WorldWideScience

Sample records for aqueous ion testing

  1. Protons and Hydroxide Ions in Aqueous Systems.

    Science.gov (United States)

    Agmon, Noam; Bakker, Huib J; Campen, R Kramer; Henchman, Richard H; Pohl, Peter; Roke, Sylvie; Thämer, Martin; Hassanali, Ali

    2016-07-13

    Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics. PMID:27314430

  2. Process for separating cesium ions from aqueous solutions

    International Nuclear Information System (INIS)

    A precipitation agent is added to the aqueous solution and the resulting precipitate containing Cs+ ions is separated from the solution. By this process, caesium is to be separated selectively compared with other alkaline metal ions with great efficiency from aqueous solutions, particularly aqueous MAW (medium activity waste). This is achieved by using a sodium tetraphenyl borate attracting electrons to the phenyl rings and having substitutes. (orig./PW)

  3. Interactions between calcium phosphate and heavy metal ions in aqueous solution

    OpenAIRE

    Fernane F.; Boudia S.; Saouli H.

    2013-01-01

    Synthetic and natural calcium phosphates were tested for removal metallic pollution in aqueous solution. Calcium phosphates with Ca/P ratio between 1,33 and 1,67 are fluently called apatite. They have a strong capacity to immobilize metallic ions when they are brought into contact with aqueous solutions. Ca2+ ions can substituted completely or partly by cations such as metallic ions (Ni2+; Cu2+; Co2+ and Cd2+). PO43− ions can be replaced by anions such as AsO43−, CO32−, … etc. Sorption of Cu2...

  4. Ion Association, Solubilities, and Reduction Potentials in Aqueous Solution.

    Science.gov (United States)

    Russo, Steven O.; Hanania, George I. H.

    1989-01-01

    Incorporates the combined effects of ionic strength and ion association to show how calculations involving ionic equilibria are carried out. Examines the variability of reduction potential data for two aqueous redox systems. Provides several examples. (MVL)

  5. Enhanced resistance to oxidative decomposition of aqueous electrolytes for aqueous lithium-ion batteries.

    Science.gov (United States)

    Miyazaki, Kohei; Shimada, Toshiki; Ito, Satomi; Yokoyama, Yuko; Fukutsuka, Tomokazu; Abe, Takeshi

    2016-04-11

    An efficient electrolyte solution containing organic sulfonates for use in aqueous rechargeable lithium-ion batteries (ARLBs) is shown to provide a wide potential window and enable a high operating voltage for ARLBs. PMID:26911197

  6. Aqueous vanadium ion dynamics relevant to bioinorganic chemistry: A review.

    Science.gov (United States)

    Kustin, Kenneth

    2015-06-01

    Aqueous solutions of the four highest vanadium oxidation states exhibit four diverse colors, which only hint at the diverse reactions that these ions can undergo. Cationic vanadium ions form complexes with ligands; anionic vanadium ions form complexes with ligands and self-react to form isopolyanions. All vanadium species undergo oxidation-reduction reactions. With a few exceptions, elucidation of the dynamics of these reactions awaited the development of fast reaction techniques before the kinetics of elementary ligation, condensation, reduction, and oxidation of the aqueous vanadium ions could be investigated. As the biological roles played by endogenous and therapeutic vanadium expand, it is appropriate to bring the results of the diverse kinetics studies under one umbrella. To achieve this goal this review presents a systematic examination of elementary aqueous vanadium ion dynamics. PMID:25578410

  7. Advances of aqueous rechargeable lithium-ion battery: A review

    Science.gov (United States)

    Alias, Nurhaswani; Mohamad, Ahmad Azmin

    2015-01-01

    The electrochemical characteristic of the aqueous rechargeable lithium-ion battery has been widely investigated in efforts to design a green and safe technology that can provide a highly specific capacity, high efficiency and long life for high power applications such as the smart grid and electric vehicle. It is believed that the advantages of this battery will overcome the limitations of the rechargeable lithium-ion battery with organic electrolytes that comprise safety and create high fabrication cost issues. This review focuses on the opportunities of the aqueous rechargeable lithium-ion battery compared to the conventional rechargeable lithium-ion battery with organic-based electrolytes. Previously reported studies are briefly summarised, together with the presentation of new findings based on the conductivity, morphology, electrochemical performance and cycling stability results. The factors that influence the electrochemical performance, the challenges and potential of the aqueous rechargeable lithium-ion battery are highlighted in order to understand and maintained the excellent battery performance.

  8. Adsorption of lead ions from aqueous solutions using clinoptilolite

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Blažev, Krsto; Krstev, Aleksandar

    2014-01-01

    The adsorption of lead ions from synthetic aqueous solutions was performed by using natural zeolite (clinoptilolite). In order to determine the effectivity of clinoptilolite a series of experiments were performed under batch conditions from single ion solutions. Experiments were carried out at different initial concentration of lead ions, different initial pH values and different adsorbent mass. The adsorption kinetics is reasonably fast. It means that in the first 20 min approximately 90...

  9. Adsorption of copper ions from aqueous solutions on natural zeolite

    OpenAIRE

    Zendelska, Afrodita; Golomeova, Mirjana; Blažev, Krsto; Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2015-01-01

    The adsorption of copper ions from synthetic aqueous solutions on natural zeolite (clinoptilolite) was examined. In order to determine the rate of adsorption and the copper uptake at equilibrium, a series of experiments were performed under batch conditions from single ion solutions. Equilibrium data were evaluated based on adsorption (Langmuir and Freundlich) isotherms. The adsorption kinetics is reasonably fast. In the first 20 min of the experiment, approximately 80% of Cu2+ io...

  10. Ion equilibrium in aqueous solutions of pectin materials

    International Nuclear Information System (INIS)

    By means of electro conductivity method the comparative study of ion equilibrium of pectin materials of apple, orange and sunflower in aqueous solution at various ph was conducted. According to experimental data on specific conductivity the value of equivalent conductivity, level, functions and dissociation constant were evaluated. (author)

  11. EXAFS studies of actinide ions in aqueous solution

    International Nuclear Information System (INIS)

    The applicability of the EXAFS technique in the study of actinide systems is discussed. Uranium L/sub III/-edge spectra obtained on an in-lab rotating anode EXAFS facility are presented and analyzed for crystalline UO2F2 and aqueous solutions containing hexavalent uranium ions. Methods for the extension of the technique to more dilute systems are discussed

  12. Benzimidazole Based 'Turn on' Fluorescent Chemodosimeter for Zinc Ions in Mixed Aqueous Medium.

    Science.gov (United States)

    Sharma, Shilpa; Pradeep, Chullikkattil P; Dhir, Abhimanew

    2016-07-01

    Benzimidazole based compound 3 is designed and synthesized. The compound 3 is evaluated as fluorogenic sensor for metal ions in mixed aqueous solutions. Among all the metal ions tested, the compound 3 selectively senses Zn(2+) ions. The imine bond of 3 gets cleaved by Zn(2+) ions. Thus, 3 behave as 'turn on' fluorescent chemodosimeter for Zn(2+) ions with limit of detction in micromolar range. Furthurmore, we demonstated that 3 can detect Zn(2+) ions in cells of Allium cepa. Graphical Abstract Benzimidazole based ligand 3 is designed and synthesized which behave as chemodosimeter for Zn(2+) ions. We further demonstrated that 3 can detect Zn(2+) ions in cells of Allium cepa. PMID:27262442

  13. Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

    Science.gov (United States)

    Dietz, M.L.; Horwitz, E.P.; Bartsch, R.A.; Barrans, R.E. Jr.; Rausch, D.

    1999-03-30

    A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution. 4 figs.

  14. Preferential adsorption of uranium ions in aqueous solutions by polymers

    International Nuclear Information System (INIS)

    Amidoxime fiber and triazine fiber were prepared by chemical modification of commercially available polyacrylonitril fiber. It was found that the Amidoxime fiber is efficient to adsorb uranium ions in the artificial sea water. The efficiency of the preferential adsorption decreases by treatment the material with an acid-or an alkaline-solution. The triazine fiber adsorbs uranium ions only in aqueous solutions of such uranyl acetate, in the absence of other ions. In the artificial sea water, it adsorbs other ions instead of uranium. The preferential adsorption of uranium ions was further investigated with a series of polystyrenesulfonamides. Among the polystyrene derivatives, those having carboxyl groups, derived from imino diacetic acid (PSt-Imi), β-alanine (PSt-Ala), glycine (PSt-Gly), and sarcosine (PSt-Sar) were qualified for further discussion. However, it was found that the amount of adsorption of uranium ions by PSt-Imi decreases with increasing the volume of the artificial sea water and/or the duration of the treatment. Taking into account the facts, the preferential adsorption of uranium ions by PSt-Imi in aqueous solution was discussed in detail. (author)

  15. Ion Movement in Polypyrrole/Dodecylbenzenesulphonate Films in aqueous and non-aqueous electrolytes

    DEFF Research Database (Denmark)

    Vidanapathirana, K.; Careem, M.A.; Skaarup, Steen; West, Keld

    The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements. Investigati......The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements....... Investigations were carried out using aqueous and non-aqueous electrolytes to study the effect of solvent on the ion movement during redox processes. When PPy films are cycled in aqueous electrolytes transport of both anion and cation occurs during oxidation and reduction. However, when cycled in the nonaqueous...

  16. Process for recovering pertechnetate ions from an aqueous solution also containing other ions

    Science.gov (United States)

    Rogers, R.; Horwitz, E.P.; Bond, A.H.

    1997-02-18

    A solid/liquid process for the separation and recovery of TcO{sub 4}{sup {minus}1} ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO{sub 4}{sup {minus}1} ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO{sub 4}{sup {minus}1} ions in such an aqueous solution that is free from MoO{sub 4}{sup {minus}2} ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 15 figs.

  17. Non-aqueous electrolytes for lithium ion batteries

    Science.gov (United States)

    Chen, Zonghai; Amine, Khalil

    2015-11-12

    The present invention is generally related to electrolytes containing anion receptor additives to enhance the power capability of lithium-ion batteries. The anion receptor of the present invention is a Lewis acid that can help to dissolve LiF in the passivation films of lithium-ion batteries. Accordingly, one aspect the invention provides electrolytes comprising a lithium salt; a polar aprotic solvent; and an anion receptor additive; and wherein the electrolyte solution is substantially non-aqueous. Further there are provided electrochemical devices employing the electrolyte and methods of making the electrolyte.

  18. Heterocyclic ring based colorimetric and fluorescent chemosensor for transition metal ions in an aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Udhayakumari, Duraisamy [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Velmathi, Sivan, E-mail: velmathis@nitt.edu [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Boobalan, Maria susai [Department of Chemistry, St. Joseph' s College (Autonomous), Tiruchirappalli 620002 (India); Venkatesan, Parthiban; Wu, Shu-Pao [Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)

    2015-02-15

    Heterocyclic ring based R1–R3 have been synthesized from the simple condensation method. R1–R3 exhibit highly selective and sensitive recognition towards transition metal ions in an aqueous medium via visual color change and were further confirmed by UV–vis and fluorescent spectroscopic methods. Fluorescent turn on and turn off behavior was observed for receptors tested with transition metal ions. The interaction of transition metal ions and receptors R1–R3 was confirmed to adopt 1:1 binding stoichiometry. Micromolar detection limit was found for R1–R3 with metal ions. DFT theoretical calculations were employed to understand the sensing mechanism of the sensors towards the metal ions. R1 and R2 were also successfully demonstrated as a fluorescent probe for detecting Cu{sup 2+} ions in living cells. - highlights: • R1–R3 act as colorimetric and fluorescent sensors for metal ions. • Receptors (R1–R3) detect Cu{sup 2+} ions in aqueous solution at nanomolar levels. • R1 and R2 act as a fluorescent probe for detecting Cu{sup 2+} ions in living cells.

  19. High-molar-mass hyaluronan behavior during testing its radical scavenging capacity in organic and aqueous media: effects of the presence of manganese(II) ions.

    Science.gov (United States)

    Rapta, Peter; Valachová, Katarína; Gemeiner, Peter; Soltés, Ladislav

    2009-02-01

    This study compares the radical scavenging capacity of high-molar-mass hyaluronan (HA) using standardized methods applying 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and 2,2'-azinobis[3-ethylbenzthiazoline sulfonate] (ABTS) radical cations as oxidants. Additionally, spin-trapping technique combined with electron paramagnetic resonance (EPR) was used to evaluate the ability of HA to scavenge reactive radicals. The thermal decomposition of K2S2O8 in pure H2O or in a H2O/dimethyl sulfoxide (DMSO) mixture at 333 K was used as a source of reactive paramagnetic species. We found that HA does not exhibit radical-scavenging activity when DPPH radicals or ABTS(.+) radical cations are used as oxidant, but that HA is an effective radical scavenger at low concentrations, if the oxidation reactions are initiated by the decomposition of K2S2O8. At higher HA concentrations, a more complex behavior and prooxidant HA action was observed. The influence of Mn(II) ions on the reaction mechanisms of radical generation and termination in the K2S2O8/H2O/DMSO system in the presence of HA was studied in detail. PMID:19235158

  20. Aqueous corrosion behaviour of ion-implanted metals

    International Nuclear Information System (INIS)

    We can now look back at 10 years of application of ion beams in corrosion studies. Therefore, after the introduction, we first attempt to give an overview of what has been accomplished during this period in the field of aqueous corrosion, with emphasis on developments in more recent years. Then we present a more detailed discussion of some particular examples of research which make use of different types of corrosion protection mechanism as well as applications of different types of ion beam technique to metal surfaces. These examples include the application of ion beam mixing and ion-beam-assisted vapour deposition to (i) the prevention of localized corrosion, (ii) the reduction of hydrogen uptake by metals (the formation of 'migration barriers'), (iii) corrosion protection by means of ion-beam-mixed monolayers and multilayers of aluminium and boron and (iv) ion-beam-modified carbon layers and their influence on the corrosion of mild steel. Following these examples, we attempt to deduce recommendations for the future application of ion beams in corrosion science. (orig.)

  1. A lithium ion battery using an aqueous electrolyte solution

    Science.gov (United States)

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-01-01

    Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg−1. It will be a promising energy storage system with good safety and efficient cooling effects. PMID:27328707

  2. A lithium ion battery using an aqueous electrolyte solution

    Science.gov (United States)

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-06-01

    Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg‑1. It will be a promising energy storage system with good safety and efficient cooling effects.

  3. A lithium ion battery using an aqueous electrolyte solution.

    Science.gov (United States)

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-01-01

    Energy and environmental pollution have become the two major problems in today's society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg(-1). It will be a promising energy storage system with good safety and efficient cooling effects. PMID:27328707

  4. A method for separating uranium from an aqueous solution containing uranyl ions and contaminating ions

    International Nuclear Information System (INIS)

    Description is given of a method for separating uranium from contaminating ions in an aqueous solution containing uranyl ions. In a first step, the contaminating ions are extracted by a first solvent containing a reagent capable of forming a soluble complex with the uranyl ions. The solvent is separated by means of a separator liquid, which is subsequently extracted by a solvent containing an amine, then, said amine is separated by means of a sufficient amount of ammonium carbonate solution for precipitating an uranium complex which is subsequently recovered. This can be applied to the extraction of uranium from phosphoric or sulphuric solutions or from sodium carbonate

  5. Experimental tests for 36cl removal from aqueous solution

    International Nuclear Information System (INIS)

    This paper presents the experimental tests of a chlorine separation and purification method from aqueous samples with knowing content of Co, Cs, Eu, Ni and Sr stable elements. The method is based on the property of chloride ions to form a silver chloride white precipitate, followed by the use of the extraction chromatography on the strong anionic resin (Bio-Rad AG® 1-X4) to purify chlorine. The concentrations of Co, Cs, Eu, Ni and Sr (separated from Cl by using precipitation method) were measured by ICP-OES. The silver chloride precipitate was dissolved in 25 % NH3 solution and loaded onto the anionic resin. The chloride ions were strongly retained on the resin and eluted with a proper solution. The final solution, containing chloride ions, was converted to a form compatible with the spectrophotometric and Mohr titration techniques, which were used to determine chloride concentration. The separation yields of Co, Cs, Eu, Ni and Sr from Cl are very good. More than 98 % from the initial concentration of chlorine was recovered. (authors)

  6. Recovery of niobium anions from aqueous solutions by ion flotation

    International Nuclear Information System (INIS)

    In principle the feasibility of recovering niobates (K2NbOF5 and K2NbF7) from aqueous media by ion flotation was established. When using quaternary ammonium bases or amines as the collectors, the optimal conditions lie in the interval pH = 5.0-9.0. The interaction of niobates with cationic surfactants may proceed through an anion-exchange mechanism. The presence of acid in the solution suppresses this interaction, owing to the competition from the anions that are present and owing to binding of the surface-active collectors into a complex. 3 figures

  7. Removal of uranyl ions from aqueous solutions using barium titanate

    International Nuclear Information System (INIS)

    Remediation of water sources contaminated with radioactive waste products is a major environmental issue that demands new and more efficient technologies. For this purpose, we report a highly efficient ion-exchange material for the removal of radioactive nuclides from aqueous solutions. The kinetic characteristics of adsorption of uranyl ions on the surface of barium titanate were investigated using a spectrophotometric method under a wide range of conditions. By controlling the pH it was possible to exert fine control over the speciation of uranium, and by optimizing the temperature and grain size of the exchanger, almost total removal was achieved in a matter of just hours. The highest efficiency (>90 % removal) was realized at high temperature (80 deg C). Moreover, the effect of competitive ion adsorption from a range of different cations and anions was quantified. Adsorption was found to follow first-order kinetics and both Freundlich and Langmuir isotherms could be applied to this system. The results of a mathematical treatment of the kinetic data combined with the observation that adsorption was independent of stirring speed and dependent on the ion-exchanger grain size, indicate that the dominant mechanism influencing adsorption is particle spreading. The adsorption behavior was not influenced by exposure to high-intensity gamma radiation, indicating potential for use of this ion-exchanger in systems containing radioactive material. These results will be of use in the development of uranium extraction systems for contaminated water sources. (author)

  8. A new ion exchanger for the removal of cesium from aqueous solutions

    International Nuclear Information System (INIS)

    A new exchange potassium copper nickel hexacyanoferrates(II) was prepared. It was characterized by chemical composition and surface area measurements. The removal of cesium from aqueous solution by ion exchange was studied as function of shaking time. pH and concentration of acids, salts and cesium. The data indicates high value of distribution coefficient over a wide range of pH, nitric and hydrochloric acids concentration and in the presence of higher concentration of Na and K ions. A potassium copper nickel hexacyanoferrate(II) column was also tested for elution of cesium using 8 M ammonium nitrate solution. (author)

  9. Quick analytical method for the determination of iodide and iodate ions in aqueous solutions

    International Nuclear Information System (INIS)

    An analytical quick-test method was developed to determine iodide and iodate ions in aqueous solutions using solid phase extraction cartridges for sample preparation. Work was focussed on finding simple, but efficient conditions for quantitative separation of iodate and iodide. Iodine amounts were then determined by standard methods. Ion-exchange absorbers in cartridge form were used. Selectivity and yield of the species separation were studied at pH value of 5-10 and various solution compositions using 131I radioactive tracer. The electrolytes used were diluted alkaline, nitrate and boric acid-borate solutions. Application to nuclear reactor cooling water analysis or environmental investigations and monitoring is proposed. (author)

  10. A New Efficient Analytical Method for Picolinate Ion Measurements in Complex Aqueous Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Parazols, M.; Dodi, A. [CEA Cadarache, Lab Anal Radiochim and Chim, DEN, F-13108 St Paul Les Durance (France)

    2010-07-01

    This study focuses on the development of a new simple but sensitive, fast and quantitative liquid chromatography method for picolinate ion measurement in high ionic strength aqueous solutions. It involves cation separation over a chromatographic CS16 column using methane sulfonic acid as a mobile phase and detection by UV absorbance (254 nm). The CS16 column is a high-capacity stationary phase exhibiting both cation exchange and RP properties. It allows interaction with picolinate ions which are in their zwitterionic form at the pH of the mobile phase (1.3-1.7). Analysis is performed in 30 min with a detection limit of about 0.05 {mu}M and a quantification limit of about 0.15 {mu}M. Moreover, this analytical technique has been tested efficiently on complex aqueous samples from an effluent treatment facility. (authors)

  11. Application of dolochar in the removal of cadmium and hexavalent chromium ions from aqueous solutions

    International Nuclear Information System (INIS)

    Graphical abstract: Dolochar - a waste material from sponge iron industry, is put to test as an adsorbent for removal of cadmium and hexavalent chromium ions from aqueous solutions. The sample consists of lots of voids and pores. Batch adsorption experiments have indicated that, higher pH and temperature enhances sorption for cadmium ions. The adsorption for chromium is found better at acidic pH in comparison to alkaline pH. The adsorption is well fitted to Langmuir isotherm model compared to the Freundlich model indicating monolayer adsorption. The kinetics of adsorption better fit to pseudo second order model.. Display Omitted Highlights: → Dolochar, a waste material is generated during the production of sponge iron. → Dolochar consists of metallic iron, carbon, and lime bearing phases along with lots of voids and pores. → It was found to be an good adsorbent for the removal of cadmium and hexavalent chromium ions from aqueous solutions. → The adsorption follows Langmuir isotherm and kinetics of adsorption better fit of pseudo second order model. - Abstract: Dolochar, a waste material generated in sponge iron industry, is processed and put to test as an adsorbent for removal of Cd(II) and Cr(VI) ions from aqueous solutions. The dolochar samples were characterised to determine the different phases and their distribution by reflection microscopy. The analysis indicated that the sample consists of metallic iron, fused carbon, and Ca-Mg bearing phases (Ca-Mg-silicate-oxide) along with lots of voids and pores. The fixed carbon (FC) content of the material is 13.8% with a Langmuir surface area of 81.6 m2/g and micropore area of 34.1 m2/g. Batch adsorption experiments have been conducted to study the sorption behaviour of Cd(II) and Cr(VI) ions on dolochar as a function of particle size, contact time, adsorbent dosages, pH and temperature. It is observed that higher pH and temperature enhances sorption of Cd(II) ions. In contrast, the adsorption for Cr(VI) is

  12. Speciation of aluminum in aqueous solutions using ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Bertsch, P.M.; Anderson, M.A.

    1989-03-15

    An ion chromatographic method in which aluminum (AI) is quantitatively determined via postcolumn derivatization with Tiron (4,5-dihydroxy-m-benzenedisulfonic acid) was evaluated for its utility as a method for speciating AI in aqueous solutions. Fluro-, oxalato-, and citratoaluminum complexes were identified by distinct peaks within chromatograms of AI solutions when the appropriate ligand was added. Excellent quantitative agreement between predicted species concentrations (via the thermodynamic speciation model GEOCHEM) and those determined by ion chromatography was obtained for samples prepared in the eluent matrix. The predominantly outer sphere sulfatoaluminum complexes were not observed to elute as singly charged species, but rather exhibited a retention time indistinguishable from the AI(H/sub 2/O)6(3+) species. It is concluded that inner sphere AI complexes (generally possessing relatively high association constants) possess adequate kinetic stability to withstand degradation during the ion exchange process, whereas outer sphere complexes apparently readily dissociate in the presence of the sulfonate exchange sites. Deviations in sample ionic strength (mu) and pH from that of the eluent resulted in some redistribution among species, the degree of which was ligand specific.

  13. A Type of Lithium-ion Battery Based on Aqueous electrolyte

    Institute of Scientific and Technical Information of China (English)

    G.J.Wang; N.H.Zhao; L.J.Fu; B.Wang; Y.P.Wu

    2007-01-01

    1 Introduction A new type of rechargeable lithium ion battery with an aqueous electrolyte was announced by W. Li et al. in 1994[1].This type of battery uses the lithium intercalation compounds LiMn2O4 and VO2 as electrode materials and an alkaline aqueous electrolytic solution. By this combination, the disadvantages of the non-aqueous Li-ion battery type, i.e. high cost and safety problems could be faded away[2]. So this type of aqueous Li-ion battery was regarded as the promising power for electric veh...

  14. 'PET' vs. 'push-pull' induced ICT: a remarkable coumarinyl-appended pyrimidine based naked eye colorimetric and fluorimetric sensor for the detection of Hg2+ ions in aqueous media with test trips.

    Science.gov (United States)

    Goswami, Shyamaprosad; Das, Avijit Kumar; Maity, Sibaprasad

    2013-12-14

    A novel colorimetric and fluorescent chemosensor based on 7-(diethylamino)-3-(pyrimidin-4-yl)-2H-chromen-2-one (PYC) has been designed and synthesized for the detection of Hg(2+) in the presence of other competing metals in mixed aqueous media. The PYC exhibits naked eye color change from green to red, and the fluorescence color changes from yellowish green to light orange with Hg(2+). It also shows a red shift in wavelength of about 80 nm in absorption spectra. Test strips based on PYC were fabricated, which could act as convenient and efficient Hg(2+) test kits. PMID:24096453

  15. Advanced material and approach for metal ions removal from aqueous solutions

    OpenAIRE

    Turhanen, Petri A; Vepsäläinen, Jouko J; Peräniemi, Sirpa

    2015-01-01

    A Novel approach to remove metals from aqueous solutions has been developed. The method is based on a resin free, solid, non-toxic, microcrystalline bisphosphonate material, which has very low solubility in water (59 mg/l to ion free Milli-Q water and 13 mg/l to 3.5% NaCl solution). The material has been produced almost quantitatively on a 1 kg scale (it has been prepared also on a pilot scale, ca. 7 kg) and tested successfully for its ability to collect metal cations from different sources, ...

  16. Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

    Energy Technology Data Exchange (ETDEWEB)

    Fish, D. [Lawrence Berkeley National Lab., CA (United States)

    1996-10-01

    The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished.

  17. Stability of metal ions in aqueous environmental samples

    International Nuclear Information System (INIS)

    The time lapse between the collection of aqueous environmental samples and the analysis affects the original ionic concentration. Studies have proven the nonionic species in a water sample have more of an effect on the veracity of an analysis than the ''container wall'' effect, and that adjustment to a pH of 2 at sample collection time is a ''Pyrrhic victory.'' Lead, for example, will commonly increase an order of magnitude when unfiltered samples are adjusted to a pH of 2 upon collection. This effect is greatest when elemental ions are present in the ng ml-1 range and lessens as the original ionic concentration increases. Data are presented that behooves filtration of stream water and rainwater samples prior to any acidification step. The need to acidify the resulting filtrate is also discussed. Lithium, sodium, potassium, cesium, magnesium, calcium, strontium, manganese, iron, copper, silver, zinc, cadmium, aluminum, indium, and lead are examined. The insoluble phase retained on the filter can be digested with acid and also analyzed. The separate analysis of the filtrate and filter will give a true representation of the occurrence of these metals in nature. Flame and flameless atomic aborption and emission are used to perform the trace analyses

  18. Electrochemical removal of indium ions from aqueous solution using iron electrodes

    International Nuclear Information System (INIS)

    The removal of indium ions from aqueous solution was carried out by electrocoagulation in batch mode using an iron electrode. Various operating parameters that could potentially affect the removal efficiency were investigated, including the current density, pH variation, supporting electrolyte, initial concentration, and temperature. The optimum current density, supporting electrolyte concentration, and temperature were found to be 6.4 mA/cm2, 0.003N NaCl, and 298 K, respectively. When the pH values lower than 6.1, the removal efficiencies of indium ions via electrocoagulation were up to 5 times greater than those by adding sodium hydroxide. The indium ion removal efficiency decreased with an increase in the initial concentration. Results for the indium ion removal kinetics at various current densities show that the kinetic rates conformed to the pseudo-second-order kinetic model with good correlation. The experimental data were also tested against different adsorption isotherm models for describing the electrocoagulation process. The adsorption of indium ions preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules.

  19. Electrochemical removal of indium ions from aqueous solution using iron electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Wei-Lung, E-mail: wlchou@sunrise.hk.edu.tw [Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 34 Chung-Chie Road, Sha-Lu, Taichung 433, Taiwan (China); Huang, Yen-Hsiang [Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 34 Chung-Chie Road, Sha-Lu, Taichung 433, Taiwan (China)

    2009-12-15

    The removal of indium ions from aqueous solution was carried out by electrocoagulation in batch mode using an iron electrode. Various operating parameters that could potentially affect the removal efficiency were investigated, including the current density, pH variation, supporting electrolyte, initial concentration, and temperature. The optimum current density, supporting electrolyte concentration, and temperature were found to be 6.4 mA/cm{sup 2}, 0.003N NaCl, and 298 K, respectively. When the pH values lower than 6.1, the removal efficiencies of indium ions via electrocoagulation were up to 5 times greater than those by adding sodium hydroxide. The indium ion removal efficiency decreased with an increase in the initial concentration. Results for the indium ion removal kinetics at various current densities show that the kinetic rates conformed to the pseudo-second-order kinetic model with good correlation. The experimental data were also tested against different adsorption isotherm models for describing the electrocoagulation process. The adsorption of indium ions preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules.

  20. Measurement of Cadmium Ion in the Presence of Metal-Binding Biopolymers in Aqueous Sample

    OpenAIRE

    Jian Pu; Kensuke Fukushi

    2013-01-01

    In aqueous environment, water-soluble polymers are effectively used to separate free metal ions from metal-polymer complexes. The feasibilities of four different analytical techniques, cadmium ion-selective electrode, dialysis sack, chelate disk cartridge, and ultrafiltration, in distinguishing biopolymer-bound and nonbound cadmium in aqueous samples were investigated. And two different biopolymers were used, including bovine serum albumin (BSA) and biopolymer solution extracted from cultivat...

  1. Biosorption of Lead Ions from Aqueous Solution Using Ficus benghalensis L.

    OpenAIRE

    Venkateswara Rao Surisetty; Janusz Kozinski; L. Rao Nageswara

    2013-01-01

    Ficus benghalensis L., a plant-based material leaf powder, is used as an adsorbent for the removal of lead ions from aqueous solution using the biosorption technique. The effects of process parameters such as contact time, adsorbent size and dosage, initial lead ion concentration, and pH of the aqueous solution on bio-sorption of lead by Ficus benghalensis L. were studied using batch process. The Langmuir isotherm was more suitable for biosorption followed by Freundlich and Temkin isotherms w...

  2. The Influence of Iron Ions on the Aqueous Photocatalytic Oxidation of Deicing Agents

    OpenAIRE

    D. Klauson; S. Preis

    2007-01-01

    An experimental research into aqueous photocatalytic oxidation (PCO) of the deicing compounds, 2-ethoxyethanol (2-EE), diethylene glycol monomethyl ether (DEGMME), and ethylene glycol (EG) was undertaken. The addition of iron ions to the acidic aqueous solutions to be treated displayed complex influence on the oxidation efficiency of the above mentioned substances, resulting in a sharp increase of the PCO efficiency at smaller concentrations of iron ions followed by a drastic decrease with th...

  3. Aqueous Rechargeable Zinc/Aluminum Ion Battery with Good Cycling Performance.

    Science.gov (United States)

    Wang, Faxing; Yu, Feng; Wang, Xiaowei; Chang, Zheng; Fu, Lijun; Zhu, Yusong; Wen, Zubiao; Wu, Yuping; Huang, Wei

    2016-04-13

    Developing rechargeable batteries with low cost is critically needed for the application in large-scale stationary energy storage systems. Here, an aqueous rechargeable zinc//aluminum ion battery is reported on the basis of zinc as the negative electrode and ultrathin graphite nanosheets as the positive electrode in an aqueous Al2(SO4)3/Zn(CHCOO)2 electrolyte. The positive electrode material was prepared through a simple electrochemically expanded method in aqueous solution. The cost for the aqueous electrolyte together with the Zn negative electrode is low, and their raw materials are abundant. The average working voltage of this aqueous rechargeable battery is 1.0 V, which is higher than those of most rechargeable Al ion batteries in an ionic liquid electrolyte. It could also be rapidly charged within 2 min while maintaining a high capacity. Moreover, its cycling behavior is also very good, with capacity retention of nearly 94% after 200 cycles. PMID:26716878

  4. Aqueous CO2 vs. aqueous extraction of soils as a preparative procedure for acute toxicity testing

    International Nuclear Information System (INIS)

    This study was to determine if contaminated soils extracted with supercritical CO2 (SFE) would yield different results from soils extracted with an aqueous media. Soil samples from an abandoned oil refinery were subjected to aqueous and SFE extraction. Uncontaminated control sites were compared with contaminated sites. Each extract was analyzed for 48 hour acute Ceriodaphnia LC50s and Microtox reg-sign EC50s. Comparisons were then made between the aqueous extracts and the SFE extracts. An additional study was made with HPLC chromatographs of the SFE contaminated site extracts to determine if there was a correlation between LC50 results and peak area of different sections of the chromatograph. The 48 hour Ceriodaphnia LC50 of one contaminated site showed a significant increase in toxicity with the supercritical extract compared to the aqueous extract. All contaminated sites gave toxic responses with the supercritical procedure. The Microtox reg-sign assay showed a toxic response with 2 of the 3 contaminated sites for both aqueous and SFE extracts. Results indicate that the Ceriodaphnia assays were more sensitive than Microtox reg-sign to contaminants found in the refinery soil. SFE controls did not show adverse effects with the Ceriodaphnia, but did have a slight effect with Microtox reg-sign. The best correlation (r2 > 0.90) between the Ceriodaphnia LC50s and the peak areas of the chromatographs was obtained for sections with an estimated log Kow of 1 to 5. SFE extraction provided a fast, efficient and inexpensive method of collecting and testing moderately non-polar to strongly non-polar organic contaminants from contaminated soils

  5. ABEC trademark resins: From aqueous biphasic novelties to selective aqueous biphasic extraction chromatographic resins for metal ions

    International Nuclear Information System (INIS)

    We have recently been allowed patents on the use of polyethylene glycol-grafted resins for chaotropic metal ion separations based on the concepts of aqueous biphasic extraction. The concept and realization of the technology was developed by collaborative research between university and national laboratories. Commercialization of the technology was accomplished by licensing the technology to a specialty separations company itself started based on the foundation of technology transfer. This tripartite interaction was facilitated by the joint interest and membership of all involved parties in the Industrial ampersand Engineering Chemistry Division. This presentation will highlight the research which led to the adaptation of aqueous biphasic partitioning to ABEC trademark resins for metal ion separations. The role of the I ampersand EC Division and its Separation Science ampersand Technology Subdivision in facilitating such technology transfer will also be discussed

  6. Sorption of Ni(II), Cu(II) and Fe(III) ions from Aqueous Solutions Using Activated Carbon

    International Nuclear Information System (INIS)

    An activated carbon was tested for its ability to remove transition metal ions from aqueous solutions. Physical, chemical and liquid-phase adsorption characterizations of the carbon were done following standard procedures. Studies on the removal of Ni(II), Cu(II) and Fe(III) ions were attempted by varying adsorbate dose, pH of the metal ion solution and time in batch mode. The equilibrium adsorption data were fitted with Freundlich and Langmuir and the isotherm constants were evaluated, equilibrium time of the different three metal ions were determined. pH was found to have a significant role to play in the adsorption. The processes were endothermic and the thermodynamic parameters were evaluated. Desorption studies indicate that ion-exchange mechanism is operating

  7. New-concept Batteries Based on Aqueous Li+/Na+ Mixed-ion Electrolytes

    OpenAIRE

    Liang Chen; Qingwen Gu; Xufeng Zhou; Saixi Lee; Yonggao Xia; Zhaoping Liu

    2013-01-01

    Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li+/Na+ mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. On...

  8. Biosorption of some ions on different bacterial species from aqueous and radioactive waste solutions

    International Nuclear Information System (INIS)

    The uptake of metal ions, cerium, Ce(III); cobalt, Co(II); thorium, Th(IV); and uranium U(VI) by Bacillus pumilus-LRW1, Bacillus cereus-LRW2 and Micrococcus lylae-LRW3 from aqueous solution was examined as a function of metal ion concentration, pH, temperature, and the presence of some foreign ions. The bacterial species exhibited high affinity to accumulate metal ions from their solutions at pH 4-5.0 ± 0.5. The amount of each ion (in mg) accumulated by one gram dry weight of each bacteria was calculated. The uptake by the Bacillus cereus-LRW2 from aqueous solutions and simulated radioactive wastes were also investigated. Electron microscopic investigations showed that the ions were accumulated around the cell wall. (author)

  9. Removal of lead and zinc ions from aqueous solutions using clinoptilolite

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Blažev, Krsto

    2014-01-01

    The removed of lead and zinc ions from synthetic aqueous solutions was performed using clinoptilolite. In order to determine the effectivity of clinoptilolite a series of experiments were performed under batch conditions from single ion solutions. Experiments were carried out at different initial ions concentration, different initial pH values and different adsorbent mass. The adsorption kinetics is reasonably fast. It means that in the first 20 min approximately 90% o...

  10. Ion exchange during heavy metal bio-sorption from aqueous solution by dried biomass of macrophytes.

    Science.gov (United States)

    Verma, V K; Tewari, Saumyata; Rai, J P N

    2008-04-01

    In this study, potentials of oven dried biomass of Eichhornia crassipes, Valisneria spiralis and Pistia stratiotes, were examined in terms of their heavy metal (Cd, Ni, Zn, Cu, Cr and Pb) sorption capacity, from individual-metal and multi-metal aqueous solutions at pH 6.0+/-0.1 (a popular pH of industrial effluent). V. spiralis was the most and E. crassipes was the least efficient for removal of all the metals. Cd, Pb and Zn were efficiently removed by all the three biomass. Cd was removed up to 98% by V. spiralis. Sorption data for Cr, Ni and Cd fitted better to Langmuir isotherm equation, while, the sorption data for Pb, Zn and Cu fitted better to Freundlich isotherm equation. In general, the presence of other metal ions did not influence significantly the targeted metal sorption capacity of the test plant biomasses. Ion exchange was proven the main mechanism involved in bio-sorption and there was a strong ionic balance between adsorbed (H(+) and M(2+)) to the released ions (Na(+) and K(+)) to and from the biomass. No significant difference was observed in the metal exchanged amount, by doubling of metal concentration (15-30 mg/l) in the solution and employing individual-metal and multi-metal solutions. PMID:17513104

  11. Ion mixing, hydration, and transport in aqueous ionic systems

    International Nuclear Information System (INIS)

    The enhancement effect on the ion mobility of fluoride (and that of chloride) in a polycationic system, as the chloride content increases, is shown to also exist in other more simple ionic systems with cations such as the cesium ion and an organic ammonium ion. As the chloride content increases, in addition to the finding that there is more unbound water associated with the cation, we also observe that the average lifetime of a hydrogen bond decreases. This change to the hydrogen bonds is correlated to significant changes to both the structural and dynamical properties of water. The more disordered water structure and faster water dynamics are hypothesized to be also responsible for the enhanced ion mobilities. Furthermore, when either the chloride content or hydration level is changed, the self-diffusion constant of each co-ion changes by almost the same factor, implying the existence of a single universal transport mechanism that determines ion mobilities

  12. Elaboration and characterization of hybrid lithium-ion conducting membranes for aqueous lithium-air batteries

    OpenAIRE

    Lancel, Gilles

    2016-01-01

    Aqueous lithium-air batteries could be a revolution in energy storage, but the main limitation is the use of a thick glass-ceramic lithium ionic conductor to isolate the metallic lithium from the aqueous electrolyte. This makes the system more fragile, limits its cyclability and increases ohmic resistance. The aim of this work is to replace the glass-ceramic by a hybrid membrane made by electrospinning, which combines water tightness, flexibility and lithium-ions conductivity. The ionic condu...

  13. The Influence of Iron Ions on the Aqueous Photocatalytic Oxidation of Deicing Agents

    Directory of Open Access Journals (Sweden)

    D. Klauson

    2007-07-01

    Full Text Available An experimental research into aqueous photocatalytic oxidation (PCO of the deicing compounds, 2-ethoxyethanol (2-EE, diethylene glycol monomethyl ether (DEGMME, and ethylene glycol (EG was undertaken. The addition of iron ions to the acidic aqueous solutions to be treated displayed complex influence on the oxidation efficiency of the above mentioned substances, resulting in a sharp increase of the PCO efficiency at smaller concentrations of iron ions followed by a drastic decrease with the increasing iron ion concentrations. The phenomena observed can be explained by the electron scavenging effect of the iron ions and the competitive adsorption of iron ions and the oxidized substances on titanium dioxide surface. The carbonic acids determined as the PCO by-products allow outlining some reaction pathways for the substances under consideration.

  14. Iodine K-edge EXAFS analysis of iodide ion-cyclodextrin inclusion complexes in aqueous solution

    International Nuclear Information System (INIS)

    We study the structure of inclusion complexes of α-, β-, γ-cyclodextrin with mono-iodide ion in aqueous solution by means of iodine K-edge EXAFS spectroscopy. The analysis is based on the assumption that two kinds of iodide ions exist in KI-cyclodextrin aqueous solution i.e. hydrated mono-iodide ions and one-one mono-iodide-cyclodextrin inclusion complexes. In KI-α-cyclodextrin system, iodine K-edge EXAFS analyse show that the average coordination number of the oxygen atoms in water molecules in the first hydration shell decreases as the fraction of included ions increases. This result suggests that dehydration process accompanies the formation of the inclusion complex. This is not found in the case of β-cyclodextrin, indicating that in this case the iodide ions are included together with the whole first hydration shell.

  15. Electroreduction of uranyl ion in aqueous calcium nitrate solutions

    International Nuclear Information System (INIS)

    The electroreduction of uranyl ions in buffered and unbuffered 0.5 M calcium nitrate has been studied using polarography, cyclic voltammetry, chronopotentiometry, and chronoamperometry. The results are compared with those in molten calcium nitrate tetrahydrate. (author)

  16. Removal of trace quantities of cadmium from aqueous iodide solutions by ion flotation

    International Nuclear Information System (INIS)

    Cadmium ions react with the collector, ethylhexadecyldimethylammonium bromide (EHDABr) to form a surface active sublate which can be removed from aqueous iodide solutions by ion flotation. A typical ion flotation procedure involves passing air through a 250-ml solution containing 5 ppm Cd2+, 0.120 M I- and 1 x 10 -3M EHDABr at a flow rate of 20 ml/min for 2 hrs. The procedure is simple and efficient. Chromium, copper and zinc ions do not interfere under the experimental conditions. (author)

  17. Equilibrium Studies of Zinc Ions Removal from Aqueous Solutions by Adsorption on Natural Zeolite

    OpenAIRE

    Zendelska, Afrodita; Golomeova, Mirjana; Blažev, Krsto; Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2014-01-01

    The aim of this study is to use natural zeolite (clinoptilolite) as an adsorbent for the removal of zinc ions from synthetic aqueous solutions. In order to determine the zinc uptake at equilibrium a series of experiments were performed under batch conditions from ion solutions. Experiments were carried out at different initial concentracion of zinc ions and at different initial pH values at 20± 1°C. The adsorption isotherm of the zinc ions on the adsorbent was determined and corre...

  18. Characterization of aqueous silver nitrate solutions for leakage tests

    OpenAIRE

    José Ferreira Costa; Walter Luiz Siqueira; Alessandro Dourado Loguercio; Alessandra Reis; Elizabeth de Oliveira; Cláudia Maria Coelho Alves; José Roberto de Oliveira Bauer; Rosa Helena Miranda Grande

    2011-01-01

    OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silv...

  19. Delayed Onset of Crystallinity in Ion-Containing Aqueous Nanodrops.

    Science.gov (United States)

    Cooper, Richard J; DiTucci, Matthew J; Chang, Terrence M; Williams, Evan R

    2016-01-13

    Water exhibits remarkable properties in confined spaces, such as nanometer-sized droplets where hundreds of water molecules are required for crystalline structure to form at low temperature due to surface effects. Here, we investigate how a single ion affects the crystallization of (H2O)n clusters with infrared photodissociation spectroscopy of size-selected La(3+)(H2O)n nanodrops containing up to 550 water molecules. Crystallization in the ion-containing nanodrops occurs at n ≥ 375, which is approximately 100 more water molecules than what has been reported for neutral water clusters. This frustration of crystallinity reveals that La(3+) disrupts the hydrogen-bonding network of water molecules located remotely from the ion, a conclusion that is supported by molecular dynamics simulations. Our findings establish that a trivalent ion can pattern the H-bond network of water molecules beyond the third solvation shell, or to a distance of ∼1 nm from the ion. PMID:26714195

  20. Biosorption of lead from aqueous solutions by ion-imprinted tetraethylenepentamine modified chitosan beads.

    Science.gov (United States)

    Liu, Bingjie; Chen, Wei; Peng, Xiaoning; Cao, Qiqi; Wang, Qianrui; Wang, Dongfeng; Meng, Xianghong; Yu, Guangli

    2016-05-01

    In this paper, the bio-based ion-imprinted tetraethylenepentamine (TEPA) modified chitosan beads using Pb(II) as imprinted ions (Pb-ITMCB) were chemically synthesized, characterized and applied to selectively adsorb Pb(II) ions from aqueous solutions containing other metal ions, which has the same concentration as that of Pb(II) ions. Batch adsorption experiments were performed to evaluate the adsorption conditions, selectivity and reusability. FTIR, SEM and TEM technologies were used to elucidate the mechanism of Pb-ITMCB adsorbing Pb(II) ions. The results showed that the adsorption capacity of Pb-ITMCB for Pb(II) ions reached 259.68mg/g at pH 6, 40°C. The adsorption data could be fitted well with pseudo-second order kinetics model and Langmuir isotherm model. Compared with other metal cations, Pb(II) ions showed an overall affinity of being adsorbed by Pb-ITMCB. With the participation of active groups including NH2, NH and OH, the adsorption reaction took place both inside and on the surface of Pb-ITMCB. It indicated that Pb-ITMCB is a comparatively promising biosorbent for selective removal of Pb(II) ions from aqueous solutions. PMID:26836613

  1. Fluorescent zinc-terpyridine complex containing coordinated peroxo counter ion in aqueous medium

    Indian Academy of Sciences (India)

    S Kapoor; M S Sastry

    2000-08-01

    We describe a mixed ligand-zinc (10) complex containing coordinated peroxo ion and 2,2'2"-terpyridine and exhibiting fluorescence in the visible region (473 nm) on excitation at 390 nm in aqueous medium at room temperature. We also discuss the unusual phenomenon of enhancement of this fluorescence intensity on addition of some transition metal ions (35, 310, 40 and 39 electronic configurations).

