ion beams of varying intensities were computed. A proper modeling of the emissivity is shown to be important for beam heating of thin silicon membranes. (orig.)

Understanding interaction of curcumin and metal ions on electrode surfaces using EDXRF

Science.gov (United States)

Joseph, Daisy; Kumar, K. Krishna; Narayanan, S. Sriman

2018-04-01

A chemically modified electrode was developed for determination of metal ions (Cd, Pb, Zn, Co, Hg). The modifier used for the study was Curcumin. Curcumin acts as a complexing agent at the surface of the electrode for preconcentration of metal ions from electrolyte to electrode surface and stripped back to electrolyte during analysis. EDXRF was used to analyze these electrodes and it was concluded that the PCR modified electrode favored effective chelation for lead and mercury.

A new cerium (III) ion selective electrode based on 2,9-dihydroxy-1,10-diphenoxy-4,7-dithia decane, a novel synthetic ligand

Energy Technology Data Exchange (ETDEWEB)

Rounaghi, Gholamhossein, E-mail: ghrounagh@yahoo.com [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Zadeh Kakhki, Roya Mohammad; Sadeghian, Hamid [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

2011-11-30

Highlights: > An ISE based on a new ionophore is used successfully to determine cerium (III) cation over the concentration range 1.0 x 10{sup -1}-2.1 x 10{sup -9} mol l{sup -1}. > It has a fast response time of 10 s. > It has comparatively good selectivities with respect to metal cations. > It can be used in a pH range of 5.0-8.0. > It also was used as an indicator electrode in potentiometric determination of F{sup -} ion in some real sample preparations. - Abstract: In the present study, a novel electrode based on 2,9-dihydroxy-1,10-diphenoxy-4,7-dithiadecane (DHDPDTD) that is selective to cerium (III) cations was evaluated electrochemically, and a Nerenstian slope (19.3 {+-} 1 mV decade{sup -1}) over a concentration range of 1.0 x 10{sup -8}-1.0 x 10{sup -1} M and a detection limit of 2.1 x 10{sup -9} M were observed. The proposed electrochemical sensor displayed a rapid response time of 10 s, improved selectivity towards Ce (III) cations in the presence of alkali, alkaline earth, transition and heavy metal cations, and could be used in a pH range of 5.0-8.0. Additionally, the proposed sensor was used as an indicator in the potentiometric titration of fluoride and the determination of F{sup -} ions in real samples.

Quantum Interference and Selectivity through Biological Ion Channels.

Science.gov (United States)

Salari, Vahid; Naeij, Hamidreza; Shafiee, Afshin

2017-01-30

The mechanism of selectivity in ion channels is still an open question in biology for more than half a century. Here, we suggest that quantum interference can be a solution to explain the selectivity mechanism in ion channels since interference happens between similar ions through the same size of ion channels. In this paper, we simulate two neighboring ion channels on a cell membrane with the famous double-slit experiment in physics to investigate whether there is any possibility of matter-wave interference of ions via movement through ion channels. Our obtained decoherence timescales indicate that the quantum states of ions can only survive for short times, i.e. ≈100 picoseconds in each channel and ≈17-53 picoseconds outside the channels, giving the result that the quantum interference of ions seems unlikely due to environmental decoherence. However, we discuss our results and raise few points, which increase the possibility of interference.