  2. Equilibrium Studies of Some Metal Ions onto Modified Orange Mesocarp Extract in Aqueous Solution

    OpenAIRE

    Ibezim-Ezeani, Millicent U.; Okoye, Francis A.; Akaranta, Onyewuchi

    2012-01-01

    This paper examines the equilibrium removal of Zinc, Copper, Nickel and Cobalt ions from aqueous solutions by cation exchange resins synthesized using orange mesocarp extract. The percentage metal ion exchange of Carboxylated-Toluene Di-isocyanate Orange Mesocarp Extract Resin (CTOR) increased with increase in pH of the solution phase, while that of Sulphonated-Toluene Di-isocyanate Orange Mesocarp Extract Resin (STOR) was relatively uniform with increase in solution pH. The results also show...

  3. Structure, hydrolysis and diffusion of aqueous vanadium ions from Car-Parrinello molecular dynamics

    CERN Document Server

    Jiang, Zhen; Alexandrov, Vitaly

    2016-01-01

    A molecular level understanding of the properties of electroactive vanadium species in aqueous solution is crucial for enhancing the performance of vanadium redox flow batteries (RFB). Here, we employ Car-Parrinello molecular dynamics (CPMD) simulations based on density functional theory to investigate the hydration structures, first hydrolysis reaction and diffusion of aqueous V$^{2+}$, V$^{3+}$, VO$^{2+}$, and VO$_2^+$ ions at 300 K. The results indicate that the first hydration shell of both V$^{2+}$ and V$^{3+}$ contains six water molecules, while VO$^{2+}$ is coordinated to five and VO$_2^+$ to three water ligands. The first acidity constants (p$K_\\mathrm{a}$) estimated using metadynamics simulations are 2.47, 3.06 and 5.38 for aqueous V$^{3+}$, VO$_2^+$ and VO$^{2+}$, respectively, while V$^{2+}$ is predicted to be a fairly weak acid in aqueous solution with a p$K_\\mathrm{a}$ value of 6.22. We also show that the presence of chloride ions in the first coordination sphere of the aqueous VO$_2^+$ ion has a...

  4. Advanced material and approach for metal ions removal from aqueous solutions

    Science.gov (United States)

    Turhanen, Petri A.; Vepsäläinen, Jouko J.; Peräniemi, Sirpa

    2015-01-01

    A Novel approach to remove metals from aqueous solutions has been developed. The method is based on a resin free, solid, non-toxic, microcrystalline bisphosphonate material, which has very low solubility in water (59 mg/l to ion free Milli-Q water and 13 mg/l to 3.5% NaCl solution). The material has been produced almost quantitatively on a 1 kg scale (it has been prepared also on a pilot scale, ca. 7 kg) and tested successfully for its ability to collect metal cations from different sources, such as ground water and mining process waters. Not only was this material highly efficient at collecting several metal ions out of solution it also proved to be regenerable and reusable over a number of adsorption/desorption, which is crucial for environmental friendliness. This material has several advantages compared to the currently used approaches, such as no need for any precipitation step. PMID:25758924

  5. Advanced material and approach for metal ions removal from aqueous solutions.

    Science.gov (United States)

    Turhanen, Petri A; Vepsäläinen, Jouko J; Peräniemi, Sirpa

    2015-01-01

    A Novel approach to remove metals from aqueous solutions has been developed. The method is based on a resin free, solid, non-toxic, microcrystalline bisphosphonate material, which has very low solubility in water (59 mg/l to ion free Milli-Q water and 13 mg/l to 3.5% NaCl solution). The material has been produced almost quantitatively on a 1 kg scale (it has been prepared also on a pilot scale, ca. 7 kg) and tested successfully for its ability to collect metal cations from different sources, such as ground water and mining process waters. Not only was this material highly efficient at collecting several metal ions out of solution it also proved to be regenerable and reusable over a number of adsorption/desorption, which is crucial for environmental friendliness. This material has several advantages compared to the currently used approaches, such as no need for any precipitation step. PMID:25758924

  6. Removal of Heavy Metal Ions From Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    maziar noei

    2014-12-01

    Full Text Available The removal of Zn(II, V(II,  by  silica aerogel has been found to be concentration, , contact time, adsorbent dose and temperature dependent. ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on silica aerogel  was satisfied. The applicability of the Lagergren kinetic model has also been investigated. Thermodynamic constant (Kad , standard free energy ( ∆G0 ,enthalpy (∆H0 and entropy (∆S0 were calculated for predicting the nature of adsorption

  7. Applications of FETAX: Use in aqueous soil extract testing

    International Nuclear Information System (INIS)

    Frog Embryo Teratogenesis Assay-Xenopus (FETAX) testing of a series of diverse hazardous waste site soil samples was performed to evaluate the efficacy of FETAX as a rapid development toxicity screening tool. Soil samples were collected from six different hazardous waste sites, three from eastern and three from western Washington state. The type of waste site samples studied based on the contaminants identified included: heavy metals (2), creosote, petroleum products (2), and chlorinated pesticide contaminated sites. Three to five samples from each site representing baseline and increasing levels of contamination were collected. Aqueous extracts of the soil samples were prepared and used for FETAX studies. Samples collected from the creosote and petroleum product contaminated sites induced greater levels of embryolethal effects, although embryonic malformation was also observed. The metal contaminated sites induced greater levels of embryonic malformation, but induced little embryolethality. The chlorinated pesticide contaminated site samples caused moderate levels of embryonic deformities, but failed to induce embryolethal effects. Results from these studies suggested that FETAX was sensitive enough to detect low levels of developmental toxicants, but robust enough to be suitable for aqueous soil extract testing

  8. Experimental measurement and modeling of the distribution of solvent and ions between an aqueous phase and an ion exchange resin

    DEFF Research Database (Denmark)

    Christensen, Søren Gregers; Thomsen, Kaj

    2005-01-01

    The distribution of solutes and solvent between an aqueous solution of salt and an ion exchange resin has been measured at ambient temperature. The experiments have been performed for aqueous solutions of KNO3, KCl, Ca(NO3)2 and CaCl2 in the concentration range of 0-3N. The absorption has been...... measured for 3 gel type and 3 macroreticular resins with a degree of crosslinking varying from 10.5 to 18.5%. The experimental results have been modeled with the Extended UNIQUAC model combined with an elastic term taking the elastic properties of the resin structure into account. The model shows very good...

  9. Detection of copper ions from aqueous solutions using layered double hydroxides thin films deposited by PLD

    Science.gov (United States)

    Vlad, A.; Birjega, R.; Matei, A.; Luculescu, C.; Nedelcea, A.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2015-10-01

    Layered double hydroxides (LDHs) thin films with Mg-Al were deposited using pulsed laser deposition (PLD) technique. We studied the ability of our films to detect copper ions in aqueous solutions. Copper is known to be a common pollutant in water, originating from urban and industrial waste. Clay minerals, including layered double hydroxides (LDHs), can reduce the toxicity of such wastes by adsorbing copper. We report on the uptake of copper ions from aqueous solution on LDH thin films obtained via PLD. The obtained thin films were characterized using X-ray Diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results in this study indicate that LDHs thin films obtained by PLD have potential as an efficient adsorbent for removing copper from aqueous solution.

  10. A New Fluorescent Sensor for Transition Metal Ions in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new fluorescent sensor consisted of fluorenyl and dioxotetraaza unit, namely, 2,10-dimethyl-6-(9-fluorenyl)-1,4,8,11-tetraazaundencane-5,7-dione (L), was synthesized. It is a fluorescent sensor for transition metal ions in aqueous solution.

  11. Advanced High-Voltage Aqueous Lithium-Ion Battery Enabled by "Water-in-Bisalt" Electrolyte.

    Science.gov (United States)

    Suo, Liumin; Borodin, Oleg; Sun, Wei; Fan, Xiulin; Yang, Chongyin; Wang, Fei; Gao, Tao; Ma, Zhaohui; Schroeder, Marshall; von Cresce, Arthur; Russell, Selena M; Armand, Michel; Angell, Austen; Xu, Kang; Wang, Chunsheng

    2016-06-13

    A new super-concentrated aqueous electrolyte is proposed by introducing a second lithium salt. The resultant ultra-high concentration of 28 m led to more effective formation of a protective interphase on the anode along with further suppression of water activities at both anode and cathode surfaces. The improved electrochemical stability allows the use of TiO2 as the anode material, and a 2.5 V aqueous Li-ion cell based on LiMn2 O4 and carbon-coated TiO2 delivered the unprecedented energy density of 100 Wh kg(-1) for rechargeable aqueous Li-ion cells, along with excellent cycling stability and high coulombic efficiency. It has been demonstrated that the introduction of a second salts into the "water-in-salt" electrolyte further pushed the energy densities of aqueous Li-ion cells closer to those of the state-of-the-art Li-ion batteries. PMID:27120336

  12. Biological removal of metal ions from aqueous process streams

    International Nuclear Information System (INIS)

    Aqueous waste streams from nuclear fuel processing operations may contain trace quantities of heavy metals such as uranium. Conventional chemical and physical treatment may be ineffective or very expensive when uranium concentrations in the range of 10 to 100 g/m3 must be reduced to 1 g/m3 or less. The ability of some microorganisms to adsorb or complex dissolved heavy metals offers an alternative treatment method. Uranium uptake by Saccharomyces cerevisiae NRRL Y-2574 and a strain of Pseudomonas aeruginosa was examined to identify factors which might affect a process for the removal of uranium from wastewater streams. At uranium concentrations in the range of 10 to 500 g/m3, where the binding capacity of the biomass was not exceeded, temperature, pH, and initial uranium concentration were found to influence the rate of uranium uptake, but not the soluble uranium concentration at equilibrium. 6 figs

  13. Electric Double-Layer Effects Induce Separation of Aqueous Metal Ions.

    Science.gov (United States)

    Ji, Qinghua; An, Xiaoqiang; Liu, Huijuan; Guo, Lin; Qu, Jiuhui

    2015-11-24

    Metal ion separation is crucial to environmental decontamination, chromatography, and metal recovery and recycling. Theoretical studies have suggested that the ion distributions in the electric double-layer (EDL) region depend on the nature of the ions and the characteristics of the charged electrode surface. We believe that rational design of the electrode material and device structure will enable EDL-based devices to be utilized in the separation of aqueous metal ions. On the basis of this concept, we fabricate an EDL separation (EDLS) device based on sandwich-structured N-functionalized graphene sheets (CN-GS) for selective separation of aqueous toxic heavy metal ions. We demonstrate that the EDLS enables randomly distributed soluble ions to form a coordination-driven layer and electrostatic-driven layer in the interfacial region of the CN-GS/solution. Through tuning the surface potential of the CN-GS, the effective separation of heavy metal ions (coordination-driven layer) from alkali or alkaline earth metal ions (electrostatic-driven layer) can be achieved. PMID:26481603

  14. Mechanisms of Ions Adsorption by Nanodiamonds in Aqueous Suspensions

    Directory of Open Access Journals (Sweden)

    K.A. Laptinskiy

    2013-12-01

    Full Text Available This work is devoted to the study of adsorption properties and adsorption mechanisms of the original (I6, modified (I6COOH nanodiamonds and charcoal dispersed in water, with respect to dissolved ions (Cu2 +, Pb2 +, NO3 –, CH3COO – using optical spectroscopy methods: Raman and IR spectroscopies, absorption, dynamic light scattering. Mechanisms of anions and cations adsorption were studied.

  15. Sodium Titanium Phosphate as Anode Materials for Aqueous Sodium-ion Batteries

    Science.gov (United States)

    Wu, Wei

    different salt concentrations) and the oxygen dissolved in the electrolyte on Na0.44MnO2/NaTi 2(PO4)3 sodium-ion battery system has been studied. High rate performance with an increased salt concentration electrolyte has been discovered and the oxygen effect has been extensively studied. Different charge methods have been tested on the aqueous sodium-ion battery systems and the capacity fading mechanisms have been studied.

  16. Removal of copper ions from aqueous solutions by kaolinite and batch design

    International Nuclear Information System (INIS)

    The removal of copper ions from aqueous solutions by kaolinite was investigated by using a batch-type method. Effects of factors such as pH, ionic strength, temperature, acid-activation and calcination on copper adsorption were investigated. The uptake of copper was determined from changes in concentration as measured by atomic absorption spectrometry. The extent of copper adsorption increased with increasing pH and temperature and with decreasing ionic strength, acid-activation and calcination temperature. The Langmuir and Freundlich adsorption models were used to determine the isotherm parameters associated with the adsorption process. The results provide support for the adsorption of copper ions onto kaolinite. Thermodynamic parameters indicated the endothermic nature of copper adsorption on kaolinite. The experimental results were applied a batch design. As a result, the kaolinite may be used for removal of copper ions from aqueous solutions

  17. Non-aqueous electrolyte for lithium-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Amine, Khalil; Zhang, Lu; Zhang, Zhengcheng

    2016-01-26

    A substantially non-aqueous electrolyte solution includes an alkali metal salt, a polar aprotic solvent, and an organophosphorus compound of Formula IA, IB, or IC: ##STR00001## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently hydrogen, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, alkenoxy, alkynoxy, cycloalkoxy, aryloxy, heterocyclyloxy, heteroaryloxy, siloxyl, silyl, or organophosphatyl; R.sup.5 and R.sup.6 are each independently alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, or heteroaryl; R.sup.7 is ##STR00002## and R.sup.8, R.sup.9 and R.sup.10 are each independently alkyl, cycloalkyl, aryl, heterocyclyl, or heteroaryl; provided that if the organophosphorus compound is of Formula IB, then at least one of R.sup.5, and R.sup.6 are other than hydrogen, alkyl, or alkenyl; and if the organophosphorus compound is of Formula IC, then the electrolyte solution does not include 4-methylene-1,3-dioxolan-2-one or 4,5-dimethylene-1,3-dioxolan-2-one.

  18. The interaction between oxytetracycline and divalent metal ions in aqueous and mixed solvent systems.

    Science.gov (United States)

    Tongaree, S; Flanagan, D R; Poust, R I

    1999-01-01

    The effects of pH, mixed solvent systems, and divalent metal ions on oxytetracycline (OTC) solubility and the interactions between OTC and metal ions in aqueous and mixed solvent systems were investigated. OTC solubility profiles were obtained for pH 4-9. The cosolvents studied were glycerin, propylene glycol, PEG 400, and 2-pyrrolidone with the following metal ions: magnesium, calcium, and zinc. OTC and its interactions with these metal ions were evaluated by solubility, NMR, circular dichroism (CD), and electron diffraction (ED) methods. At pH 5.6, no complexation occurred with these metal ions, but OTC zwitterion formed aggregates in aqueous solutions as shown by NMR spectra. The hydration of the metal ions was observed to affect OTC aggregation, with Mg+2 causing the greatest OTC aggregation. At pH 7.5, OTC aggregation and metal-OTC complexation were observed in solutions with Ca+2 and Mg+2. Zinc ion was found to decrease OTC solubility because of zincate formation, which caused anionic OTC to precipitate. Electron diffraction revealed a relationship between OTC and metal-OTC complex crystallinity and solubility behavior. The zinc-OTC complex exhibited the highest crystallinity and lowest solubility at pH 8.0. Various cosolvents generally enhanced OTC solubility, with 2-pyrrolidone having the best solubility power. In OTC-metal-2-pyrrolidone and OTC-Zn(+2)-PEG 400 systems, circular dichroism provided evidence for the formation of soluble ternary complexes. PMID:10578513

  19. The separation of uranium ions by natural and modified diatomite from aqueous solution

    International Nuclear Information System (INIS)

    In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na2CO3 and K2SO4. The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 μmol/g and 667.40 μmol/g, respectively. The desorptive solutions of HCl, NaOH, Na2CO3, K2SO4, CaCO3, humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1 M HCl.

  20. Colorimetric and fluorogenic recognition of Hg2+ and Cr3+ in acetonitrile and their test paper recognition in aqueous media with the aid of rhodamine based sensors.

    Science.gov (United States)

    Patidar, Rajesh; Rebary, Babulal; Paul, Parimal

    2015-03-01

    Two new rhodamine derivatives (L1 and L2) were synthesized, characterized and their ion recognition property has been investigated. Both of the ionophores exhibit colorimetric and fluorogenic response for Hg(2+) and Cr(3+) ions among large number of alkali, alkaline earth and transition metal ions tested in acetonitrile. Detail studies on determination of binding constant, binding mode, reversibility of binding, lower detection limit have been carried out. Detection of metal ions in aqueous media has also been demonstrated by preparation of simple, convenient and disposable test paper sensors with two approaches viz. filter paper and membrane filter loaded with these ionophores. Both of these methods responded sharply to both the metal ions (Hg(2+) and Cr(3+)) in aqueous solution, detectable by bared-eye. For better sensing at low concentration of metal ions, reprecipitation followed by filtration enrichment of ligands on membrane filter was employed. PMID:25666715

  1. Symmetric Cell with LiMn_2O_4 for Aqueous Lithium-ion Battery

    OpenAIRE

    Park, Sun-Il; Okada, Shigeto; Yamaki, Jun-ichi

    2011-01-01

    The electrochemical characteristics of LiMn_2O_4 in aqueous electrolyte solutions have been investigated with respect to its use as both the cathode and anode active materials in a new type rechargeable battery system. The results of cyclic voltammetry show that LiMn_2O_4 reversibly intercalated/deintercalated Li^+ ions at potentials below the potentials of hydrogen and oxygen evolution in a neutral aqueous solution. Thus, it could be used as both the cathode system is about 110mAh/g, based o...

  2. Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2014-09-01

    Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

  3. Selective ion exchange onto Slovakian natural zeolites in aqueous solutions

    International Nuclear Information System (INIS)

    Ion exchange isotherms have been measured and plotted for the uptake of cesium, barium, cobalt, zinc, silver and ammonium onto clinoptilolite- and mordenite-rich tuffs of Slovakian origin selectively for both the natural and near homoionic Na form as well, using the radioanalytical determination. The higher quality clinoptilolite-rich tuff has been proven to be effective for a potential radionucleides removal in native form according to the following selectivity sequence: Ag+,Ba2,Cs+>NH4+>Co2+, while parent tuff in Na exchanged variety exhibited a little different sequence according to: Ag+ > NH4+ > Ba2+ > Cs+. The raw and Na exchanged mordenite-rich tuffs proved subsequently more or less similar selectivity: Ag+ > Zn2+ > Cs+, Ba2+ > Co2+ and Ag+ > Zn2+. (author)

  4. New chemistry of the uranyl ion in non aqueous media

    International Nuclear Information System (INIS)

    This work deals with new aspects of the chemistry of the uranyl(VI) ion {UO2}2+ in anhydrous polar organic solvents such as the activation of the reputedly inert U-Oyl bond and the controlled reduction of this species which represent a particularly active field of research that attracts much attention for both its fundamental aspects and applications. Treatment of uranyl(VI) compounds UO2X'2 (X' = I, OTf, Cl) with Me3SiX (X = Cl, Br, I) reagents, in various anhydrous polar organic solvents, has been first considered. In most cases, reduction into tetravalent species with complete de-oxygenation of the uranyl {UO2}2+ ion is observed. The reaction is particularly efficient in acetonitrile where the tetravalent [UX4(MeCN)4] complexes, which are useful precursors in uranium chemistry, are isolated. In the course of these reactions, the influence of the solvent, the nature of X' and X in the UO2X'2 precursor and the Me3SiX reagent are pointed out. Reaction of the uranyl(VI) UO2X2 (X = I, Cl, OTf, NO3) precursors with the anionic MC5R5 (M = K, R = H, Me; M= Li, R = Me; M= Tl, R = H) reagents did not lead to the organometallic [(η5-C5R5)nUO2X2-n] species (n = 1, 2) but to pentavalent uranyl(V) complexes. This method is a facile and rapid route towards the formation of stable pentavalent uranyl which offers promising sources for further U(V) chemical developments and for fundamental and applied interests. Their structure is strongly dependent on the nature of the solvent, the additional ligands X and of the M+ cation. In pyridine, the {UO2(py)5}+ ion appears to be an ubiquitous and a quite stable entity. The coordinating properties of the basic oxo groups, which coordinate easily to M+ ions (M= Li, K, Tl), favour structural diversity with formation of hetero-polymetallic complexes such as [{UO2(py)5}{MX(py)2}] (M= Li, X I), [{UO2(py)5}{MX2(py)2}]∞ (M= K, Tl, X= OTf; M= K, X= I), [{UO2(py)5}(M2X3)]∞ (M= Li, X= OTf) or [{UO2(py)5}2(M3X5)]∞ (M= K; X= OTf). With

  5. Biosorption of heavy metal ions from aqueous solution by red macroalgae.

    Science.gov (United States)

    Ibrahim, Wael M

    2011-09-15

    Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment. PMID:21798665

  6. Characterization of aqueous silver nitrate solutions for leakage tests

    Directory of Open Access Journals (Sweden)

    José Ferreira Costa

    2011-06-01

    Full Text Available OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled and three brands of silver nitrate salt (Merck, Synth or Cennabras at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h and concentrations (1, 5, 25, 50% of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%. RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9. Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm. In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000. CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were

  7. Characterization of aqueous silver nitrate solutions for leakage tests

    Science.gov (United States)

    COSTA, José Ferreira; SIQUEIRA, Walter Luiz; LOGUERCIO, Alessandro Dourado; REIS, Alessandra; de OLIVEIRA, Elizabeth; ALVES, Cláudia Maria Coelho; BAUER, José Roberto de Oliveira; GRANDE, Rosa Helena Miranda

    2011-01-01

    Objectives To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. Material and Methods A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50%) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%). Results The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000). Conclusions Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were capable of

  8. Reanalysis of the Aqueous Spectrum of the Neptunyl(V) [NpO2(+)] Ion.

    Science.gov (United States)

    Edelstein, Norman M

    2015-11-12

    The actinyl ions, consisting of the dioxoactinde(VI) and dioxoactinide(V) ions, are unique in the periodic table. However, very few quantitative studies of the spectra of these ions have been performed. In this paper the analysis of the optical spectrum of the aqueous neptunyl(V) [NpO2(+)] ion in 1 M HClO4 is reexamined. The species in solution is assumed to be the linear NpO2(+) ion surrounded in the equatorial plane by five oxygen atoms from five H2O molecules. The neptunyl(V) ion has the 5f(2) open-shell configuration, and the low-lying optical transitions (up to ∼20 000 cm(-1)) observed are primarily from the two 5f electrons occupying the 5fφ and 5fδ orbitals. The conventional parametric theory used for f(n) systems is applied to these low-lying transitions utilizing the intensity calculations that Matiska et al.1 have performed for this ion and the data reported by Eisenstein and Pryce.2 Possible ratios for the Slater electrostatic repulsion parameters are obtained from the data for the isoelectronic ion U(4+) (5f(2)) in various host crystals. The results are consistent with earlier crystal field analyses of the 5f(1) neptunyl(VI) [NpO2(2+)] ion. PMID:26487013

  9. Thiosemicabazone based fluorescent chemosensor for transition metal ions in aqueous medium

    International Nuclear Information System (INIS)

    Highly efficient fluorescent chemosensors for metal ions have been synthesized by using thiosemicarbazide and aromatic aldehydes. Detection of transition metal ions was performed via UV–vis and fluorescence spectroscopic methods. This is the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex were confirmed by using B–H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg2+, Zn2+, Co2+, Ni2+ and Sn2+ ions is due to the inhibition of photoinduced electron transfer mechanism whereas, quenching of fluorescence is attributed to the photoinduced electron transfer mechanism in case of Cu2+ and Mn2+ ions. -- Graphical abstract: Three highly sensitive aromatic thiosemicarbazones act as a fluorescent chemosensor for cations. Detection of transition metal ions was performed via UV–vis and fluorescence spectroscopic methods. This represents the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex was confirmed by using B–H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg2+ , Zn2+, Co2+, Ni2+ and Sn2+ ions is due to the inhibition of photoinduced electron transfer whereas, in the case of Cu2+ and Mn2+ ions quenching of fluorescence occurring is attributed to the photoinduced electron transfer mechanism. Highlights: • The receptors were synthesized and studied for its optical/fluorescence emission properties. • R1+Zn2+/Co2+/Ni2+ and R2+Hg2+/Sn2+ exhibits fluorescence enhancement via inhibition of PET. • R1+Cu2+ and R3+Mn2+ exhibits fluorescence quenching via PET mechanism

  10. MWCNTs based high sensitive lateral flow strip biosensor for rapid determination of aqueous mercury ions.

    Science.gov (United States)

    Yao, Li; Teng, Jun; Zhu, Mengya; Zheng, Lei; Zhong, Youhao; Liu, Guodong; Xue, Feng; Chen, Wei

    2016-11-15

    Here, we describe a disposable multi-walled carbon nanotubes (MWCNTs) labeled nucleic acid lateral flow strip biosensor for rapid and sensitive detection of aqueous mercury ions (Hg(2+)). Unlike the conventional colloidal gold nanoparticle based strip biosensors, the carboxylated MWCNTs were selected as the labeling substrate because of its high specific surface area for immobilization of recognition probes, improved stability and enhanced detection sensitivity of the strip biosensor. Combining the sandwich-type of T-Hg(2+)-T recognition mechanism with the optical properties of MWCNTs on lateral flow strip, optical black bands were observed on the lateral flow strips. Parameters (such as membrane category, the MWCNTs concentration, the amount of MWCNT-DNA probe, and the volume of the test probe) that govern the sensitivity and reproducibility of the sensor were optimized. The response of the optimized biosensor was highly linear over the range of 0.05-1ppb target Hg(2+), and the detection threshold was estimated at 0.05 ppb within a 15-min assay time. The sensitivity was 10-fold higher than the conventional colloidal gold based strip biosensor. More importantly, the stability of the sensor was also greatly improved with the usage of MWCNTs as the labeling. PMID:27183284

  11. A negative ion source test facility

    Energy Technology Data Exchange (ETDEWEB)

    Melanson, S.; Dehnel, M., E-mail: morgan@d-pace.com; Potkins, D.; Theroux, J.; Hollinger, C.; Martin, J.; Stewart, T.; Jackle, P.; Withington, S. [D-Pace, Inc., P.O. Box 201, Nelson, British Columbia V1L 5P9 (Canada); Philpott, C.; Williams, P.; Brown, S.; Jones, T.; Coad, B. [Buckley Systems Ltd., 6 Bowden Road, Mount Wellington, Auckland 1060 (New Zealand)

    2016-02-15

    Progress is being made in the development of an Ion Source Test Facility (ISTF) by D-Pace Inc. in collaboration with Buckley Systems Ltd. in Auckland, NZ. The first phase of the ISTF is to be commissioned in October 2015 with the second phase being commissioned in March 2016. The facility will primarily be used for the development and the commercialization of ion sources. It will also be used to characterize and further develop various D-Pace Inc. beam diagnostic devices.

  12. investigations for the separation of radioisotopes and selected metal ions from dilute aqueous solutions and aqueous waste simulant by foaming

    International Nuclear Information System (INIS)

    co precipitate flotation (CPF) investigations show that cesium can be efficiently separated from aqueous solutions by coprecipitation with zine hexacyanoferrate (II) (ZnHCF) and subsequent flotation of the precipitate . collectors of different types were tested but cetyl pyridinium chloride showed the best performance. before undertaking the flotation investigations , coprecipitation of Cs with ZnHCF was studied to determine the optimal coprecipitation conditions. the developed CPF process was applied successfully for 137Cs removal from process wastewater and low level liquid radioactive waste simulant. the obtained results compare favourably with data published for cesium removal by coprecipitation or adsorption processes. besides, CPF seems to be more advantageous

  13. Water rotational jump driven large amplitude molecular motions of nitrate ions in aqueous potassium nitrate solution

    CERN Document Server

    Banerjee, Puja; Bagchi, Biman

    2016-01-01

    Molecular dynamics simulations of aqueous potassium nitrate solution reveal a highly complex rotational dynamics of nitrate ions where, superimposed on the expected continuous Brownian motion, are large amplitude angular jumps that are coupled to and at least partly driven by similar large amplitude jump motions in water molecules which are associated with change in the hydrogen bonded water molecule. These jumps contribute significantly to rotational and translational motions of these ions. We explore the detailed mechanism of these correlated (or, coupled) jumps and introduce a new time correlation function to decompose the coupled orientational- jump dynamics of solvent and solute in the aqueous electrolytic solution. Time correlation function provides for the unequivocal determination of the time constant involved in orientational dynamics originating from making and breaking of hydrogen bonds. We discover two distinct mechanisms-both are coupled to density fluctuation but are of different types.

  14. Synthesis and Electrochemical Performance of a Lithium Titanium Phosphate Anode for Aqueous Lithium-Ion Batteries

    KAUST Repository

    Wessells, Colin

    2011-01-01

    Lithium-ion batteries that use aqueous electrolytes offer safety and cost advantages when compared to today\\'s commercial cells that use organic electrolytes. The equilibrium reaction potential of lithium titanium phosphate is -0.5 V with respect to the standard hydrogen electrode, which makes this material attractive for use as a negative electrode in aqueous electrolytes. This material was synthesized using a Pechini type method. Galvanostatic cycling of the resulting lithium titanium phosphate showed an initial discharge capacity of 115 mAh/g and quite good capacity retention during cycling, 84% after 100 cycles, and 70% after 160 cycles at a 1 C cycling rate in an organic electrolyte. An initial discharge capacity of 113 mAh/g and capacity retention of 89% after 100 cycles with a coulombic efficiency above 98% was observed at a C/5 rate in pH -neutral 2 M Li2 S O4. The good cycle life and high efficiency in an aqueous electrolyte demonstrate that lithium titanium phosphate is an excellent candidate negative electrode material for use in aqueous lithium-ion batteries. © 2011 The Electrochemical Society.

  15. Aqueous sodium borohydride induced thermally stable porous zirconium oxide for quick removal of lead ions

    Science.gov (United States)

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-03-01

    Aqueous sodium borohydride (NaBH4) is well known for its reducing property and well-established for the development of metal nanoparticles through reduction method. In contrary, this research paper discloses the importance of aqueous NaBH4 as a precipitating agent towards development of porous zirconium oxide. The boron species present in aqueous NaBH4 play an active role during gelation as well as phase separated out in the form of boron complex during precipitation, which helps to form boron free zirconium hydroxide [Zr(OH)4] in the as-synthesized condition. Evolved in-situ hydrogen (H2) gas-bubbles also play an important role to develop as-synthesized loose zirconium hydroxide and the presence of intra-particle voids in the loose zirconium hydroxide help to develop porous zirconium oxide during calcination process. Without any surface modification, this porous zirconium oxide quickly adsorbs almost hundred percentages of toxic lead ions from water solution within 15 minutes at normal pH condition. Adsorption kinetic models suggest that the adsorption process was surface reaction controlled chemisorption. Quick adsorption was governed by surface diffusion process and the adsorption kinetic was limited by pore diffusion. Five cycles of adsorption-desorption result suggests that the porous zirconium oxide can be reused efficiently for removal of Pb (II) ions from aqueous solution.

  16. SINGLE AND DOUBLE IMPRINTED POLYMER FOR SELECTIVE RECOGNITION OF Cd(II) IONS IN AQUEOUS MEDIA

    OpenAIRE

    Ebru Birlik ÖZKÜTÜK; Elif ÖZALP; Gülgün İŞLER

    2010-01-01

    In this paper, we have reported the synthesis of a new single and double-imprinted polymeric material for the separation of Cd(II) ions in aqueous solutions. Chitosan has choosen as the Cd(II) metal complexing big polymer for single and double imprinted polymers. In the synthesis of single imprinted polymer, Cd(II)-complexed chitosan has crosslinked by epichlorohydrin. In the synthesis of double imprinted polymer, Cd(II)-complexed chitosan was reacted with 3-mercaptopropyl-trimethoxysilane. ...

  17. Biologically derived melanin electrodes in aqueous sodium-ion energy storage devices

    OpenAIRE

    Kim, Young Jo; Wu, Wei; Chun, Sang-Eun; Whitacre, Jay F.; Bettinger, Christopher J.

    2013-01-01

    Here we present important findings related to biologically derived pigments for potential use as battery electrodes. Namely, we report the synthesis, fabrication, and characterization of melanins as materials for use in aqueous sodium-ion batteries. We demonstrate the use of naturally occurring melanins as active electrode materials in charge storage devices. Furthermore, the performance of melanin anodes is comparable to many commonly available synthetic organic electrode materials. The stru...

  18. The electrochemical reduction of perrhenate ion in non–aqueous dimethylsulfoxide solutions

    OpenAIRE

    Leila Kudreeva; Zh. Kulbayeva; Andrey Kurbatov; Mikhail Nauryzbayev; M. Ainamkulova

    2012-01-01

    The electrochemical deposition of perrenate ion in non – aqueous dimethylsulphoxide solutions of electrolytes investigation. The obtained polarization curves show that several waves are observed before electrochemical deposition of renium. The results of x-ray spectral analysis and electron microscopy allowed to determine the fact that these waves correspond to formation of a passivating film, which is formed at reduction of the solvent, on the surface of a metal substrate. 

  19. Degradation of acid red 14 by silver ion-catalyzed peroxydisulfate oxidation in an aqueous solution

    OpenAIRE

    RASOULIFARD, Mohammad Hossein; MOHAMMADI, Seied Mohammad Mahdi DOUST

    2012-01-01

    Silver ion (Ag1+)-catalyzed peroxydisulfate was studied for the degradation of acid red 14 (AR-14) in an aqueous medium. The effect of different parameters, such as temperature, peroxydisulfate concentration, and dye and Ag1+ concentrations, were investigated. Application of Ag1+-catalyzed peroxydisulfate, as an advanced oxidation process, introduces an effectual method for wastewater treatment. An accelerated reaction using S2O82- to destroy dyes can be achieved via chemical activat...

  20. Revised Ionic Radii of Lanthanoid(III) Ions in Aqueous Solution

    International Nuclear Information System (INIS)

    A new set of ionic radii in aqueous solution has been derived for lanthanoid(III) cations starting from a very accurate experimental determination of the ion water distances obtained from extended X-ray absorption fine structure (EXAFS) data. At variance with previous results, a very regular. trend has been obtained, as expected for this series of elements. A general procedure to compute ionic radii in solution by combining the EXAFS technique and molecular dynamics (MD) structural data has been developed. This method can be applied to other ions allowing one to determine ionic radii in solution with an accuracy comparable to that of the Shannon crystal ionic radii. (authors)

  1. ADSORPTION OF Mg(II) ION FROM AQUEOUS SOLUTION ON CHITOSAN BEADS AND CHITOSAN POWDER

    OpenAIRE

    Sari Edi Cahyaningrum

    2010-01-01

    A basic investigation on the removal of Mg(II) ion from aqueous solution by chitosan beads wasconducted in a batch adsorption system. The influence of different experimental parameters; pH,agitation period and different concentration of Mg(II) ion was evaluated. A pH 7.0 was found to be anoptimum pH for Mg(II) adsorption onto chitosan powder and chitosan beads. The Langmuir andFreundlich adsorption isotherm models were applied to describe the isotherms and isotherm constantsfor the adsorption...

  2. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    OpenAIRE

    Uzaşçı Sesil; Tezcan Filiz; Bedia Erim F.

    2014-01-01

    Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI) was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI) adsorpt...

  3. Removal of copper ions from aqueous solutions by a new sorbent: Polyethyleneiminemethylene phosphonic acid

    OpenAIRE

    Ferrah, Nacer; ABDERRAHIM, Omar; DIDI, Mohamed Amine; VILLEMIN, Didier

    2011-01-01

    The sorption of copper(II) from sulphate medium on an extractant polymer containing phosphonic acid has been studied in batch mode. Since the extraction kinetics were fast, with a mixture of 0.01 g of extractant and 5 mL of copper(II) 31.75 mg/L solution, extraction equilibrium was reached within 20 min of mixing. The sorption process follows a pseudo-second-order kinetics. The influence of some parameters such as initial copper(II) ion concentration, initial pH of aqueous solution, ion stren...

  4. Magnetic separation of Dy(III) ions from homogeneous aqueous solutions

    International Nuclear Information System (INIS)

    The possibility to enrich paramagnetic dysprosium(III) ions in a magnetic field gradient is proved by means of interferometry, which may open the route for a magnetic separation of rare earth ions from aqueous solutions. The separation dynamics are studied for three different concentrations of DyCl3 and compared with those found recently in a sulphate solution of the 3d ion Mn(II). In view of the similar-sized hydration spheres for Dy(III) and Mn(II), the slower separation dynamics in DyCl3 is attributed to both a higher densification coefficient and the strong impact of Brownian motion due to the absence of ion-pair clusters

  5. Reaction of nitrite ion with hydroxylamine-N-sulfonate in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Oblath, S.B.; Markowitz, S.S.; Novakov, T.; Chang, S.G.

    1983-02-16

    The reaction between nitrite ion and hydroxylamine-N-sulfonate (HAMS) has been investigated in aqueous solutions; nitrous oxide and sulfate ions are the major products. The reaction kinetics exhibit first-order dependence on nitrite ion, second-order dependence on hydrogen ion in the pH region of 4-5, and between zero- and first-order dependence on HAMS, depending on the concentration. An activation energy of 30 kJ/mol was determined for the reaction in the temperature range of 10-40/sup 0/C. The ionic strength dependence was studied in the range of 0.2-1.5 M. Oxalate, tartrate, and phthalate buffer systems were found to enhance the rate of reaction to varying degrees. An empirical rate law and the determined rate constants are reported. The results are examined in terms of a mechanism that consists of the nitrosation of HAMS, followed by a decomposition into products.

  6. Oxidative degradation of spent ion-exchange resins and alpha-bearing wastes in aqueous medium

    International Nuclear Information System (INIS)

    Different treatment processes of spent ion-exchange resins aiming at volume reduction are under development or on fullscale operation. A new volume reduction technique for treatment of ion-exchange resin materials was developed using hydrogen peroxide as oxidizing agent in presence of catalyst. Details information for this technique is introduced in this report. A newly developed simple and economically attractive technique for oxidative decomposition of spent ion-exchange resins was studied aiming at achieving remarkable volume and weight reduction. Different factors affecting semi-continuous oxidative degradation process e.g. effect of addition rate of oxidant, pH value, grain size of resin as well as type and concentration of catalyst were studied, keeping the reaction time and weight of resins constant for both cationite and anionite forms. In conclusion, the oxidative degradation of ion-exchange resin in aqueous medium could be considered as a very attractive process. (M.N.)

  7. Study on the adsorption of heavy metal ions from aqueous solution on modified SBA-15

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2013-01-01

    Full Text Available Amino-functionalized SBA-15 mesoporous silica was prepared, characterized, and used as an adsorbent for heavy metal ions. The organic - inorganic hybrid material was obtained by a grafting procedure using SBA-15 silica with 3-aminopropyl-triethoxysilane and bis(2,4,4-trimethylpentyl phosphinic acid (Cyanex 272, respectively. The structure and physicochemical properties of the materials were characterized by means of elemental analysis, X-ray diffraction (XRD, nitrogen adsorption - desorption, thermogravimetric analysis, FTIR spectroscopy and immersion calorimetry. The organic functional groups were successfully grafted onto the SBA-15 surface and the ordering of the support was not affected by the chemical modification. The behavior of the grafted solids was investigated for the adsorption of heavy metal ions from aqueous solutions. The hybrid materials showed high adsorption capacity and high selectivity for zinc ions. Other ions, such as cooper and cobalt were absorbed by the modified SBA-15 material.

  8. Removal of ammonium ion from aqueous solution by natural Turkish (Yildizeli) zeolite for environmental quality

    Energy Technology Data Exchange (ETDEWEB)

    Saltali, Kadir [Department of Soil Science, Faculty of Agriculture, University of Gaziosmanpasa, 60240 Tokat (Turkey)]. E-mail: kadirs@gop.edu.tr; Sari, Ahmet [Department of Chemistry, Faculty of Art and Science, University of Gaziosmanpasa, 60240 Tokat (Turkey); Aydin, Mehmet [Graduate School of Natural and Applied Sciences, University of Gaziosmanpasa, 60240 Tokat (Turkey)

    2007-03-06

    The purposes of this study were to investigate the removal efficiency of ammonium (NH{sub 4} {sup +}) ion from aqueous solution using the natural Turkish (Yildizeli) zeolite and to characterize equilibrium isotherms. Experiments were carried out using batch method as a function of the solution pH, shaking time, dosage of adsorbent, and temperature. All these factors affected NH{sub 4} {sup +} ion removal from aqueous solution. Equilibrium modelling data were fitted to linear Langmuir and Freundlich models. Dubinin-Redushckevich (D-R) isotherm was applied to describe the nature of ion exchange of NH{sub 4} {sup +} and found that it occurred physically. Thermodynamics parameters such as change in free energy ({delta}G{sup o}), enthalpy ({delta}H{sup o}) and entropy ({delta}S{sup o}) were also calculated. These parameters confirmed that ion exchange of NH{sub 4} {sup +} by the zeolite was feasible, spontaneous and exothermic in nature. Based on the results, it can be concluded that the natural Turkish (Yildizeli) zeolite is suitable for the removal of NH{sub 4} {sup +} ions in wastewater treatments and agricultural purposes to in terms of sustainability of environmental quality.

  9. Removal of ammonium ion from aqueous solution by natural Turkish (Yildizeli) zeolite for environmental quality

    International Nuclear Information System (INIS)

    The purposes of this study were to investigate the removal efficiency of ammonium (NH4+) ion from aqueous solution using the natural Turkish (Yildizeli) zeolite and to characterize equilibrium isotherms. Experiments were carried out using batch method as a function of the solution pH, shaking time, dosage of adsorbent, and temperature. All these factors affected NH4+ ion removal from aqueous solution. Equilibrium modelling data were fitted to linear Langmuir and Freundlich models. Dubinin-Redushckevich (D-R) isotherm was applied to describe the nature of ion exchange of NH4+ and found that it occurred physically. Thermodynamics parameters such as change in free energy (ΔGo), enthalpy (ΔHo) and entropy (ΔSo) were also calculated. These parameters confirmed that ion exchange of NH4+ by the zeolite was feasible, spontaneous and exothermic in nature. Based on the results, it can be concluded that the natural Turkish (Yildizeli) zeolite is suitable for the removal of NH4+ ions in wastewater treatments and agricultural purposes to in terms of sustainability of environmental quality

  10. Self-motion of a phenanthroline disk on divalent metal ion aqueous solutions coupled with complex formation

    OpenAIRE

    Nakata, Satoshi; Arima, Yoshie

    2008-01-01

    The self-motion of a 1,10-phenanthroline disk on divalent metal ion aqueous solutions was investigated as a simple autonomous motor coupled with complex formation. The characteristic features of motion (continuous and oscillatory motion) and their concentration regions differed among metal ions, and the frequency of oscillatory motion depended on the temperature of the aqueous solution. The nature of the characteristic motion is discussed in relation to the stability constant of complex forma...

  11. A Valence Bond Model for Aqueous Cu(II) and Zn(II) Ions in the AMOEBA Polarizable Force Field

    OpenAIRE

    Xiang, Jin Yu; Ponder, Jay W.

    2012-01-01

    A general molecular mechanics (MM) model for treating aqueous Cu2+ and Zn2+ ions was developed based on valence bond (VB) theory and incorporated into the AMOEBA polarizable force field. Parameters were obtained by fitting molecular mechanics energies to that computed by ab initio methods for gas phase tetra- and hexa-aqua metal complexes. Molecular dynamics (MD) simulations using the proposed AMOEBA-VB model were performed for each transition metal ion in aqueous solution and solvent coordin...

  12. Experimental Study on Surface Reactions of Heavy Metal Ions With Quartz—Aqueous Ion Concentration Dependence

    Institute of Scientific and Technical Information of China (English)

    吴宏海; 吴大清; 等

    1999-01-01

    Adsorption of divalent metal ions,including Cu2+,Pb2+,Zn2+,Cd2+ and Ni2+,on quartz surface was measured as a function of metal ion concentration at 30℃under condi tions of solution pH=6.5 and ion strength I=0.1mol/L.Results of the experimental measuements can be described very well by adsorption isoterm dquations of Freudlich.The correlation coefficients(r)of adsorption isotherm lines are>0.96.Moreover,the exprimental data were interpreted on the basis of surface complexation model.Te experimental results showed that the monodentate-coordinated metal ion surface complex species(SOM+)are predominant over the bidentate-coordinated metal ion surface complex species[(SO)2M]formed only by the ions Cu2+,Zn2+ and Ni2+,And the relevant apparent surface complexation constants are lgKM=2.2-3.3 in order of KCd≥KPb>KZn>KNi≥KCu,and lgβM=5.8-6.8 in oder of βNi>βZn>βCu.Therefore,the reactive ability of the ions onto mineral surface of quartz follows the order of Cd>Pb>Zn>Ni>Cu under the above-mentioned solution conditions.The apparent surface complexation constants,influenced by the surface potential,surface species and hydrolysis of metal ions,depend mainly on the Born solvation coefficeient of the metal ions.

  13. Flexible Aqueous Lithium-Ion Battery with High Safety and Large Volumetric Energy Density.

    Science.gov (United States)

    Dong, Xiaoli; Chen, Long; Su, Xiuli; Wang, Yonggang; Xia, Yongyao

    2016-06-20

    A flexible and wearable aqueous lithium-ion battery is introduced based on spinel Li1.1 Mn2 O4 cathode and a carbon-coated NASICON-type LiTi2 (PO4 )3 anode (NASICON=sodium-ion super ionic conductor). Energy densities of 63 Wh kg(-1) or 124 mWh cm(-3) and power densities of 3 275 W kg(-1) or 11.1 W cm(-3) can be obtained, which are seven times larger than the largest reported till now. The full cell can keep its capacity without significant loss under different bending states, which shows excellent flexibility. Furthermore, two such flexible cells in series with an operation voltage of 4 V can be compatible with current nonaqueous Li-ion batteries. Therefore, such a flexible cell can potentially be put into practical applications for wearable electronics. In addition, a self-chargeable unit is realized by integrating a single flexible aqueous Li-ion battery with a commercial flexible solar cell, which may facilitate the long-time outdoor operation of flexible and wearable electronic devices. PMID:27159823

  14. Diffusion Coefficient of Iodide ions in Aqueous Medium and in Vacuum: An Appraisal

    International Nuclear Information System (INIS)

    Diffusion Coefficient of iodide ion was determined through cyclic voltammetric technique and compared with the values in literature. The contribution of (a) the fractal surface of the electrode, and (b) possible involvement of subsequent chemical reaction (EC) to the peak current affecting the diffusion coefficient were analyzed. It was concluded that the diffusion coefficient obtained via peak current of the cyclic voltammogram corrected for sweep dependence could be relied upon. The diffusion coefficient, D, of ion in aqueous media is deduced to be 1.95 (± 0.05) *10 /sup -5/ cm /sup 2/ s /sup -1/. Fractal analysis showed there is very negligible effect of fractal surface of the electrode. Diffusion coefficient of iodide ion in vacuum was calculated from equation , where h is Planck constant and mI-, is the mass of iodide ion. D of in vacuum came out to be much smaller, 2.5 *10 /sup -6/ cm /sup 2/ s /sup -1/, as compared to the one in aqueous solution. This D may be considered as the lower limit of the diffusion coefficient of a species, here. (author)

  15. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

    KAUST Repository

    Naganuma, Tamaki

    2014-01-01

    Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

  16. Removal of Cu (II) ions from aqueous solutions by turmeric powder

    International Nuclear Information System (INIS)

    Copper is an essential nutrient, but it is toxic at high intake levels. The presence of copper(II) ions causes serious toxicological concerns, it is usually known to deposit in brain, skin, liver, pancreas and myocardium. In this work the ability of turmeric to remove copper (II) ions from aqueous solution was studied. Adsorption of metals ions by turmeric powder may be used as a natural remedy for sequestration of toxic metals which are ingested through daily food intake It was found that adsorption increased with increasing contact time, pH, temperature, adsorbent dose. The equilibrium data were satisfactorily described by Freundlich isotherm model. Adsorption of Cu (II) by turmeric powder was followed by pseudo 2/sub nd/ order kinetics. (author)

  17. Removal of phosphate ions from aqueous solution using Tunisian clays minerals and synthetic zeolite

    Institute of Scientific and Technical Information of China (English)

    Noureddine Hamdi; Ezzeddine Srasra

    2012-01-01

    Phosphate ions are usually considered to be responsible for the algal bloom in receiving water bodies and aesthetic problems in water.From the environmental point of view,the management of such contaminant and valuable resource is very important.The present work deals with the removal of phosphate ions from aqueous solutions using kaolinitic and smectic clay minerals and synthetic zeolite as adsorbent.The pH effect and adsorption kinetic were studied.It was found that phosphate could be efficiently removed at acidic pH (between 4 and 6) and the second order model of kinetics is more adopted for all samples.The isotherms of adsorption of phosphate ions by the two clays and the zeolite samples show that the zeolite has the highest rate of uptake (52.9 mg P/g).Equilibrium data were well fitted with Langmuir and Freundlich isotherm.

  18. Biosorption of Cr (VI) ion from aqueous solution by maize husk: isothermal, kinetics and thermodynamic study

    International Nuclear Information System (INIS)

    The kinetics, equilibrium and thermodynamic of the biosorption of Cr (VI) ion onto maize husk biomass from aqueous solution were investigated. The effects of contact time, initial metal concentration, pH, temperature as well as modification with oxalic acid on biosorption capacity were studied. The maximum biosorption capacity of the untreated corn shaft biomass (UTCS) was found to be 28.49 mg g-1 which slightly increased to 29.33 mg g/sup -1/ when treated with oxalic acid treated corn shaft biomass (ATCS). The kinetics studies showed that the biosorption process of the metal ion fitted well with second order model. The calculated thermodynamic parameters (delta Go, delta Ho and delta S') showed that the biosorption of Cr (VI) ion onto the biomass maize husk is feasible, spontaneous and exothermic in nature. (author)

  19. Removal of phosphate ions from aqueous solution using Tunisian clays minerals and synthetic zeolite.

    Science.gov (United States)

    Hamdi, Noureddine; Srasra, Ezzeddine

    2012-01-01

    Phosphate ions are usually considered to be responsible for the algal bloom in receiving water bodies and aesthetic problems in water. From the environmental point of view, the management of such contaminant and valuable resource is very important. The present work deals with the removal of phosphate ions from aqueous solutions using kaolinitic and smectic clay minerals and synthetic zeolite as adsorbent. The pH effect and adsorption kinetic were studied. It was found that phosphate could be efficiently removed at acidic pH (between 4 and 6) and the second order model of kinetics is more adopted for all samples. The isotherms of adsorption of phosphate ions by the two clays and the zeolite samples show that the zeolite has the highest rate of uptake (52.9 mg P/g). Equilibrium data were well fitted with Langmuir and Freundlich isotherm. PMID:22894095

  20. Removal of Lead (II Ions from Aqueous Solutions onto Activated Carbon Derived from Waste Biomass

    Directory of Open Access Journals (Sweden)

    Murat Erdem

    2013-01-01

    Full Text Available The removal of lead (II ions from aqueous solutions was carried out using an activated carbon prepared from a waste biomass. The effects of various parameters such as pH, contact time, initial concentration of lead (II ions, and temperature on the adsorption process were investigated. Energy Dispersive X-Ray Spectroscopy (EDS analysis after adsorption reveals the accumulation of lead (II ions onto activated carbon. The Langmuir and Freundlich isotherm models were applied to analyze equilibrium data. The maximum monolayer adsorption capacity of activated carbon was found to be 476.2 mg g−1. The kinetic data were evaluated and the pseudo-second-order equation provided the best correlation. Thermodynamic parameters suggest that the adsorption process is endothermic and spontaneous.

  1. Electrochemical behavior of LiCoO2 as aqueous lithium-ion battery electrodes

    KAUST Repository

    Ruffo, Riccardo

    2009-02-01

    Despite the large number of studies on the behavior of LiCoO2 in organic electrolytes and its recent application as a positive electrode in rechargeable water battery prototypes, a little information is available about the lithium intercalation reaction in this layered compound in aqueous electrolytes. This work shows that LiCoO2 electrodes can be reversibly cycled in LiNO3 aqueous electrolytes for tens of cycles at remarkably high rates with impressive values specific capacity higher than 100 mAh/g, and with a coulomb efficiency greater than 99.7%. Stable and reproducible cycling measurements have been made using a simple cell design that can be easily applied to the study of other intercalation materials, assuming that they are stable in water and that their intercalation potential range matches the electrochemical stability window of the aqueous electrolyte. The experimental arrangement uses a three-electrode flooded cell in which another insertion compound acts as a reversible source and sink of lithium ions, i.e., as the counter electrode. A commercial reference electrode is also present. Both the working and the counter electrodes have been prepared as thin layers on a metallic substrate using the procedures typical for the study of electrodes for lithium-ion batteries in organic solvent electrolytes. © 2008 Elsevier B.V. All rights reserved.

  2. Adsorption of Heavy Metal Ions from Aqueous Solutions by Zeolite Based on Oil Shale Ash: Kinetic and Equilibrium Studies

    Institute of Scientific and Technical Information of China (English)

    BAO Wei-wei; ZOU Hai-feng; GAN Shu-cai; XU Xue-chun; JI Gui-juan; ZHENG Ke-yan

    2013-01-01

    Na-A zeolite was successfully synthesized via the alkaline fusion method with oil shale ash as the raw material.The adsorption capacity of it was tested by removing CU2+,Ni2+,Pb2+ and Cd2+ from aqueous solutions.The results reveal the maximum adsorption capacity of adsorbent for Pb2+,Cu2+,Cd2+ and Ni2+ were 224.72,156.74,118.34 and 53.02 mg/g,respectively.The effects of contact time and pH value of solutions on the adsorption efficiency of the zeolite were evaluated.Besides,The equilibrium adsorption data and the batch kinetic data were correlated with Langmuir and Freundlich models and the pseudo-first-order and pseudo-second-order models separately.The results show that the Langmuir isotherm and the pseudo-second-order equation were more suitable for the adsorption of Na-A zeolite for the metal ions.In addition,Thermodynamic parameters of the adsorption(the Gibbs free energy,entropy,and enthalpy) were also evaluated and discussed.The results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions and the synthesized zeolite was an effective adsorbent for the removal of metal ions from aqueous solution.

  3. BIOSORPTION OF TERNARY CADMIUM, NICKEL AND COBALT IONS FROM AQUEOUS SOLUTION ONTO SACCHAROMYCES CEREVISIAE CELLS: BATCH AND COLUMN STUDIES

    Directory of Open Access Journals (Sweden)

    Maedeh Galedar

    2013-01-01

    Full Text Available The aim of this study was to remove cadmium, nickel and cobalt ions from aqueous solutions using yeast, Saccharomyces cerevisiae, pre-treated with ethanol. The cells are immobilized using polysulfone in both batch and continuous systems. To optimize the adsorption capacity of the yeast biomass, a batch system was used to investigate the effects of initial pH, initial biomass dose and initial metal ion concentration. Optimum conditions were obtained at pH 8 with a biomass of and ion concentrations of 8 and 100 mg L-1, respectively. Under these conditions, the maximum uptake capacity was 3.1 mg g-1 for cadmium, 1.2 mg g-1 for nickel and 0.68 mg g-1 for cobalt. To estimate the biomass uptake capacity of the ethanol pretreated S. cerevisiae, the isothermal Langmuir model was found to be a better fit with a correlation coefficient of R2 -1, bead column height of 25 cm and the input flow rate of 1 mL min-1. The calculated uptake capacity of the metal ions was 3.74 mg g-1 for cadmium, 1.57 mg g-1 for nickel and 1.56 mg g-1 for cobalt. The Thomas model (0.95242<0.9957 was shown to be more consistent compared with the test results. Polysulfone immobilization of yeast was found to increase removal by 48% compared to non-immobilized ethanol pr-treated yeast.

  4. Ion source test bench facility at IUAC, New Delhi

    International Nuclear Information System (INIS)

    Ion source test bench facility has been developed at IUAC for research and development works related to the studies of the efficient production of sputtered negative ions using single cathode SNICS and gas cathodes. This ion source test bench facility has been installed at Ion source room of Pelletron accelerator. The paper reports the installation and initial test results of this setup. (author)

  5. Radiation chemical behavior of aqueous butanal oxime solutions irradiated with helium ion beams

    Science.gov (United States)

    Costagliola, A.; Venault, L.; Deroche, A.; Garaix, G.; Vermeulen, J.; Omnee, R.; Duval, F.; Blain, G.; Vandenborre, J.; Fattahi-Vanani, M.; Vigier, N.

    2016-02-01

    Samples of butanal oxime in aqueous solution have been irradiated with the helion (4He2+) beam of the ARRONAX (Nantes) and the CEMHTI (Orléans) cyclotrons. The consumption yield of butanal oxime has been measured by gas-chromatography coupled with mass spectrometry. Yields of gaseous products (mainly H2) have also been measured by micro-gas-chromatography. Butanal oxime can react with H• radicals by abstraction mechanism to enhance H2 production. Yields of liquid phase products (hydrogen peroxide and nitrite ion) have been measured by colorimetric methods. Butanal oxime acts as a scavenger of OH• radical to inhibit the production of H2O2. The observation of the radiolytic products allows then to discuss a degradation mechanism of butanal oxime in aqueous solutions.

  6. Extraction of lithium ion from alkaline aqueous media by a liquid surfactant membrane

    International Nuclear Information System (INIS)

    Extraction of lithium ion from aqueous alkaline media by a liquid surfactant membrane was performed using a mixture of LIX54 and TOPO as the extractant. Stripping of lithium from the kerosene solution to the acid solution was suppressed with increasing content of polyamine (ECA) surfactant. The extraction rate of lithium by the liquid membrane could be interpreted taking account of an interfacial resistance due to ECA. It was confirmed that swelling of the (W/O) emulsion drops by water permeation through the liquid membrane is evaluated in terms of a change in osmotic pressure gradient between the external and internal aqueous phases during the lithium extraction. In the present operation, the extraction ratio of Li+ from the external feed and the uptake into the internal phase reached as high as 95%. (author)

  7. Shellac-coated iron oxide nanoparticles for removal of cadmium(II) ions from aqueous solution.

    Science.gov (United States)

    Gong, Jilai; Chen, Long; Zeng, Guangming; Long, Fei; Deng, Jiuhua; Niu, Qiuya; He, Xun

    2012-01-01

    This study describes a new effective adsorbent for cadmium removal from aqueous solution synthesized by coating a shellac layer, a natural biodegradable and renewable resin with abundant hydroxyl and carboxylic groups, on the surface of iron oxide magnetic nanoparticles. Transmission Electron Microscopy (TEM) imaging showed shellac-coated magnetic nanoparticle (SCMN) adsorbents had a core-shell structure with a core of 20 nm and shell of 5 nm. Fourier Transform Infrared Spectroscopic analysis suggested the occurrence of reaction between carboxyl groups on the SCMN adsorbent surface and cadmium ions in aqueous solution. Kinetic data were well described by pseudo second-order model and adsorption isotherms were fitted with both Langmuir and Freundlich models with maximum adsorption capacity of 18.80 mg/g. SCMN adsorbents provided a favorable adsorption capacity under high salinity conditions, and cadmium could easily be desorbed using mild organic acid solutions at low concentration. PMID:23513435

  8. Aspiration tests in aqueous foam using a breathing simulator

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, M.M.

    1995-12-01

    Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.

  9. Electrophoretic method for the determination of diffusion coefficients of ions in aqueous solutions

    International Nuclear Information System (INIS)

    The electrophoretic method was recently developed for the determination of diffusion coefficients of ions in aqueous solution. By solving the Fick's second law in the presence of unlimited media and constant quantity of diffusing species we obtain a relationship between the diffusion coefficient and the standard deviation of the distribution profile. The diffusion coefficients of Cd(II), In(III), Zr(IV), Hf(IV), Pu(VI) and [InDTPA]2- in nitric acid solution were determined as well as the effective charge of In-DTPA complex at pH 4.50. (author)

  10. Chemiluminescence initiated by laser-induced excitation of lanthanide and actinide ions in aqueous solutions

    International Nuclear Information System (INIS)

    Data on luminol chemiluminescence in solutions containing Sm(III), U(IV), and Pu(IV) are presented. Chemiluminescence was induced by multiquantum excitation of lanthanide and actinide ions in the range of 4f- and 5f-electron transitions by the schemes: two steps - one color and two steps - two colors with the use of dye lasers. We observed chemiluminescence of chemiluminogen (luminol) caused by multiquantum excitation of lanthanides and actinides in aqueous solutions by laser radiation. A multistep scheme of chemiluminescence excitation makes this procedure not only highly sensitive but also highly selective procedure of detection of substances

  11. Hydration properties and ionic radii of actinide(III) ions in aqueous solution

    International Nuclear Information System (INIS)

    Ionic radii of actinide(III) cations (from U(III) to Cf(III)) in aqueous solution have been derived for the first time starting from accurate experimental determination of the ion-water distances obtained by combining extended X-ray absorption fine structure (EXAFS) results and molecular dynamics (MD) structural data. A strong analogy has been found between the lanthanide and actinide series concerning hydration properties. The existence of a contraction of the An-O distance along the series has been highlighted, while no decrease of the hydration number is evident up to Cf(III). (authors)

  12. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  13. Electro-enhanced removal of copper ions from aqueous solutions by capacitive deionization.

    Science.gov (United States)

    Huang, Shu-Yun; Fan, Chen-Shiuan; Hou, Chia-Hung

    2014-08-15

    This study was performed to determine the feasibility of electrosorptive removal of copper ions from aqueous solutions using a capacitive deionization process. The electrosorptive potential of copper ions was determined using cyclic voltammetry measurements, and copper electrodeposition could be suppressed at a voltage less than 0.8 V. Importantly, the experimental results demonstrated a significant enhancement of electrosorption capability of copper ions using the activated carbon electrodes under electro-assistance, associated with electrical double-layer charging. At 0.8 V, the equilibrium electrosorption capacity was enhanced to 24.57 mg/g based on the Langmuir model, and the electrosorption constant rate was increased to 0.038 min(-1) simulated by a first-order kinetics model. Moreover, the activated carbon electrode showed great regeneration performance for the removal of low level copper ions. Additional experiments regarding electrosorption selectivity were performed in the presence of sodium chloride, natural organic matter, or dissolved silica. Copper ions that were preferentially electroadsorbed on the electrode surface can be effectively removed in a competitive environment. Therefore, the electrosorption process using activated carbon electrodes can be recommended to treat copper solutions at low concentrations for wastewater treatment and water purification. PMID:24937658

  14. Adsorptive removal of nickel(II) ions from aqueous environment: A review.

    Science.gov (United States)

    Raval, Nirav P; Shah, Prapti U; Shah, Nisha K

    2016-09-01

    Among various methods adsorption can be efficiently employed for the treatment of heavy metal ions contaminated wastewater. In this context the authors reviewed variety of adsorbents used by various researchers for the removal of nickel(II) ions from aqueous environment. One of the objectives of this review article is to assemble the scattered available enlightenment on a wide range of potentially effective adsorbents for nickel(II) ions removal. This work critically assessed existing knowledge and research on the uptake of nickel by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites. The system's performance is evaluated with respect to the overall metal removal and the adsorption capacity. In addition, the equilibrium adsorption isotherms, kinetics and thermodynamics data as well as various optimal experimental conditions (solution pH, equilibrium contact time and dosage of adsorbent) of different adsorbents towards Ni(II) ions were also analyzed. It is evident from a literature survey of more than 190 published articles that agricultural solid waste materials, natural materials and biosorbents have demonstrated outstanding adsorption capabilities for Ni(II) ions. PMID:27149285

  15. Surface activated carbon nanospheres for fast adsorption of silver ions from aqueous solutions.

    Science.gov (United States)

    Song, Xianghua; Gunawan, Poernomo; Jiang, Rongrong; Leong, Susanna Su Jan; Wang, Kean; Xu, Rong

    2011-10-30

    We report the synthesis and activation of colloidal carbon nanospheres (CNS) for adsorption of Ag(I) ions from aqueous solutions. CNS (400-500 nm in diameter) was synthesized via simple hydrothermal treatment of glucose solution. The surface of nonporous CNS after being activated by NaOH was enriched with -OH and -COO(-) functional groups. Despite the low surface area (nanoparticles on the external surface of CNS. The kinetic data can be well fitted to the pseudo-second-order kinetics model. The adsorbed silver can be easily recovered by dilute acid solutions and the CNS can be reactivated by the same treatment with NaOH solution. The excellent adsorption performance and reusability have also been demonstrated in a continuous mode. The NaOH activated CNS reported here could represent a new type of low-cost and efficient adsorbent nanomaterials for removal of trace Ag(I) ions for drinking water production. PMID:21862215

  16. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    Directory of Open Access Journals (Sweden)

    Uzaşçı Sesil

    2014-07-01

    Full Text Available Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI adsorption capacity determined from Langmuir isotherm was 36.5 mg/g dry alginate beads. Our study suggests that barium alginate beads can be used as cost-effective and efficient adsorbents for the removal of chromium (VI from contaminated waters.

  17. Systematic investigations of foam separation of nickel (l l) from dilute aqueous solutions; by ion flotation

    International Nuclear Information System (INIS)

    this series of papers deal with a systematic investigation of application of different foam separation techniques for the removal of nickel (l l) from dilute aqueous solutions and to compare the effectiveness of the different techniques. in the present work, the feasibility of the use of sodium lauryl sulphate (Nals) and cetyl trimethyl ammonium bromide (CTAB) as collectors to separate nickel (l l) at Ph values below the precipitation point of Ni (OH)2 was investigated using the ion flotation technique. the different factors that might affect the separation efficiency were investigated . both collectors were found to produce hydrated froths leading to rather low concentrations of the metal ion in the foam phase. however, nals was the most effective giving recoveries >95% and it was therefore extensively investigated . possible means to improve the foam separation efficiency of solubilized nickel are generally proposed . preliminary results using the surfactant : aerosol 18 as a collector are very promising

  18. A novel agricultural waste adsorbent for the removal of lead (II) ions from aqueous solutions.

    Science.gov (United States)

    Ibrahim, M N Mohamad; Ngah, W S Wan; Norliyana, M S; Daud, W R Wan; Rafatullah, M; Sulaiman, O; Hashim, R

    2010-10-15

    The present study explores the ability of modified soda lignin (MSL) extracted from oil palm empty fruit bunches (EFB) in removing lead (II) ions from aqueous solutions. The effect of contact time, point zero charge (pH(pzc)) and pH of the solution, initial metal ion concentration and adsorbent dosage on the removal process were investigated. Furthermore, the MSL is characterized by SEM, XRF, FT-IR and surface area analysis. Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The kinetic data obtained at different initial concentrations were analyzed using pseudo-first-order and pseudo-second-order models. The results provide strong evidence to support the hypothesis of adsorption mechanism. PMID:20619537

  19. Effect of Temperature on the Removal of Cesium and Strontium Ions from Aqueous Solutions Using Zeolite A

    International Nuclear Information System (INIS)

    Ion exchange experiments between synthetic zeolite A and aqueous solutions of cesium and strontium ions were conducted at constant total ion concentrations of 0.1 N and at different temperatures in the range from 25 to 60 degree C. Thermodynamic equilibrium constants, calculated from the corresponding Kielland's plots, were used for the calculation of . δG degree δH degree and δS degree. The obtained data indicated that zeolite A exhibits higher affinity for Cs+ and Sr+2 ions from solution than host Na+ ions

  20. Removal of cadmium and zinc ions from aqueous solution by living Aspergillus niger

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-guo; FAN Ting; ZENG Guang-ming; LI Xin; TONG Qing; YE Fei; ZHOU Ming; XU Wei-hua; HUANG Yu-e

    2006-01-01

    The potential of living Aspergillus niger to remove cadmium and zinc from aqueous solution was investigated. Effects of pH, initial concentration, contact time, temperature and agitation rate on the biosorption of Cd(Ⅱ) and Zn(Ⅱ) ions were studied. The optimum adsorption pH value for Cd(Ⅱ) and Zn(Ⅱ) were 4.0 and 6.0. The best temperature and agitation rate were in the range of 25-30 ℃ and 120 r/min for all metal ions. Under the optimal conditions, the maximum uptake capacities of Cd(Ⅱ) and Zn( Ⅱ ) ions are 15.50 mg/g and 23.70 mg/g at initial concentrations of 75 mg/L and 150 mg/L, respectively. Biosorption equilibrium is established within 24 h for cadmium and zinc ions. The adsorption data provide an excellent fit to Langmuir isotherm model. The results of the kinetic studies show that the rate of adsorption follows the pseudo-second order kinetics.

  1. Biosorption of chromium(VI) ion from aqueous solutions using walnut, hazelnut and almond shell.

    Science.gov (United States)

    Pehlivan, Erol; Altun, Türkan

    2008-06-30

    The potential to remove Cr(VI) ion from aqueous solutions through biosorption using, the shells of Walnut (WNS) (Juglans regia), Hazelnut (HNS) (Corylus avellana) and Almond (AS) (Prunus dulcis) was investigated in batch experiments. The equilibrium adsorption level was determined to be a function of the solution contact time and concentration. Kinetic experiments revealed that the dilute chromium solutions reached equilibrium within 100 min. The biosorptive capacity of the shells was dependent on the pH of the chromium solution, with pH 3.5 being optimal. Adsorption of Cr(VI) ion uptake is in all cases pH-dependent showing a maximum at equilibrium pH values between 2.0 and 3.5, depending on the biomaterial, that correspond to equilibrium pH values of 3.5 for (WNS), 3.5 for (HNS) and 3.2 for (AS). The adsorption data fit well with the Langmuir isotherm model. The sorption process conformed to the Langmuir isotherm with maximum Cr(VI) ion sorption capacities of 8.01, 8.28, and 3.40 mg/g for WNS, HNS and AS, respectively. Percentage removal by WNS, HNS and AS was 85.32, 88.46 and 55.00%, respectively at a concentration of 0.5 mM. HNS presented the highest adsorption capacities for the Cr(VI) ion. PMID:18179865

  2. Ion-imprinted chitosan gel beads for selective adsorption of Ag⁺ from aqueous solutions.

    Science.gov (United States)

    Zhang, Meng; Helleur, Robert; Zhang, Yan

    2015-10-01

    In this study, the Ag(+)-imprinted chitosan gel beads were synthesized to selectively adsorb Ag(+) from bimetallic aqueous solutions containing the same molar concentration of Ag(+) and Cu(2+). The Ag(+)-imprinting not only helps to achieve extremely high selectivity of Ag(+), but also enhances the uptake capacity of the target Ag(+) by protecting some amine groups, the primary binding sites of metal ions from cross-linking. The maximum uptake of Ag(+) by the ion-imprinted chitosan beads was found to be 89.20 mg g(-1) at 25.0°C with an initial Ag(+) concentration of 352.95 mg L(-1) and the biosorbent dosage of 1.0 g L(-1). The adsorption equilibrium and kinetics of Ag(+) by the ion-imprinted chitosan beads can be better described by Langmuir isotherm and the intraparticle diffusion model. FTIR and XPS analyses suggested that amine functional groups involve the binding of Ag(+) via complexation at higher solution pH (3.0 ≤ pH ≤ 5.0) and ion exchange at lower solution pH (1.0 ≤ pH < 3.0). PMID:26076618

  3. SINGLE AND DOUBLE IMPRINTED POLYMER FOR SELECTIVE RECOGNITION OF Cd(II IONS IN AQUEOUS MEDIA

    Directory of Open Access Journals (Sweden)

    Ebru Birlik ÖZKÜTÜK

    2010-12-01

    Full Text Available In this paper, we have reported the synthesis of a new single and double-imprinted polymeric material for the separation of Cd(II ions in aqueous solutions. Chitosan has choosen as the Cd(II metal complexing big polymer for single and double imprinted polymers. In the synthesis of single imprinted polymer, Cd(II-complexed chitosan has crosslinked by epichlorohydrin. In the synthesis of double imprinted polymer, Cd(II-complexed chitosan was reacted with 3-mercaptopropyl-trimethoxysilane. Then, the polymeric beads have crosslinked with tetraethoxysilane (TEOS. The imprinted cadmium ions have removed from the polymeric matrix by 0.1M HNO3 (to prepare Cd(II templates. Optimum pH for rebinding of Cd(II on the single and double-imprinted polymers was 7.0. Equilibrium binding time and sorbent capacity have been found as 120 and 60 min, 342 and 172 mg g-1 for single and double imprinted polymers, respectively. In selectivity studies, it has been found that double imprinted results in increased affinity of the material toward Cd(II ion over other competitor metal ions with the same charge. The prepared single and double-imprinted polymers have repeatedly used and regenerated for thirty times without a significant decrease in polymer binding affinities.

  4. Binding of iron, zinc, and lead ions from aqueous solution by shea butter (Butyrospermun Parkii) seed husks

    Energy Technology Data Exchange (ETDEWEB)

    Eromosele, I.C.; Otitolaye, O.O. (Federal Univ. of Technology, Yola, Adamawa State (Nigeria))

    1994-08-01

    Several workers have reported on the potential use of agricultural products as substrates for the removal of metal ions from aqueous solutions. These studies demonstrated that considerable amounts of metal ions can be removed from aqueous solutions by cellulosic materials. The merit in the use of the latter is their relative abundance and cheapness compared to conventional materials for the removal of toxic metal ions from waste-waters. In some of the studies, chemical modification of cellulosic materials significantly enhanced their ion-binding properties, providing greater flexibility in their applications to a wide range of heavy metal ions. Shea butter plant (Butyrospermun Parkii) normally grows in the wild within the guinea-savana zone of Nigeria. The seeds are a rich source of edible oils and the husks are usually discarded. The husk is thus available in abundance and, hence, there is reason to examine its ion-binding properties for its possible application in the removal of toxic metal ions from industrial waste-waters. This paper reports on preliminary studies of the sorption of iron, zinc and lead ions from aqueous solution by modified and unmodified shea butter seed husks. 8 refs., 5 figs., 1 tab.

  5. Testing of laser ablation ion source for JYFLTRAP

    OpenAIRE

    Poleshchuk, Kateryna

    2015-01-01

    In this work, we have constructed and tested a laser ablation ion source for JYFLTRAP Penning trap at the IGISOL (Ion Guide Isotope Separator On-line) facility. The calibration of the Penning trap parameters requires reference ions or ion clusters that have well-known masses with relatively small mass uncertainty. These ions and ion clusters can be created with certain solid targets, which contain large amounts of isotopes of reference masses and by using a laser for target ablation. In this ...

  6. Reaction between zinc and cadmium ions and iodate ions in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, V.A.; Dezhina, G.S.; Shmyd' ko, I.I.; Shmyd' ko, L.I. (Sibirskij Tekhnologicheskij Inst., Krasnoyarsk (USSR))

    1983-01-01

    The composition is determined by solubility of zinc and cadmium iodates in lithium perchlorate-iodate solutions at 25 deg and constant ion forces, being equal to 0.5; 1.0; 2.0 and 3.0, and constants of formation of zinc and cadmium iodate complexes are calculated. Constants of complexing at infinite dilution are determined; for ZnIO/sub 3//sup +/ and CdIO/sub 3//sup +/ they are equal to 1.49+-0.01 and 1.87+-0.02 respectively, as well as values of solubility products Zn(IOsub(3))sub(2)(pKsub(ssub(0))sup(0)=5.63+-0.07) and Cd(IOsub(3))sub(2)(pKsub(ssub(0))sup(0)=7.43+-0.03).

  7. On reaction between zinc and cadmium ions and iodate ions in aqueous solutions

    International Nuclear Information System (INIS)

    The composition is determined by solubility of zinc and cadmium iodates in lithium perchlorate-iodate solutions at 25 deg and constant ion forces, being equal to 0.5; 1.0; 2.0 and 3.0, and constants of formation of zinc and cadmium iodate complexes are calculated. Constants of complexing at infinite dilution are determined; for ZnIO3+ and CdIO3+ they are equal to 1.49+-0.01 and 1.87+-0.02 respectively, as well as values of solubility products Zn(IOsub(3))sub(2)(pKsub(ssub(0))sup(0)=5.63+-0.07) and Cd(IOsub(3))sub(2)(pKsub(ssub(0))sup(0)=7.43+-0.03)

  8. BIOSORPTION STUDIES OF CADMIUM (II IONS FROM AQUEOUS SOLUTIONS ONTO ORANGE RIND (CITRUS SINENSIS L. OSBECK

    Directory of Open Access Journals (Sweden)

    Satish A. Bhalerao

    2015-03-01

    Full Text Available The biosorption studies for effective removal of cadmium (II ions from aqueous solutions using orange rind (Citrus sinensis L. Osbeck, cost effective biosorbent, was carried out in batch system. FTIR analysis of biosorbent confirmed that carboxyl, hydroxyl, carbonyl group which was responsible for biosorption of cadmium (II ions. The SEM represents porous structure with surface area. The effects of operational factors including solution pH, biosorbent dose, initial cadmium (II ions concentration, contact time and temperature were studied. The optimum solution pH for cadmium (II ions biosorption by biosorbent was 7.0 with the optimal removal 80.30 %. The biosorbent dose 5 mg/ml was enough for optimal removal of 65.15 %. The biosorption process was relatively fast and equilibrium was achieved after 90 minutes of contact. The experimental equilibrium biosorption data were analysed by four widely used two-parameters Langmuir, Freundlich, Dubinin-Kaganer-Redushkevich (DKR and Temkin isotherm models. Langmuir isotherm model provided a better fit with the experimental data than Freundlich, Temkin and Dubinin-Kaganer-Redushkevich (DKR isotherm models by high correlation coefficient value (R2 = 0.911. The maximum adsorption capacity determined from Langmuir isotherm was found to be 83.33 mg/g of biosorbent. Simple kinetic models such as pseudo-first-order, pseudo-second-order, Elovich equation and Weber and Morris intra-particle diffusion rate equation were employed to determine the adsorption mechanism. Results clearly indicates that the pseudo-second-order kinetic model (R2 = 0.998 was found to be correlate the experimental data strongest than other three kinetic models and this suggests that chemical adsorption process was more dominant. Thermodynamic study revealed that the biosorption process was spontaneous, endothermic and increasing randomness of the solid solution interfaces. Orange rind (Citrus sinensis L. Osbeck was successfully used for the

  9. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    Science.gov (United States)

    Suryanti, Venty; Hastuti, Sri; Pujiastuti, Dwi

    2016-02-01

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution.

  10. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    International Nuclear Information System (INIS)

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution

  11. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Suryanti, Venty, E-mail: venty@mipa.uns.ac.id; Hastuti, Sri; Pujiastuti, Dwi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Sebelas Maret University Jl. Ir. Sutami 36A, Surakarta, Central Java 57126 (Indonesia)

    2016-02-08

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution.

  12. Radiation-induced reduction of metal ions in aqueous solution systems and its application

    International Nuclear Information System (INIS)

    Introduction: Promotion of chemical reactions by adding oxide particles to aqueous solution under the irradiation of ionizing radiations has been paid attention especially from the practical viewpoint, so that hydrogen production and decomposition of toxic organic compounds studied. On the other hand, redox of metal ions has not been studied very much since successive reactions after the redox become complicated due to equilibrium between reactant and product, and to transformation of dissolved species by varying pH and coexisting ions... In the present study, reduction behavior of metal ions in aqueous solution systems irradiated by r-ray and electron beam was measured, the reduced amount was compared with that by water radiolysis, and then the promotion of reduction by adding oxide particles was found out quantitatively. Experimental: Samples were prepared by dissolving metal salts (Ce(IV), Cr(VI), Pt(IV),...) in 0.4 mol/L sulfuric acid or 0.1 mol/l sodium perchlorate solution and then by adding 1-10 wt% oxide particles such as TiO2, Al2O3 or SiO2 to the solution. The irradiation of sample was made without stirring the particles in the solution mainly by using 60Co γ-ray source (dose rate: 1-30 kGy/h) at Takasaki Research Institute, JAEA; the absorbed dose of sample was estimated by using dosimeters of dichromate solution and/or CTA film. Just after irradiated, the sample was passed through a membrane filter to be separated into solution and solid components; absorption spectrum of metal ions in the solution was observed, and the reduced amount determined from difference in the absorbance before and after the irradiation. Results and discussion: Figure 1 shows absorption spectra of Ce(IV) ion in 0.4 mol/L H2SO4 solution under the γ-ray irradiation as typical results. Fig.1(a) illustrates that the reduction was observed in the solution without the oxide particles as stoichiometry in the one-electron reduction by water radiolysis has been used as a dosimeter, and

  13. 60Co-gamma radiolysis of the trisoxalato cobalt(III) ions in deoxygenated neutral aqueous solution

    International Nuclear Information System (INIS)

    Radiolysis of the trisoxalato cobalt(III) ions in deoxygenated neutral aqueous medium have been undertaken at low and high doses. At low doses, the rate of radiolysis is independent of the concentration of the complex ion in the range 3.24 x 10-3 to 10-2 mol dm-3 and is enhanced by the addition of free oxalate ions. On prolonged irradiation, the rate of degradation gradually increases. Initially H and e-sub(aq) reduces the complex ion, but at later stages, oxalate ion radical C2O4sup(.1-), produced by the interaction of OH radicals with the generated C2O42- ions during the radiolysis, also reduce the [Co(C2O4)3]3- ions. (author)

  14. Adsorption of Cd(II and Pb(II Ions from Aqueous Solution byActivated Carbon

    Directory of Open Access Journals (Sweden)

    Hayder Mohammed Abdul-Hameed

    2009-01-01

    Full Text Available Heavy metal consider as major environmental pollutants. Many of industrial wastewater effluents contain a wide range of these heavy metals. The adsorption of Cd2+ and Pb2+ metal ions from aqueous solution by activated carbon was studied. The results showed that maximum adsorption capacity occurred at 486.9×10-3 mg/kg for Pb2+ ion and 548.8×10-3 mg/kg for Cd2+ ion. The adsorption in a mixture of the metal ions had a balancing effect on the adsorption capacity of the activated carbon. The adsorption capacity of each metal ion was affected by the presence of other metal ions rather than its presence individually. The study showed the presence of other heavy metals attribute to the reduction in the activated carbon capacity, and the adsorption process was found to obeys the Freundlich isotherm for both ions.

  15. Evaluation of Two Biosorbents in the Removal of Metal Ions in Aqueous Using a Pilot Scale Fixed-bed System

    Directory of Open Access Journals (Sweden)

    Andre Gadelha Oliveira

    2014-05-01

    Full Text Available The aim of the present work was to investigate the adsorption of toxic metal ions copper, nickel and zinc from aqueous solutions using low cost natural biomass (sugar cane bagasse and green coconut fiber in pilot scale fixed-bed system. The Hydraulic retention time (HRT was 229 minutes and the lowest adsorbent usage rate (AUR found was 0.10 g.L-1 for copper using green coconut fibers. The highest values of adsorption capacities founded were 1.417 and 2.772 mg.g-1 of Cu(II ions for sugarcane bagasse and green coconut fibers, respectively. The results showed that both sugarcane bagasse and green coconut fiber presented potential in the removal of metal ions copper, nickel and zinc ions from aqueous solution and the possible use in wastewater treatment station.

  16. Removal of copper ions from aqueous solution by calcium alginate immobilized kaolin

    Institute of Scientific and Technical Information of China (English)

    Yanhui Li; Yanzhi Xia; Bing Xia; Quansheng Zhao; Fuqiang Liu; Pan Zhang; Qiuju Du; Dechang Wang; Da Li; Zonghua Wang

    2011-01-01

    Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin (kaolin/CA), was prepared using a sol-gel method. The effects of contact time, pH, adsorbent dose, and temperature on Cu2+ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.

  17. First Observation of Electron Transfer Mediated Decay in Aqueous Solutions: A Novel Probe of Ion Pairing

    CERN Document Server

    Unger, I; Thürmer, S; Aziz, E F; Cederbaum, L S; Muchová, E; Slavíček, P; Winter, B; Kryzhevoi, N V

    2016-01-01

    A major goal of many spectroscopic techniques is to provide comprehensive information on the local chemical environment. Electron transfer mediated decay (ETMD) is a sensitive probe of the environment since it is actively involved in this non-local radiationless decay process through electron and energy transfer steps. We report the first experimental observation of ETMD in the liquid phase. Using liquid-jet X-ray photoelectron spectroscopy we explore LiCl aqueous solution, and detect low-energy electrons unambiguously emerging from the ETMD processes of core-ionized Li+. We interpret the experimental results with molecular dynamics and high-level ab initio calculations. By considering various solvation-structure models we show that both water molecules and Cl- anions can participate in ETMD, with each process having its characteristic spectral fingerprint. Different ion associations lead to different spectral shapes. The potential application of the unique sensitivity of the ETMD spectroscopy to the local hy...

  18. Poly(2-FurylMethylenesulfide as a Resin to Uptake of Metal Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Damasceno J.

    2002-01-01

    Full Text Available The polymerization of poly (2- furyl methylenesulfide -- POLYTHIOFURFURAL -- was performed in an 0.36 mol/L aqueous solution of furfuraldehyde, saturated by bubbling hydrogen sulfide for 2 h at different temperatures. The reaction product was thoroughly washed and dried at 40 °C under vacuum. Poly (2-furyl methylenesulfyde is a yellow powder with a rather unpleasant odor. The polythiofurfural obtained [ -CH(C4H3O-S-] is a furan with thiols end groups. These are active adsorption centers for metal ions. The polythiofurfural was soluble in acetone and chloroform and its yields attained 80%. Morphological analysis by Scanning Eletronic Microscopy indicates a regular and dense surface in an interesting spacial arrangement. Preliminary isotherms adsorption studies indicate specific affinity forNi (II and Co (II and different capacity adsorption, 0.022 and 0.045 mmol per gram, respectively.

  19. Alkaline deoxygenated graphene oxide as adsorbent for cadmium ions removal from aqueous solutions.

    Science.gov (United States)

    Liu, Jun; Du, Hongyan; Yuan, Shaowei; He, Wanxia; Yan, Pengju; Liu, Zhanhong

    2015-01-01

    Alkaline deoxygenated graphene oxide (aGO) was prepared through alkaline hydrothermal treatment and used as adsorbent to remove Cd(II) ions from aqueous solutions for the first time. The characterization results of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectra indicate that aGO was successfully synthesized. The batch adsorption experiments showed that the adsorption kinetics could be described by the pseudo-second-order kinetic model, and the isotherms equilibrium data were well fitted with the Langmuir model. The maximum adsorption capacity of Cd(II) on aGO was 156 mg/g at pH 5 and T=293 K. The adsorption thermodynamic parameters indicated that the adsorption process was a spontaneous and endothermic reaction. The mainly adsorption mechanism speculated from FT-IR results may be attributed to the electrostatic attraction between Cd2+ and negatively charged groups (-CO-) of aGO and cation-π interaction between Cd2+ and the graphene planes. The findings of this study demonstrate the potential utility of the nanomaterial aGO as an effective adsorbent for Cd(II) removal from aqueous solutions. PMID:26038925

  20. Nanoalginate based biosorbent for the removal of lead ions from aqueous solutions: Equilibrium and kinetic studies.

    Science.gov (United States)

    Geetha, P; Latha, M S; Pillai, Saumya S; Koshy, Mathew

    2015-12-01

    Population explosion, depletion of water resources and prolonged droughts and floods due to climatic change lead to scarcity of pure and hygienic drinking water in most of the developing countries. Recently nanomaterials attained considerable attention as biosorbent for water purification purpose. However difficulties in removing polymeric surfactants and organic solvents used for nanoproduction and instability of the generated nanoparticles limit the scope of this approach in water cleanup. Here, we describe a novel green method for synthesizing polysaccharide nanoparticles in aqueous medium using honey as the capping agent. The highly stable alginate nanoparticles, characterized by various microscopic and spectroscopic techniques, exhibited a maximum uptake capacity of 333 mg g (-1)of Pb(II) ions from aqueous solution. The effect of various parameters such as initial metal concentration, pH, contact time, temperature and adsorbent dose on sorption process was investigated in batch mode technique. The maximum removal percentage was 94.81 at 45 °C and at pH 4.5 in 60 min contact time. The biosorption followed Freundlich model indicating multilayer adsorption and pseudo second order kinetics. The mechanism involves both surface adsorption and pore diffusion. The positive values of ΔH°, ∆S° and the negative value of ΔG°, confirmed the endothermic nature, randomness and spontaneity of biosorption process. PMID:26164724

  1. Biosorption of copper (II) ions from synthetic aqueous solutions by drying bed activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Benaissa, H., E-mail: ho_benaissa@yahoo.fr [Laboratory of Sorbent Materials and Water Treatment, Department of Chemistry, Faculty of Sciences, University of Tlemcen, P.O. Box 119, 13000 Tlemcen (Algeria); Elouchdi, M.A. [Laboratory of Sorbent Materials and Water Treatment, Department of Chemistry, Faculty of Sciences, University of Tlemcen, P.O. Box 119, 13000 Tlemcen (Algeria)

    2011-10-30

    Highlights: {yields} Dried activated sludge has been investigated for the removal of copper ions from aqueous synthetic solutions, in batch conditions. {yields} Copper uptake was time contact, initial copper concentration, initial pH solution and copper salt type dependent. {yields} Maximum copper uptake obtained was q{sub m} = 62.50 mg/g (0.556 mmol/g) under the investigated experimental conditions. - Abstract: In the present work, the usefulness of dried activated sludge has been investigated for the removal of copper ions from synthetic aqueous solutions. Kinetic data and equilibrium sorption isotherm were measured in batch conditions. The influence of some parameters such as: contact time, initial copper concentration, initial pH of solution and copper salt nature on copper biosorption kinetics has been studied. Copper uptake was time contact, initial copper concentration, initial pH solution and copper salt type dependent. Maximum copper sorption was found to occur at initial pH 5. Two simplified kinetic models including a first-order rate equation and a pseudo second-order rate equation were selected to describe the biosorption kinetics. The process followed a pseudo second-order rate kinetics. The process mechanism was found to be complex, consisting of external mass transfer and intraparticle mass transfer diffusion. Copper biosorption process was particle-diffusion-controlled, with some predominance of some external mass transfer at the initial stages for the different experimental parameters studied. Langmuir and Freundlich models were used to describe sorption equilibrium data at natural pH of solution. Results indicated that the Langmuir model gave a better fit to the experimental data than the Freundlich model. Maximum copper uptake obtained was q{sub m} = 62.50 mg/g (0.556 mmol/g) under the investigated experimental conditions. Scanning electron microscopy coupled with X-ray energy dispersed analysis for copper-equilibrated dried activated sludge

  2. Adsorption of uranium ions by crosslinked polyester resin functionalized with acrylic acid from aqueous solutions

    International Nuclear Information System (INIS)

    In this paper, the crosslinked polyester resin containing acrylic acid functional groups was used for the adsorption of uranium ions from aqueous solutions. For this purpose, the crosslinked polyester resin of unsaturated polyester in styrene monomer (Polipol 353, Poliya) and acrylic acid as weight percentage at 80 and 20%, respectively was synthesized by using methyl ethyl ketone peroxide (MEKp, Butanox M60, Azo Nobel)-cobalt octoate initiator system. The adsorption of uranium ions on the sample (0.05 g copolymer and 5 mL of U(VI) solution were mixed) of the crosslinked polyester resin functionalized with acrylic acid was carried out in a batch reactor. The effects of adsorption parameters of the contact time, temperature, pH of solution and initial uranium(VI) concentration for U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid were investigated. The adsorption data obtained from experimental results depending on the initial U(VI) concentration were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The adsorption capacity and free energy change were determined by using D-R isotherm. The obtained experimental adsorption data depending on temperature were evaluated to calculate the thermodynamic parameters of enthalpy (ΔHo), entropy (ΔSo) and free energy change (ΔGo) for the U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid from aqueous solutions. The obtained adsorption data depending on contact time were analyzed by using adsorption models such as the modified Freundlich, Elovich, pseudo-first order and pseudo-second-order kinetic models. (author)

  3. Formation and Dynamics of Ion-Stabilized Gas Nanobubble Phase in the Bulk of Aqueous NaCl Solutions.

    Science.gov (United States)

    Bunkin, Nikolai F; Shkirin, Alexey V; Suyazov, Nikolay V; Babenko, Vladimir A; Sychev, Andrey A; Penkov, Nikita V; Belosludtsev, Konstantin N; Gudkov, Sergey V

    2016-02-25

    Ion-stabilized gas nanobubbles (the so-termed "bubstons") and their clusters are investigated in bulk aqueous solutions of NaCl at different ion concentrations by four independent laser diagnostic methods. It turned out that in the range of NaCl concentration 10(-6) stirrer at different stirring rates. Different regimes of the bubston generation, resulting from various techniques of processing the liquid samples, were explored. PMID:26849451

  4. Dissociative CdSe/ZnS Quantum Dot-Molecule Complex for Luminescent Sensing of Metal Ions in Aqueous Solutions

    OpenAIRE

    Baranov, A. V.; Orlova, A. O.; Maslov, V. G.; Toporova, Yu. A.; Ushakova, E. V.; Federov, A.; Artemyev, M. V.; Perova, T. S.; Berwick, Kevin

    2010-01-01

    The optical properties of dissociative luminescent sensors based on a complex consisting of highly luminescent hydrophobic core/shell CdSe/ZnS quantum dots (QDs) and 1-(2-pyridilazo)-2-naphtol (PAN) molecules in organic solutions and a polymer film are reported. It is demonstrated, using Ni2+ and Co2+ ions as an illustrative example, that the QD/PAN sensor may have applications in the quantitative luminescent sensing of metal ions in aqueous solutions.

  5. Analysis of products of thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution

    International Nuclear Information System (INIS)

    Some methods of capillary gas chromatography, such as GC, GC-MS GC-FT-IR, are used to analyze the products of thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution. From the results of GC-MS the molecular weight of products can be determined, and from the results of GC-FT-IR some molecular structure information of products can be obtained. By this way the products, 5,6-Dihydro-thymine, 5-Hydroxyl-5-Methylhydantoin, 5-Hydroxyl-6-Hydro-thymine, 5-Hydro-6-Hydroxyl thymine, 5-Hydroxymethyluracil, Trans-Thymine glycol, Cis-Thymine glycol and dimers are determined without separation of them from samples. Though these products are as same as those products of thymine irradiated by γ rays in N2O saturated aqueous solution, the mechanism of thymine irradiated by heavy ion beam in aqueous solution is different from that by γ rays. The main products of thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution are hydroxyl adducts at 5-6 band of thymine, while the main products of thymine irradiated by γ ray in N2O saturated aqueous solution are dimers of thymine

  6. Selective fluorescent probes based on CN isomerization and intramolecular charge transfer (ICT) for zinc ions in aqueous solution.

    Science.gov (United States)

    Li, Lei; Liu, Feng; Li, Hong-Wei

    2011-09-01

    As the second most abundant transition-metal ion in the human body, Zn2+ plays crucial roles in many important biological processes; while in the environment, an excessive concentration of Zn2+ may reduce the soil microbial activity resulting in phytotoxic effects. Therefore, developing effective and sensitive detection method for Zn2+ has become crucially important and necessary both in life and environment science. Two new fluorescence probes, 2-((2-hydroxynaphthalen-1-yl)methyleneamino)-3-(1H-imidazol-5-yl) propanoic acid (2) and 2-hydroxy-2-((2-hydroxynaphthalen-1-yl) methyleneamino) acetic acid (3), were easily prepared by a one step reaction between 2-hydroxy-1-naphthaldehyde with histidine and serine, respectively, in ethanol. The optical properties of them were investigated by fluorescence spectra, which displayed specific and sensitive recognition to Zn2+ and especially avoided the interference of Cd2+ when they were tested against a range of physiological and environmentally relevant metal ions in aqueous solution. The responsive mechanism of the two probes to Zn2+ were involved both the CN isomerization and ICT, which were clarified by NBO charge analysis and the HOMO-LUMO energy gap calculation by using B3LYP/6-31G density functional theory. PMID:21665525

  7. Selective fluorescent probes based on C dbnd N isomerization and intramolecular charge transfer (ICT) for zinc ions in aqueous solution

    Science.gov (United States)

    Li, Lei; Liu, Feng; Li, Hong-Wei

    2011-09-01

    As the second most abundant transition-metal ion in the human body, Zn 2+ plays crucial roles in many important biological processes; while in the environment, an excessive concentration of Zn 2+ may reduce the soil microbial activity resulting in phytotoxic effects. Therefore, developing effective and sensitive detection method for Zn 2+ has become crucially important and necessary both in life and environment science. Two new fluorescence probes, 2-((2-hydroxynaphthalen-1-yl)methyleneamino)-3-(1H-imidazol-5-yl) propanoic acid ( 2) and 2-hydroxy-2-((2-hydroxynaphthalen-1-yl) methyleneamino) acetic acid ( 3), were easily prepared by a one step reaction between 2-hydroxy-1-naphthaldehyde with histidine and serine, respectively, in ethanol. The optical properties of them were investigated by fluorescence spectra, which displayed specific and sensitive recognition to Zn 2+ and especially avoided the interference of Cd 2+ when they were tested against a range of physiological and environmentally relevant metal ions in aqueous solution. The responsive mechanism of the two probes to Zn 2+ were involved both the C dbnd N isomerization and ICT, which were clarified by NBO charge analysis and the HOMO-LUMO energy gap calculation by using B3LYP/6-31G density functional theory.

  8. The effect of temperature on radiolysis of iodide ion diluted aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorbovitskaya, T.; Tiliks, J. [Latvia Univ., Lab. of Radiation Chemistry, Riga (Latvia)

    1996-12-01

    To investigate the radiolysis of iodine containing aqueous solutions a flow type facility (ITF) has a possibility to irradiate aqueous solutions in the steel vessel with {sup 60}Co {gamma}-rays and continuously (on line) to analyze the products of radiolysis both in liquid and in gaseous phases. By means of ITF the formation of I{sub ox} (I{sub 2} + I{sub 3}{sup -} + HOI), IO{sub 3}{sup -}, H{sub 2}O{sub 2} was studied in 10{sup -5} - 10{sup -3} mol/dm{sup 3} CsI aqueous solutions by their radiolysis at dose rate 4.5 kGv/h for six hours in region of temperatures from 313 to 404 K. Some experiments in glass ampoules were also performed. The steady-state concentrations of I{sub ox} and IO{sub 3}{sup -} decreased with increasing temperature as linear function of inverted temperature. The effect decreased with decreasing concentration of iodide ion. As the result, at high temperatures (T{>=}380 K) the steady-state concentration of I{sub ox} does not depend essentially on the iodide ion initial concentration. Molecular iodine (I{sub 2}) released from the solution was the main radiolysis product in gaseous phase. Its steady-state concentration increased with increasing temperature because of iodine solubility in the water and decreased at the same time because the radiolytic iodine concentrations decreased. Therefore the most volatility of irradiated 10{sup -3} and 10{sup -4}M CsI solutions was observed at the temperature about 350 K. The volatility of 10{sup -5}M solutions gradually decreased with increasing temperature. The experimental data were explained on the base of the hypothesis that the reaction between I{sub 2} and radiolytic H{sub 2}O{sub 2} was the limit one determining the temperature dependence of I{sub ox} and IO{sub 3}{sup -}steady-state concentrations. Its activation energy was estimated to be 27,5 kcal.mol{sup -1}. The temperature dependence for reaction (IO{sup -} + H{sub 2}O{sub 2}) was also estimated. (author) 8 figs., 1 tab., 17 refs.

  9. Selective flotation of zinc(II) and silver(I) ions from dilute aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Charewicz, W.A.; Holowiecka, B.A.; Walkowiak, W. [Wroclaw Univ. of Tech. (Poland)

    1999-09-01

    An experimental investigation is presented of the batch competitive flotation of zinc(II) and silver(I) ions from dilute aqueous solutions with sodium dodecylsulfate and ammonium tetradecysulfonate as anionic surfactants and with cetylpyridinium chloride as a cationic surfactant. The sequence of growing affinity of metal cations to anionic surfactants is the same as the sequence of ionic potential values of the studied cations: AG{sup +} < Zn{sup 2+}. The presence of potassium sulfate in aqueous solution has a negative influence of Zn{sup 2+} foam separation with a anionic surfactant which is due to competition for the surfactant between Zn{sup 2+} and K{sup +} cations. Also, the effect of inorganic ligands (i.e., thiosulfates, thiocyanates, and cyanides) on the selectivity of ion flotation of Zn(II) and Ag(I) is established. Results are discussed in terms of the complex species of zinc(II) and silver(I). At a total S{sub 2}O{sub 3}{sup 2{minus}} concentration of 3 {times} 10{sup {minus}6} M, the silver(I) is floated as a mixture of anions [Ag(S{sub 2}O{sub 3})]{sup {minus}} and [Ag(S{sub 2}O{sub 3}){sub 2}]{sup 3{minus}}, whereas zinc(II) remains in the aqueous phase as Zn{sup 2+}. At total concentrations of SCN{sup {minus}} from 1 {times} 10{sup {minus}4} to 2 {times} 10{sup {minus}3} M, silver(I) is floated as a mixture of [Ag(SCN){sub 2}]{sup {minus}} and AgSCN species. Partial separation of zinc(II) from silver(I) can be achieved in the presence of CN{sup {minus}} ligands at total concentrations varying from 2.5 {times} 10{sup {minus}4} to 1.0 {times} 10{sup {minus}3} M. The affinity of the studied cyanide complexes to cetylpyridinium chloride follows the order [Ag(CN){sub 2}]{sup {minus}} < [Zn(CN){sub 4}]{sup 2{minus}} + [Zn(CN){sub 3}]{sup {minus}}.

  10. Effects of Metal Ions on Viscosity of Aqueous Sodium Carboxylmethylcellulose Solution and Development of Dropping Ball Method on Viscosity

    Science.gov (United States)

    Set, Seng; Ford, David; Kita, Masakazu

    2015-01-01

    This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the…

  11. On the influence of hydronium and hydroxide ion diffusion on the hydrogen and oxygen evolution reactions in aqueous media

    DEFF Research Database (Denmark)

    Wiberg, Gustav Karl Henrik; Arenz, Matthias

    2015-01-01

    We present a study concerning the influence of the diffusion of H+ and OH- ions on the hydrogen and oxygen evolution reactions (HER and OER) in aqueous electrolyte solutions. Using a rotating disk electrode (RDE), it is shown that at certain conditions the observed current, i.e., the reaction rate...

  12. Thermochemical study of the processes of complexation of cobalt(II) ions with L-histidine in aqueous solution

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2015-09-01

    Thermal effects of the complexation of cobalt(II) ions with L-histidine at 298.15 K and several values of the ionic strength against the background of KNO3 are determined by means of direct calorimetry. The standard thermodynamic characteristics of the reactions of complexation in the aqueous solution have been calculated.

  13. Kinetic studies on the removal of cesium and strontium ions from aqueous solutions using prepared zeolite-A

    International Nuclear Information System (INIS)

    Preparation and characterization of zeolite-A exchanger were carried out for kinetic studies on the removal of cesium and strontium ions from aqueous solutions. Ion exchange experiments were constant ion-concentration and different temperatures in the range from 25 c degree to 60± c degree. Analysis of the respective rate data in accordance with Hellferich model was performed for the calculation of effective diffusion coefficient (Di), activation energy (Ea) and entropy changes (ΔS) of the exchange process of both ions. A simplified first-order kinetic model was achieved to interpret the kinetic data and the effect of temperature on the overall rate constant (K) of adsorption for both ions was studied. The obtained data indicated that prepared zeolite-A exhibited higher affinity for Cs+ ions from their aqueous solutions than the host Na+ ion. The amount adsorbed of cesium ions (mg/g) is much lower than that of zeolite-A. The amount adsorbed of both studied increases by increasing temperature

  14. Synthesis of Mesoporous Adsorbent and its Application for Heavy Metal Ions Removal from Aqueous Solution

    International Nuclear Information System (INIS)

    The mesoporous silicas were synthesized via the evaporation-induced self-assembly (EISA) in the experiment. Cetyltrimethyl ammonium bromide (CTAB) was used as the template, and the silicon source was tetraethoxyorthosilicate (TEOS). The mesoporous silicas were characterized by nitrogen adsorption-desorption analysis, FTIR, TEM and SEM. The mesoporous silicas (adsorbent) exhibited higher pore diameter (centered at 5.57 nm), BET surface area (457.3 m2·g-1) and pore volume (0.563 cm2·g-1). The mesoporous silicas were used as the adsorbent to remove the heavy metal ions from aqueous solution. The following order of equilibrium adsorption capacity for Cu2+, Co2+, Ag+ and As3+ on adsorbent was: Ag+>Cu2+>Co2+>As3+. Analysis of adsorption kinetics showed that Cu2+, Co2+, Ag+ and As3+ adsorption fit the pseudo-second-order nonlinear model significantly. The removal rate for heavy metal ions was high, and the adsorbent can be regenerated by acid treatment without altering its properties.

  15. The effect of magnesium ions on dielectric relaxation in semidilute DNA aqueous solutions

    CERN Document Server

    Grgičin, Danijel; Ivek, Tomislav; Tomić, Silvia; Podgornik, Rudi

    2013-01-01

    The effect of magnesium ion Mg2+ on the dielectric relaxation of semidilute DNA aqueous solutions has been studied by means of dielectric spectroscopy. Two dielectric relaxations in the 100 Hz - 100 MHz frequency range, originating in the motion of DNA counterions, were probed as a function of DNA and Mg2+ ion concentration in added MgCl2 salt. The high-frequency mode in the MHz range, stemming from the structural organization of the DNA network, reveals de Gennes-Pfeuty-Dobrynin correlation length as the pertinent fundamental length scale for sufficiently low concentration of added salt. No relaxation fingerprint of DNA denaturation bubbles, leading to exposed hydrophobic core scaling, was detected at low DNA concentrations, thus indicating an increased stability of the double-stranded conformation as compared to the case of DNA solutions with univalent counterions. The presence of Mg2+ does not change qualitatively the low frequency mode in the kHz range correlated with single DNA conformational properties....

  16. Adsorption of indium(III) ions from aqueous solution using chitosan-coated bentonite beads

    Energy Technology Data Exchange (ETDEWEB)

    Calagui, Mary Jane C. [College of Engineering, Cagayan State University, Cagayan Valley 3500 (Philippines); School of Graduate Studies, Mapua Institute of Technology, Manila 1800 (Philippines); Senoro, Delia B. [School of Graduate Studies, Mapua Institute of Technology, Manila 1800 (Philippines); Kan, Chi-Chuan [Institute of Hot Spring Industrial, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan (China); Salvacion, Jonathan W.L. [School of Graduate Studies, Mapua Institute of Technology, Manila 1800 (Philippines); Futalan, Cybelle Morales [Operations Department, Frontier Oil Corporation, Makati City 1229 (Philippines); Wan, Meng-Wei, E-mail: peterwan@mail.chna.edu.tw [Department of Environmental Engineering and Science, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan (China)

    2014-07-30

    Highlights: • A more acidic pH causes a decrease in adsorption capacity. • The kinetic data follow the pseudo-second order equation. • Equilibrium data correlated well with Langmuir isotherm. • Removal of indium is a spontaneous and endothermic process. - Abstract: Batch adsorption study was utilized in evaluating the potential suitability of chitosan-coated bentonite (CCB) as an adsorbent in the removal of indium ions from aqueous solution. The percentage (%) removal and adsorption capacity of indium(III) were examined as a function of solution pH, initial concentration, adsorbent dosage and temperature. The experimental data were fitted with several isotherm models, where the equilibrium data was best described by Langmuir isotherm. The mean energy (E) value was found in the range of 1–8 kJ/mol, indicating that the governing type of adsorption of indium(III) onto CCB is essentially physical. Thermodynamic parameters, including Gibbs free energy, enthalpy, and entropy indicated that the indium(III) ions adsorption onto CCB was feasible, spontaneous and endothermic in the temperature range of 278–318 K. The kinetics was evaluated utilizing the pseudo-first order and pseudo-second order model. The adsorption kinetics of indium(III) best fits the pseudo-second order (R{sup 2} > 0.99), which implies that chemical sorption as the rate-limiting step.

  17. Adsorption of indium(III) ions from aqueous solution using chitosan-coated bentonite beads

    International Nuclear Information System (INIS)

    Highlights: • A more acidic pH causes a decrease in adsorption capacity. • The kinetic data follow the pseudo-second order equation. • Equilibrium data correlated well with Langmuir isotherm. • Removal of indium is a spontaneous and endothermic process. - Abstract: Batch adsorption study was utilized in evaluating the potential suitability of chitosan-coated bentonite (CCB) as an adsorbent in the removal of indium ions from aqueous solution. The percentage (%) removal and adsorption capacity of indium(III) were examined as a function of solution pH, initial concentration, adsorbent dosage and temperature. The experimental data were fitted with several isotherm models, where the equilibrium data was best described by Langmuir isotherm. The mean energy (E) value was found in the range of 1–8 kJ/mol, indicating that the governing type of adsorption of indium(III) onto CCB is essentially physical. Thermodynamic parameters, including Gibbs free energy, enthalpy, and entropy indicated that the indium(III) ions adsorption onto CCB was feasible, spontaneous and endothermic in the temperature range of 278–318 K. The kinetics was evaluated utilizing the pseudo-first order and pseudo-second order model. The adsorption kinetics of indium(III) best fits the pseudo-second order (R2 > 0.99), which implies that chemical sorption as the rate-limiting step

  18. A solubility model for aqueous solutions containing sodium, fluoride, and phosphate ions

    International Nuclear Information System (INIS)

    A significant problem in the processing of radioactive wastes is uncontrolled precipitation in solutions containing hydroxide, fluoride, and phosphate ions. A computational model is developed to calculate thermodynamic phase equilibria in aqueous solutions of fluoride, phosphate, and hydroxide up to 100 C. A variety of data are used, including isopiestic and electromotive force measurements, freezing point data, vapor pressure data at 100 C, heat capacities, heats of dilution, and solubility measurements. Pitzer's ion-interaction treatment is used to model electrolyte solutions, and many unknown parameters are determined from existing data through nonlinear least-squares fitting. Phase equilibria are determined by minimization of the total Gibbs energy using a modification of the code SOLGASMIX. Results calculated using the model accurately predict phase equilibria from many quantitative experiments. Qualitative experiments are performed to evaluate calculated solubilities in regions of sparse or nonexistent data; the calculated results are reasonable and exhibit a general qualitative agreement with such data. Model predictions are useful in understanding problems that may arise in the treatment of waste streams containing fluoride and phosphate anions in highly caustic solutions

  19. Metal ion mediated synthesis of molecularly imprinted polymers targeting tetracyclines in aqueous samples.

    Science.gov (United States)

    Qu, Guorun; Zheng, Sulian; Liu, Yumin; Xie, Wei; Wu, Aibo; Zhang, Dabing

    2009-10-01

    Molecularly imprinted polymers (MIPs) prepared in water-containing systems are more appropriate as adsorption materials in analyte extraction from biological samples. However, water as a polar solvent involved in the synthesis of MIPs frequently disrupts non-covalent interactions, and causes non-specific binding. In this study Fe(2+) was used as mediator to prepare MIPs, targeting tetracyclines (TCs) of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC), with TC as template molecule and methacrylic acid (MAA) as functional monomer. The subsequent binding assay indicated that Fe(2+) was responsible for substantially improved specific binding in recognition of TCs by decreasing the non-specific binding. Spectrophotometric analysis suggested the existence of the strong interactions among TC, metal ions and MAA in the mixture of methanol and water. Moreover, mass spectrometric measurements verified that Fe(2+) could bridge between TC and MAA to form a ternary complex of one TC, one Fe(2+) and four MAAs with a mass of 844.857. Furthermore, combined with molecularly imprinted solid-phase extraction (MISPE) for sample pretreatment, HPLC-UV analysis data revealed good performance of the obtained MIPs as adsorbents. The recoveries of TC, OTC and CTC in urine samples were 80.1-91.6%, 78.4-89.3% and 78.2-86.2%, respectively. This research strategy provides an example for preparation of desirable water-compatible MIPs extracting target drugs from aqueous samples by introducing metal ion as mediator into conventional polymerization system. PMID:19726243

  20. Long Term Stability Testing Results for Savannah River Site Organic and Aqueous Waste streams

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) has tasked MSE Technology Applications, Inc. (MSE) with evaluating the long-term stability of various commercially available sorbent materials to solidify two organic surrogate waste streams (both volatile and nonvolatile), a volatile organic waste stream with a residual aqueous phase, an aqueous waste stream, and an aqueous waste stream with a residual organic phase. The Savannah River Site (SRS) legacy plutonium/uranium extraction (PUREX) process waste and the F-Canyon PUREX waste constituted the volatile organic wastes and various oils constituted the nonvolatile organic waste stream. The aqueous waste streams included a rainwater waste stream and an aqueous organic waste stream. MSE also evaluated the PUREX waste stream with a residual aqueous component with and without aqueous-type sorbent materials. Based on testing performed at MSE, the rainwater waste stream was successfully solidified by SRS personnel using two different sorbents. Several small oil wastes were also successfully solidified by SRS personnel using granular clay sorbents based on information provided by MSE from the oils waste stream testing and 75,706 Liters (L) [20,000 gallons (gal)] of the F-Canyon PUREX waste was solidified at Waste Consolidation Specialists (WCS). Solidification of the various surrogate waste streams listed above was performed from 2004 to 2006 at the MSE testing and evaluation facility located at the Mike Mansfield Advanced Technology Center in Butte, Montana. This paper summarizes the comparison of the initial liquid release testing (LRT) values with LRT results obtained over three years later in an attempt to understand the long-term stability characteristics of the solidified waste streams. The paper also includes solidification results for B-25 box samples generated late in 2005. (authors)

  1. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions.

    Science.gov (United States)

    Choi, Jun-Ho; Kim, Heejae; Kim, Seongheun; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O-D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O-D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O-D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O-D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O-D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O-D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O-D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O-D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O-D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O-D stretch mode is shown to be important and the asymmetric line shapes of the O-D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We anticipate that this

  2. Magnetic ion-imprinted and –SH functionalized polymer for selective removal of Pb(II) from aqueous samples

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Bin; Deng, Fang [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); Zhao, Yu [Technology Center of China Tobacco Hunan Industrial Corporation, Changsha 410007 (China); Luo, Xubiao, E-mail: luoxubiao@126.com [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian, E-mail: sllou@hnu.edu.cn [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); Au, Chaktong [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China)

    2014-02-15

    A magnetic ion-imprinted polymer (Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP) functionalized with –SH groups for the selective removal of Pb(II) ions from aqueous samples was synthesized by surface imprinting technique combined with a sol–gel process using 3-mercaptopropyl trimethoxysilane as monomer, tetraethyl orthosilicate as cross-linking agent, and Pb(II) ion as template. The Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP was characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectrometry. Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP showed higher capacity and selectivity than that of Fe{sub 3}O{sub 4}@SiO{sub 2}-NIP. The effects of initial concentration of Pb(II) and pH of medium on adsorption capacity of Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP were studied. The experimental data fits well with the Langmuir adsorption isotherm. The maximum Pb(II)-sorption capacity calculated from Langmuir isotherm is 32.58 mg/g and 16.50 mg/g for Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP and Fe{sub 3}O{sub 4}@SiO{sub 2}-NIP, respectively. Kinetics studies show that the adsorption process obeys a pseudo-second-order kinetic model with high correlation coefficient (R{sup 2} = 0.9982). The separation factor of Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP for Pb(II)/Cu(II), Pb(II)/Zn(II), and Pb(II)/Co(II) are 50.54, 52.14, and 37.39, respectively. The adsorption thermodynamic parameters ΔG, ΔH and ΔS were −4.98 kJ/mol, 3.27 kJ/mol and 28.84 J/mol/K, respectively. In addition, the spent Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP can be refreshed by simple washing with aqueous HCl solution, and there is no significant decrease in adsorption capacity after a test of up to five cycles, demonstrating that the Fe{sub 3}O{sub 4}@SiO{sub 2}-IIP is stable and reusable.

  3. Magnetic ion-imprinted and -SH functionalized polymer for selective removal of Pb(II) from aqueous samples

    Science.gov (United States)

    Guo, Bin; Deng, Fang; Zhao, Yu; Luo, Xubiao; Luo, Shenglian; Au, Chaktong

    2014-02-01

    A magnetic ion-imprinted polymer (Fe3O4@SiO2-IIP) functionalized with -SH groups for the selective removal of Pb(II) ions from aqueous samples was synthesized by surface imprinting technique combined with a sol-gel process using 3-mercaptopropyl trimethoxysilane as monomer, tetraethyl orthosilicate as cross-linking agent, and Pb(II) ion as template. The Fe3O4@SiO2-IIP was characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectrometry. Fe3O4@SiO2-IIP showed higher capacity and selectivity than that of Fe3O4@SiO2-NIP. The effects of initial concentration of Pb(II) and pH of medium on adsorption capacity of Fe3O4@SiO2-IIP were studied. The experimental data fits well with the Langmuir adsorption isotherm. The maximum Pb(II)-sorption capacity calculated from Langmuir isotherm is 32.58 mg/g and 16.50 mg/g for Fe3O4@SiO2-IIP and Fe3O4@SiO2-NIP, respectively. Kinetics studies show that the adsorption process obeys a pseudo-second-order kinetic model with high correlation coefficient (R2 = 0.9982). The separation factor of Fe3O4@SiO2-IIP for Pb(II)/Cu(II), Pb(II)/Zn(II), and Pb(II)/Co(II) are 50.54, 52.14, and 37.39, respectively. The adsorption thermodynamic parameters ΔG, ΔH and ΔS were -4.98 kJ/mol, 3.27 kJ/mol and 28.84 J/mol/K, respectively. In addition, the spent Fe3O4@SiO2-IIP can be refreshed by simple washing with aqueous HCl solution, and there is no significant decrease in adsorption capacity after a test of up to five cycles, demonstrating that the Fe3O4@SiO2-IIP is stable and reusable.

  4. Magnetic ion-imprinted and –SH functionalized polymer for selective removal of Pb(II) from aqueous samples

    International Nuclear Information System (INIS)

    A magnetic ion-imprinted polymer (Fe3O4@SiO2-IIP) functionalized with –SH groups for the selective removal of Pb(II) ions from aqueous samples was synthesized by surface imprinting technique combined with a sol–gel process using 3-mercaptopropyl trimethoxysilane as monomer, tetraethyl orthosilicate as cross-linking agent, and Pb(II) ion as template. The Fe3O4@SiO2-IIP was characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectrometry. Fe3O4@SiO2-IIP showed higher capacity and selectivity than that of Fe3O4@SiO2-NIP. The effects of initial concentration of Pb(II) and pH of medium on adsorption capacity of Fe3O4@SiO2-IIP were studied. The experimental data fits well with the Langmuir adsorption isotherm. The maximum Pb(II)-sorption capacity calculated from Langmuir isotherm is 32.58 mg/g and 16.50 mg/g for Fe3O4@SiO2-IIP and Fe3O4@SiO2-NIP, respectively. Kinetics studies show that the adsorption process obeys a pseudo-second-order kinetic model with high correlation coefficient (R2 = 0.9982). The separation factor of Fe3O4@SiO2-IIP for Pb(II)/Cu(II), Pb(II)/Zn(II), and Pb(II)/Co(II) are 50.54, 52.14, and 37.39, respectively. The adsorption thermodynamic parameters ΔG, ΔH and ΔS were −4.98 kJ/mol, 3.27 kJ/mol and 28.84 J/mol/K, respectively. In addition, the spent Fe3O4@SiO2-IIP can be refreshed by simple washing with aqueous HCl solution, and there is no significant decrease in adsorption capacity after a test of up to five cycles, demonstrating that the Fe3O4@SiO2-IIP is stable and reusable.

  5. RPC test with heavy-ion beams

    International Nuclear Information System (INIS)

    The Time-of-Flight (ToF) wall of the Compressed Baryonic Matter (CBM) experiment, conceptualized on the basis of high-resolution timing Multi-gap Resistive Plate Chambers (MRPCs), is intended to account for concise hadron identification at an unprecedented event rate of 10 MHz in Au+Au collisions. Comprehensive performance tests of several purpose-built multi-strip MRPC prototypes foreseen for different rate regions of the planned 120 m2 ToF wall are an essential instrument to study the response and the limitations of the current design. Such evaluation studies were carried out both under SIS-18 heavy-ion beam load at GSI in the fall of 2012 and under cosmic irradiation in the lab throughout the year 2013. Particle flux conditions of up to a few tens of kHz/cm2 as expected to impinge on the ToF wall in future CBM runs can be provided at the SIS-18 accelerator. A generic calibration scheme for MRPCs with strip read-out has been developed and will be described. Preliminary results concerning key characteristics like efficiency and timing resolution of a multi-strip MRPC demonstrator are presented, as well as an outlook to the specifications and requirements of a planned high-rate in-beam test at GSI in 2014.

  6. Formation of La3+, Pr3+, Eu3+, Er3+, and Lu3+ complexes with chloride ions, in aqueous medium

    International Nuclear Information System (INIS)

    The constants of stability of the complexes of La3+, Pr3+, Eu3+, Er3+, and Lu3+ with Cl- ions, its were determined, in the aqueous medium of HCI - HClO4 and by a solvent extraction method. The dinonyl naphtalene sulfonic acid in n-heptane was used as extractant. The lanthanides concentration, it was measured by a VIS spectrophotometry method and by another radiochemical. The ions specific interaction theory (SIT) it was used for the extrapolation to ionic force 0 M. The results indicate that the stability constants of the LnCI2+ species diminishes when increasing the ion force and the charge density. (Author)

  7. Fluorescent single-stranded DNA-based assay for detecting unchelated Gadolinium(III) ions in aqueous solution.

    Science.gov (United States)

    Edogun, Osafanmwen; Nguyen, Nghia Huu; Halim, Marlin

    2016-06-01

    The main concern pertaining to the safety of Gadolinium(III)-based contrast agents (GBCAs) is the toxicity caused by the unchelated ion, which may be inadvertently present in the solution due most commonly to excess unreacted starting material or dissociation of the complexes. Detecting the aqueous free ion during the synthesis and preparation of GBCA solutions is therefore instrumental in ensuring the safety of the agents. This paper reports the development of a sensitive fluorogenic sensor for aqueous unchelated Gadolinium(III) (Gd(III)). Our design utilizes single-stranded oligodeoxynucleotides with a specific sequence of 44 bases as the targeting moiety. The fluorescence-based assay may be run at ambient pH with very small amounts of samples in 384-well plates. The sensor is able to detect nanomolar concentration of Gd(III), and is relatively unresponsive toward a range of biologically relevant ions and the chelated Gd(III). Although some cross-reactivity with other trivalent lanthanide ions, such as Europium(III) and Terbium(III), is observed, these are not commonly found in biological systems and contrast agents. This convenient and rapid method may be useful in ascertaining a high purity of GBCA solutions. Graphical abstract Fluorescent aptamer-based assay for detecting unchelated Ln(III) ions in aqueous solution. PMID:27071762

  8. Diffusion of inorganic ion aqueous solution into hydrophilic polymer fiber and molecular orientation

    International Nuclear Information System (INIS)

    The adsorption process of iodine to nylon 6 (polyamide-6), as well as deiodination process, has been an issue of controversy in the past half century from the view points related to the conversion of hydrogen bonding (α phase vs. γ phase). In the researches since late '80s, it has been revealed that the adsorption or inclusion of iodine to polyamides causes formations of various kind of structures to be called complexes whether they are crystalline or amorphous, and the formation of complex is reflected on the physical properties (especially on adsorption and ion mobility). Among them, it has been reported about both the doubly-oriented samples and the non-oriented samples that the ion diffusion causes molecular chain orientation during the complex formation. In the present experiment the change of molecular orientation in the early stage of the complex formation is studied by the time-resolved measurement with synchrotron radiation facility at SPring-8. Through-view and edge-view diffraction patterns of doubly oriented nylon 6 and non-oriented one were measured at 0.1 nm wavelength introducing I2-KI aqueous solution. It is observed that the formation of complex (i.e. diffusion of polyiodine) is attained in about 0.3 to 0.4 sec. even in non-oriented sample. From the analysis of the diffraction behavior, it is summarized that the inclusion of iodine into the crystalline phase of nylon 6 is possible from either sides of the molecular directions, namely normal diffusion and parallel diffusion. It is concluded that the diffusion and adsorption of inorganic ions including polyiodine to polyamide causes not only the formation of complexes in the crystalline phase but also give motive force to change structure in the surrounding non-crystalline region. (S. Funahashi)

  9. Removal of mercury(II) ions in aqueous solution using the peel biomass of Pachira aquatica Aubl: kinetics and adsorption equilibrium studies.

    Science.gov (United States)

    Santana, Andrea J; Dos Santos, Walter N L; Silva, Laiana O B; das Virgens, Cesário F

    2016-05-01

    Mercury is a highly toxic substance that is a health hazard to humans. This study aims to investigate powders obtained from the peel of the fruit of Pachira aquatica Aubl, in its in natura and/or acidified form, as an adsorbent for the removal of mercury ions in aqueous solution. The materials were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The infrared spectra showed bands corresponding to the axial deformation of carbonyls from carboxylic acids, the most important functional group responsible for fixing the metal species to the adsorbent material. The thermograms displayed mass losses related to the decomposition of three major components, i.e., hemicellulose, cellulose, and lignin. The adsorption process was evaluated using cold-vapor atomic fluorescence spectrometry (CV AFS) and cold-vapor atomic absorption spectrometry (CV AAS). Three isotherm models were employed. The adsorption isotherm model, Langmuir-Freundlich, best represented the adsorption process, and the maximum adsorption capacity was predicted to be 0.71 and 0.58 mg g(-1) at 25 °C in nature and acidified, respectively. Adsorption efficiencies were further tested on real aqueous wastewater samples, and removal of Hg(II) was recorded as 69.6 % for biomass acidified and 76.3 % for biomass in nature. Results obtained from sorption experiments on real aqueous wastewater samples revealed that recovery of the target metal ions was very satisfactory. The pseudo-second-order model showed the best correlation to the experimental data. The current findings showed that the investigated materials are potential adsorbents for mercury(II) ion removal in aqueous solution, with acidified P. aquatica Aubl being the most efficient adsorbent. PMID:27084802

  10. Investigation of the effect of the uranyl ion on proton-spin-relaxation times in aqueous solutions

    International Nuclear Information System (INIS)

    The purpose of this project was to determine the effect of the uranyl ion on the spin-lattice relaxation time of protons in aqueous solutions. A flowmeter using nuclear magnetic resonance (NMR) techniques is being designed for monitoring the flow rate of aqueous solutions which are acidic, contain plutonium and uranium ions, chemical waste, and radioactive waste materials. The spin-lattice relaxation time is critical to the design of a flowmeter using nuclear magnetic resonance techniques. Experimental studies showed that spin-lattice relaxation time did not change for different molar concentrations of sample solutions of uranyl nitrate and uranyl acetate prepared from pure laboratory chemicals dissolved in distilled water. Therefore, it was concluded that the uranyl ion does not contribute to the relaxation process for protons in water

  11. Polyvinyl alcohol fibers with functional phosphonic acid group. Synthesis and adsorption of uranyl (VI) ions in aqueous solutions

    International Nuclear Information System (INIS)

    PVA functionalized with vinylphosphonic acid was prepared as a new adsorbent for uranyl (VI) adsorption from aqueous solutions. The vinylphosphonic acid was cografted onto PVA fibers by preirradiation grafting technique. The adsorbent were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The adsorbent was observed to possess a fibrous structure and was bonded with phosphonic acid groups successfully. The adsorbent was used for the adsorption of low levels uranyl (VI) ions from aqueous solutions. The influence of analytical parameters including pH, adsorption time, amount of adsorbent, metal ion concentration, and temperature were investigated on the recovery of uranyl (VI) ion in aqueous solution. The maximum adsorption capacity (32.1 mg g-1) and fast equilibrium time (30 min) were achieved at pH of 4.5 at room temperature. Thermodynamic parameters (ΔH° = 2.695 kJ mol-1; ΔS° = 31.15 J mol-1 K-1; ΔG° = -6.748 kJ mol-1) show the adsorption of an exothermic process and spontaneous nature, respectively. The possible coordination mechanism was illustrated. Adsorption and desorption coexist in aqueous solutions and then the system becomes equilibrium. (author)

  12. Process for recovering organic values from aqueous solutions containing both organic values and scale-forming ions

    Energy Technology Data Exchange (ETDEWEB)

    Blytas, G.C.; Diaz, Z.

    1989-03-07

    A process is described for the recovery of organic values from aqueous solutions containing both organic values and scale-forming ions, consisting of: electrodialyzing as feed an organic value-containing aqueous solution containing scale-forming ions in a membrane-containing electrodialysis unit to obtain: (1) a concentrate stream containing a major portion of the scale-forming ions from the feed, and (2) a diluate stream containing a major portion of the organic values in the feed, supplying to the side of the membranes within the electrodialysis unit forming the concentrate stream an aqueous carrier stream substantially free of organic values, and in an amount sufficient to substantially reduce or prevent the formation of scale on the membranes, withdrawing the concentrate stream from the electrodialysis unit, fractionating the dilute stream by fractionation-distillation, recycling the overhead fraction as at least a portion of the aqueous carrier stream supplied to the side of the membranes forming the concentrate stream within the electrodialysis unit, and withdrawing the organic product stream from the fractionation distillation step.

  13. Removal of Lead(II) Ions from Aqueous Solution Using L. Seed Husk Ash as a Biosorbent.

    Science.gov (United States)

    Shi, Bingfang; Zuo, Weiyuan; Zhang, Jinlei; Tong, Haijuan; Zhao, Jinhe

    2016-05-01

    The removal of heavy metals, especially from wastewater, has attracted significant interest because of their toxicity, tendency to bioaccumulate, and the threat they pose to human life and the environment. Many low-cost sorbents have been investigated for their biosorption capacity toward heavy metals. However, there are no reports available on the removal of Pb(II) from aqueous solution by of L. seed husk ash. In this work, use of seed husk ash for the removal of Pb(II) from wastewater was investigated as a function of contact time and the initial pH of the solution. Kinetics and equilibrium constants were obtained from batch experiments. Our study shows that the adsorption process follows pseudo-second-order kinetics. Moreover, the Langmuir absorption model gave a better fit to the experimental data than the Freundlich equation. The maximum adsorption capacity of the husk ash was 263.10 mg g at 298 K and pH 5.0, and this is higher than the previously reported data obtained using other sorbents. The results obtained confirm that seed husk ash is an effective sorbent for the removal of Pb(II) from aqueous solution. Analysis of infrared spectra of the husk ash after absorption of Pb(II) suggested that OH, C=O, C-O, Si-O-Si, and O-Si-O groups were important for the Pb(II) ion removal. Moreover, practical tests on this biosorbent for Pb(II) removal in real wastewater samples successfully demonstrated that seed husk ash constitutes an efficient and cost-effective technology for the elimination of heavy metals from industrial effluent. PMID:27136166

  14. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

    2010-08-01

    Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

  15. Infrared spectroscopy of aqueous ionic salt mixtures at low concentrations: ion pairing in water.

    Science.gov (United States)

    Max, Jean-Joseph; Chapados, Camille

    2007-09-21

    The analysis by infrared spectroscopy of aqueous mixtures of NaI and CsCl was made in order to obtain information at the molecular level of the mixing of these two salts taken as model systems of strong electrolytes in water. In previous papers [J.-J. Max and C. Chapados, J. Chem. Phys. 115, 2664 (2001) and J.-J. Max et al., ibid. 126, 184507 (2007)] it was reported that a pure salt in water forms pairs of monoions to which are attached a fixed number of water molecules, giving solvated water species. Due to their interaction with the ion pairs, the solvated water molecules are strongly perturbed, modifying the IR water spectrum being monitored. After taking the IR spectrum of pure water, a small volume of NaI 2M was added and the IR spectrum taken. Then a small volume of CsCl 2M was added and a new IR spectrum taken. This procedure was repeated to obtain a series of 38 spectra in the 0.05M-0.83M concentration range. Factor analysis made on the series revealed the presence of three types of water: pure water and two salt solvated waters. The number of solvated water molecules on the two salts taken together is ten. Since NaI and CsCl have, respectively, 3.5 and 3.0 solvated water molecules, it was concluded that a reaction occurred in the solutions forming NaCl and CsI that have, respectively, five water molecules each for a total of ten. The analysis of the spectra of the orthogonal factors supports this attribution. These results provide additional proof of ion pairing in water. Furthermore, comparing the band displacements and intensity variations observed on the solvated water species to that of pure water indicates that the dielectric milieu surrounding the ion pairs is not constant. These results do not support the classical view of Debye-Huckel that considers that the ions are independent and the dielectric milieu constant. The present results give some in situ information on the reaction that goes on in "simple" electrolyte systems whose reactivity and

  16. Fluorometric selective detection of fluoride ions in aqueous media using Ag doped CdS/ZnS core/shell nanoparticles.

    Science.gov (United States)

    Boxi, Siddhartha Sankar; Paria, Santanu

    2016-01-14

    The presence of fluoride ions in drinking water plays an important role in human health. For that reason, maintaining the optimum concentration of fluoride ions in drinking water is essential, as both low and excess (above the permissible level) concentrations can cause different health problems, such as fluorosis, urolithiasis, kidney failure, cancer, and can even lead to death. So, development of a simple and low cost method for the detection of fluoride ions in water is highly desirable. In this study, a fluorometric method based on Ag-CdS/Ag-ZnS core/shell nanoparticles is developed for fluoride ion detection. The method was tested in aqueous solution at different pH values. The selectivity and sensitivity of the fluorescence probe was checked in the presence of other anions (Cl(-), Br(-), I(-), NO3(-) SO4(2-), HCO3(-), HPO4(2-), CH3COO(-), and H2PO4(-)) and found there is no significant interference of these associated ions. The fluoride ion concentration was varied in the range 190-22 800 μg L(-1) and a lower detection limit was obtained as 99.7 μg L(-1). PMID:26645767

  17. Thermodynamic study of the adsorption of chromium ions from aqueous solution on waste corn cobs material

    Directory of Open Access Journals (Sweden)

    Rafael A. Fonseca-Correa

    2014-12-01

    Full Text Available The paper shows the results of a study obtaining activated carbon from corn cobs and determining its use as an adsorbent for the removal of Cr3+ from aqueous solutions. The finely ground precursor was subjected to pyrolysis at 600 and 900 °C in a nitrogen atmosphere and chemical activation with H2O2 and HNO3. The effects of pyrolysis conditions and activation method on the physicochemical properties of the materials obtained were tested. The samples were characterised chemically and texturally. Were obtained microporous activated carbons of well-developed surface area varying from 337 to 1213 m2/g and exhibited differences acid-base character of the surface. The results obtained shows that a suitable good option of the activation procedure for corncobs permits the production of economic adsorbents with high sorption capacity for Cr3+ from aqueous solutions. A detailed study of immersion calorimetry was performed with carbons prepared from corn cobs to establish possible relationships with these materials between the enthalpies of immersion and textural and chemical parameters.

  18. On the radiolysis of iodide, nitrate and nitrite ions in aqueous solution: An experimental and modelling study

    International Nuclear Information System (INIS)

    Highlights: → Nitrate lowers volatile iodine yields in irradiated and Ar-sparged CsI solutions. → Radiolysis products (NO32-, HNO3- and H2NO3) reduce volatile iodine species. → Iodine reduction by radiolysis products is enhanced by dissolved O2. → N2O-sparged and irradiated CsI solutions with nitrite ions support new reactions. → Evidence shows importance of nitrate and nitrite ions in iodine radiolysis. - Abstract: High radiation fields are predicted in the atmospheres in the reactor containment under postulated severe accident conditions. In particular, an experimental and modelling project (PARIS) has provided results, which show that nitrogen dioxide was the dominant measured species at high doses (>1 kGy) in air/steam mixtures. In addition, nitrite and nitrate ions were measured in the post-test containment sumps in some Phebus FP in-reactor integral experiments; but their separate effects on iodine volatility from irradiated aqueous solutions of iodide using appear unreported in open literature. To address this issue, this paper presents an overview of the results of an experimental and modelling study carried out at PSI, Switzerland. The experimental study consisted of small-scale irradiations of CsI, boric acid and tracer containing aqueous solutions. Tests were first carried out without nitrate or nitrite ions to obtain results to confirm expected iodine behaviour by correlation with predicted results, which were generated by concurrently developed code (PSIodine). The solutions were sparged with N2O, argon and air to provide different net oxidation systems and to remove volatile iodine for measurement. Since the radiation chemistry of N2O-saturated iodide solutions is well established and the measured I2 yields and final pH correlate very well with the PSIodine code predictions, the effect of added nitrite ions to these solutions has provided results, which support the correct choice of relevant reactions for inclusion in the nitrate-model. Both

  19. Kinetics of mercury ions removal from synthetic aqueous solutions using by novel magnetic p(GMA-MMA-EGDMA) beads.

    Science.gov (United States)

    Bayramoğlu, Gülay; Arica, M Yakup

    2007-06-01

    Poly(glycidylmethacrylate-methylmethacrylate), p(GMA-MMA-EGDMA), magnetic beads were prepared via suspension polymerization in the presence of ferric ions. The epoxy groups of the beads were converted into amino groups via ring opening reaction of the ammonia and, the aminated magnetic beads were used for the removal of Hg(II) ions from aqueous solution in a batch experiment and in a magnetically stabilized fluidized bed reactor (MFB). The magnetic p(GMA-MMA-EGDMA) beads were characterized with scanning electron microscope (SEM), FT-IR and ESR spectrophotometers. The optimum removal of Hg(II) ions was observed at pH 5.5. The maximum adsorption capacity of Hg(II) ions by using the magnetic beads was 124.8+/-2.1 mgg(-1) beads. In the continuous MFB reactor, Hg(II) ions adsorption capacity of the magnetic beads decreased with an increase in the flow-rate. The maximum adsorption capacity of the magnetic beads in the MFB reactor was 139.4+/-1.4 mgg(-1). The results indicate that the magnetic beads are promising for use in MFB for removal of Hg(II) ions from aqueous solution and/or waste water treatment. PMID:17118552

  20. Kinetics of mercury ions removal from synthetic aqueous solutions using by novel magnetic p(GMA-MMA-EGDMA) beads

    Energy Technology Data Exchange (ETDEWEB)

    Bayramoglu, Guelay [Biochemical Processing and Biomaterial Research Laboratory, Faculty of Science, Kirikkale University, 71450 Yahsihan, Kirikkale (Turkey)]. E-mail: gbayramoglu@kku.edu.tr; Arica, M. Yakup [Biochemical Processing and Biomaterial Research Laboratory, Faculty of Science, Kirikkale University, 71450 Yahsihan, Kirikkale (Turkey)

    2007-06-01

    Poly(glycidylmethacrylate-methylmethacrylate), p(GMA-MMA-EGDMA), magnetic beads were prepared via suspension polymerization in the presence of ferric ions. The epoxy groups of the beads were converted into amino groups via ring opening reaction of the ammonia and, the aminated magnetic beads were used for the removal of Hg(II) ions from aqueous solution in a batch experiment and in a magnetically stabilized fluidized bed reactor (MFB). The magnetic p(GMA-MMA-EGDMA) beads were characterized with scanning electron microscope (SEM), FT-IR and ESR spectrophotometers. The optimum removal of Hg(II) ions was observed at pH 5.5. The maximum adsorption capacity of Hg(II) ions by using the magnetic beads was 124.8 {+-} 2.1 mg g{sup -1} beads. In the continuous MFB reactor, Hg(II) ions adsorption capacity of the magnetic beads decreased with an increase in the flow-rate. The maximum adsorption capacity of the magnetic beads in the MFB reactor was 139.4 {+-} 1.4 mg g{sup -1}. The results indicate that the magnetic beads are promising for use in MFB for removal of Hg(II) ions from aqueous solution and/or waste water treatment.

  1. Speciation of phytate ion in aqueous solution Thermodynamic parameters for protonation in NaCl

    International Nuclear Information System (INIS)

    Phytate protonation enthalpies and entropies were determined by direct calorimetric titrations, in sodium chloride aqueous media at different ionic strengths (0.1≤I/mol L-1≤1) and at t=25 deg. C. Only the first seven protonation steps were taken into account, since the remaining five protons of phytic acid could be considered as 'strongly acidic' (log KiH≤1, 8≤i≤12). The analysis of results evidenced slight variations among enthalpy and entropy values, for the same protonation step (i), at different ionic strengths. TΔSi values for each protonation step are significantly higher than the corresponding enthalpy changes, revealing the entropic nature of the bond involved in phytate protonation. The enthalpy changes for phytate protonation generally increase for each protonation step, as typical for phosphate ligands. Dependence on ionic strength for both log KiH and ΔHi was taken into account by Specific ion Interaction Theory (SIT). Useful predictive relationships for the dependence of TΔS on ΔG and on protonation step 'i' were proposed

  2. Effective removal of Cu (II) ions from aqueous solution by amino-functionalized magnetic nanoparticles

    International Nuclear Information System (INIS)

    A novel magnetic nano-adsorbent (MNP-NH2) has been developed by the covalent binding of 1,6-hexadiamine on the surface of Fe3O4 nanoparticles for removal of Cu2+ ions from aqueous solution. Various factors affecting the uptake behavior such as contact time, temperature, pH, salinity, amount of MNP-NH2 and initial concentration of Cu2+ were investigated. The kinetics was evaluated utilizing the Lagergren pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion models. The equilibrium data were analyzed using Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. The adsorption was relatively fast and the equilibrium was established within 5 min, and its kinetics followed the pseudo-second-order mechanism, evidencing chemical sorption as the rate-limiting step of sorption mechanism. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities was 25.77 mg g-1 at pH 6, and 298 K. Thermodynamic parameters showed that the adsorption process was spontaneous, endothermic and chemical in nature. The successive adsorption-desorption studies indicated that the MNP-NH2 sorbent kept its adsorption and desorption efficiencies constant over 15 cycles. Importantly, MNP-NH2 was able to remove 98% of Cu2+ from polluted river and tap water.

  3. Nickel Hexacyanoferrate Nanoparticle Electrodes For Aqueous Sodium and Potassium Ion Batteries

    KAUST Repository

    Wessells, Colin D.

    2011-12-14

    The electrical power grid faces a growing need for large-scale energy storage over a wide range of time scales due to costly short-term transients, frequency regulation, and load balancing. The durability, high power, energy efficiency, and low cost needed for grid-scale storage pose substantial challenges for conventional battery technology.(1, 2)Here, we demonstrate insertion/extraction of sodium and potassium ions in a low-strain nickel hexacyanoferrate electrode material for at least five thousand deep cycles at high current densities in inexpensive aqueous electrolytes. Its open-framework structure allows retention of 66% of the initial capacity even at a very high (41.7C) rate. At low current densities, its round trip energy efficiency reaches 99%. This low-cost material is readily synthesized in bulk quantities. The long cycle life, high power, good energy efficiency, safety, and inexpensive production method make nickel hexacyanoferrate an attractive candidate for use in large-scale batteries to support the electrical grid. © 2011 American Chemical Society.

  4. Removal of aqueous uranyl ions by magnetic functionalized carboxymethylcellulose and adsorption property investigation

    International Nuclear Information System (INIS)

    Highlights: • The solvent in this synthetic is only water, it is very friendly to the environment. • Adsorbent with active surface rich in functional groups. • A magnetism is linked to this material and make it easy to separation. • Synthesis is in a facile pathway, the temperature are lower than 100 °C. • The maximum adsorption capacity toward uranium(VI) is 122.48 mg/g at 45 °C. - Abstract: Magnetic carboxymethylcellulose (CMC/Fe3O4) was used as a framework adsorption material to remove uranium ions from aqueous solutions. Carboxyl functional groups were grafted onto the CMC/Fe3O4. The maximum adsorption capacity of the magnetic composite toward U(VI) was 122.48 mg/g. Kinetic and thermodynamic parameters of the adsorption process were estimated. The pseudo-second-order model was more suitable and it proved to be an endothermic and spontaneous process. The Langmuir and Freundlich models were applied to evaluate the adsorption isotherm. The data matched well with Langmuir model after equilibrium was reached and with Freundlich model before equilibrium was reached

  5. Speciation of phytate ion in aqueous solution Thermodynamic parameters for protonation in NaCl

    Energy Technology Data Exchange (ETDEWEB)

    De Stefano, Concetta; Milea, Demetrio; Sammartano, Silvio

    2004-12-01

    Phytate protonation enthalpies and entropies were determined by direct calorimetric titrations, in sodium chloride aqueous media at different ionic strengths (0.1{<=}I/mol L{sup -1}{<=}1) and at t=25 deg. C. Only the first seven protonation steps were taken into account, since the remaining five protons of phytic acid could be considered as 'strongly acidic' (log K{sub i}{sup H}{<=}1, 8{<=}i{<=}12). The analysis of results evidenced slight variations among enthalpy and entropy values, for the same protonation step (i), at different ionic strengths. T{delta}S{sub i} values for each protonation step are significantly higher than the corresponding enthalpy changes, revealing the entropic nature of the bond involved in phytate protonation. The enthalpy changes for phytate protonation generally increase for each protonation step, as typical for phosphate ligands. Dependence on ionic strength for both log K{sub i}{sup H} and {delta}H{sub i} was taken into account by Specific ion Interaction Theory (SIT). Useful predictive relationships for the dependence of T{delta}S on {delta}G and on protonation step 'i' were proposed.

  6. Tests of a Laser Ion Source at the Heidelberg Electron Beam Ion Trap

    OpenAIRE

    Mironov, V; Trinczek, M.; Werdich, A.; González Martínez, A.; Guo, P; X. Zhang; Braun, J.; Crespo López-Urrutia, J.; Höhr, C.; Ullrich, J.

    2003-01-01

    A laser ion source (LIS) has been designed and successfully tested for loading the Heidelberg electron beam ion trap (H-EBIT) with ions of practically all solid-state elements. A pulsed YAG:Nd3þ laser (30 mJ, 8 ns) is used to produce plasma from a solid target. Lowly charged ions are extracted from the plasma and accelerated by a short high-voltage pulse, generating a pulsed ion beam with energy of up to 6 keV per charge. The ion beam is transported into the EBIT, decelerated and captured wit...

  7. Fabrication of a green porous lignin-based sphere for the removal of lead ions from aqueous media

    International Nuclear Information System (INIS)

    Highlights: • A porous lignin-based sphere was prepared from lignosulfonate by a gelation method. • The porous lignin-based sphere (PLS) had a high porosity and pore volume. • The PLS showed high adsorption efficiency for lead ions from aqueous media. • Bed column test proved the potential of PLS for continuous treatment of effluent. - Abstract: A green porous lignin-based sphere (PLS) had been fabricated by a feasible gelation-solidification method from lignosulfonate cross-linked with sodium alginate and epichlorohydrin. The prepared sphere was characterized by Fourier transform infrared spectrometry, scanning electron microscopy, mercury intrusion porosimetry, and thermo gravimetric analysis. The results demonstrated the PLS had a large amount of mesopores (d = 20.7 nm) with a high porosity of 87.66% and a total pore volume of 0.416 cm3/g. Batchwise adsorption experiments indicated the PLS possessed excellent adsorption efficiency (95.6 ± 3.5%) for lead ions at an initial concentration of 25.0 mg/L. The adsorption process could be well fitted by intra-particle diffusion model and Langmuir isotherm model. Application of the PLS in bed column mode for the continuous treatment of lead solution exhibited prolonged breakthrough time from 75 min to 100 min as the bed column heights increased from 0.5 cm to 2.5 cm which was much better than the alkaline lignin column (2.5 cm height, breakthrough time = 60 min). The results strongly suggested the high possibility of the porous sphere being applied for the continuous treatment of heavy metals rich wastewater in industry

  8. The ion-selective field-effect transistor application for enzyme analysis of toxic admixtures in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Pavluchenko A. S.

    2010-06-01

    Full Text Available The article describes design and production technology of pH-sensors based on ion-selective field-effect transis-tors (ISFET intended for enzyme analysis of inhibiting admixtures in aqueous solutions, and architecture of the multichannel measuring system built upon the ISFET-sensors. The characteristics of developed prototypes are given and the ways for further improvement of system design, metrological performance and operating parameters are outlined.

  9. Sequestration of U(VI) from aqueous solutions using precipitate ion imprinted polymers endowed with oleic acid functionalized magnetite

    International Nuclear Information System (INIS)

    The use of a polymeric sorbent material embedded with oleic acid coated magnetic particles as selective sorbents for the removal of U(VI) ions from industrial waste effluents was studied. In the presence of other competing ions [Th(IV) and Ni(II)], U(VI) was preferentially adsorbed. Inclusion of nano-magnetic particles in the polymer matrix aided the separation of the sorbents from aqueous solutions by application of external magnetic field. High recoveries indicated that the sorbent is suitable for application in contaminated water. (author)

  10. Formation of ozone in the reaction between the ozonide radical ion, O3-, and the carbonate radical ion, CO3-, in aqueous alkaline solutions

    International Nuclear Information System (INIS)

    Ozone forms in aqueous alkaline solutions by a reaction between the O3- and CO3- radical ions. This reaction has been demonstrated under conditions favorable for the generation of suitable concentrations of these ions by a high-pressure pulse radiolysis technique. The reaction is O3- + CO3- → O3 + CO32-. Its rate constant k/sub (O3-+CO3-)/ of (6 +- 2) x 107 dm3 mol-1 s-1 has been determined by computer simulation of the reactions involved

  11. ADSORPTION OF Pb2+ IONS FROM AQUEOUS SOLUTIONS ONTO BAEL TREE LEAF POWDER: ISOTHERMS, KINETICS AND THERMODYNAMICS STUDY

    Directory of Open Access Journals (Sweden)

    P. SENTHIL KUMAR

    2009-12-01

    Full Text Available In this study, bael tree (BT leaf powder was used as an adsorbent for removal of Pb2+ ions from aqueous solutions through batch equilibrium technique. The influence of pH, equilibrium time, temperature, adsorbent dosage and initial concentration of metal ions on adsorbed amount of metals ions were investigated. Studies showed that the pH of aqueous solutions affected Pb2+ ions removal as a result of removal efficiency increased with increasing solution pH. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich equations. The monolayer adsorption capacity is 4.065 mg/g with the correlation coefficient of 0.993. The experiments showed that highest removal rate was 84.93% at solution pH 5, contact time 60 min and initial concentration of 50 mg/L. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy have also been evaluated and it has been found that the sorption process was feasible, spontaneous and exothermic in nature. Three simplified kinetic models including a pseudo-first-order equation, pseudo-second-order equation and intraparticle diffusion equation were selected to follow the adsorption process. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was shown that the adsorption of Pb2+ ions could be described by the pseudo-second order equation, suggesting that the adsorption process is presumable a chemisorption.

  12. Runaway of energetic test ions in a toroidal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Eilerman, S., E-mail: eilerman@wisc.edu; Anderson, J. K.; Sarff, J. S.; Forest, C. B.; Reusch, J. A.; Nornberg, M. D.; Kim, J. [Department of Physics, University of Wisconsin–Madison and Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, Madison, Wisconsin 53706 (United States)

    2015-02-15

    Ion runaway in the presence of a large-scale, reconnection-driven electric field has been conclusively measured in the Madison Symmetric Torus reversed-field pinch (RFP). Measurements of the acceleration of a beam of fast ions agree well with test particle and Fokker-Planck modeling of the runaway process. However, the runaway mechanism does not explain all measured ion heating in the RFP, particularly previous measurements of strong perpendicular heating. It is likely that multiple energization mechanisms occur simultaneously and with differing significance for magnetically coupled thermal ions and magnetically decoupled tail and beam ions.

  13. A valence bond model for aqueous Cu(II) and Zn(II) ions in the AMOEBA polarizable force field.

    Science.gov (United States)

    Xiang, Jin Yu; Ponder, Jay W

    2013-04-01

    A general molecular mechanics (MM) model for treating aqueous Cu(2+) and Zn(2+) ions was developed based on valence bond (VB) theory and incorporated into the atomic multipole optimized energetics for biomolecular applications (AMOEBA) polarizable force field. Parameters were obtained by fitting MM energies to that computed by ab initio methods for gas-phase tetra- and hexa-aqua metal complexes. Molecular dynamics (MD) simulations using the proposed AMOEBA-VB model were performed for each transition metal ion in aqueous solution, and solvent coordination was evaluated. Results show that the AMOEBA-VB model generates the correct square-planar geometry for gas-phase tetra-aqua Cu(2+) complex and improves the accuracy of MM model energetics for a number of ligation geometries when compared to quantum mechanical (QM) computations. On the other hand, both AMOEBA and AMOEBA-VB generate results for Zn(2+)-water complexes in good agreement with QM calculations. Analyses of the MD trajectories revealed a six-coordination first solvation shell for both Cu(2+) and Zn(2+) ions in aqueous solution, with ligation geometries falling in the range reported by previous studies. PMID:23212979

  14. Water-soluble polymers for recovery of metal ions from aqueous streams

    Science.gov (United States)

    Smith, Barbara F.; Robison, Thomas W.

    1998-01-01

    A process of selectively separating a target metal contained in an aqueous solution by contacting the aqueous solution containing a target metal with an aqueous solution including a water-soluble polymer capable of binding with the target metal for sufficient time whereby a water-soluble polymer-target metal complex is formed, and, separating the solution including the water-soluble polymer-target metal complex from the solution is disclosed.

  15. Colorimetric disposable paper coated with ZnO@ZnS core-shell nanoparticles for detection of copper ions in aqueous solutions.

    Science.gov (United States)

    Sadollahkhani, Azar; Hatamie, Amir; Nur, Omer; Willander, Magnus; Zargar, Behrooz; Kazeminezhad, Iraj

    2014-10-22

    In this study, we have proposed a new nanoparticle-containing test paper sensor that could be used as an inexpensive, easy-to-use, portable, and highly selective sensor to detect Cu(2+) ions in aqueous solutions. This disposable paper sensor is based on ZnO@ZnS core-shell nanoparticles. The core-shell nanoparticles were synthesized using a chemical method and then they were used for coating the paper. The synthesis of the ZnO@ZnS core-shell nanoparticles was performed at a temperature as low as 60 °C, and so far this is the lowest temperature for the synthesis of such core-shell nanoparticles. The sensitivity of the paper sensor was investigated for different Cu(2+) ion concentrations in aqueous solutions and the results show a direct linear relation between the Cu(2+) ions concentration and the color intensity of the paper sensor with a visual detection limit as low as 15 μM (∼0.96 ppm). Testing the present paper sensor on real river turbulent water shows a maximum 5% relative error for determining the Cu(2+) ions concentration, which confirms that the presented paper sensor can successfully be used efficiently for detection in complex solutions with high selectivity. Photographs of the paper sensor taken using a regular digital camera were transferred to a computer and analyzed by ImageJ Photoshop software. This finding demonstrates the potential of the present disposable paper sensor for the development of a portable, accurate, and selective heavy metal detection technology. PMID:25275616

  16. Cytotoxicity of aqueous extracts of Rosmarinus officinalis L. (Labiatae) in plant test system.

    Science.gov (United States)

    Cardoso, G H S; Dantas, E B S; Sousa, F R C; Peron, A P

    2014-11-01

    This study investigated the cytotoxic activity of Rosmarinus officinalis L. (rosemary) aqueous extract on the cell cycle of Allium cepa. To this end, crude aqueous leaf extracts at four concentrations, 0.02, 0.04, 0.06 and 0.08 mg/mL, were tested on A. cepa meristematic root cells, at exposure times of 24 and 48 h. Slides were prepared by the crushing technique, and cells analyzed throughout the cell cycle, totaling 5,000 for each control group and concentration. The four concentrations tested, including the lowest and considered ideal for use, at all exposure times, showed a significant antiproliferative effect on the cell cycle of this test system and presented a high number of cells in prophase. Our results evidenced the cytotoxicity of rosemary extracts, under the studied conditions. PMID:25627599

  17. Adsorption of cadmium ions from aqueous solution using granular activated carbon and activated clay

    Energy Technology Data Exchange (ETDEWEB)

    Wasewar, Kailas L. [Department of Chemical Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra (India); Kumar, Pradeep; Teng, Tjoon Tow [Environmental Technology Division, School of Industrial Technology, University Science of Malaysia, Minden, Penang (Malaysia); Chand, Shri; Padmini, Bina N. [Department of Chemical Engineering, Indian Institute of Technology, Roorkee (India)

    2010-07-15

    The present study was aimed at removing cadmium ions from aqueous solution through batch studies using adsorbents, such as, granular activated carbon (GAC) and activated clay (A-clay). GAC was of commercial grade where as the A-clay was prepared by acid treatment of clay with 1 mol/L of H{sub 2}SO{sub 4}. Bulk densities of A-clay and GAC were 1132 and 599 kg/m{sup 3}, respectively. The surface areas were 358 m{sup 2}/g for GAC and 90 m{sup 2}/g for A-clay. The adsorption studies were carried out to optimize the process parameters, such as, pH, adsorbent dosage, and contact time. The results obtained were analyzed for kinetics and adsorption isotherm studies. The pH value was optimized at pH 6 giving maximum Cd removal of 84 and 75.2% with GAC and A-clay, respectively. The adsorbent dosage was optimized and was found to be 5 g/L for GAC and 10 g/L for A-clay. Batch adsorption studies were carried out with initial adsorbate (Cd) concentration of 100 mg/L and adsorbent dosage of 10 g/L at pH 6. The optimum contact time was found to be 5 h for both the adsorbents. Kinetic studies showed Cd removal a pseudo second order process. The isotherm studies revealed Langmuir isotherm to better fit the data than Freundlich isotherm. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  18. Batch adsorption of cadmium ions from aqueous solution by means of olive cake

    International Nuclear Information System (INIS)

    The use of natural adsorbent such as olive cake to replace expensive imported synthetic adsorbent is particularly appropriate for developing countries such as Jordan. In this study, batch adsorption experiments were carried out for the removal of cadmium ions from its aqueous solution using olive cake as adsorbent. Parameters effects such as temperature, pH and adsorbent dose on the adsorption process were studied. The adsorbent used in this study exhibited as good sorption at approximately pH 6 at temperatures 28, 35 and 45 deg. C. The removal efficiency was found to be 66% at pH 6 and temperature 28 deg. C. The equilibrium data were analyzed using Langmuir and Freundlich isotherm models to calculate isotherm constants. The experimental results were in a good agreement with these models. Results show that when an increasing in temperature from 28 to 45 deg. C, the maximum adsorption capacity (qmax) is decreased from 65.4 to 44.4 mg/g and Freundlich constant (Kf) decreased from 19.9 to 15.7. The thermodynamic parameters for the adsorption process data were evaluated using Langmuir isotherm. The free energy change (ΔGo) and the enthalpy change (ΔHo) showed that the process was feasible and exothermic, respectively. The dynamic data fitted to the first order, Lagergren-first order and pseudo second-order kinetic models. The experimental results indicated that the pseudo second-order reaction model provided the best description for these data with a correlation coefficient of 0.99. The adsorption rate constant was calculated as 8.4 x 10-3 g mg-1 min-1 at 28 deg. C

  19. Effects of ion concentration on the hydrogen bonded structure of water in the vicinity of ions in aqueous NaCl solutions

    Indian Academy of Sciences (India)

    A Nag; D Chakraborty; A Chandra

    2008-01-01

    Molecular dynamics simulations of dilute and concentrated aqueous NaCl solutions are carried out to investigate the changes of the hydrogen bonded structures in the vicinity of ions for different ion concentrations. An analysis of the hydrogen bond population in the first and second solvation shells of the ions and in the bulk water is done. Although essentially no effect of ions on the hydrogen bonding is observed beyond the first solvation shell of the ions for the dilute solutions, for the concentrated solutions a noticeable change in the average number of water-water hydrogen bonds is observed in the second solvation shells of the ions and even beyond. However, the changes in the average number of hydrogen bonds are found to be relatively less when both water-water and ion-water hydrogen bonds are counted. Thus, the changes in the total number of hydrogen bonds per water are not very dramatic beyond the first solvation shell even for concentrated solutions.

  20. Surface functionalized magnetic PVA microspheres for rapid naked-eye recognizing of copper(II) ions in aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • The functionalized groups were immobilized onto surface of magnetic PVA microspheres via a series of reaction. • The PAR-MPVA microspheres had excellent detection for copper ions by nake-eye. • The PAR-MPVA microspheres could be conveniently separated by a magnet. • The PAR-MPVA microspheres had preeminent reusability and stability. - Abstract: We proposed a robust method for surface-functionalizing magnetic polyvinyl alcohol microspheres to detect heavy metal ions in aqueous solutions. The prepared chemosensor (PAR-MPVA) was characterized through scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectra (XPS). In neutral solutions, PAR-MPVA selectively recognized diatomic heavy metal ions, as indicated with a color change from earth yellow to red; in strong acidic solutions, the chemosensor only selectively detected Cu2+. PAR-MPVA microspheres had a detection limit as low as 0.5 μM by naked-eye and 0.16 μM by UV–vis spectrometer for Cu2+. Moreover, the sensor possessed magnetism for effective recovery, could easily be regenerated by a solution of EDTA, and also displayed perferable stability. The PAR-MPVA microspheres possessed preeminent properties of detecting copper (II) ions in aqueous solutions

  1. Determination of U oxidation state in anoxic (N2) aqueous solutions. Method development and testing

    International Nuclear Information System (INIS)

    The report describes the development and testing of a method for determining uranium oxidation state in aqueous solutions in inert (N2) atmosphere. The method included the separation of the tetravalent and hexavalent states by anion-exchange chromatography in HCl medium, followed by analysis of the uranium contents of each of the fractions by ICP-MS. The tests of the study demonstrated the suitability of the method for analysing the oxidation states of uranium at the low concentrations representative for U solubilities in anoxic groundwater. Additionally, the results obtained give some information on the redox state of the aqueous solutions in inert (N2) atmosphere. Obviously, the trace oxygen content in the atmosphere of the box is enough to cause slightly oxidizing conditions for uranium in the absence of reducing agents (e.g. H2, iron). (10 refs.)

  2. Development of ion beams for space effects testing using an ECR ion source

    Science.gov (United States)

    Benitez, Janilee; Hodgkinson, Adrian; Johnson, Mike; Loew, Tim; Lyneis, Claude; Phair, Larry

    2013-04-01

    At LBNL's 88-Inch Cyclotron and Berkeley Accelerator Space Effects (BASE) Facility, a range of ion beams at energies from 1 to 55 MeV/nucleon are used for radiation space effects testing. By bombarding a component with ion beams the radiation component of the space environment can be simulated and single event effects (SEEs) determined. The performance of electronic components used in space flight and high altitude aircraft can then be evaluated. The 88- Inch Cyclotron is coupled to the three electron cyclotron resonance ion sources (ECR, AECR-U, VENUS). These ion sources provide a variety of ion species, ranging from protons to heavy ions such as bismuth, for these tests. In particular the ion sources have been developed to provide "cocktails", a mixture of ions of similar mass-to-charge ratio, which can be simultaneously injected into the cyclotron, but selectively extracted from it. The ions differ in both their linear energy transfer (LET) deposited to the part and in their penetration depth into the tested part. The current heavy ion cocktails available are the 4.5, 10, 16, and 30 MeV per nucleon.

  3. Development of ion beams for space effects testing using an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Janilee; Hodgkinson, Adrian; Johnson, Mike; Loew, Tim; Lyneis, Claude; Phair, Larry [Nuclear Science Division, Lawrence Berkeley National Lab One Cyclotron Road, Berkeley, CA 94720 (United States)

    2013-04-19

    At LBNL's 88-Inch Cyclotron and Berkeley Accelerator Space Effects (BASE) Facility, a range of ion beams at energies from 1 to 55 MeV/nucleon are used for radiation space effects testing. By bombarding a component with ion beams the radiation component of the space environment can be simulated and single event effects (SEEs) determined. The performance of electronic components used in space flight and high altitude aircraft can then be evaluated. The 88- Inch Cyclotron is coupled to the three electron cyclotron resonance ion sources (ECR, AECR-U, VENUS). These ion sources provide a variety of ion species, ranging from protons to heavy ions such as bismuth, for these tests. In particular the ion sources have been developed to provide {sup c}ocktails{sup ,} a mixture of ions of similar mass-to-charge ratio, which can be simultaneously injected into the cyclotron, but selectively extracted from it. The ions differ in both their linear energy transfer (LET) deposited to the part and in their penetration depth into the tested part. The current heavy ion cocktails available are the 4.5, 10, 16, and 30 MeV per nucleon.

  4. An interesting spectroscopic method for chromofluorogenic detection of cyanide ion in aqueous solution: Disruption of intramolecular charge transfer (ICT)

    Indian Academy of Sciences (India)

    Abdolhamid Alizadeh; Sohrab Ghouzivand; Mohammad M Khodaei; Mehdi Ardalani

    2016-04-01

    5-[4-(dimethylamino)benzylidene) pyrimidine-2,4,6(1H,3H,5H)]-trione (DMP-3H), the receptor was synthesized which played a chemosensor role for cyanide ion (CN−) in aqueous solution with colorimetric and fluorescence turn-off responses. Upon addition of CN− ion into the solution containing the receptor, a color change visible to the naked eye was observed from yellow to colourless and also, the fluorescence of the solution was immediately quenched. Moreover, DMP-3H exhibited a selective response to cyanide ion over many other anions such as F−, Cl−, Br−, I−, SO$^{2−}_{3}$ , OCN−, ClO$^{−}_{3}$ , CO$^{2−}_{3}$ , IO$^{−}_{3}$ , N$^{−}_{3}$ , C$_{2}$O$^{2−}_{4}$ and SCN−. The detection limit toward CN− was 8.1 × 10−7 mol.L−1, which is satisfactory enough for monitoring CN− levels in physiological and environmental systems.

  5. A relativistic study of the photochemistry of the uranyl(VI) ion in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Real, F.; Wahlgren, U. [Alballova University Center, Stockholm University, Fysikum, 104-91 Stockholm, (Sweden); Vallet, V. [Laboratoire PhLAM, Universite des Sciences et Technologies de Lille 1 CNRS UMR8523, 59655 Villeneuve d Ascq Cedex, (France); Marian, C. [Institut fur Theoretische Chemie und Computerchemie Heinrich-Heine-Universitat Universitatsstr. 40225 Dusseldorf (Georgia); Grenthe, I. [KTH Royal Institute of Technology, Inorganic Chemistry Se-10044 Stockholm, (Sweden)

    2007-07-01

    Complete text of publication follows: The U-O bond in the uranyl(VI) ion is in general considered to be kinetically inert in thermal reactions, such as isotope exchange reactions. However, a fast isotope exchange can take place in photochemical reactions under UV irradiation as exemplified by the reaction: U{sup 17}O{sub 2}(H{sub 2}O){sub 5}{sup 2+} + H{sub 2}*0 {yields} U{sup 17}O{sub 2}(H{sub 2}O){sub 5}{sup 2+} + H{sub 2}O (1) Under daylight, no exchange takes place, or the rate of exchange is very slow. This suggests that the reaction involves the excited-states of the uranyl(VI). 1) A comparison between wave-function theory and density-functional theory: The first part of this talk will discuss benchmark calculations of the excited states of the bare uranyl(VI) ion so that we can choose the computational cost effective ab initio method for the study of the photochemistry of actinide compounds. Before exploring the mechanism of exchange it is necessary to have information on the chemistry of the excited states and their electronic structure. It seems reasonable to assume that 'yl'-isotope exchange is related to the U-O{sub yl} stretching modes and following the work of Pierloot and van Besien [1] we have therefore studied the a{sub g}- and a{sub u}-modes of the U-O{sub yl} bond using different methods such as CASPT2, TD-DFT and DFT-MRCI and different basis set and description of the heavy-element. The scalar-relativistic effects were included using either the Douglas-Kroll Hamiltonian in the case of all-electron calculations or an RECP small core from the Stuttgart Library. The {sup 3}{gamma}{sub g} state seems to be a good candidate for the photochemically 'active' state where the increase of the U-O{sub yl} localizes the wave function and gives distant 'yl' oxygen attains radical character. 2) Photochemistry of the uranyl(VI) in aqueous solution: In the case of the photochemistry of the uranyl(VI), we suggest that the first step

  6. A peptide-based fluorescent chemosensor for measuring cadmium ions in aqueous solutions and live cells.

    Science.gov (United States)

    Wang, Peng; Wu, Jiang; Liu, Lixuan; Zhou, Panpan; Ge, Yushu; Liu, Dan; Liu, Weisheng; Tang, Yu

    2015-11-01

    A novel peptide fluorescent chemosensor (H2L) with a lysine backbone and both -NH2 sites conjugated with cysteine and dansyl groups has been designed and synthesized by solid phase peptide synthesis with Fmoc chemistry. This chemosensor is a promising analytical tool for detecting Cd(2+) based on the photo-induced electron transfer (PET) effect by turn-on response in 100% aqueous solutions. As designed, H2L exhibits excellent cell permeation and low biotoxicity as well as displaying relatively high selectivity and sensitivity. The chemosensor penetrated live HeLa cells and detected intracellular Cd(2+) by turn-on response. The binding stoichiometry and affinity, interference test, pH sensitivity, fluorescence quantum yield, quantum mechanical calculations, lifetimes, and cytotoxicity of the chemosensor H2L to Cd(2+) were also investigated. Moreover, H2L exhibits low biotoxicity with a limit of detection (LOD) for Cd(2+) of about 52 nM, implying that H2L can be used as a highly selective and sensitive peptide fluorescent chemosensor in biological systems. PMID:26411376

  7. Test ion transport in a collisional, field-reversed configuration

    International Nuclear Information System (INIS)

    Diffusion of test-ions in a flux-coil generated, collisional, field-reversed configuration is measured via time-resolved tomographic reconstruction of Ar+ optical emission in the predominantly nitrogen plasma. Azimuthal test ion diffusion across magnetic field lines is found to be classical during the stable period of the discharge. Test ion radial confinement is enhanced by a radial electric field, reducing the observed outward radial transport rate below predictions based solely on classical cross-field diffusion rates. Test ion diffusion is ∼500 m2 s−1 during the stable period of the discharge. The electric field inferred from plasma potential measurements and from equilibrium calculations is consistent with the observed reduction in argon transport. (paper)

  8. Preparation and Characterization of Poly(ethyl hydrazide-Grafted Oil Palm Empty Fruit Bunch Fibre for the Removal of Cu(II Ions from an Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Siti Mariam Mohd Nor

    2013-07-01

    Full Text Available Poly(ethyl hydrazide-grafted oil palm empty fruit bunch fibre (peh-g-opefb was successfully prepared by heating poly(methyl acrylate-grafted opefb (pma-g-opefb at 60 °C for 4 h with a solution of hydrazine hydrate (15% v/v in ethanol. The Fourier transform infrared spectrum of the product shows a secondary amine peak at 3267 cm−1, with amide carbonyl peaks at 1729 cm−1 and 1643 cm−1. The chelating ability of peh-g-opefb was tested with copper ion in aqueous solution. A batch adsorption study revealed that maximum adsorption of copper ion was achieved at pH 5. An isotherm study showed the adsorption follows a Langmuir model, with a maximum adsorption capacity of 43.48 mg g−1 at 25 °C. A kinetic study showed that the adsorption of copper ion rapidly reaches equilibrium and follows a pseudo–second-order kinetic model, with a constant rate of 7.02 × 10−4 g mg−1 min−1 at 25 °C. The Gibbs free energy, ∆G⁰, value is negative, indicating a spontaneous sorption process. Entropy, ∆S⁰, gives a positive value, indicating that the system is becoming increasingly disordered after the adsorption of copper ion. A positive enthalpy value, ∆H⁰, shows that the endothermic process takes place during the adsorption and is more favourable at high temperatures.

  9. Preparation and characterization of poly(ethyl hydrazide)-grafted oil palm empty fruit bunch fibre for the removal of Cu(II) ions from an aqueous environment.

    Science.gov (United States)

    Johari, Ili Syazana; Yusof, Nor Azah; Haron, Md Jelas; Nor, Siti Mariam Mohd

    2013-01-01

    Poly(ethyl hydrazide)-grafted oil palm empty fruit bunch fibre (peh-g-opefb) was successfully prepared by heating poly(methyl acrylate)-grafted opefb (pma-g-opefb) at 60 °C for 4 h with a solution of hydrazine hydrate (15% v/v) in ethanol. The Fourier transform infrared spectrum of the product shows a secondary amine peak at 3267 cm⁻¹, with amide carbonyl peaks at 1729 cm⁻¹ and 1643 cm⁻¹. The chelating ability of peh-g-opefb was tested with copper ion in aqueous solution. A batch adsorption study revealed that maximum adsorption of copper ion was achieved at pH 5. An isotherm study showed the adsorption follows a Langmuir model, with a maximum adsorption capacity of 43.48 mg g-1 at 25 °C. A kinetic study showed that the adsorption of copper ion rapidly reaches equilibrium and follows a pseudo-second-order kinetic model, with a constant rate of 7.02 × 10⁻⁴ g mg⁻¹ min⁻¹ at 25 °C. The Gibbs free energy, ∆G⁰, value is negative, indicating a spontaneous sorption process. Entropy, ∆S⁰, gives a positive value, indicating that the system is becoming increasingly disordered after the adsorption of copper ion. A positive enthalpy value, ∆H⁰, shows that the endothermic process takes place during the adsorption and is more favourable at high temperatures. PMID:23873385

  10. Adsorption of cadmium (II) ions from aqueous solution by a new low-cost adsorbent-Bamboo charcoal

    International Nuclear Information System (INIS)

    Batch adsorption experiments were conducted for the adsorption of Cd (II) ions from aqueous solution by bamboo charcoal. The results showed that the adsorption of Cd (II) ions was very fast initially and the equilibrium time was 6 h. High pH (≥8.0) was favorable for the adsorption and removal of Cd (II) ions. Higher initial Cd concentrations led to lower removal percentages but higher adsorption capacity. As the adsorbent dose increased, the removal of Cd increased, while the adsorption capacity decreased. Adsorption kinetics of Cd (II) ions onto bamboo charcoal could be best described by the pseudo-second-order model. The adsorption behavior of Cd (II) ions fitted Langmuir, Temkin and Freundlich isotherms well, but followed Langmuir isotherm most precisely, with a maximum adsorption capacity of 12.08 mg/g. EDS analysis confirmed that Cd (II) was adsorbed onto bamboo charcoal. This study demonstrated that bamboo charcoal could be used for the removal of Cd (II) ions in water treatment.

  11. Speciation of phytate ion in aqueous solution. Cadmium(II) interactions in aqueous NaCl at different ionic strengths

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Concetta de; Milea, Demetrio; Porcino, Nunziatina; Sammartano, Silvio [Universita di Messina, Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Messina (Italy)

    2006-09-15

    Interactions between myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate) (phytic acid) and cadmium(II) were studied by using potentiometry (at 25 C with the ISE-H{sup +} glass electrode) in different metal to ligand (Phy) ratios (1:1{<=}Cd{sup 2+}:Phy{<=}4:1) in NaCl{sub aq} at different ionic strengths (0.1{<=}I/mol L{sup -1}{<=}1). Nine Cd{sub i}H{sub j}Phy{sup (12-2i-j)-} species are formed with i=1 and 2 and 4{<=}j{<=}7; and trinuclear Cd{sub 3}H{sub 4}Phy{sup 2-}. Dependence of complex formation constants on ionic strength was modeled by using Specific ion Interaction Theory (SIT) equations. Phytate and cadmium speciation are also dependent on the metal to ligand ratio. Stability of Cd{sub i}H{sub j}Phy{sup (12-2i-j)-} species was modeled as a function of both the ligand protonation step (j) and the number of metal cations bound to phytate (i), and relationships found were used for the prediction of species other than those experimentally determined (mainly di- and tri-protonated complexes), allowing the possibility of modeling Phy and Cd(II) behavior in natural waters and biological fluids. A critical evaluation of phytate sequestering ability toward cadmium(II) has been made under several experimental conditions, and the determination of an empirical parameter has been proposed for an objective ''quantification'' of this ability. A thorough analysis of literature data on phytate-cadmium(II) complexes has been performed. (orig.)

  12. Recovery of metals from simulant spent lithium-ion battery as organophosphonate coordination polymers in aqueous media.

    Science.gov (United States)

    Perez, Emilie; Andre, Marie-Laure; Navarro Amador, Ricardo; Hyvrard, François; Borrini, Julien; Carboni, Michaël; Meyer, Daniel

    2016-11-01

    An innovative approach is proposed for the recycling of metals from a simulant lithium-ion battery (LIBs) waste aqueous solution. Phosphonate organic linkers are introduced as precipitating agents to selectively react with the metals to form coordination polymers from an aqueous solution containing Ni, Mn and Co in a hydrothermal process. The supernatant is analyzed by ICP-AES to quantify the efficiency and the selectivity of the precipitation and the materials are characterized by Scanning Electron Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Thermogravimetric Analyses (TGA) and nitrogen gas sorption (BET). Conditions have been achieved to selectively precipitate Manganese or Manganese/Cobalt from this solution with a high efficiency. This work describes a novel method to obtain potentially valuable coordination polymers from a waste metal solution that can be generalized on any waste solution. PMID:27362538

  13. Imatinib intermediate as a two in one dual channel sensor for the recognition of Cu²⁺ and I⁻ ions in aqueous media and its practical applications.

    Science.gov (United States)

    Patil, Samadhan R; Nandre, Jitendra P; Jadhav, Devising; Bothra, Shilpa; Sahoo, S K; Devi, Manisha; Pradeep, Chullikkattil P; Mahulikar, Pramod P; Patil, Umesh D

    2014-09-21

    An imatinib intermediate, 6-methyl-N-[4-(pyridin-3-yl)pyrimidin-2-yl]benzene-1,3-diaminepyridopyrimidotoluidine (PPT-1), was developed for the colorimetric sensing of Cu(2+) ions in aqueous solution. With Cu(2+), the receptor PPT-1 showed a highly selective naked-eye detectable color change from colorless to red over the seventy other tested cations. The colorimetric sensing ability of PPT-1 was successfully utilized in the preparation of test strips and supported silica for the real samples analysis to detect Cu(2+) ions from 100% aqueous environment. Moreover, the iodide-sensing ability of receptor PPT-1 was explored among the ten examined anions. PMID:25056090

  14. Portable test bench for the studies concerning ion sources and ion beam extraction and focusing systems

    International Nuclear Information System (INIS)

    A portable test bench is described, which was designed to check ion sources, ion beam extraction and focusing systems before its use in a 600 KeV Cockcroft-Walton accelerator. The vacuum possibilities of the system are specially analyzed in connection with its particular use. The whole can be considered as a portable accelerator of low energy (50 keV). (Author)

  15. Adsorption of heavy metal ions from aqueous solutions by bio-char, a by-product of pyrolysis

    Science.gov (United States)

    Kılıç, Murat; Kırbıyık, Çisem; Çepelioğullar, Özge; Pütün, Ayşe E.

    2013-10-01

    Bio-char, a by-product of almond shell pyrolysis, was used as an alternative adsorbent precursor for the removal of heavy metal ions from aqueous solutions. The adsorption potential of almond shell bio-char for Ni(II) and Co(II) removal was investigated. Adsorption experiments were carried out by varying pH, adsorbent dosage, initial metal ion concentrations, contact time and temperature to determine the optimum conditions. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The results showed that bio-char derived from pyrolysis of biomass can be used as a low-cost and effective adsorbent for removal of heavy metal ions from aqueous solutions.

  16. Adsorption of heavy metal ions from aqueous solutions by bio-char, a by-product of pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kılıç, Murat [Department of Chemical Engineering, Faculty of Engineering, Anadolu University, 26555 Eskişehir (Turkey); Kırbıyık, Çisem [Department of Chemical Engineering, Faculty of Engineering, Selçuk University, 42075 Konya (Turkey); Çepelioğullar, Özge [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University, 34469 Istanbul (Turkey); Pütün, Ayşe E., E-mail: aeputun@anadolu.edu.tr [Department of Chemical Engineering, Faculty of Engineering, Anadolu University, 26555 Eskişehir (Turkey)

    2013-10-15

    Bio-char, a by-product of almond shell pyrolysis, was used as an alternative adsorbent precursor for the removal of heavy metal ions from aqueous solutions. The adsorption potential of almond shell bio-char for Ni(II) and Co(II) removal was investigated. Adsorption experiments were carried out by varying pH, adsorbent dosage, initial metal ion concentrations, contact time and temperature to determine the optimum conditions. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin–Radushkevich (D–R) and Temkin isotherm models. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The results showed that bio-char derived from pyrolysis of biomass can be used as a low-cost and effective adsorbent for removal of heavy metal ions from aqueous solutions.

  17. Adsorption of heavy metal ions from aqueous solutions by bio-char, a by-product of pyrolysis

    International Nuclear Information System (INIS)

    Bio-char, a by-product of almond shell pyrolysis, was used as an alternative adsorbent precursor for the removal of heavy metal ions from aqueous solutions. The adsorption potential of almond shell bio-char for Ni(II) and Co(II) removal was investigated. Adsorption experiments were carried out by varying pH, adsorbent dosage, initial metal ion concentrations, contact time and temperature to determine the optimum conditions. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin–Radushkevich (D–R) and Temkin isotherm models. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The results showed that bio-char derived from pyrolysis of biomass can be used as a low-cost and effective adsorbent for removal of heavy metal ions from aqueous solutions.

  18. Cell Design for Electrochemical Characterizations of Metal-Ion Batteries in Organic and Aqueous Electrolyte.

    Science.gov (United States)

    Bani Hashemi, Amir; La Mantia, Fabio

    2016-08-16

    Understanding the gas evolution in batteries, caused by decomposition of the electrolyte, is of fundamental importance for improving the long-time performances and cycle life of the battery systems. In general, this phenomenon causes simultaneously an irreversible energy and charge loss, as well as an increase of the internal resistance. Here, we introduce a new cell design capable of performing electrochemical impedance spectroscopy (EIS) and differential electrochemical mass spectroscopy (DEMS) with high resolution. Detailed aspects of the cell fabrication and the different components of the cell are extensively explained. Impedance measurements were validated by using symmetric electrodes. The possibility of performing long-term DEMS measurements was tested on graphite electrodes in Ethylene Carbonate/Dimethyl Carbonate (1:1), 1 M LiPF6 as an electrolyte. Finally, the cell was used to detect hydrogen evolution on the zinc negative electrode of a zinc-ion battery based on copper hexacyanoferrate. PMID:27439309

  19. High resolution X-ray emission spectroscopy of water and aqueous ions using the micro-jet technique

    International Nuclear Information System (INIS)

    Graphical abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl2. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the way for the study of biochemical systems in physiological media. - Abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl2. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the way for the

  20. High resolution X-ray emission spectroscopy of water and aqueous ions using the micro-jet technique

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Kathrin M.; Koennecke, Rene; Ghadimi, Samira; Golnak, Ronny [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Soldatov, Mikhail A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu 344090 (Russian Federation); Hodeck, Kai F. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Soldatov, Alexander [Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu 344090 (Russian Federation); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.de [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Freie Universitaet Berlin, FB Physik, Arnimallee 14, D-14195 Berlin (Germany)

    2010-11-25

    Graphical abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl{sub 2}. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the way for the study of biochemical systems in physiological media. - Abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl{sub 2}. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the

  1. Heterogeneous collision velocity for hydrated ions in aqueous solutions is nearly 10{sup 4} cm/s

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, O.S. [Cornell Univ. Medical College, New York, NY (United States); Feldberg, S.W. [Brookhaven National Lab., Upton, NY (United States)

    1996-03-14

    The heterogeneous collision velocity (v{sub o}, units of centimeters/second) is the average velocity of a solution particle toward a surface. V{sub o} thus defines the maximum flux of the particles to the surface. Einstein argued that v{sub o} in condensed phases and in gases may be deduced in a precisely analogous manner and that v{sub o} in aqueous solution therefore should be nearly 10{sup 4} cm/s (for particles with a mass of 100 Da). Values of v{sub o} for several aqueous monovalent cations (Na{sup +}, K{sup +}, Rb{sup +}, Cs{sup +} and NH{sub 4}{sup +}) were estimated from steady-state limiting current measurements through single gramicidin A channels spanning lipid bilayer membranes. The collisional and diffusional current components were separated by making use of the different viscosities of H{sub 2}O and D{sub 2}O solutions. The transfer of ions from the bulk solution to the channel entrance is modeled using a hemispherical entrance and an extension of the classical analysis of diffusion to a (hemi)sphere in which we relax the assumption that the jump distance (associated with three-dimensional diffusion of an ion in the bulk phase) be small compared to the hemispherical capture radius. Our estimate of v{sub o} agrees well with the prediction of Einstein. We therefore conclude that ion dehydration (only partially hydrated ions can pass through the gramicidin A channel) cannot be a rate-controlling step - a conclusion that is consistent with known rate constants for water exchange for these ions. 36 refs., 7 figs., 1 tab.

  2. Heavy ion tests on programmable VLSI

    International Nuclear Information System (INIS)

    The radiation from space environment induces operation damages in onboard computers systems. The definition of a strategy, for the Very Large Scale Integrated Circuitry (VLSI) qualification and choice, is needed. The 'upset' phenomena is known to be the most critical integrated circuit radiation effect. The strategies for testing integrated circuits are reviewed. A method and a test device were developed and applied to space applications candidate circuits. Cyclotron, synchrotron and Californium source experiments were carried out

  3. CYCLIC VOLTAMMETRY STUDIES OF COPPER (II) AND TELLURIUM (IV) IONS IN ACIDIC AQUEOUS SOLUTIONS FOR THIN FILM DEPOSITION

    OpenAIRE

    SARAVANAN NAGALINGAM; GEOK BEE TEH

    2014-01-01

    Cyclic voltammetry studies of copper (II) and tellurium (IV) ions in acidic aqueous solutions were carried out to determine the optimum condition for copper telluride thin film deposition. The voltammetry studies include reversible scans at different solution pH. Based on the voltammogram, suitable deposition conditions was determined to be in the range of -0.35 V to -0.45 V versus Ag/AgCl at pH values between 2.0 to 2.2 under non diffusion-limited conditions.

  4. Biosorption of Fe(II) and Mn(II) Ions from Aqueous Solution by Rice Husk Ash

    OpenAIRE

    Ying Zhang; Jiaying Zhao; Zhao Jiang; Dexin Shan; Yan Lu

    2014-01-01

    Rice husk ash (RHA), an agricultural waste, was used as biosorbent for the removal of Iron(II) and Manganese(II) ions from aqueous solutions. The structural and morphological characteristics of RHA and its elemental compositions before and after adsorption of Fe(II) and Mn(II) were determined by scanning electron microscopic (SEM) and X-ray fluorescence (XRF) analyses. Batch experiments were carried out to determine the influence of initial pH, contact time, adsorbent dosage, and initial conc...

  5. Method for the preparation of uranium compounds via electrolytic amalgamation of uranium ion directly from an aqueous solution

    International Nuclear Information System (INIS)

    The preparation of nuclear fuels such as uranium dioxide, carbide and nitride employing the ammonium uranate, (NH4)2U2O7, as starting material usually must undergo a series of chemical and metallurgical processes at relatively high temperature and under strictly controlled working condition. A simple method for the preparation of these nuclear fuels has evolved with respect to the electrolytic amalgamation of uranium ion directly from an aqueous solution. The thereby obtained uranium amalgam maybe thermally decomposed into a fine metallic powder which reacts readily with water vapor, methane and nitrogen gas to bring forth uranium dioxide, carbide and nitride, respectively

  6. Adsorption of Zn(II) and Cd(II) ions onto magnesium and activated carbon composite in aqueous solution

    International Nuclear Information System (INIS)

    Magnesium and coconuts shell activated carbon composite was prepared to selectively remove heavy metals ions in aqueous solution. Zinc(II) and cadmium(II) ions were used to clarify the adsorption capacity of the composite in comparison with no magnesium containing activated carbon. Influence of the initial heavy metal concentration, time course and solution temperature on the adsorption amounts were examined for the two adsorbents, and surface chemistry of the adsorbents was also characterized using Boehm titration. The magnesium composite adsorbed greater amount of Zn(II) and Cd(II) ions than the no magnesium counterpart. The adsorption amount of Cd(II) was not influenced with rise in solution temperature for the composite, whereas decrease in adsorption was observed for the counterpart. The loaded magnesium was estimated to be combined with carbon surface via oxygen bridge. Cadmium(II) was adsorbed onto the composite surface by ion exchange process with releasing equivalent amount of Mg(II) from the carbon surface, while Zn(II) would adsorb onto the composite by not only the ion exchange, but also the electrostatic interaction with the Cπ electrons on the graphite surface from the experimental results.

  7. Testing the Markov condition in ion channel recordings

    CERN Document Server

    Timmer, J

    1997-01-01

    A statistical test is presented to decide whether data are adequately described by probabilistic functions of finite state Markov chains (''hidden Markov models'') as applied in the analysis of ion channel data. Particularly, the test can be used to decide whether a system obeys the Markov condition. Simulation studies are performed in order to investigate the sensitivity of the proposed test against violations of the model assumptions. The test can be applied analogously to Markov models.

  8. LHC BFPP Quench Test with Ions (2015)

    CERN Document Server

    Schaumann, Michaela; Bahamonde Castro, Cristina; Auchmann, Bernhard; Chetvertkova, Vera; Giachino, Rossano; Jowett, John; Kalliokoski, Matti; Lechner, Anton; Mertens, Tom; Ponce, Laurette; CERN. Geneva. ATS Department

    2016-01-01

    The 2015 Pb-Pb collision run of the LHC operated at a beam energy of 6.37Z TeV. The power of the secondary beams emitted from the interaction point by the bound-free pair production (BFPP) process reached new levels while the propensity of the bending magnets to quench is higher at the new magnetic field levels. This beam power is about 70 times greater than that contained in the luminosity debris and is focussed on a specific location. As long foreseen, orbit bumps were introduced in the dispersion suppressors around the highest luminosity experiments to mitigate the risk of quenches by displacing and spreading out these losses. Because the impact position and intensity of these secondary beams is well known and can be tracked easily with the Beam Loss Monitors (BLMs), the BFPP1 beam (208Pb81+ ions), which is the most intense, provides a tool to accurately measure the steady state quench limit of the LHC main dipoles. At the moment the exact quench limit is not known, but this knowledge is important to asses...

  9. KINETIC AND EQUILIBRIUM STUDIES OF ADSORPTION OF LEAD (II) IONS FROM AQUEOUS SOLUTION USING COIR DUST (Cocos nucifera L.) AND IT’S MODIFIED EXTRACT RESINS

    OpenAIRE

    Israel, Aniekeme-Abasi; Okon, Okon; Umoren, Saviour; Eduok, Ubong

    2013-01-01

    Metal detoxification of waste water and industrial effluents are of increasing importance to industrialization in the twenty first century. The ability of coconut (cocos nucifera L) coir dust (CD), carbohydrate toluenediisocyanate resin (CTR) and sulphonated toluenediisocyanate resin (STR) to remove Pb(II) ions from aqueous solution by ion exchange was studied. Percentage ion exchange efficiency of the resins were found to increase in the order CD(65)> CTR(52) >STR(48). The extent of removal ...

  10. Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids(ILs) as solvents has been investigated.The distribution ratio of Sr2+ can reach as high as 103 under certain conditions,much larger than that in DCH18C6/n-octanol system.The extraction capacity depends greatly on the structure of ionic liquids.In Ils-based extraction systems,the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na+ and K+ in the aqueous phase.It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.

  11. Thin-layer chromatography of 49 metal ions on stannic antimonate in aqueous and mixed solvent systems containing dimethylsulfoxide: quantitative separation of uranium from numerous metal ions

    International Nuclear Information System (INIS)

    Thin-layer chromatography of 40 metal ions in 31 aqueous and mixed solvent systems has been performed on stannic antimonate ion-exchange material. Dimethylsulfoxide has been utilized to resolve such binary mixtures as La3+ and Ce3+ from Pr3+, Nd3+, and Sm3+; VO2+ from Ti4+, Nb5+, and Ta5+; Ga3+ from In3+, Tl+, and Y3+; Fe3+ from VO2+; and Mg2+ from Al3+. Quantitative separation of 200 to 800 μg U from its binary mixtures and from the synthetic mixtures containing Mg2+, Bi3+, Fe3+, Th4+, Ce4+, Cr3+, Zr4+, Hf4+, Ti4+ Mn2+, Cu2+, Ce3+, In3+, Y3+, Ca2+, Co2+, Tl+, Nb5+, and Ag+ has been obtained

  12. Control system for the CSNS ion source test stand

    International Nuclear Information System (INIS)

    A penning plasma surface H- ion source test stand for the CSNS has just been constructed at the IHEP. In order to achieve a safe and reliable system, nearly all devices of the ion source are designed to have the capability of both local and remote operation function. The control system consists of PLCs and EPICS real-time software tools separately serving device control and monitoring, PLC integration and OPI support. This paper summarizes the hardware and software implementation satisfying the requirements of the ion source control system.(authors)

  13. Synthesis and crystal structure of imidazole containing amide as a turn on fluorescent probe for nickel ion in aqueous media. An experimental and theoretical investigation

    Science.gov (United States)

    Annaraj, B.; Mitu, L.; Neelakantan, M. A.

    2016-01-01

    Imidazole containing amide fluorescence probe (PAIC) for Ni2+ was designed and successfully synthesized in good yield by reaction between 1-methyl-1H-imidazole-2-carboxylic acid and L-phenylalanine methyl ester. The probe was characterized by FTIR, 1H NMR, ESI-MS, UV-vis and fluorescence spectroscopy. Single crystal XRD analysis reveals that PAIC crystallizes in a monoclinic crystal lattice system with the space group of P21/n. Chemosensor property of PAIC was tested against different metal ions by UV-vis and fluorescent techniques in aqueous medium. Test results show that PAIC has high selectivity for Ni2+ compared to other metal ions (Na+, K+, Ca2+, Ag+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Mn2+, Zn2+ and Pb2+). Time-dependent density functional theory (TD-DFT) and configuration interaction singles (CIS) calculations were carried out to understand the sensing mechanism. The practical applicability of PAIC was tested in real water samples.

  14. Effect of addition of heavy metal ion on decolouration and degradation of azo dye in aqueous solution by gamma irradiation combined with ozone

    International Nuclear Information System (INIS)

    In decomposition of azo dyes solution by simultaneous application of gamma-ray and ozone treatment, the effect of addition of heavy metal ion upon decolouration and decomposition was studied. Cupric ion was used as a heavy metal ion. For the aqueous solution with and without addition of cupric ion, the degree of decolouration of 552 nm, the changes of pH, the reduction of TOC and BOD were measured as function of dose under condition of fixed concentration of ozone. It appeared that the addition of cupric ion played a positive role in decomposition of azo dye solution, but played a negative role in decolouration

  15. Removal of copper (II) from aqueous solutions by flotation using polyaluminum chloride silicate (PAX-XL60 S) as coagulant and carbonate ion as activator.

    Science.gov (United States)

    Ghazy, S E; Mahmoud, I A; Ragab, A H

    2006-01-01

    Flotation is a separation technology for removing toxic heavy metal ions from aqueous solutions. Here a simple and rapid flotation procedure is presented for the removal of copper(II) from aqueous solutions. It is based on the use of polyaluminum chloride silicate (PAX-XL60 S) as coagulant and flocculent, carbonate ion as activator and oleic acid (HOL) as surfactant. Both ion and precipitate flotation are included depending on the solution pH. Ion and precipitate flotation in the aqueous HOL-PAX-XL60 S-Cu2+-CO3(2-) system gave powerful preferential removal of Cu2+ (F -100%) over the HOL-PAX-XL60 S-Cu2+ system containing no CO3(2+) ion (F approximately 86%). The role of CO3(2-) ion is also evident from decreasing the dose of PAX-XL60 S from 700 mg l(-1) to 200 mg l(-1). The other parameters, influencing the flotation process, namely: metal ion, surfactant and PAX-XL60 S concentrations, ionic strength, temperature and foreign ions were examined. Moreover, the procedure was successfully applied to recover Cu2+ ions from different volumes up to 11 and from natural water samples. PMID:16457175

  16. Synthesis and characterization of a nanomagnetic ion imprinted polymer for selective extraction of silver ions from aqueous samples

    International Nuclear Information System (INIS)

    A magnetic ion imprinted polymer (mag-IIP) for the selective extraction of silver ions was synthesized by using functionalized magnetite (Fe3O4) nanoparticles as the magnetic core, silver ion as the template, salen as the ligand, 4-vinylpyridine as the functional monomer, and ethylene glycol dimethacrylate as the cross linker. A magnetic non-imprinted polymer was also prepared by an analogous procedure. The mag-IIP was characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction analysis, thermal analysis and scanning electron microscopy. The silver ions retained by the mag-IIP were eluted using the thiourea solution at a pH of ∼3 and then determined by the flame atomic absorption spectrometry. The conditions for the extraction and preconcentration were optimized. The maximum sorption capacity of the mag-IIP is 28.2 mg g−1 of Ag(I) ions. When preconcentrating a 150 mL sample, the enhancement factor is 293, and the detection limit is 50 ng L−1. The method was successfully applied to the determination of silver ions in (spiked) water samples and in the certified reference materials BCR 288 and CPB-1. (author)

  17. Sorption properties of low calorific value Greek lignites: Removal of lead, cadmium, zinc and copper ions from aqueous solutions

    International Nuclear Information System (INIS)

    The removal of metal ions (Pb, Cd, Zn, and Cu) from spiked aqueous solutions using four lignite samples (TH2, TH7, MT2, and MT8) of different quality, from different areas in Greece, was investigated. Cation exchange capacity, humic and fulvic acid content, and the BET specific surface area of the samples were determined, proximate and ultimate analyses were conducted and the mineralogy of their low temperature ash was studied. Equilibrium and kinetic studies were performed in batch conditions. Competitive adsorption of the four elements examined was also investigated. It was observed that the four lignite samples were considerably effective in removing Pb, Cd, Zn, and Cu ions from aqueous solutions, with the sample MT2 being the most effective. Among the elements, Pb appeared to have the strongest affinity based on a mass uptake by lignite samples. The same behaviour was observed during the competitive adsorption experiments. Kinetic experiments proved that, in all cases, equilibrium was achieved within 45 min. Sorption isotherm studies were conducted by varying the initial concentration of the elements. MATLAB software was used to fit experimental data to Langmuir and Freundlich equations. The data were better fitted to the Langmuir equation. Attempt was made to correlate the adsorption behaviour of the lignite samples with the mineralogy of their low temperature ashes and their content in humic and fulvic acids.

  18. Lithium Ion Testing at NSWC Crane in Support of NASA Goddard Space Flight Center

    Science.gov (United States)

    Brown, Harry; Jung, David; Lee, Leonine

    2010-01-01

    This viewgraph presentation reviews Lithium Ion Cell testing at the Naval Surface Warfare Center in Crane, India. The contents include: 1) Quallion 15 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 2) Lithion 50 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 3) ABSL 5 Ahr Lithium-Ion Battery, LRO-LLO Life Cycle Test, SDO-GEO Life Cycle Test; and 4) A123 40 Ahr Lithium-Ion Battery, GPM Life Cycle Test, MMS Life Cycle Test.

  19. Diglycolamic acid modified silica gel for the separation of hazardous trivalent metal ions from aqueous solution.

    Science.gov (United States)

    Suneesh, A S; Syamala, K V; Venkatesan, K A; Antony, M P; Vasudeva Rao, P R

    2015-01-15

    The surface of the silica gel was modified with diglycolamic acid moieties and the product (Si-DGAH) was characterized by elemental analysis, TG-DTA, (1)H and (29)Si NMR and scanning electron microscopy (SEM). The adsorption behavior of hazardous americium (III) and europium (III) in Si-DGAH was studied from aqueous nitric acid medium to examine the feasibility using the modified silica for the separation of Am(III) and Eu(III) from aqueous wastes. In this context, the effect of various parameters such as the duration of equilibration, and concentrations of europium, nitric acid, sodium nitrate and diethylenetriaminepentaacetic acid (DTPA) in aqueous phase, on the distribution coefficient (K(d)) of Am(III) and Eu(III) was investigated. The distribution coefficient of ∼10(3) mL/g (>99.9% extraction) was obtained for both Am(III) and Eu(III) at pH 3, and the K(d) values decreased with increase in the concentration of nitric acid. Rapid kinetics of extraction in the initial stages of equilibration, followed by the establishment of equilibrium occurred within 30 min. The extraction data were fitted into Langmuir adsorption model and the apparent europium extraction capacity was determined. Europium loading capacity of the sorbent was determined at various feed pH by column method. The study indicated the possibility of using diglycolamic acid-modified silica for the separation of Eu(III) and Am(III) from aqueous wastes. PMID:25454425

  20. Ion Pairing in Aqueous Lithium Salt Solutions with Monovalent and Divalent Counter-Anions

    Czech Academy of Sciences Publication Activity Database

    Pluhařová, Eva; Mason, Philip E.; Jungwirth, Pavel

    2013-01-01

    Roč. 117, č. 46 (2013), s. 11766-11773. ISSN 1089-5639 R&D Projects: GA MŠk LH12001 Grant ostatní: MŠMT(CZ) LM2010005 Institutional support: RVO:61388963 Keywords : lithium * aqueous solution * neutron scattering * molecular dynamics * polarizability Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.775, year: 2013

  1. [The Quantitative Analysis of Raman Spectroscopy to Sulfate Ion in Aqueous Solution].

    Science.gov (United States)

    Wang, Qian-qian; Sun, Qiang

    2016-02-01

    As a non-destructive and non-contact method, Raman spectroscopy has been widely applied in many research fields. Based on vibrational wavenumber, Raman spectroscopy is usually applied to determine the molecular species. Therefore, Raman quantitative analysis is necessary. In this study, according to the theoretical analysis of Raman intensity, Raman quantitative measurement should be fulfilled by relative intensity ratio, which can be divided into internal and external standards. This eliminates the influence of the measurement conditions. For aqueous solution, it is reasonable to treat the OH stretching band of water as an internal standard to determine the solute concentrations in aqueous solution. The Raman spectra of Na₂SO₄-H₂O, K₂SO₄-H₂O and NaCl-Na₂SO₄-H₂O are recorded in the paper. In addition, the Raman OH stretching band of water can be fitted into two Gaussian sub-bands. The intensity proportion I(SO₄²⁻)/I(W) is used to determine the molarity of sulfate in aqueous solution, where I(SO₄²⁻) represents the intensity of sulfate band and I(W) represents the sum of the two sub-bands of Raman OH stretching bands of water. Therefore, Raman spectroscopy can be utilized to measure the SO₄²⁻concentrations in aqueous solutions. PMID:27209744

  2. Molecular design of Calix[4]arene derivatives for uranyl ion extraction from aqueous media

    International Nuclear Information System (INIS)

    Uranyl ion extraction is an important part of nuclear waste reprocessing. Use of organic ligands having chelating property with uranyl ions is a promising tool in this area, because of the possibility to improve the selectivity and the affinity of the ligands towards uranyl ions. In this study, Calix[4]arene derivatives containing B, Al, C, Si, N, P, O and S elements in bridging positions were designed and their chelating energetics with uranyl cation are calculated by means of DFT methods.

  3. Removal of corper(II) Ions from aqueous solution by a lactic acid bacterium

    OpenAIRE

    M. Yilmaz(Department of Physics, Gazi University, Ankara); T. Tay; M. Kivanc; H. Turk

    2010-01-01

    Enterococcus faecium, a lactic acid bacterium (LAB), was evaluated for its ability to remove copper(II) ions from water. The effects of the pH, contact time, initial concentration of copper(II) ions, and temperature on the biosorption rate and capacity were studied. The initial concentrations of copper(II) ions used to determine the maximum amount of biosorbed copper(II) ions onto lyophilised lactic acid bacterium varied from 25 mg L-1 to 500 mg L-1. Maximum biosorption capacities were attain...

  4. OPTIMISATION OF COPPER AND ZINC IONS REMOVAL FROM AQUEOUS SOLUTION BY COAL FLY ASH AS AN ADSORBENT

    Directory of Open Access Journals (Sweden)

    MOYO ,M

    2012-04-01

    Full Text Available Rapid urbanization and industrialization of our world has led to accumulation of enormous number of contaminants in our environment. Heavy metal ions hold a superlative position in that list and are responsible for contaminating soil, air and water in many parts of the world. Adsorption technology is emerging as a sustainable effective solution. The possibility of using Coal fly ash as an alternative adsorbent for divalent metal ions (Zn2+, Cu2+ removal from simulated solutions was studied. The coal fly ash was characterised by Brunauer Emmet Teller (BET, X-ray diffraction (XRD, X-ray Fluorescence Spectroscopy (XRF and Fourier transforminfrared (FT-IR. Optimum adsorption conditions were determined as a function of pH, adsorbent dosage and contact time for Zn2+ and Cu2+ removal. The adsorption of metal ions was found to be pH dependant.Equilibrium data fitted well to the Freundlich model with R2 values as 0.9932, 0.9971 for Cu2+, Zn2+, respectively. The study showed that disposed coal fly ash could be used as an efficient adsorbent material for the removal of metal ions from aqueous solution.

  5. Performance and cost characteristics of multi-electron transfer, common ion exchange non-aqueous redox flow batteries

    Science.gov (United States)

    Laramie, Sydney M.; Milshtein, Jarrod D.; Breault, Tanya M.; Brushett, Fikile R.; Thompson, Levi T.

    2016-09-01

    Non-aqueous redox flow batteries (NAqRFBs) have recently received considerable attention as promising high energy density, low cost grid-level energy storage technologies. Despite these attractive features, NAqRFBs are still at an early stage of development and innovative design techniques are necessary to improve performance and decrease costs. In this work, we investigate multi-electron transfer, common ion exchange NAqRFBs. Common ion systems decrease the supporting electrolyte requirement, which subsequently improves active material solubility and decreases electrolyte cost. Voltammetric and electrolytic techniques are used to study the electrochemical performance and chemical compatibility of model redox active materials, iron (II) tris(2,2‧-bipyridine) tetrafluoroborate (Fe(bpy)3(BF4)2) and ferrocenylmethyl dimethyl ethyl ammonium tetrafluoroborate (Fc1N112-BF4). These results help disentangle complex cycling behavior observed in flow cell experiments. Further, a simple techno-economic model demonstrates the cost benefits of employing common ion exchange NAqRFBs, afforded by decreasing the salt and solvent contributions to total chemical cost. This study highlights two new concepts, common ion exchange and multi-electron transfer, for NAqRFBs through a demonstration flow cell employing model active species. In addition, the compatibility analysis developed for asymmetric chemistries can apply to other promising species, including organics, metal coordination complexes (MCCs) and mixed MCC/organic systems, enabling the design of low cost NAqRFBs.

  6. Removal of chromium (VI) ions from aqueous solution by adsorption onto two marine isolates of Yarrowia lipolytica

    International Nuclear Information System (INIS)

    The removal of chromium (VI) ions from aqueous solutions by the biomass of two marine strains of Yarrowia lipolytica (NCIM 3589 and 3590) was studied with respect to pH, temperature, biomass, sea salt concentration, agitation speed, contact time and initial concentration of chromium (VI) ions. Maximum biosorption was observed at pH 1.0 and at a temperature of 35 deg. C. Increase in biomass and sea salts resulted in a decreased metal uptake. With an agitation speed of 130 rpm, equilibrium was attained within 2 h. Under optimum conditions, biosorption was enhanced with increasing concentrations of Cr (VI) ions. NCIM 3589 and 3590 displayed a specific uptake of Cr (VI) ions of 63.73 ± 1.3 mg g-1 at a concentration of 950 ppm and 46.09 ± 0.23 mg g-1 at 955 ppm, respectively. Scatchard plot analysis revealed a straight line allowing the data to be fitted in the Langmuir model. The adsorption data obtained also fitted well to the Freundlich isotherm. The surface sequestration of Cr (VI) by Y. lipolytica was investigated with a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) as well as with ED-X-ray fluorescence (ED-XRF). Fourier transform infrared (FTIR) spectroscopy revealed the involvement of carboxyl, hydroxyl and amide groups on the cell surfaces in chromium binding.

  7. Removal of chromium (VI) ions from aqueous solution by adsorption onto two marine isolates of Yarrowia lipolytica

    Energy Technology Data Exchange (ETDEWEB)

    Bankar, Ashok V.; Kumar, Ameeta R. [Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411 007 (India); Zinjarde, Smita S., E-mail: smita@unipune.ernet.in [Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411 007 (India)

    2009-10-15

    The removal of chromium (VI) ions from aqueous solutions by the biomass of two marine strains of Yarrowia lipolytica (NCIM 3589 and 3590) was studied with respect to pH, temperature, biomass, sea salt concentration, agitation speed, contact time and initial concentration of chromium (VI) ions. Maximum biosorption was observed at pH 1.0 and at a temperature of 35 deg. C. Increase in biomass and sea salts resulted in a decreased metal uptake. With an agitation speed of 130 rpm, equilibrium was attained within 2 h. Under optimum conditions, biosorption was enhanced with increasing concentrations of Cr (VI) ions. NCIM 3589 and 3590 displayed a specific uptake of Cr (VI) ions of 63.73 {+-} 1.3 mg g{sup -1} at a concentration of 950 ppm and 46.09 {+-} 0.23 mg g{sup -1} at 955 ppm, respectively. Scatchard plot analysis revealed a straight line allowing the data to be fitted in the Langmuir model. The adsorption data obtained also fitted well to the Freundlich isotherm. The surface sequestration of Cr (VI) by Y. lipolytica was investigated with a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) as well as with ED-X-ray fluorescence (ED-XRF). Fourier transform infrared (FTIR) spectroscopy revealed the involvement of carboxyl, hydroxyl and amide groups on the cell surfaces in chromium binding.

  8. Role of Citrate Ions in the Phosphonate-based Inhibitor System for Mild Steel in Aqueous Chloride Media

    Directory of Open Access Journals (Sweden)

    G. Gunasekaran

    2005-01-01

    Full Text Available The corrosion inhibition efficiency of phosphonic acid and its derivatives for the inhibition of corrosion of mild steel in neutral chloride media is decided by its ability to form protectivefilm over the surface. In this context, the effect of addition of metal cations and certain organic compounds, such as citrate in conjugation with phosphonic acid to impart synergistic corrosion inhibition has been explored. The experiments were carried out using various concentrations of trisodium citrate and zinc ions in an aqueous solution of 2-carboxyethyl phosphonic acid (2CEPA at 25 ppm. The corrosion characteristics have been determined using electrochemical impedance spectroscopy together with determination of corrosion rate by weight-loss method. It has been observed that a combination of inhibitive ions, namely citrate, ZCEPA, and zinc ions at 25 ppm gives 96 per cent inhibition efficiency and this corrosion inhibition is due to the formation of a protective film. By increasing the concentration of citrate beyond 25 ppm, the corrosion inhibition efficiency decreases. This paper discusses the role of citrate and zinc ions in imparting added corrosion inhibition ability using 2CEPA on the basis of experimental results.

  9. PAH toxicity at aqueous solubility in the fish embryo test with Danio rerio using passive dosing

    DEFF Research Database (Denmark)

    Seiler, Thomas-Benjamin; Best, Nina; Fernqvist, Margit Møller;

    2014-01-01

    As part of the risk assessment process within REACh, prior to manufacturing and distribution of chemical substances their (eco)toxicological impacts have to be investigated. The fish embryo toxicity test (FET) with the zebrafish Danio rerio has gained a high significance as an in vitro alternative...... to animal testing in (eco)toxicology. However, for hydrophobic organic chemicals it remains a technical challenge to ensure constant freely dissolved concentration at the maximum exposure level during such biotests. Passive dosing with PDMS silicone was thus applied to control the freely dissolved...... further data to support the close relationship between the chemical activity and the toxicity of hydrophobic organic compounds. Passive dosing from PDMS silicone enabled reliable toxicity testing of (highly) hydrophobic substances at aqueous solubility, providing a practical way to control toxicity...

  10. Ni(II) ion-imprinted solid-phase extraction and preconcentration in aqueous solutions by packed-bed columns

    International Nuclear Information System (INIS)

    Solid-phase extraction (SPE) columns packed with materials based on molecularly imprinted polymers (MIPs) were used to develop selective separation and preconcentration for Ni(II) ion from aqueous solutions. SPE is more rapid, simple and economical method than the traditional liquid-liquid extraction. MIPs were used as column sorbent to increase the grade of selectivity in SPE columns. In this study, we have developed a polymer obtained by imprinting with Ni(II) ion as a ion-imprinted SPE sorbent. For this purpose, NI(II)-methacryloylhistidinedihydrate (MAH/Ni(II)) complex monomer was synthesized and polymerized with cross-linking ethyleneglycoldimethacrylate to obtain [poly(EGDMA-MAH/Ni(II))]. Then, Ni(II) ions were removed from the polymer getting Ni(II) ion-imprinted sorbent. The MIP-SPE preconcentration procedure showed a linear calibration curve within concentration range from 0.3 to 25 ng/ml and the detection limit was 0.3 ng/ml (3 s) for flame atomic absorption spectrometry (FAAS). Ni(II) ion-imprinted microbeads can be used several times without considerable loss of adsorption capacity. When the adsorption capacity of nickel imprinted microbeads were compared with non-imprinted microbeads, nickel imprinted microbeads have higher adsorption capacity. The Kd (distribution coefficient) values for the Ni(II)-imprinted microbeads show increase in Kd for Ni(II) with respect to both Kd values of Zn(II), Cu(II) and Co(II) ions and non-imprinted polymer. During that time Kd decreases for Zn(II), Cu(II) and Co(II) ions and the k' (relative selectivity coefficient) values which are greater than 1 for imprinted microbeads of Ni(II)/Cu(II), Ni(II)/Zn(II) and Ni(II)/Co(II) are 57.3, 53.9, and 17.3, respectively. Determination of Ni(II) ion in sea water showed that the interfering matrix had been almost removed during preconcentration. The column was good enough for Ni determination in matrixes containing similar ionic radii ions such as Cu(II), Zn(II) and Co(II)

  11. Structure of hydrated complexes formed by metal ions of groups I-III of the Periodic table in aqueous electrolyte solutions under ambient conditions

    International Nuclear Information System (INIS)

    Published and authors' experimental data on the structure of aqueous electrolyte solutions under standard conditions were generalized to ascertain the dependences of the solution structural parameters on chemical nature of dissolved compounds of alkali, alkaline-earth metals, cadmium, scandium, yttrium, lanthanum and indium. Hydrate complexes of metal ions formed in aqueous solutions were systematized, depending on cation size, charge and structure of their external electronic shell

  12. Shape and size of simple cations in aqueous solutions: A theoretical reexamination of the hydrated ion via computer simulations

    Science.gov (United States)

    Martínez, José M.; Pappalardo, Rafael R.; Marcos, Enrique Sánchez

    1999-01-01

    The simplest representation of monoatomic cations in aqueous solutions by means of a sphere with a radius chosen on the basis of a well-defined property (that of the bare ion or its hydrate) is reexamined considering classical molecular dynamics simulations. Two charged sphere-water interaction potentials were employed to mimic the bare and hydrated cation in a sample of 512 water molecules. Short-range interactions of trivalent cations were described by Lennard-Jones potentials which were fitted from ab initio calculations. Five statistically independent runs of 150 ps for each of the trivalent spheres in water were carried out in the microcanonical ensemble. A comparison of structural and dynamical properties of these simple ion models in solution with those of a system containing the Cr3+ hydrate ([Cr(H2O)6]3+) is made to get insight into the size and shape definition of simple ions in water, especially those that are highly charged. Advantages and shortcomings of using simple spherical approaches are discussed on the basis of reference calculations performed with a more rigorous hydrated ion model [J. Phys. Chem. B 102, 3272 (1998)]. The importance of nonspherical shape for the hydrate of highly charged ions is stressed and it is paradoxically shown that when spherical shape is retained, the big sphere representing the hydrate leads to results of ionic solution worse than those obtained with the small sphere. A low-cost method to generate hydrated ion-water interaction potentials taking into account the shape of the ionic aggregate is proposed.

  13. Test particle model of pickup ions at comet Halley

    International Nuclear Information System (INIS)

    A test particle treatment is used to investigate some of the details of the pickup cometary ions observed at comet Halley. The effects of the large-scale magnetic and motional electric fields, as described by an MHD model of the comet, produce the characteristic V shape seen in Giotto observations in simulated energy-time spectrograms. It is demonstrated that scattering produced by the addition of magnetic field fluctuations can obscure the tendency of the large-scale field to deflect energetic ions picked up in the outer coma from the tail axis. The fact that the V is so clearly observed in the Giotto spectrogram thus suggests that although scattering must be invoked to explain the isotropic pitch angle distributions and highest energy ions, it does not have a major effect on the overall pickup ion spectrum. copyright American Geophysical Union 1988

  14. Recoil chemistry of iodine-128 in neutral aqueous solutions of mixtures of iodates and nitrate ions

    International Nuclear Information System (INIS)

    Recoil reactions in thermal neutron irradiated aqueous solutions of potassium, sodium and ammonium iodates in the presence of nitrite additive have been studied at 298.3 and 77 K. The per cent retention values of 128I obtained upon irradiation at 77 K are higher. The yields of radioiodate and radioperiodate decrease whereas that of radioiodide increases with increase in nitrite concentration. A suitable mechanism is suggested to explain the results. (author)

  15. Reactive Geochemical Transport Modeling of Concentrated Aqueous Solutions: Supplement to TOUGHREACT User's Guide for the Pitzer Ion-Interaction Model

    OpenAIRE

    Zhang, Guoxiang; Spycher, Nicolas; Xu, Tianfu; Sonnenthal, Eric; Steefel, Carl

    2006-01-01

    In this report, we present: -- The Pitzer ion-interaction theory and models -- Input file requirements for using the TOUGHREACT Pitzer ion-interaction model and associated databases -- Run-time error messages -- Verification test cases and application examples. For the main code structure, features, overall solution methods, description of input/output files for parameters other than those specific to the implemented Pitzer model, and error messages, see the TOUGHREACT User's Guide (Xu e...

  16. Preparation and characterization of novel P(HEA/IA) hydrogels for Cd2+ ion removal from aqueous solution

    International Nuclear Information System (INIS)

    Highlights: • Hydrogels based on 2-hydroxyethyl acrylate and itaconic acid (P(HEA/IA)) were synthesized. • Cd2+ ion removal was investigated. • The surface and cross-section of hydrogels were observed by SEM and AFM. • The adsorption kinetics and isotherms of cadmium ions on the hydrogel were studied. • Approximately 95% of the adsorbed cadmium could be recovered by 0.1 M HNO3 treatment. - Abstract: Series of novel hydrogels based on 2-hydroxyethyl acrylate (HEA) and itaconic acid (IA), P(HEA/IA) copolymers, were prepared by free radical cross-linking copolymerization and investigated as potential adsorbents for Cd2+ removal from aqueous solution. The hydrogels before and after Cd2+ adsorption were characterized using FTIR, DSC, SEM/EDX, AFM and DMA analysis. The swelling results showed that these hydrogels are pH and temperature sensitive. In order to evaluate adsorption behavior of samples various factors affecting the Cd2+ uptake behavior, such as: contact time, temperature, pH, ionic strength, adsorbent weight, competitive ions and initial concentration of the metal ions were investigated. Five adsorption isotherms and two kinetic models were studied. The adsorption behavior can be very well described by the pseudo-second order kinetic model and Langmuir isotherm. Multicomponent adsorption studies revealed that adsorption of cadmium depends on the type of metal ions present in the system. Desorption studies showed that hydrogel can be reused three times with only 15% loss of adsorption capacity. All results indicate that the sample with the highest IA content is the most promising adsorbent for Cd2+ removal

  17. Preparation and characterization of novel P(HEA/IA) hydrogels for Cd{sup 2+} ion removal from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Antić, Katarina M.; Babić, Marija M.; Vuković, Jovana J. Jovašević [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade (Serbia); Vasiljević-Radović, Dana G. [Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Njegoseva 12, Belgrade (Serbia); Onjia, Antonije E. [Vinca Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, Belgrade (Serbia); Filipović, Jovanka M. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade (Serbia); Tomić, Simonida Lj., E-mail: simonida@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade (Serbia)

    2015-05-30

    Highlights: • Hydrogels based on 2-hydroxyethyl acrylate and itaconic acid (P(HEA/IA)) were synthesized. • Cd{sup 2+} ion removal was investigated. • The surface and cross-section of hydrogels were observed by SEM and AFM. • The adsorption kinetics and isotherms of cadmium ions on the hydrogel were studied. • Approximately 95% of the adsorbed cadmium could be recovered by 0.1 M HNO{sub 3} treatment. - Abstract: Series of novel hydrogels based on 2-hydroxyethyl acrylate (HEA) and itaconic acid (IA), P(HEA/IA) copolymers, were prepared by free radical cross-linking copolymerization and investigated as potential adsorbents for Cd{sup 2+} removal from aqueous solution. The hydrogels before and after Cd{sup 2+} adsorption were characterized using FTIR, DSC, SEM/EDX, AFM and DMA analysis. The swelling results showed that these hydrogels are pH and temperature sensitive. In order to evaluate adsorption behavior of samples various factors affecting the Cd{sup 2+} uptake behavior, such as: contact time, temperature, pH, ionic strength, adsorbent weight, competitive ions and initial concentration of the metal ions were investigated. Five adsorption isotherms and two kinetic models were studied. The adsorption behavior can be very well described by the pseudo-second order kinetic model and Langmuir isotherm. Multicomponent adsorption studies revealed that adsorption of cadmium depends on the type of metal ions present in the system. Desorption studies showed that hydrogel can be reused three times with only 15% loss of adsorption capacity. All results indicate that the sample with the highest IA content is the most promising adsorbent for Cd{sup 2+} removal.

  18. Environmental Testing of the NEXT PM1R Ion Engine

    Science.gov (United States)

    Snyder, John S.; Anderson, John R.; VanNoord, Jonathan L.; Soulas, George C.

    2007-01-01

    The NEXT propulsion system is an advanced ion propulsion system presently under development that is oriented towards robotic exploration of the solar system using solar electric power. The subsystem includes an ion engine, power processing unit, feed system components, and thruster gimbal. The Prototype Model engine PM1 was subjected to qualification-level environmental testing in 2006 to demonstrate compatibility with environments representative of anticipated mission requirements. Although the testing was largely successful, several issues were identified including the fragmentation of potting cement on the discharge and neutralizer cathode heater terminations during vibration which led to abbreviated thermal testing, and generation of particulate contamination from manufacturing processes and engine materials. The engine was reworked to address most of these findings, renamed PM1R, and the environmental test sequence was repeated. Thruster functional testing was performed before and after the vibration and thermal-vacuum tests. Random vibration testing, conducted with the thruster mated to the breadboard gimbal, was executed at 10.0 Grms for 2 min in each of three axes. Thermal-vacuum testing included three thermal cycles from 120 to 215 C with hot engine re-starts. Thruster performance was nominal throughout the test program, with minor variations in a few engine operating parameters likely caused by facility effects. There were no significant changes in engine performance as characterized by engine operating parameters, ion optics performance measurements, and beam current density measurements, indicating no significant changes to the hardware as a result of the environmental testing. The NEXT PM1R engine and the breadboard gimbal were found to be well-designed against environmental requirements based on the results reported herein. The redesigned cathode heater terminations successfully survived the vibration environments. Based on the results of this test

  19. Kinetic studies for sorption of some metal ions from aqueous acid solutions onto TDA impregnated resin

    International Nuclear Information System (INIS)

    Kinetic studies for sorption of uranium, thorium and cobalt ions from hydrochloric acid solutions using tri-dodecyl amine (TDA) loaded on Amberlite XAD4 (polystyrene resin supplied by Rohm and Haas) using the batch technique, have been evaluated and assessed. Analysis of the respective data in accordance with three kinetic models revealed that the particle diffusion mechanism is the rate determining step, and the sorption for each metal ion on the impregnated sorbent follows the first order reversible kinetics. Values of the first order rate constants, rate constants of intraparticle transport, and the particle diffusion coefficients for the studied ions were determined. Sorption isotherms, which have been evaluated from the distribution coefficients for these ions, were found in good fit with the Langmuir and Freundlich isotherms. (author)

  20. Influence of persulfate ions on the removal of phenol in aqueous solution using electron beam irradiation

    International Nuclear Information System (INIS)

    The removal of phenol (Co = 100 μM) during electron beam irradiation was studied in pure water and in the presence of HCO3- and Br- ions. It was found that the introduction of S2O82- ions (1 mM), by generating SO4-· radicals increases the radiation yield of phenol removal. 90% removal of phenol was obtained with radiation doses 600 and 1200 Gy with and without S2O82- ions respectively. This system induced smaller oxygen consumption with smaller concentration of catechol and hydroquinone found in the solution. HCO3- and Br- have an inhibiting effect in the presence as in the absence of S2O82-. In most cases, the introduction of S2O82- ions in water radiolysis system can advantageously increase the yield of organic compounds removal by oxidation.

  1. Lysozyme net charge and ion binding in concentrated aqueous electrolyte solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kuehner, Daniel E.; Engmann, Jan; Fergg, Florian; Wernick, Meredith; Blanch, Harvey W. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering; Prausnitz, John M. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

    1999-02-01

    Hydrogen-ion titrations were conducted for hen-egg-white lysozyme in solutions of potassium chloride over the range pH 2.5--11.5 and for ionic strengths to 2.0 M. The dependence of lysozyme`s net proton charge, z{sub p}, on pH and ionic strength in potassium chloride solution is measured. From the ionic-strength dependence of z{sub p}, interactions of lysozyme with potassium and chloride ions are calculated using the molecular-thermodynamic theory of Fraaije and Lyklema. Lysozyme interacts preferentially with up to 12 chloride ions at pH 2.5. The observed dependence of ion-protein interactions on pH and ionic strength is explained in terms of electric-double-layer theory. New experimental pK{sub a} data are reported for 11 amino acids in potassium chloride solutions of ionic strength to 3.0 M.

  2. Solubility of drugs in aqueous solutions. Part 5. Thermodynamic consistency test for the solubility data.

    Science.gov (United States)

    Ruckenstein, E; Shulgin, I

    2005-03-23

    This paper is devoted to the verification of the quality of experimental data regarding the solubility of sparingly soluble solids, such as drugs, environmentally important substances, etc. in mixed solvents. A thermodynamic consistency test based on the Gibbs-Duhem equation for ternary mixtures is suggested. This test has the form of an equation, which connects the solubilities of the solid, and the activity coefficients of the constituents of the solute-free mixed solvent in two mixed solvents of close compositions. The experimental data regarding the solubility of sparingly soluble substances can be verified with the suggested test if accurate data for the activity coefficients of the constituents of the solute-free mixed solvent are available. The test was applied to a number of systems representing the solubilities of sparingly soluble substances in mixed solvents. First, the test was scrutinized for four nonaqueous systems for which accurate solubility data were available. Second, the suggested test was applied to a number of systems representing experimental data regarding the solubility of sparingly soluble substances in aqueous mixed solvents. PMID:15725556

  3. Durability testing of heavy ion irradiated crystalline ceramics

    International Nuclear Information System (INIS)

    The purpose of this report is to assess the effects of heavy-ion irradiation on the durability of pyrochlore-rich baseline ceramics and single-phase pyrochlore, zirconolite and brannerite ceramics. Development of a titanate-based crystalline ceramic form to immobilize surplus weapons-useable plutonium for disposition is the mission of the Plutonium Immobilization Project (PIP). A major development and testing activity for this program is performance testing and qualification of the wasteform for a repository. As part of the performance testing, the leaching behavior of the ceramic form must be evaluated to determine the anticipated repository behavior. To study the impact of radiation damage on the performance of the ceramic, the damage must be accelerated using techniques such as 238Pu doping and ion irradiation. The purpose of this report is to assess the effects of heavy-ion irradiation on the durability of pyrochlore-rich baseline ceramics and single-phase pyrochlore, zirconolite and brannerite ceramics. Ion irradiation of ceramic pellet surfaces will transform the outermost several tenths of microns of the surface into a metamict (i.e., noncrystalline) state. Short-term monolithic leach tests on unirradiated and irradiated samples should elucidate any significant differences in the durability of the undamaged crystalline surface versus the damaged metamict surface. Data developed under this task will support a preliminary integrated data report to be supplied to the Office of Civilian Radioactive Waste Management (RW) for use in the license application for the candidate Yucca Mountain repository

  4. Colorimetric and fluorescent sensor for selective sensing of Hg2+ ions in semi aqueous medium

    International Nuclear Information System (INIS)

    A highly sensitive and selective detection of Hg2+ ion with simple salophen probe was developed. In DMSO: water (40:60, v/v) solution, Hg2+ ions coordinate with imine and shows color turn-off from yellow to colorless. Receptor 1 showed its ability for sensing Hg2+ cations sensitively through three channels: colorimetric, UV–vis and fluorescence spectroscopy. Hg2+ ions coordinate to the imine (Receptor 1) through NONO binding site forming 1:1 complex. It exhibits fluorescent 'Turn-on' behavior based on solvent polarity. The detection limit of our receptor with mercury is 1 μg L−1. -- Graphical abstract: A highly sensitive and rapid detection of Hg2+ with simple salophen probe was developed. In DMSO: water (40:60, v/v) solution, Hg2+ ions coordinate with imine and shows color turn-off from yellow to colorless. Receptor 1 showed its ability for sensing Hg2+ cations sensitively through three channels: colorimetric, UV–vis and Fluorescence Spectroscopy. Hg2+ ions coordinate to the imine (Receptor 1) through the NONO binding site forming 1:1 complex. It exhibits fluorescent 'Turn-on' behavior based on solvent polarity. The detection limit of our receptor with mercury is 1 μg L−1. Highlights: ► Hg2+ ions coordinate with imine and shows color turn-off from yellow to colorless. ► The binding constant of the receptor 1 (DMSO) with Hg2+ ion (DMSO) is 1.35×105. ► Hg2+ ions coordinate to the imine through NONO binding site forming 1:1 complex. ► The receptor 1 shows fluorescent 'Turn-on' behavior based on solvent polarity. ► The detection limit of receptor 1 with mercury is 1 μg L−1

  5. Physicochemical characterization of the retardation of aqueous Cs+ ions by natural kaolinite and clinoptilolite minerals

    OpenAIRE

    Shahwan, Talal; Akar, Dilek; Eroğlu, Ahmet E.

    2005-01-01

    The aim of this study was to carry out kinetic, thermodynamic, and surface characterization of the sorption of Cs+ ions on natural minerals of kaolinite and clinoptilolite. The results showed that sorption followed pseudo-second-order kinetics. The activation energies were 9.5 and 13.9 kJ/mol for Cs+ sorption on kaolinite and clinoptilolite, respectively. Experiments performed at four different initial concentrations of the ion revealed that the percentage sorption of Cs+ on clinoptilolite ra...

  6. Kinetic studies of zinc ions removal from aqueous solution by adsorption on natural zeolite

    OpenAIRE

    Zendelska, Afrodita; Golomeova, Mirjana; Blažev, Krsto; Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2014-01-01

    The kinetics of zinc adsorption onto natural zeolite (clinoptilolite) were studied with respect to initial metal ion concentration, adsorbent mass and initial pH value. In order to select the main rate-determining step in the overall uptake mechanism, a series of experiments were performed under batch conditions from single ion solutions. Data obtained from the kinetic experiments are interpreted in terms of Pseudo-second order kinetic model, Weber and Morris model and mod...

  7. Coordination and Hydrolysis of Plutonium Ions in Aqueous Solution using Car-Parrinello Molecular Dynamics Free Energy Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Odoh, Samuel O.; Bylaska, Eric J.; De Jong, Wibe A.

    2013-11-27

    Car-Parrinello molecular dynamics (CPMD) simulations have been used to examine the hydration structures, coordination energetics and the first hydrolysis constants of Pu3+, Pu4+, PuO2+ and PuO22+ ions in aqueous solution at 300 K. The coordination numbers and structural properties of the first shell of these ions are in good agreement with available experimental estimates. The hexavalent PuO22+ species is coordinated to 5 aquo ligands while the pentavalent PuO2+ complex is coordinated to 4 aquo ligands. The Pu3+ and Pu4+ ions are both coordinated to 8 water molecules. The first hydrolysis constants obtained for Pu3+ and PuO22+ are 6.65 and 5.70 respectively, all within 0.3 pH units of the experimental values (6.90 and 5.50 respectively). The hydrolysis constant of Pu4+, 0.17, disagrees with the value of -0.60 in the most recent update of the Nuclear Energy Agency Thermochemical Database (NEA-TDB) but supports recent experimental findings. The hydrolysis constant of PuO2+, 9.51, supports the experimental results of Bennett et al. (Radiochim. Act. 1992, 56, 15). A correlation between the pKa of the first hydrolysis reaction and the effective charge of the plutonium center was found.

  8. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework.

    Science.gov (United States)

    Demir, Selvan; Brune, Nicholas K; Van Humbeck, Jeffrey F; Mason, Jarad A; Plakhova, Tatiana V; Wang, Shuao; Tian, Guoxin; Minasian, Stefan G; Tyliszczak, Tolek; Yaita, Tsuyoshi; Kobayashi, Tohru; Kalmykov, Stepan N; Shiwaku, Hideaki; Shuh, David K; Long, Jeffrey R

    2016-04-27

    Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr(2+), Fe(3+), Nd(3+), and Am(3+), from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

  9. Extraction of Lanthanide and Actinide Ions from Aqueous Mixtures Using a Carboxylic Acid-Functionalized Porous Aromatic Framework

    Science.gov (United States)

    2016-01-01

    Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability. Herein, we present a study of the adsorption of selected metal ions, Sr2+, Fe3+, Nd3+, and Am3+, from aqueous solutions employing a carbon-based porous aromatic framework, BPP-7 (Berkeley Porous Polymer-7). This material displays high metal loading capacities together with excellent adsorption selectivity for neodymium over strontium based on Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. Based in part upon X-ray absorption spectroscopy studies, the stronger adsorption of neodymium is attributed to multiple metal ion and binding site interactions resulting from the densely functionalized and highly interpenetrated structure of BPP-7. Recyclability and combustibility experiments demonstrate that multiple adsorption/stripping cycles can be completed with minimal degradation of the polymer adsorption capacity. PMID:27163056

  10. Removal of Th(IV) ions from aqueous solution using bi-functionalized algae-yeast biosorbent

    International Nuclear Information System (INIS)

    Composites could be more effective adsorbents than inorganic and organic components individually. In the present study, the red macro marine algae, Jania Rubens and yeast, Saccharomyces cerevisiae immobilized on silica gel were used as a constituent of bi-functionalized biosorbent to remove thorium ions from aqueous solution. Optimum biosorption conditions were determined as a function of pH, initial Th(IV) concentration, contact time, temperature, volume/mass ratio and co-ion effect. The morphological analysis of the biocomposite was performed by the scanning electron microscopy and functional groups in the biosorbent were determined by FT-IR spectroscopy. In order to find the adsorption characteristics, Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms were applied to the adsorption data. The data were well described by Langmuir adsorption isotherms while the fit of Freundlich adsorption isotherms and Dubinin-Radushkevich equation to adsorption data was poor. Using the equilibrium constant value obtained at different temperature, the thermodynamics properties of the biosorption (ΔGdeg, ΔHdeg and ΔSdeg) were also determined. The results show that biosorption of Th(IV) ions onto biocomposite was exothermic nature, spontaneous and more favorable at lower temperature under examined conditions. (author)

  11. Detection of sub-ppm traces of aqueous heavy-metal ions using micro-electro-mechanical beam resonators

    Science.gov (United States)

    Rahafrooz, Amir; Pourkamali, Siavash

    2009-11-01

    Capacitive silicon micro-mechanical resonators have been utilized in this work as ultra-sensitive mass sensors for the detection of trace amounts of copper ions in water samples. The approach is based on the reduction of aqueous metal ions by the silicon in a resonant structure and consequently deposition of a very thin metal layer on the resonator surface changing its resonant frequency. Measurements demonstrate successful detection of sub-ppm concentrations of copper(II) ions in water. Relatively large frequency shifts (hundreds of ppm) have been measured for resonators exposed to copper concentrations as low as 4 µM (0.26 ppm). An analytical model for the resonant frequency of the resulting complex beams has been derived and used to calculate the thickness of the deposited copper layer based on the measured frequency shifts. The model shows that the measured frequency shifts correspond to only a few atomic layers of copper (as thin as ~7 Å) deposited on the resonator surfaces. This corresponds to a mass sensitivity of more than 4000 Hz µg-1 cm-2 which is much larger than the highest mass sensitivities measured for quartz crystal microbalances.

  12. PSOC cycle testing method for lithium-ion secondary batteries

    Science.gov (United States)

    Kato, Ken; Negishi, Akira; Nozaki, Ken; Tsuda, Izumi; Takano, Kiyonami

    A cycle testing procedure is proposed which carries out charge and discharge in a partial state of charge (PSOC) with some testing levels such as an averaged state of charge, temperature, etc. The PSOC cycle test with this procedure was carried out for a commercial lithium-ion cell for about 20,000 cycles, and the testing procedure and test results are discussed. The features of the degradation due to PSOC cycle test in the tested lithium-ion cell were clarified as follows. The degradation during the PSOC cycle test was greater at higher environmental temperature. The degradation was greatest at a high average SOC, and smallest at SOC=50%. The degradation increased again at a low average SOC. In the test results for 2 years with 20,000 PSOC cycles, which converted to 2200 cycles of full-capacity charge and discharge, capacity degradation was 32% even at the greatest degradation at 318 K and 8% or less at 278 K. The proposed testing procedure is useful for evaluating a cell used on partial charge and discharge cycles.

  13. Exploring Ion-Ion Interactions in Aqueous Solutions by a Combination of Molecular Dynamics and Neutron Scattering

    Czech Academy of Sciences Publication Activity Database

    Kohagen, Miriam; Pluhařová, E.; Mason, Philip E.; Jungwirth, Pavel

    2015-01-01

    Roč. 6, č. 9 (2015), s. 1563-1567. ISSN 1948-7185 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : ion pairing * molecular dynamics * neutron scattering Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 7.458, year: 2014 http://pubs.acs.org/doi/pdf/10.1021/acs.jpclett.5b00060

  14. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    International Nuclear Information System (INIS)

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  15. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  16. Complexation of trivalent lanthanides and other metal ions by 4-methoxybenzylidenepyruvate, in aqueous solution

    International Nuclear Information System (INIS)

    Complex formation equilibria involving M-4-MeO-BP binary systems in aqueous solution, where M=Y(III), La(III) to Lu(III), except Pm(III), Sc(III), Ga(III), In(III), Co(II), Ni(II), Cu(II), Pb(II), UO2(II) and Th(IV); 4-MeO-BP=4-methoxybenzylidenepyruvate have been investigated spectrophotometrically at 250C and ionic strength 0.500M. Coordination centres in 4-MeO-BP are suggested

  17. Removal of chromium (VI) ions from aqueous solutions by using Kiwi shell

    OpenAIRE

    KHAJESADEGH, Maryam; SABERMAHANİ, Fatemeh; MADADİ MAHANİ, Nosrat

    2015-01-01

    Abstract. Kiwi shell, an waste material, was investigated as an adsorbent for the removal of Cr(IV) toxic metal from aqueous solutions. Batch experiments have been performed as a function of pH, contact time, dose of sorbent, initial Cr(IV) concentration, strength ionic and temperature. The experiments showed that the adsorption process was quick and the equilibrium attained within 20 min. Evaluation using Langmuir gave sorption capacity 6.23 mg g-1. Chromium uptake by Kiwi shell was best des...

  18. Beam tests of a 10 GHz compact ECR ion source

    International Nuclear Information System (INIS)

    Ion source for medical facilities should have characteristics of easy maintenance, low electric power, good stability and long operation time without maintenance (one year or more). The 10 GHz compact Electron Cyclotron Resonance (ECR) Ion Source with all permanent magnets has been developed 2003. The maximum mirror magnetic field on the beam axis are 0.59 T at the extraction side and 0.87 T at the gas injection side. The minimum B strength is 0.25 T. The size of the source is 300 mm in diameter and 290 mm in length. Details of the design and the results of preliminary beam test are reported. (author)

  19. Possible Time-Dependent Effect of Ions and Hydrophilic Surfaces on the Electrical Conductivity of Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Marija Zupancic

    2012-03-01

    Full Text Available The purpose of this work was to determine the influence of mechanical and electrical treatment on the electrical conductivity of aqueous solutions. Solutions were treated mechanically by iteration of two steps: 1:100 dilution and vigorous shaking. These two processes were repeated until extremely dilute solutions were obtained. For electrical treatment the solutions were exposed to strong electrical impulses. Effects of mechanical (as well as electrical treatment could not be demonstrated using electrical conductivity measurements. However, significantly higher conductivity than those of the freshly prepared chemically analogous solutions was found in all aged solutions except for those samples stored frozen. The results surprisingly resemble a previously observed weak gel-like behavior in water stored in closed flasks. We suggest that ions and contact with hydrophilic glass surfaces could be the determinative conditions for the occurrence of this phenomenon.

  20. Influence of Operating Conditions on the Removal Cd Ions from Aqueous Media by Adsorption Using Chlamydomonas Reinhardtii

    Institute of Scientific and Technical Information of China (English)

    Jiang Yongbin; Zhu Yi; Ji Hongbing

    2010-01-01

    Chlamydomonas reinhardtii(C.reinhardtii)was used to study adsorption of cadmium(Cd)from aqueous media within various experimental conditions.Results showed that the adsorption process was very fast,with most of the adsorption occurring within30 min of contact time and the equilibrium state was reached in about 60 min.The adsorption ability of the algae increases with the increasing adsorptions sites on cells.Maximum adsorption was observed at the initial Cd concentration of 100 mg/L and pH 6.0.The adsorption was markedly inhibited in the presence of calcium and magnesium ions at 10 mM and the Cd removal efficiency was reduced by 16.54% and 14.99% respectively.This study would be a finding of note with regard to practical wastewater treatment.

  1. Pengaruh Konsentrasi Karbon Terhadap Performa Elektrokimia Katoda Lifepo4 Untuk Aplikasi Baterai Lithium Ion Tipe Aqueous Electrolyte

    Directory of Open Access Journals (Sweden)

    Ade Okta Yurwendra

    2014-09-01

    Full Text Available Baterai lithium ion rechargeable telah dipertimbangkan sebagai sebuah sumber tenaga listrik yang digunakan untuk berbagai aplikasi. LiFePO4 yang digunakan sebagai katoda, dipilih karena memiliki sifat yang ramah lingkungan tetapi memiliki konduktivitas yang lemah. LiFePO4 dilakukan proses konduktif coating menggunakan sukrosa dengan pemanasan 600oC selama 3 jam didalam atmosfer argon untuk membentuk karbon coating LiFePO4 (LiFePO4/C dengan variasi persentase berat karbon 9%, 14.5%, dan 17.8% karbon. Dari analisis cyclic voltammetry penambahan karbon coating dapat meningkatkan stabilitas didalam aqueous electrolyte. Hasil galvanostatic charge/discharge didapatkan hasil terbaik pada LiFePO4/C dengan persentase berat karbon 9% dengan kapasitas discharge 13.3 mAhg-1 dan mengalami penurunan kapasitas sebesar 2.2% setelah cycle ke 100. Penambahan karbon yang berlebihan menurunkan kapasitas LiFePO4

  2. Kinetic Approach to the Mechanism of Redox Reaction of Pyrocatechol Violet and Nitrite Ion in Aqueous Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    A. Adetoro

    2011-10-01

    Full Text Available The kinetics of the oxidation of Pyrocatechol violet (PCVH by nitrite ion (NO2- in aqueous acidic medium has been studied at 24±1ºC, I = 0.50 mol/dm3(NaCl, [H+] = 1.0×10-3 mol/dm3. The reaction is first order to [PCVH] and half order to [NO2-]. The redox reaction displayed a 1:1 stoichiometry and obeys the rate law: d[PCVH]/dt = (a + b[H+] [PCVH][NO2-]½. The second-order rate constant increases with increase in acid concentration and ionic strength. This system displayed positive salt effect while spectroscopic investigation and Michaelis-Menten plot showed evidence of intermediate complex formation in the course of the reaction. A plausible mechanism has been proposed for the reaction.

  3. Limit diffusion coefficients and some aqueous ions of 5f and 4f elements, thermodynamic consequences for actinides

    International Nuclear Information System (INIS)

    The diffusion of the aqueous ions of Am3+, Cm3+, Cf3+, Es3+ and for comparison, Ce3+, Eu3+, Gd3+, Tm3+, Yb3+ was investigated in aqueous LiCl-HCl solutions (pH=2.5) at 25.000C by the open-ended capillary method. The diffusion coefficients obtained in the limit of zero ionic strength are used to estimate the hydrated radius of the considered elements and, consequently, the average number h of water molecules involved. A single S-shaped curve is obtained when this number h is plotted versus the cristallographic radius of the lanthanide (III) and actinide (III) cations. A similar change is assumed, for the inner sphere hydration number, from which values can be derived for actinides. From these results ΔHsub(hyd)sup(0) values have been calculated using a general analytical expression of the hydration enthalpie developped in this work. Finally, data of the sum of ionization potentials are proposed for the transuranium elements

  4. The removal of sodium and cadmium ions from dilute aqueous solutions using foam separation

    International Nuclear Information System (INIS)

    Cationic metallic ions, Na+ and Cd2+, were flotated by using foam separation technique in a continuous flow system. Experiments were carried out mainly on the conditions such that the pH range was limited within 1.3 to 4.0 and collector (sodium dodecylbenzenesulfonate, M.W.=348.48) concentration was stoichiometrically greater than that of the colligend (Cadmium). Surface excess of colligend was greatly influenced by the co-existing H+ ion under constant concentration of collector and colligend ions within a pH range less than 4.0, and in turn, only slightly by the co-existing collector concentration under constant concentration of H+ ion and colligend (pH=4.0). It was also established that a considerable difference between mono- and divalent cationic metallic ions for the affinity to neutralize the negatively charged surface on gas-liquid interface was observed and verified by use of Gouy-Chapman diffuse double-layer theory, except for high concentration range of the co-existing collector forming micellaneous metal-collector complexes. (auth.)

  5. Removal of corper(II Ions from aqueous solution by a lactic acid bacterium

    Directory of Open Access Journals (Sweden)

    M. Yilmaz

    2010-06-01

    Full Text Available Enterococcus faecium, a lactic acid bacterium (LAB, was evaluated for its ability to remove copper(II ions from water. The effects of the pH, contact time, initial concentration of copper(II ions, and temperature on the biosorption rate and capacity were studied. The initial concentrations of copper(II ions used to determine the maximum amount of biosorbed copper(II ions onto lyophilised lactic acid bacterium varied from 25 mg L-1 to 500 mg L-1. Maximum biosorption capacities were attained at pH 5.0 and 6.0. Temperature variation between 20°C and 40°C did not affect the biosorption capacity of the bacterial biomass. The highest copper(II ion removal capacity was 106.4 mg per g dry biomass. The correlation regression coefficients show that the biosorption process can be well defined by the Freundlich equation. The change in biosorption capacity with time was found to fit a pseudo-second-order equation.

  6. Quantitative Determination of Ammonium Ion in Aqueous Environment Using Rieglers Solution and Artificial Neural Network

    International Nuclear Information System (INIS)

    A quantitative analysis has been conducted to determine the concentration of ammonium (NH4+) ion in solution by using Ultraviolet-visible spectrophotometry method and artificial neural network (ANN). Rieglers reagent was used to form Riegler-NH4+ complex. The characterisations of Rieglers reagent in solution such as photo stability, pH effect, reagent concentration, dynamic range and reproducibility were conducted. The colour change of the Rieglers reagent after reaction with NH4+ was yellow to red. The Rieglers reagent responds linearly to NH4+ ion concentration in the range of 1-7 ppm with optimum response at pH 7. Satisfactory reproducibility (2.0-2.8 %) were obtained with this reagent. The effect of interfering ions that may contain in the leachate on the determination of NH4+ ion was also studied. The application of ANN enabled the extension of the useful dynamic concentration range of NH4+ ion to 1-24 ppm. The best ANN architecture for Riegler-NH4+ complex was built from 29 hidden neurons, 21,389 epochs number and 0.001 % learning rate which produced sum square error (SSE) value of 0.0483 with an average calibration error of 1.4136. (author)

  7. Thermal Environmental Testing of NSTAR Engineering Model Ion Thrusters

    Science.gov (United States)

    Rawlin, Vincent K.; Patterson, Michael J.; Becker, Raymond A.

    1999-01-01

    NASA's New Millenium program will fly a xenon ion propulsion system on the Deep Space 1 Mission. Tests were conducted under NASA's Solar Electric Propulsion Technology Applications Readiness (NSTAR) Program with 3 different engineering model ion thrusters to determine thruster thermal characteristics over the NSTAR operating range in a variety of thermal environments. A liquid nitrogen-cooled shroud was used to cold-soak the thruster to -120 C. Initial tests were performed prior to a mature spacecraft design. Those results and the final, severe, requirements mandated by the spacecraft led to several changes to the basic thermal design. These changes were incorporated into a final design and tested over a wide range of environmental conditions.

  8. Electron-Transfer Oxidation of Chlorophenols by Uranyl Ion Excited State in Aqueous Solution. Steady-State and Nanosecond Flash Photolysis Studies

    OpenAIRE

    Sarakha, Mohamed; Bolte, Michèle; Burrows, Hugh D.

    2000-01-01

    The oxidation of chlorophenols by photoexcited uranyl ion was studied in aqueous solution at concentrations where the ground-state interactions were negligible. Nanosecond flash photolysis showed that a clean electron-transfer process from the chlorophenols to the excited uranyl ion is involved. This is suggested to lead to the formation of a U(V)/chlorophenoxyl radical pair complex. The efficiency of this charge-transfer process is unity for the three chlorophenols. However, low product yiel...

  9. The Application of Response Surface Methodology for Lead Ion Removal from Aqueous Solution Using Intercalated Tartrate-Mg-Al Layered Double Hydroxides

    OpenAIRE

    Yamin Yasin; Maszlin Mohamad; Faujan B. H. Ahmad

    2013-01-01

    Layered double hydroxide intercalated with tartrate (tartrate-Mg-Al) was used as an adsorbent to remove lead ions from aqueous solutions. The effects of various optimization parameters such as contact time, solution pH, lead ion concentrations, and adsorbent dosage were investigated by the use of Response Surface Methodology (RSM). The Response Surface Methodology (RSM) based on a four-level four-variable Central Composite Rotatable Design (CCRD) was employed to evaluate the interactive effec...

  10. Ti-substituted tunnel-type Na0.44MnO2 oxide as a negative electrode for aqueous sodium-ion batteries

    Science.gov (United States)

    Wang, Yuesheng; Liu, Jue; Lee, Byungju; Qiao, Ruimin; Yang, Zhenzhong; Xu, Shuyin; Yu, Xiqian; Gu, Lin; Hu, Yong-Sheng; Yang, Wanli; Kang, Kisuk; Li, Hong; Yang, Xiao-Qing; Chen, Liquan; Huang, Xuejie

    2015-03-01

    The aqueous sodium-ion battery system is a safe and low-cost solution for large-scale energy storage, because of the abundance of sodium and inexpensive aqueous electrolytes. Although several positive electrode materials, for example, Na0.44MnO2, were proposed, few negative electrode materials, for example, activated carbon and NaTi2(PO4)3, are available. Here we show that Ti-substituted Na0.44MnO2 (Na0.44[Mn1-xTix]O2) with tunnel structure can be used as a negative electrode material for aqueous sodium-ion batteries. This material exhibits superior cyclability even without the special treatment of oxygen removal from the aqueous solution. Atomic-scale characterizations based on spherical aberration-corrected electron microscopy and ab initio calculations are utilized to accurately identify the Ti substitution sites and sodium storage mechanism. Ti substitution tunes the charge ordering property and reaction pathway, significantly smoothing the discharge/charge profiles and lowering the storage voltage. Both the fundamental understanding and practical demonstrations suggest that Na0.44[Mn1-xTix]O2 is a promising negative electrode material for aqueous sodium-ion batteries.

  11. Adsorption of Heavy Metal Ions from Aqueous Media Using Amidoximated Jute Fibres: A Comparative Study

    International Nuclear Information System (INIS)

    Jute Fibres were grafted with acrylonitrile (AN) induced by direct gamma irradiation. All the factors which affect the grafting process were investigated. The grafting at the optimum conditions was followed by amidoximation reaction. The conversion of AN into acryl amidoxime was studied by fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The treated Jute fibres were used as an adsorbent substrate for heavy metal ions such as Pb2+, Cu2+, Ni2+ and Fe2+ from their solutions. The different factors which affect the adsorption capacity of heavy metal ions, such as pH, contact time, metal ions concentrations were studied and the Langmuir adsorption isotherm was highlighted. It was found that the adsorption capacity was enhanced at acidic medium of pH 4 and increased with increasing of contact time.

  12. How to build accurate macroscopic models of actinide ions in aqueous solvents?

    International Nuclear Information System (INIS)

    Classical molecular dynamics (MD) based on parameterized force fields allow one to simulate large molecular systems on significantly long simulation times (usually, at the ns scale and above). Hence, they provide statistically relevant sampled sets of data, which may then be post-processed to estimate specific properties. However, the study of the ligand coordination dynamics around heavy ions requires the use of sophisticated force fields accounting for in particular polarization phenomena, as well as for the charge-transfer effects affecting ion/ligand interactions, which are shown to be significant in several heavy element systems. Our current efforts focus on the development of force-field models for radionuclides, with the intention of pushing as far as possible the accuracy of all competing interactions between the various elements present in solution, that is the metal, the ligands, the solvent, and the counter-ions

  13. Adsorption of divalent metal ions from aqueous solutions using graphene oxide.

    Science.gov (United States)

    Sitko, Rafal; Turek, Edyta; Zawisza, Beata; Malicka, Ewa; Talik, Ewa; Heimann, Jan; Gagor, Anna; Feist, Barbara; Wrzalik, Roman

    2013-04-28

    The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated. GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR). The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3-7 for Cu(II), 5-8 for Zn(II), 4-8 for Cd(II), 3-7 for Pb(II). The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g(-1), respectively. The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II). Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO. Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions. The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions. After adsorption, the tendency to agglomerate and precipitate is observed. Excellent dispersibility of GO and strong tendency of GO-Me(II) to precipitate open the path to removal of heavy metals from water solution. Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents. PMID:23443993

  14. Anodic behaviour of the stainless steel AISI 430 in aqueous solutions of chloride and sulphate ions

    International Nuclear Information System (INIS)

    The kinetics of the dissolution of stainless steel AISI 430 in the presence of chloride and sulphate ions has been studied in terms of the ion concentration, the pH variation, and the velocity of the working electrode. The experimental method utilized was the potentiostatic anodic polarization, and the reactants used were NaCl and Na2 SO4 at room temperature. Atomic Absorption spectrophotometry and Auger Electrons spectroscopy (AES) analyses were made in order to support the interpretation of results obtained by means of the potentiostatic polarization method. (author)

  15. The Application of Response Surface Methodology for Lead Ion Removal from Aqueous Solution Using Intercalated Tartrate-Mg-Al Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Yamin Yasin

    2013-01-01

    Full Text Available Layered double hydroxide intercalated with tartrate (tartrate-Mg-Al was used as an adsorbent to remove lead ions from aqueous solutions. The effects of various optimization parameters such as contact time, solution pH, lead ion concentrations, and adsorbent dosage were investigated by the use of Response Surface Methodology (RSM. The Response Surface Methodology (RSM based on a four-level four-variable Central Composite Rotatable Design (CCRD was employed to evaluate the interactive effects of the various optimization parameters. The parameters were contact time (6–10 h, solution pH (1–3, adsorbent dosage (0.06–0.1 g, and lead ion concentrations (10–30 mg/L. The percentage of lead ions removal for each of the parameters studied was determined by Inductively Coupled Plasma-Optical Emission Spectrophotometer. Simultaneously by increasing contact time and amount of dosage of tartrate-Mg-Al used the percentage of lead ions removal from aqueous solution will increase; however, the percentage removal decreases with an increase in pH and concentrations of lead ions. The experimental percentage removal recorded under optimum conditions was compared well with the maximum predicted value from the RSM, which suggest that Central Composite Rotatable Design of RSM can be used to study the removal of lead from aqueous solution by the use of tartrate-Mg-Al as an adsorbent.

  16. Selective and Sensitive Detection of Heavy Metal Ions in 100% Aqueous Solution and Cells with a Fluorescence Chemosensor Based on Peptide Using Aggregation-Induced Emission.

    Science.gov (United States)

    Neupane, Lok Nath; Oh, Eun-Taex; Park, Heon Joo; Lee, Keun-Hyeung

    2016-03-15

    A fluorescent peptidyl chemosensor for the detection of heavy metal ions in aqueous solution as well as in cells was synthesized on the basis of the peptide receptor for the metal ions using an aggregation-induced emission fluorophore. The peptidyl chemosensor (1) bearing tetraphenylethylene fluorophore showed an exclusively selective turn-on response to Hg(2+) among 16 metal ions in aqueous buffered solution containing NaCl. The peptidyl chemosensor complexed Hg(2+) ions and then aggregated in aqueous buffered solution, resulting in the significant enhancement (OFF-On) of emissions at around 470 nm. The fluorescent sensor showed a highly sensitive response to Hg(2+), and about 1.0 equiv of Hg(2+) was enough for the saturation of the emission intensity change. The detection limit (5.3 nM, R(2) = 0.99) of 1 for Hg(2+) ions was lower than the maximum allowable level of Hg(2+) in drinking water by EPA. Moreover, the peptidyl chemosensor penetrated live cells and detected intracellular Hg(2+) ions by the turn-on response. PMID:26872241

  17. Safety testing of 18650-style Li-Ion cells

    Energy Technology Data Exchange (ETDEWEB)

    CRAFTS,CHRIS C.; BOREK III,THEODORE T.; MOWRY,CURTIS DALE

    2000-06-08

    To address lithium-ion cell safety issues in demanding power applications, electrical and thermal abuse tests were performed on 18650 sized cells. Video and electrically monitored abuse tests in air included short circuit, forced overcharge, forced reversal, and controlled overheating (thermal) modes. Controlled overheating tests to 200 C were performed in a sealed chamber under a helium atmosphere and the gases released from the cell during thermal runaway were analyzed at regular intervals using gas chromatography and mass spectrometry. In addition to alkane and alkene solvent breakdown fragments, significant H{sub 2} was detected and evidence that HF was evolved was also found.

  18. Experimental and modeling tests of a spherically convergent ion focus

    International Nuclear Information System (INIS)

    Convergent ion focus devices have been considered as sources of fusion reactivity since early studies in the late 1960's. In general, these devices rely on the confinement and acceleration of plasma ions in a spherically or cylindrically symmetric electrostatic potential well. Ions at the edge fall into the well and converge to the central core region. This leads to a strongly increasing central density and central ion energies comparable to the depth of the potential well, resulting in considerable fusion reactivity with modest device parameters. Several schemes have been proposed for creating the potential well, with simple transparent spherical grids being the usual experimental realization. Potential applications of these fusion devices range from small low-intensity fusion-product particle sources for nuclear assaying to more intense sources for isotope generation and waste processing. Even more optimistic projections have led to discussions of fusion power generation through electrostatic confinement. Recent experiments and modeling efforts are developing a deeper understanding of the operation of these devices. Operation of a gridded spherical focus at low density has verified the classical ion flow model and demonstrated a core density enhancement factor of > 10. Probe measurements with applied potentials of ≤ 10 kV indicate a space potential distribution which is much steeper than that expected from simple space-charge-limited flow. The highest gradients are in the near-field region of the grid where the angular asymmetries of the potential distribution are also highest. Even so, central core radii of < 0.6 cm have been observed, considerably below the radius expected from single ion orbit models. Near-term future experiments are concentrating on development of nonperturbing diagnostics of the energetic ion core, achieving high core density operation, and testing predictions of flow instabilities

  19. Application of Buckmaster Electrolyte Ion Leakage Test to Woody Biofuel Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Thomas F [Forest Concepts, LLC; Dooley, James H [Forest Concepts, LLC

    2014-08-28

    In an earlier ASABE paper, Buckmaster reported that ion conductivity of biomass leachate in aqueous solution was directly correlated with activity access to plant nutrients within the biomass materials for subsequent biological or chemical processing. The Buckmaster test involves placing a sample of the particles in a beaker of constant-temperature deionized water and monitoring the change in electrical conductivity over time. We adapted the Buckmaster method to a range of woody biomass and other cellulosic bioenergy feedstocks. Our experimental results suggest differences of electrolyte leakage between differently processed woody biomass particles may be an indicator of their utility for conversion in bioenergy processes. This simple assay appears to be particularly useful to compare different biomass comminution techniques and particle sizes for biochemical preprocessing.

  20. Radiation microscope for SEE testing using GeV ions

    International Nuclear Information System (INIS)

    Radiation Effects Microscopy is an extremely useful technique in failure analysis of electronic parts used in radiation environment. It also provides much needed support for development of radiation hard components used in spacecraft and nuclear weapons. As the IC manufacturing technology progresses, more and more overlayers are used; therefore, the sensitive region of the part is getting farther and farther from the surface. The thickness of these overlayers is so large today that the traditional microbeams, which are used for REM are unable to reach the sensitive regions. As a result, higher ion beam energies have to be used (> GeV), which are available only at cyclotrons. Since it is extremely complicated to focus these GeV ion beams, a new method has to be developed to perform REM at cyclotrons. We developed a new technique, Ion Photon Emission Microscopy, where instead of focusing the ion beam we use secondary photons emitted from a fluorescence layer on top of the devices being tested to determine the position of the ion hit. By recording this position information in coincidence with an SEE signal we will be able to indentify radiation sensitive regions of modern electronic parts, which will increase the efficiency of radiation hard circuits.

  1. Ion collector design for an energy recovery test proposal with the negative ion source NIO1

    Science.gov (United States)

    Variale, V.; Cavenago, M.; Agostinetti, P.; Sonato, P.; Zanotto, L.

    2016-02-01

    Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D- beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D- and D+), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H- each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.

  2. Ion collector design for an energy recovery test proposal with the negative ion source NIO1

    Energy Technology Data Exchange (ETDEWEB)

    Variale, V., E-mail: vincenzo.variale@ba.infn.it [INFN-BA, Via Orabona 4, I-70125 Bari (Italy); Cavenago, M. [INFN – LNL, viale dell’Università 2, I-35020 Legnaro (PD) (Italy); Agostinetti, P.; Sonato, P.; Zanotto, L. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2016-02-15

    Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D{sup −} beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D{sup −} and D{sup +}), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H{sup −} each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.

  3. Ion collector design for an energy recovery test proposal with the negative ion source NIO1

    International Nuclear Information System (INIS)

    Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D− beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D− and D+), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H− each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed

  4. Thermodynamic approach of the poly-azine - f element ions interaction in aqueous conditions

    International Nuclear Information System (INIS)

    2-Amino-4,6-di-(pyridine-2-yl)-1,3,5-triazine (Adptz) was considered as a model compound for selective aromatic nitrogen extractants (poly-azines) of minor actinides. Thermodynamic data ( ΔG0, ΔH0, ΔS0) were systematically acquired for the complexation of lanthanide(III) ions as well as yttrium(III) and americium(III) in hydro-alcoholic medium. Two complementary experimental approaches were followed. Stability constants for the formation of the 1:1 complexes were evaluated from UV-visible spectrophotometry titration experiments, whereas enthalpies and entropies of reaction were obtained consistently from either temperature dependence experiments or micro-calorimetry. The interaction of Adptz with lanthanide(III) and yttrium(III) ions was found to be essentially ionic and dependent upon the hydration and size of the ion. As for americium(III) ion, stability constant and enthalpy of complexation was significantly larger. This was attributed to a partial electronic transfer from the ligand to empty orbitals of the cation. DFT calculations support this interpretation. (authors)

  5. Immobilized materials for removal of toxic metal ions from surface/groundwaters and aqueous waste streams.

    Science.gov (United States)

    Zawierucha, Iwona; Kozlowski, Cezary; Malina, Grzegorz

    2016-04-20

    Heavy metals from industrial processes are of special concern because they produce chronic poisoning in the aquatic environment. More strict environmental regulations on the discharge of toxic metals require the development of various technologies for their removal from polluted streams (i.e. industrial wastewater, mine waters, landfill leachate, and groundwater). The separation of toxic metal ions using immobilized materials (novel sorbents and membranes with doped ligands), due to their high selectivity and removal efficiency, increased stability, and low energy requirements, is promising for improving the environmental quality. This critical review is aimed at studying immobilized materials as potential remediation agents for the elimination of numerous toxic metal (e.g. Pb, Cd, Hg, and As) ions from polluted streams. This study covers the general characteristics of immobilized materials and separation processes, understanding of the metal ion removal mechanisms, a review of the application of immobilized materials for the removal of toxic metal ions, as well as the impacts of various parameters on the removal efficiency. In addition, emerging trends and opportunities in the field of remediation technologies using these materials are addressed. PMID:27044908

  6. Lysozyme Net Charge and Ion Binding in Concentrated Aqueous Electrolyte Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kuehner, Daniel E.; Engmann, Jan; Fergg, Florian; Wernick, Meredith; Blanch, Harvey W.; Prausnitz, John M.

    1999-02-01

    Hydrogen-ion titrations were conducted for hen-egg-white lysozyme in solutions of potassium chloride, over the range of pH 2.5 - 11.5 and for ionic strengths to 2. 0 M. The dependence of lysozyme's net proton charge, zP' on pH and ionic-strength in potassium-chloride solution is measured. From the ionic-strength dependence of zP' interactions of lysozynie with potassium and chloride ions are calculated using the molecular-thennodynamic theory of Fraaije and Lyklema 1. Lysozyme interacts preferentially with up to 12 chloride ions at pH 2.5. The observed dependence of ion-protein interactions on pH and ionic strength is explained in terms of electricdouble-layer theory. New experimental pKa data are reported for eleven ammo acids in potassium-chloride solutions of ionic strength to 3.0 M.

  7. Biosorption of Heavy Metal Ions from Aqueous Solutions Using a Biomaterial

    Directory of Open Access Journals (Sweden)

    Innocent OBOH

    2009-07-01

    Full Text Available An increase in population initiating rapid industrialization was found to consequently increase the effluents and domestic wastewater into the aquatic ecosystem. Heavy metals are major toxicants found in industrial wastewaters; they may adversely affect the biological treatment of wastewater. Conventional methods for the removal of heavy metals from waste waters are often cost prohibitive hence, there is a need for cheap methods for effluent treatment. The residual metallic ion concentrations were determined using an Atomic Absorption Spectrophotometer (AAS. The results obtained after contacting for 120 minutes showed that Neem leaves achieved the percent removal of 76.8, 67.5, 58.4 and 41.45 for Cu2+, Ni2+, Zn2+ and Pb2+ ions respectively. The percent removal of Ni2+ ions was 68.75 with an effective dose of 1.0 g of Neem leaves (bioadsorbent. The ability of Neem leaves to absorb metal ions as shown from the results can be used for the development of an efficient, clean and cheap technology for effluent treatment.

  8. Tracer-diffusion of sulphate ions in NaNO3 and KNO3 aqueous solutions of radio-tracer techniques (Preprint No. CT-55)

    International Nuclear Information System (INIS)

    The tracer-diffusion coefficients of sulphate ions in NaNO3 and KNO3 aqueous solutions were determined in different gel concentrations at various temperatures by radio-tracer technique. The diffusion coefficients are f ound to increase with temperature and decrease with increase in the concentration of the supporting electrolyte as well as gel concentration. (author). 9 refs

  9. Investigation of ozonide ion reaction with neptunium (6) ions in alkali aqueous solutions by the method of pulse radiolysis

    International Nuclear Information System (INIS)

    By pulse radiolysis method with spectrophotometric recording of short-living particles kinetics of O3-radical-ion reaction with Np5+ and Np6+ in alkaline solutions is investigated. Rate constant of the first reaction equals to (2.0±0.3)x106, of the second -(2.1±0.2)x105 l/(mol·c) in 0.2-2.0 mol/l of LiOH. Peculiarities of Np6+ γ-radiolysis in alkaline solutions saturated with N2O and in aerated solutions containing K2S2O8 are explained. Np7+ yield is determined by O3-behaviour which depends on Np6+ and OH- concentration

  10. Lignin-assisted exfoliation of molybdenum disulfide in aqueous media and its application in lithium ion batteries.

    Science.gov (United States)

    Liu, Wanshuang; Zhao, Chenyang; Zhou, Rui; Zhou, Dan; Liu, Zhaolin; Lu, Xuehong

    2015-06-01

    In this article, alkali lignin (AL)-assisted direct exfoliation of MoS2 mineral into single-layer and few-layer nanosheets in water is reported for the first time. Under optimized conditions, the concentration of MoS2 nanosheets in the obtained dispersion can be as high as 1.75 ± 0.08 mg mL(-1), which is much higher than the typical reported concentrations (MoS2 nanosheets are applied as electrode materials for lithium ion batteries, they show much improved electrochemical performance compared with the pristine MoS2 mineral because of the enhanced ion and electron transfer kinetics. This facile, scalable and eco-friendly aqueous-based process in combination with renewable and ultra-low-cost lignin opens up possibilities for large-scale fabrication of MoS2-based nanocomposites and devices. Moreover, herein we demonstrate that AL is also an excellent surfactant for exfoliation of many other types of layered materials, including graphene, tungsten disulfide and boron nitride, in water, providing rich opportunities for a wider range of applications. PMID:25970569

  11. Fluorimetric detection of Sn(2+) ion in aqueous medium using Salicylaldehyde based nanoparticles and application to natural samples analysis.

    Science.gov (United States)

    Patil, Kishor S; Mahajan, Prasad G; Patil, Shivajirao R

    2017-01-01

    The fluorescent 2-[(E)-(2-phenylhydrazinylidene)methyl]phenol nanoparticles (PHPNPs) were prepared by a simple reprecipitation method. The prepared PHPNPs examined by Dynamic Light Scattering show narrower particle size distribution having an average particle size of 93.3nm. The Scanning Electron Microphotograph shows distinct spherical shaped morphology of nanoparticles. The blue shift in UV-absorption and fluorescence spectra of PHPNPs with respect to corresponding spectra of PHP in acetone solution indicates H- aggregates and Aggregation Induced Enhanced Emission (AIEE) for nanoparticles. The nanoparticles show selective tendency towards the recognition of Sn(2+) ions by enhancing the fluorescence intensity preference to Cu(2+), Fe(3+), Fe(2+), Ni(2+), NH4(+), Ca(2+), Pb(2+), Hg(2+) and Zn(2+) ions, which actually seem to quench the fluorescence of nanoparticles. The studies on Langmuir adsorption plot, fluorescence lifetime of PHPNPs, DLS-Zeta sizer, UV-visible and fluorescence titration with and without Sn(2+) helped to propose a suitable mechanism of fluorescence enhancement of nanoparticles by Sn(2+) and their binding ability during complexation. The fluorescence enhancement effect of PHPNPs induced by Sn(2+) is further used to develop an analytical method for detection of Sn(2+) from aqueous medium in environmental samples. PMID:27423468

  12. Pseudo-first order and second order kinetics study of erbium ions adsorption on activated charcoal from aqueous solutions

    International Nuclear Information System (INIS)

    The adsorption of Erbium (Er) ions on activated charcoal is carried out at temperatures 10-40 deg. C from aqueous solutions to understand the kinetics behavior. The results shows that the adsorption of erbium ions increases with the rise in temperature and the adsorption process is physical in nature and attains equilibrium in about 60 minutes. A comparison of the kinetics models on the overall adsorption rate indicates that the Er/AC system is best described by the pseudo second order rate model than the pseudo first order model. The applicability of the Waber and Morris equation to the adsorption data, confirms that the intra-particle diffusion is not only the main rate determining step through out the adsorption process, but the boundary layer diffusion is also play significant role in rate determination. The Waber and Morris equation best suited to the adsorption process in the whole range is in the form of: qt = k/sub i,d/ t/sup 0.5/ + C, where ki,d is the intra-particle diffusion rate constant (g.g/sup -1/. min/sup -0.5/) and C is the constant related to boundary layer diffusion. Both these parameters were determined from the slopes and intercepts of straight lines of plots of qt vs. t/sup 0.5/ respectively. The value of C is proportional to the extent of boundary layer thickness. (author)

  13. Chromatography of 49 metal ions on stannic antimonate papers in dimethylsulfoxide: nitric acid systems and aqueous nitric acid systems

    International Nuclear Information System (INIS)

    Chromatographic separations of 49 metal ions on stannic antimonate papers have been performed using mixed solvent systems containing DMSO. Aqueous HNO3 systems have also been used. The utility of the papers has been demonstrated by achieving various difficult separations. Some of the important separations (R/sub f/ values given in parentheses) are: Cs+(0.20)-K+(0.30) and Sm3+(0.00)-Pr3+(0.72) in pure DMSO; Nb5+(0.14)-VO2+(0.95) in DMSO-6M HNO3 (1:1); Ti4+(0.00)-VO2(0.97) in DMSO-0.5M HNO3 (1:1); and Ba2+(0.06)-K+(0.52)-Sr2+(0.95), Ba2+(0.04)-Cs+(0.41)-Mg2+(0.93), and Ca2+(0.10)-Sr2+(0.94) in DMSO-0.1M HNO3 (1:1). The time of development in each case is two hours. A discussion is presented on the dependence of Ri, log R/sub f/, and R/sub M/ on pH of the solvent to understand the mechanism of the movement of metal ions on papers impregnated with inorganic materials. (U.S.)

  14. Reduction kinetics of the dioxouranium(VI) ion bound to synthetic polyelectrolytes in aqueous solutions

    International Nuclear Information System (INIS)

    The characterization of actinide ion interactions with naturally occurring polyelectrolytes (e.g., humic substances) is necessary for developing a satisfactory model of actinide behavior in ecosystems. Synthetic polyelectrolytes having only carboxylic acid functional groups can be used to assess the importance of these groups in humic substances. This study examines the reduction of the dioxouranium (VI) ion in the presence of poly (acrylic acid) and poly (maleic acid) using a viologen radical generated by pulse-radiolysis techniques. The observed rate parameters for dioxo-uranium (VI) reduction show unexpected results as a function of polyelectrolyte concentration, degree of neutralization, and contact time. These results along with a possible mechanistic interpretation are discussed

  15. Formation and Stability of the 4-Methoxyphenonium Ion in Aqueous Solution

    OpenAIRE

    Tsuji, Yutaka; Hara, Daisuke; Hagimoto, Rui; Richard, John P.

    2011-01-01

    The reaction of 2-methoxyphenylethyl tosylate (MeO-1-Ts) is first-order in [N3−]. A carbon-13 NMR analysis of the products of the reactions of MeO-1-[α–13C]Ts shows the formation of MeO-1-[β–13C]OH and MeO-1-[β–13C]N3 from the trapping of a symmetrical 4-methoxyphenonium ion reaction intermediate 2+. An analysis of the rate and product data provides a value of kaz/ks = 83 M−1 for partitioning of 2+ between addition of azide ion and solvent. These data set a limit for the lifetime of 2+ in aqu...

  16. Sono-sorption as a new method for the removal of lead ion from aqueous solution

    International Nuclear Information System (INIS)

    Sorption of Pb(II) as a toxic heavy metal ion, onto styrene-divinylbenzene co-polymer resin in the presence of ultrasound (sono-sorption) and in its absence (classical method) is presented in this work. Batch experiments were conducted to study the effect of the main parameters such as the amount of sorbent, concentration of sorbate, contact time, intensity of ultrasound and temperature on this sorption process. The equilibrium between liquid and solid phase was described by Langmuir model better than the Freundlich model. The time to reach equilibrium especially in the presence of ultrasound was very fast. This indicates that the resin mentioned has a high potential for the sorption of this pollutant ion. The isotherm constants were obtained under several different conditions. These constants were used in the calculation of the thermodynamic parameters of sorption. According to the results, the kinetics of sorption was in agreement with both pseudo-first-order and first-order reversible models

  17. Sono-sorption as a new method for the removal of lead ion from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Entezari, Mohammad H. [Department of Chemistry, Ferdowsi University of Mashhad, 91775 Mashhad (Iran, Islamic Republic of)]. E-mail: moh_entezari@yahoo.com; Bastami, Tahereh Rohani [Department of Chemistry, Ferdowsi University of Mashhad, 91775 Mashhad (Iran, Islamic Republic of)

    2006-09-21

    Sorption of Pb(II) as a toxic heavy metal ion, onto styrene-divinylbenzene co-polymer resin in the presence of ultrasound (sono-sorption) and in its absence (classical method) is presented in this work. Batch experiments were conducted to study the effect of the main parameters such as the amount of sorbent, concentration of sorbate, contact time, intensity of ultrasound and temperature on this sorption process. The equilibrium between liquid and solid phase was described by Langmuir model better than the Freundlich model. The time to reach equilibrium especially in the presence of ultrasound was very fast. This indicates that the resin mentioned has a high potential for the sorption of this pollutant ion. The isotherm constants were obtained under several different conditions. These constants were used in the calculation of the thermodynamic parameters of sorption. According to the results, the kinetics of sorption was in agreement with both pseudo-first-order and first-order reversible models.

  18. The thermodynamic characteristics of ion resolvation in aqueous solutions of dimethylformamide and dimethylsulfoxide

    International Nuclear Information System (INIS)

    Data on thermodynamic characteristics of chlorine, bromine and iodine ion resolution in mixtures of water with dimethylformamide and dimethylsulfoxide are provided and analyzed. The values presented were calculated on the basis of the volt potential differences method. It is shown the actual thermodynamic characteristics of anion transfer have positive values in contrast to cations having the opposite sign. It stems from changes in the structure of mixed solvent when passing from water to water-organic mixtures in the solution/gas phase interface. Analysis of chemical Gibbs' energies of resolvation of the ions studied suggests that anions, which can form hydrogen bonds with proton-donor solvents, are hardly solved in aprotic solutions

  19. Application of porphyrin modified SBA-15 in adsorption of lead ions from aqueous media

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Asgari

    2015-09-01

    Full Text Available Mesoporous silica SBA-15 was synthesized using P123 as surfactant and functionalized with (3-chloropropyl triethoxysilane. For the first time, the composite of THPP-SBA-15 was prepared using incorporation of tetrakis(4-hydroxyphenylporphyrin in functionalized SBA-15. The materials were characterized by BET, SEM, XRD, FT-IR, DRS, and UV–Vis spectroscopy techniques. The synthesized composite was employed as adsorbent of heavy metal ion (Pb2+ from water at room temperature. Results indicated that the presence of porphyrin in silica significantly increased heavy metal ion adsorption. The maximum adsorption capacity (qmax of THPP-SBA-15 for Pb2+ was found to be 134 mg/g.

  20. Highly focused ion beams in integrated circuit testing

    International Nuclear Information System (INIS)

    The nuclear microprobe has proven to be a useful tool in radiation testing of integrated circuits. This paper reviews single event upset (SEU) and ion beam induced charge collection (IBICC) imaging techniques, with special attention to damage-dependent effects. Comparisons of IBICC measurements with three-dimensional charge transport simulations of charge collection are then presented for isolated p-channel field effect transistors under conducting and non-conducting bias conditions

  1. Polarographic study of processes of binding of indium (3) ions in aqueous solutions of polyelectrolytes

    International Nuclear Information System (INIS)

    The effect of poly-n-styrenesulphoacid (PSSA) and its Na- and K-salts on polarographic reduction of indium (3) in the absence and presence of an indifferent electrolyte is investigated. The concentration of the electrolyte and polyelectrolyte, the molecular mass, the degree of neutralization of PSSA, and the nature of the cation affect the limiting currents of the indium (3) ions. The polarographic method is used for determining the concentration and molecular masses of the polyelectrolyte

  2. Colorimetric and fluorescent sensing of transition metal ions in aqueous medium by salicylaldimine based chemosensor

    International Nuclear Information System (INIS)

    The cation sensing property of highly sensitive chromogenic receptor N, N′-bis (salicylidine)-o-phenylene diamine (receptor 1) was studied by visual observation, UV–vis spectroscopy and fluorescence spectroscopy. The proposed study has been targeted to sense the first transition series metal cations like Fe3+, Co2+, Ni2+ and Cu2+. Binding affinity toward Cu2+ is found to be of higher magnitude compared to the other three cations mentioned. Receptor 1 on binding with Fe3+, Co2+ Ni2+ and Cu2+ ions shows fluorescence enhancement which is due to the inhibition of PET mechanism. - Graphical abstract: The cation sensing property of highly sensitive chromogenic receptor N, N′-bis (salicylidine)-o-phenylene diamine was studied by naked eye observation, UV–vis spectroscopy and fluorescence spectroscopy. The proposed study has been targeted to sense the first transition series metal cations like Fe3+, Co2+, Ni2+ and Cu2+. Binding affinity toward Cu2+ is found to be of higher magnitude compared to the other three cations mentioned. Receptor 1 on binding with Fe3+, Co2+ Ni2+ and Cu2+ ions shows fluorescence enhancement which is due to the inhibition of PET mechanism. Highlights: ► Receptor 1 serves as a multi channel probe for different transition metal cations. ► Binding constant for Cu2+ is of higher magnitude compared to the other cations. ► The ions bind to the receptor through NONO centers forming 2:1 and 1:1 complexes. ► Paramagnetic ions show fluorescent enhancement due to the inhibition of PET mechanism.

  3. Temperature effect on the association of aqueous europium and sulfate ions from luminescence decay measurement

    International Nuclear Information System (INIS)

    The luminescence lifetime for Eu2(SO4)3 and EuCl3 in H2O and D2O has been measured at 0.01 and 0.001 mol dm-3 of Eu3+ and at various temperatures from 5 to 45 deg C. The average number of water molecules coordinated to Eu3+ ion, q, is evaluated from the difference of the luminescence decay constants in the H2O and D2O solutions. By using the q value of 8.3 for aquaeuropium(III) ion in EuCl3 solutions, q values for Eu2(SO4)3 solutions were determined as a function of concentration and temperature. The average number of water molecules released from the primary hydration sphere by the inner-sphere complexation between Eu3+ and SO42- ions is given as Δq = 8.3 - q, and Δq value increases with concentration and temperature. From the values of Δq and the known equilibrium constants on the overall complexation, it is revealed that for both the unis(sulfato) and bis(sulfato) complexation the ratio of innersphere complex to outer-sphere complex increases with temperature and that about one water molecule is released from the inner hydration sphere surrounding Eu3+ ion on the formation of an inner-sphere unis(sulfato) complex. The coordination state of the unis(sulfato) complex and the thermodynamic quantities for the equilibrium between outer- and inner-sphere complexes are discussed. (author)

  4. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

    Science.gov (United States)

    Shaker, Medhat A.; Yakout, Amr A.

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51 ± 3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  5. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO₂ nanoparticles from aqueous media.

    Science.gov (United States)

    Shaker, Medhat A; Yakout, Amr A

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, (1)H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r(2)) and non-linear Chi-square (χ(2)) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters. PMID:26520475

  6. Na3V2O2(PO4)2F-MWCNT nanocomposites as a stable and high rate cathode for aqueous and non-aqueous sodium-ion batteries

    Science.gov (United States)

    Kumar, P. Ramesh; Jung, Young Hwa; Wang, Ji Eun; Kim, Do Kyung

    2016-08-01

    NASICON-type structured Na3V2O2(PO4)2F nanocubes with multi-wall carbon nanotubes (MWCNTs) composite has been synthesized by ethylene glycol-assisted hydrothermal reaction and used as a rechargeable non-aqueous and aqueous sodium-ion battery cathode material. As a cathode material for non-aqueous sodium-ion batteries, as-synthesized Na3V2O2(PO4)2F-MWCNT composite shows stable capacity of 98 mAh g-1 at 0.1 C for 120 cycles and 60 mAh g-1 at 2 C for 1800 cycles in half-cell and full-cell configurations, respectively. In aqueous electrolytes, Na3V2O2(PO4)2F-MWCNT composite delivers discharge capacity of 35 mAh g-1 at 1 C rate in half-cell and 42 mAh g-1 at 1 C rate in full-cell with NaTi2(PO4)3-MWCNT as an anode. Stable cyclability and high rate performance of Na3V2O2(PO4)2F-MWCNT nanocomposite can be attributed to the very short sodium ion diffusion length in nano cube morphology of Na3V2O2(PO4)2F as well as the carbon nanotubes matrix which endows the unbreakable conductive networks for electrons and Na+ ions.

  7. Ion Exchange Testing with SRF Resin FY2012

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

    2013-06-11

    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.0 , which was prepared and approved in response to the Test Specification 24590 PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590 PTF TEF RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

  8. Durability of API class B cement pastes exposed to aqueous solutions containing chloride, sulphate and magnesium ions

    Directory of Open Access Journals (Sweden)

    Hernández, M. E.

    2008-12-01

    Full Text Available This paper discusses a durability study conducted on API class B cement, the type used in shallow oil wells, when exposed to aggressive formation water. Its resistance to the major ions, namely –SO4=, Mg+2 and Cl-–, is related both to its capacity to assimilate the aggressive action of each harmful agent and to the changes in the chemical reactivity of some of its components. The methodology used consisted in preparing and immersing cement specimens in neutral solutions containing variable concentrations of these ions to monitor the chemical reactions taking place. These solutions were analyzed and XRD studies were conducted for over a year to identify mineralogical variations. The purposes of the study were to determine the effects of joint ionic attack on this kind of cement and to monitor the variations in the calcium concentration in the aqueous solutions of Na2SO4, MgCl2 and NaCl in contact with API class B cement pastesEste trabajo se basa en el estudio de la durabilidad de un cemento API clase B, utilizado en pozos petrolíferos someros, frente a la agresividad de las aguas de formación a las que puede estar expuesto. Su eficacia frente a la exposición a los iones más importantes –SO4=, Mg+2 y Cl-– se relaciona con su capacidad de asimilar la acción agresiva de cada agente perjudicial, así como de las reacciones químicas que sufra por la reactividad de alguno de sus compuestos. La metodología aplicada supone la preparación de probetas de este cemento y su inmersión en disoluciones neutras, conteniendo los referidos iones a distintas concentraciones, para evaluar el desarrollo de las reacciones existentes en su seno. A tal fin se realizaron análisis de las disoluciones y estudios de DRX durante más de un año para conocer su evolución mineralógica. El objetivo del trabajo ha sido determinar los efectos resultantes de los ataques conjuntos de los citados iones al referido cemento; así como la observación de las

  9. COMPETITIVE BIOSORPTION OF LEAD (II IONS FROM AQUEOUS SOLUTIONS ONTO TERMINALIA CATAPPA L. LEAVES AS A COST EFFECTIVE BIOSORBENT

    Directory of Open Access Journals (Sweden)

    Jagruti N. Jadav

    2015-03-01

    successfully used for the competitive biosorption studies of Pb(II ions from aqueous solutions and can be applied in waste water technology for remediation of heavy metal contamination.

  10. Kinetics of ion flotation of Co(II)-EDTA complexes from aqueous solutions

    International Nuclear Information System (INIS)

    The flotation kinetics of Co(II)-EDTA complexes from aqueous solutions using cetylpyridinium chloride (CPyCl) is studied and discussed in the present work. The effects of many variables on the ultimate recovery and the flotation rate are investigated. The data obtained from solutions of different pH values showed that Co(II)-EDTA complexes are successfully floated at pH 7.8. While at pH 3.4 and 11.2, both the ultimate recovery and the flotation rate are dependent on the concentration of CPyCl. Flotation of Co(II)-EDTA at different air flow rates, CPyCl concentrations and ionic strength showed that the ultimate recovery and the flotation rate are markedly affected. The other parameters (cobalt, EDTA and ethanol concentrations) had no effect on the ultimate recovery, while significantly affected the flotation rate. At the optimum conditions (Co(II):EDTA = 1:1; CPyCl:Co(II) = 4:1; pH7.8; G = 25 cm3/min), removals more than 99% are achieved for radiocobalt. The classical first-order and the second-order kinetic models are used throughout the work to analyze the experimental kinetic data. At all the studied parameters, the kinetic data of Co(II)-EDTA complexes are better fitted to the classical first-order model.

  11. Kinetics of ion flotation of Co(II)-EDTA complexes from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, Mohamed A. [Atomic Energy Authority, Cairo (Egypt). Egypt Second Research Reactor; Rashad, Ghada M.; Mahmoud, Mamdoh R. [Atomic Energy Authority, Cairo (Egypt). Nuclear Chemistry Dept.

    2015-07-01

    The flotation kinetics of Co(II)-EDTA complexes from aqueous solutions using cetylpyridinium chloride (CPyCl) is studied and discussed in the present work. The effects of many variables on the ultimate recovery and the flotation rate are investigated. The data obtained from solutions of different pH values showed that Co(II)-EDTA complexes are successfully floated at pH 7.8. While at pH 3.4 and 11.2, both the ultimate recovery and the flotation rate are dependent on the concentration of CPyCl. Flotation of Co(II)-EDTA at different air flow rates, CPyCl concentrations and ionic strength showed that the ultimate recovery and the flotation rate are markedly affected. The other parameters (cobalt, EDTA and ethanol concentrations) had no effect on the ultimate recovery, while significantly affected the flotation rate. At the optimum conditions (Co(II):EDTA = 1:1; CPyCl:Co(II) = 4:1; pH7.8; G = 25 cm{sup 3}/min), removals more than 99% are achieved for radiocobalt. The classical first-order and the second-order kinetic models are used throughout the work to analyze the experimental kinetic data. At all the studied parameters, the kinetic data of Co(II)-EDTA complexes are better fitted to the classical first-order model.

  12. Speciation of Phytate Ion in Aqueous Solution. Trimethyltin(4) Interactions in Self Medium

    International Nuclear Information System (INIS)

    In this paper the results of a potentiometric (ISE-[H+] glass electrode) investigation at t = 25 0C on the complexing ability of phytate towards trimethyltin(4) (tmt) and on the acid-base properties of tmt at high metal concentration (0.050 and 0.075 mol L-1) are reported. First we determined the hydrolytic constants of tmt in aqueous solution without further addition of background salt (self medium); in these experimental conditions we verified the formation of the following hydrolytic species: tmt(OH)0, tmt(OH)2- and the binuclear species (tmt)2(OH)+. Successively, we studied the complex formation constants obtained from the interaction of phytate anion with tmt in the same experimental conditions of hydrolytic measurements; the speciation model obtained takes into account several polynuclear species (tmtH5Phy6-; tmt2H5Phy5-; tmt3H4Phy5-; tmt3H5Phy4-; tmt4H6Phy2-; tmt5HPhy6-). A comparison with literature data is reported too

  13. The Complexes of Bisphosphonate and Magnetite Nanoparticles to Remove Uranyl Ions from Aqueous Phase

    International Nuclear Information System (INIS)

    Using tetraethyl-3-amino-propane-1,1-bisphosphonate (BP) as the functional molecule, we functionalized Fe3O4 magnetic nanoparticles via dopamine (DA) linkage to create a system with an Fe3O4-DA-BP nanostructure, which possesses high specificity for removing uranyl ions from water or blood. This work demonstrates that magnetic nanoparticles, combined with specific receptor-ligand interactions, promise a sensitive and rapid platform for the detection, recovery, and decorporation of radioactive metal toxins from biological environment

  14. Use of Composite Sorbents for the Removal of Copper (II ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Rebecca Oyedoyin Adeeyo

    2014-12-01

    Full Text Available Composite adsorbents are synthesized from two or more materials with different chemical and physical properties in order to increase their selectivity and the reusability. Researchers have developed and applied several novel composite materials for enhancing the removal of heavy metal. In this review, extensive list of composites developed via advanced technologies with specified characteristics for the removal of Cu (II ion are discussed. Emphases on their adsorption capacities, reusability, desorption and regeneration with improved mechanical strengths are presented. Conclusively, prospects and other challenges to be checked and addressed in future are outlined.

  15. Use of Composite Sorbents for the Removal of Copper (II ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Rebecca Oyedoyin Adeeyo

    2015-01-01

    Full Text Available Composite adsorbents are synthesized from two or more materials with different chemical and physical properties in order to increase their selectivity and the reusability. Researchers have developed and applied several novel composite materials for enhancing the removal of heavy metal. In this review, extensive list of composites developed via advanced technologies with specified characteristics for the removal of Cu (II ion are discussed. Emphases on their adsorption capacities, reusability, desorption and regeneration with improved mechanical strengths are presented. Conclusively, prospects and other challenges to be checked and addressed in future are outlined.

  16. Laboratory testing of waste glass aqueous corrosion; effects of experimental parameters

    International Nuclear Information System (INIS)

    A literature survey has been performed to assess the effects of the temperature, glass surface area/leachate volume ratio, leachant composition, leachant flow rate, and glass composition (actual radioactive vs. simulated glass) used in laboratory tests on the measured glass reaction rate. The effects of these parameters must be accounted for in mechanistic models used to project glass durability over long times. Test parameters can also be utilized to highlight particular processes in laboratory tests. Waste glass corrosion results as water diffusion, ion-exchange, and hydrolysis reactions occur simultaneously to devitrify the glass and release soluble glass components into solution. The rates of these processes are interrelated by the affects of the solution chemistry and glass alteration phases on each process, and the dominant (fastest) process may change as the reaction progresses. Transport of components from the release sites into solution may also affect the observed corrosion rate. The reaction temperature will affect the rate of each process, while other parameters will affect the solution chemistry and which processes are observed during the test. The early stages of corrosion will be observed under test conditions which maintain dilute leachates and the later stages will be observed under conditions that generate more concentrated leachate solutions. Typically, water diffusion and ion-exchange reactions dominate the observed glass corrosion in dilute solutions while hydrolysis reactions dominant in more concentrated solutions. Which process(es) controls the long-term glass corrosion is not fully understood, and the long-term corrosion rate may be either transport- or reaction-limited

  17. Influence of bicarbonate and carbonate ions on sonochemical degradation of Rhodamine B in aqueous phase.

    Science.gov (United States)

    Merouani, Slimane; Hamdaoui, Oualid; Saoudi, Fethi; Chiha, Mahdi; Pétrier, Christian

    2010-03-15

    The influence of bicarbonate and carbonate ions on sonolytic degradation of cationic dye, Rhodamine B (RhB), in water was investigated. As a consequence of ultrasonic cavitation that generates .OH radicals, carbonate radicals were secondary products of water sonochemistry when it contains dissolved bicarbonate or carbonate ions. The results clearly demonstrated the significant intensification of sonolytic destruction of RhB in the presence of bicarbonate and carbonate, especially at lower dye concentrations. Degradation intensification occurs because carbonate radicals sonochemically formed undergo radical-radical recombination at a lesser extent than hydroxyl radicals. The generated carbonate radicals are likely able to migrate far from the cavitation bubbles towards the solution bulk and are suitable for degradation of an organic dye such as RhB. Therefore, at low dye concentrations, carbonate radical presents a more selective reactivity towards RhB molecules than hydroxyl radical. In the presence of bicarbonate, degradation rate reached a maximum at 3 g L(-1) bicarbonate, but subsequent addition retards the destruction process. In RhB solutions containing carbonate, the oxidation rate gradually increased with increasing carbonate concentration up to 10 g L(-1) and slightly decreased afterward. Carbonate radicals sonochemically generated are suitable for total removal of COD of sonicated RhB solutions. PMID:19910116

  18. Fluorescence sensitization of gold-glutathione nanoclusters by aqueous solutions of sodium and potassium ions

    International Nuclear Information System (INIS)

    Gold nanoclusters (Au-NCs) are powerful alternatives to commonly used dyes for use in fluorescent assays and in imaging. This is due to their high brightness and biocompatibility. Glutathione protected gold nanoclusters (Au-NCs-GSH) were used to investigate the effect of sodium and potassium ions (at 0.1 to 1 mM concentrations) on their fluorescence. It was found that addition of these alkali ions does not modify the emission wavelength of AuNCs-GSH, but fluorescence intensity undergoes a gradual increase (by ∼130 %) until a plateau is reached. Fluorescence is particularly enhanced by KSCN. The effect is interpreted in terms of a decrease in the band gap of the AuNCs-GSH that depends on the nature of the anion. The results illustrate the role of anions and monovalent cations commonly used in buffers with respect to the tuning of the fluorescence of AuNCs-GSH. The findings should be taken into account when using AuNCs-GSH in assays based on fluorescence enhancement or quenching. (author)

  19. Physicochemical characterization of the retardation of aqueous Cs+ ions by natural kaolinite and clinoptilolite minerals.

    Science.gov (United States)

    Shahwan, T; Akar, D; Eroğlu, A E

    2005-05-01

    The aim of this study was to carry out kinetic, thermodynamic, and surface characterization of the sorption of Cs+ ions on natural minerals of kaolinite and clinoptilolite. The results showed that sorption followed pseudo-second-order kinetics. The activation energies were 9.5 and 13.9 kJ/mol for Cs+ sorption on kaolinite and clinoptilolite, respectively. Experiments performed at four different initial concentrations of the ion revealed that the percentage sorption of Cs+ on clinoptilolite ranged from 90 to 95, compared to 28 to 40 for the kaolinite case. At the end of a 1 week period, the percentage of Cs+ desorption from clinoptilolite did not exceed 7%, while it amounted to more than 30% in kaolinite, indicating more stable fixation by clinoptilolite. The sorption data were best described using Freundlich and D-R isotherm models. Sorption showed spontaneous and exothermic behavior on both minerals, with deltaH(0) being -6.3 and -11.4 kJ/mol for Cs+ uptake by kaolinite and clinoptilolite, respectively. Expanding the kaolinite interlayer space from 0.71 to 1.12 nm using DMSO intercalation, did not yield a significant enhancement in the sorption capacity of kaolinite, indicating that the surface and edge sites of the clay are more energetically favored. EDS mapping and elemental analysis of the surface of kaolinite and clinoptilolite revealed more intense signals on the surface of the latter with an even distribution of sorbed Cs+ onto the surfaces of both minerals. PMID:15797389

  20. A new rhodamine B based fluorometric chemodosimeter for Cu2+ ion in aqueous and cellular media

    International Nuclear Information System (INIS)

    A simple, sensitive and selective fluorescent chemo dosimeter rhodamine B phenyl hydrazide (RBPH) for Cu2+ was proposed. This probe is non fluorescent and colorless but exhibits fluorescent enhancement at 580 nm and displayed color change from colorless to pink for Cu2+ in the pH range 1–6. Fluorescence microscope experimental results reveals that this chemo sensor is cell permeable and can be used for fluorescence imaging of Cu2+ ions in living cells. This probe can detect Cu2+ with good linear relationships from 10 to 100 nM with r=0.99971 then limit of detection was found to be 0.015 nM with ±0.91% RSD at 10 nM concentrations. -- Highlights: • The new sensitive, highly selective fluorescent chemodosimeter for Cu2+ based on spirolactam ring opening process has been proposed. • The probe posse’s excellent cell permeability and it has been applied for fluorescence imaging of Cu2+ ions in MCF-7 cell lines. • The protocol has been successfully applied for copper determination in blood and urine samples

  1. Sorption of plutonium and curium on ion exchange resins in mixed aqueous organic solutions

    International Nuclear Information System (INIS)

    The sorption of the sulfate and nitrate-complexes of the actinides Pu(III), Pu(IV), Pu(VI), Am(III) and Om(III) on the ion-exchange-resins Dowex 1X8 and Dowex 50 WX8 is investigated. The strong sorbability of these actinide ions in solvents with high content of alcohol is explained by the existence of anionic complexes like Pu(III) (SO4)2-, Pu(IV) (SO4)32-, Pu(VI)O2(SO4)22-, Am(SO4)2- respectively Am(NO3)4- and Om(NO3)4-. The taking of autoradiographs from the thin-layer chromatograms by the aid of a special device and the evaluation of the autoradiographs by a particular photodensitometer are described. The measurement of the radioactivity of the α-emitting nuclides Pu 239, Am 241 and Om 242 are done by liquid-scintillation spectrometry. (author)

  2. Removal of radiocobalt ions from aqueous solutions by natural halloysite nanotubes

    International Nuclear Information System (INIS)

    In this study, natural halloysite nanotubes (HNTs) were applied to remove radiocobalt from wastewaters under various environmental parameters such as contact time, pH, ionic strength, foreign ions and temperature by using batch technique. The results indicated that the sorption of Co(II) on HNTs was dependent on ionic strength at pH 8.5. Langmuir and Freundlich models were applied to simulate the sorption isotherms of Co(II) at three different temperatures of 293, 313 and 333 K. Langmuir model fitted the sorption isotherms of Co(II) on HNTs better than Freundlich model. The thermodynamic parameters (ΔG0, ΔS0 and ΔH0) calculated from the temperature-dependent sorption isotherms manifested that the sorption of Co(II) on HNTs was an endothermic and spontaneous process. The sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange at low pH, whereas inner-sphere surface complexation or precipitation was the main sorption mechanism at high pH. The experimental results show that HNTs have good potentialities for cost-effective disposal of cobalt-bearing wastewaters. (author)

  3. Drastic nickel ion removal from aqueous solution by curcumin-capped Ag nanoparticles

    Science.gov (United States)

    Bettini, S.; Pagano, R.; Valli, L.; Giancane, G.

    2014-08-01

    A completely green synthesis protocol has been adopted to obtain silver nanoaggregates capped by the natural compound (1E, 6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-diene), also known as curcumin. The synthesis has been monitored by infrared, Raman, visible and fluorescence spectroscopies. Characterization confirms that curcumin reduces and caps the nanoparticles, and such a procedure allows its solubility in water and drastically increases curcumin stability. Silver nanoparticles (AgNPs)/curcumin complex has been dispersed in a water solution containing a known nickel ion concentration. After three days, a grey precipitate is observed and nickel concentration in the solution is reduced by about 70%.A completely green synthesis protocol has been adopted to obtain silver nanoaggregates capped by the natural compound (1E, 6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-diene), also known as curcumin. The synthesis has been monitored by infrared, Raman, visible and fluorescence spectroscopies. Characterization confirms that curcumin reduces and caps the nanoparticles, and such a procedure allows its solubility in water and drastically increases curcumin stability. Silver nanoparticles (AgNPs)/curcumin complex has been dispersed in a water solution containing a known nickel ion concentration. After three days, a grey precipitate is observed and nickel concentration in the solution is reduced by about 70%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02583k

  4. Removal of lead and cadmium ions from aqueous solution by adsorption onto micro-particles of dry plants.

    Science.gov (United States)

    Benhima, H; Chiban, M; Sinan, F; Seta, P; Persin, M

    2008-01-15

    In the present work, Pb(II) and Cd(II) ion adsorption onto inert organic matter (IOM) obtained from ground dried plants: Euphorbia echinus, Launea arborescens, Senecio anthophorbium growing in semi-arid zones of Morocco and Carpobrotus edulis as the Mediterranean plant has been studied. A suspension of plant deroed micro-particles adsorbs lead and cadmium present as ionic species, with a higher affinity for Pb(II). The kinetics and the maximum capacity adsorption depend on the type of plant as well as on the metal ions (atomic weight, ionic radius and electronegativity). The adsorption process is affected by various parameters such as contact time, solution volume to mass of plant particles ratio (m/V), particle size, solution pH and metal concentration. A dose of 25 g/l of adsorbent was optimal to obtain maximum adsorption of both metal ions. The maximum metal uptake was obtained with particles of organic matter of E. echinus>S. anthophorbium>L. arborescens, however, the differences are rather small. Two different waste water types (domestic and industrial) were tested and good results were obtained for removal of Pb(II) and Cd(II) at more than 90%. The removal of the metal and mineral ions waste water was observed for PO(4)(3-) at 88%, for NO(3)(-) at 96.5% and for metal ions (Pb(II), Cd(II), Cu(II) and Zn(II)) at about 100%, using IOM as absorbent. PMID:17869071

  5. Effect of curcumin and Cu 2+/Zn 2+ ions on the fibrillar aggregates formed by the amyloid peptide and other peptides at the organic-aqueous interface

    Science.gov (United States)

    Sanghamitra, Nusrat J. M.; Varghese, Neenu; Rao, C. N. R.

    2010-08-01

    Characteristic features of a perilous neuro-degenerative disease such as the Alzhiemer's disease is fibrillar plaque formation by the amyloid (Aβ) peptide. We have modelled the formation and disintegration of fibrils by studying the aggregate structures formed by Aβ structural motif diphenylalanine as well as insulin and bovine serum albumin at the organic-aqueous interface. Even small concentrations of curcumin in the organic medium or Cu 2+ and Zn 2+ ions in the aqueous medium are found to break down the fibrillar structures.

  6. chemical studies on the extraction of certain metal ions from aqueous solution by liquid emulsion membrane

    International Nuclear Information System (INIS)

    In this thesis four systems are addressed related to the use of liquid emulsion membranes (ELM) based on Co(III)dicarbiolide and. The system was dedicated for permeation of cadmium , cobalt Nickel and lead for use of this system for preconcentration and separation of cadmium, cobalt, nickel and lead. The work carried out in this thesis is presented in three parts, namely; introduction, experimental and results and discussion.The first chapter is the introduction which includes aim of work, basic concepts of liquid membranes; liquid emulsion membranes; different models of emulsion permeation, literature survey of extraction chemistry of cadmium, cobalt, nickel and lead. Chapter two includes the experimental part. In this part detailed outlines on the chemicals and different elements used were given. Different instruments as well as analytical techniques were outlines. The preparation of liquid emulsion membrane and the permeation techniques were presented in details. The third chapter deals with the results and discussion. This chapter is divided into four main parts, the four parts is concerned with cadmium/Co(III) dicarbolide/NTA, EDTA, DPTA and DCTA systems. In this part the permeation of Cd(II) aqueous solution by the membrane used was experimented based on liquid-liquid extraction studies of cadmium from different sodium chloride molarities (from 0.01 to 0.1 M) by 0.01 M Cobalt(III) dicarbolides. It was found that the extraction of with cadmium is higher following in the first system, the permeation of the toxic elements, Cd(II) from HCl/sodium chloride medium was carried out using liquid emulsion membrane containing Co(III)dicarbiolide in xylene as carrier, Spain 80/ Spain 85(1:3) as surfactant and NTA, EDTA, DPTA and DCTA as a stripping solutions.

  7. Beam test of compact ECR ion source for carbon therapy

    International Nuclear Information System (INIS)

    Ion source for medical facilities should have characteristics of easy maintenance, low electric power, good stability and long operation time without maintenance (one year or more). Based on the proto type compact source, a 10 GHz compact ECR ion source with all permanent magnets has been developed. Peaks of the mirror magnetic field along the beam axis are 0.59 T at the extraction side and 0.87 T at the gas injection side, respectively, while the minimum B strength is 0.25 T. The source has a diameter of 320 mm and a length of 295 mm. The result of beam tests shows that a C4+ intensity of 530 μA was obtained under an extraction voltage of 45 kV. This paper describes the design detail and the experimental results for the new source. (author)

  8. Testing double ionization mechanisms with highly-charged ions

    International Nuclear Information System (INIS)

    Double ionization of He target atoms by intermediate- to high-velocity charged ions is considered in terms of two mechanisms: (1) a two-step (TS) process in which both target electrons are removed in separate direct interactions with the projectile, and (2) a one-step mechanism in which one electron is liberated in a single projectile-target interaction followed by subsequent ''shakeoff'' (SO) of the second electron. Measured double-to-single ionization ratios are used to exhibit and test the underlying mechanisms of double ionization. It is found that these ratios exhibit a high degree of universality as a function of v/q, where v is the velocity of the ion and q is its charge. The results strongly suggest that the important factor in determining the regions of validity for TS and SO is the ionic charge divided by the impact velocity and not just the impact velocity itself

  9. Equilibrium, thermodynamic and kinetic studies for the biosorption of aqueous lead(II), cadmium(II) and nickel(II) ions on Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Seker, Ayseguel [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: aysegulseker@iyte.edu.tr; Shahwan, Talal [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: talalshahwan@iyte.edu.tr; Eroglu, Ahmet E. [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: ahmeteroglu@iyte.edu.tr; Yilmaz, Sinan [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: sinanyilmaz@iyte.edu.tr; Demirel, Zeliha [Department of Biology, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: zelihademirel@gmail.com; Dalay, Meltem Conk [Department of Bioengineering, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: meltemconkdalay@gmail.com

    2008-06-15

    The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as {delta}G{sup o}, {delta}H{sup o}and {delta}S{sup o} calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb{sup 2+} ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.

  10. Kinetics of oxidation of uranium(IV) by permanganate ion in aqueous perchlorate media

    International Nuclear Information System (INIS)

    The kinetics of oxidation of uranium(IV) by permanganate ion in 1.0 mol dm-3 perchloric acid solution has been investigated using a stopped-flow spectrophotometer. The reaction was found to be second order overall and first order in the concentrations of both reactants. The catalytic effect of the perchlorates of Hg2+, Cu2+, and Fe3+ on the reaction rate has been investigated. The activation parameters were evaluated and found to be ΔS not= 30.52 ± 1.22 kJ-1 mol-1, ΔH not= 62.89 ± 1.87 kJ mol-1, and ΔG not=53.79 ± 1.44 kJ mol-1. A tentative mechanism consistent with the kinetics is discussed. (author)

  11. Removal of Cadmium(II and Lead(II ions from aqueous phase on sodic bentonite

    Directory of Open Access Journals (Sweden)

    Luz Stella Gaona Galindo

    2013-04-01

    Full Text Available This paper describes the adsorption of Cd2+and Pb2+ions using sodic bentonite clay type Fluidgel modified. The Fluidgelbefore and after chemical modification and thermal activation was characterized by different techniques including X-ray diffraction, thermal analysis, Fourier transform infrared, surface area, helium pycnometry, cation exchange capacity and scanning electron microscopy. Pseudo-first order, pseudo-second order and intra-particle diffusion models were used to analyze the kinetic curves. Equilibrium data were analyzed using Langmuir and Freundlich models. The thermodynamic study indicated that lead adsorption process is endothermic and interactions between clays and solutions of lead occurred spontaneously, while cadmium adsorption revealed an exothermic and spontaneous nature. The maximum removal efficiencies were 97.62% for Cd(II using Fluidgelmodified chemically and 91.08% for lead by Fluidgel modified chemical and thermally.

  12. Removal of Zinc Ions from Aqueous Solution Using Polyaniline Nanocomposite Coated on Rice Husk

    Directory of Open Access Journals (Sweden)

    M. Ghorbani

    2012-01-01

    Full Text Available In this research, the preparation of polyaniline (PAn/ rice husk nanocomposite as adsorbent was discussed and the capability of adsorbing zinc is studied. The polyaniline nanocomposite was prepared in presence of KIO3 as an oxidant, coated on rice husk ash via casting method. The morphology and chemical structure of absorbent evaluated by with scanning electron microscopy (SEM and Fourier-transform infrared spectroscopy (FTIR, respectively. Batch studies were performed to evaluate the influence of various experimental parameters such as pH, adsorbent dosage and contact time. Optimum conditions for zinc removal were found to be pH 3, adsorbent dosage of 10 g/L and equilibrium time of 20 minutes. The equilibrium adsorption isotherm was better described by Langmuir adsorption isotherm model. The adsorption capacity (qmax of PAn/RH for zinc ions in terms of monolayer adsorption was 24.3 mg/g.

  13. Biosorption of Divalent ion onto Treated Prosopis juliflora Bark from Aqueous Solutions - Isothermal and Statistical Analysis

    Directory of Open Access Journals (Sweden)

    N. Muthulakshmi Andal

    2016-05-01

    Full Text Available The present work emphasizes the utilization of Prosopis juliflora bark, an agro waste material for the adsorption of Cu(II. The raw Prosopis juliflora bark (PJB is treated using 0.1N hydrochloric acid to enhance the sorption efficiency. The characterization studies of TPJB using Scanning Electron Microscopy (SEM, Energy Dispersive X-ray Analysis (EDAX, Brunauer-Emmet-Teller(BET and Barrett-Joyner-Halenda (BJH analyses carried out. The batch mode experimental set up is verified to assess the sorption capacity of the chosen material for the operating factors viz., particle sizes/ doses of the sorbent material upon a range of initial concentrations of Cu(II at different temperatures, agitation time and pH of the Cu(II- TPJB system. The amount of Cu(II ion adsorbed on to TPJB surface is found to be 43.11 mg/g (97.4% under optimized conditions, its efficiency 3 fold times more than the Ce values reported by other researchers. The sorption characteristic of TPJB is quantitatively estimated through column experiments based on the Ce value by batch mode. The removal is observed as 98%. Langmuir, Freundlich and Tempkin isothermal curves at various initial concentrations are plotted for Cu(II-TPJB system wherein the straight line fit is best suited for the Freundlich isotherm model. The results show that the response of TPJB in trapping Cu(II ions are influenced by various parameters being statistically verified using SPSS software, indicative of good correlation.

  14. Sequestering of thorium ions from aqueous media on rice husk. Equilibrium, kinetic and thermodynamic studies

    International Nuclear Information System (INIS)

    The adsorption behaviour of thorium on rice husk has been studied by optimizing different parameters like nature of electrolyte, amount of adsorbent, equilibration time, metal concentration, and temperature, employing batch method and radiotracer technique. Maximum adsorption was observed at 0.0001 mol L-1 HNO3, using 0.1 g of adsorbent for 4 cm3 of 5.19 x 10-5 mol L-1 of Th+4 solution in fifteen minutes equilibration time. The adsorption phenomenon was verified by FTIR, SEM and EDX techniques. The adsorption data was well fitted to Freundlich, Langmuir and Dubinin-Radushkevich isotherm equations. The characteristic Freundlich constants i.e. 1/n = 0.528 ± 0.019 and K = 4.88 x 10-4 ± 1.29 x 10-5 mol g-1 whereas the Langmuir constants Qm = (4.159 ± 0.234) x 10-6 mol g-1 and KL = (3.627 ± 0.328) x 104 dm3 mol-1 have been computed for the sorption system. The sorption free energy was found to be 11.24 ± 0.211 kJ mol-1 showing chemisorption nature of interaction between thorium and rice husk. The results showed that thorium adsorption on rice husk follows pseudo 2nd order with rate constant = 1.448 g mg-1 min-1. The determined negative values of ΔG indicated spontaneity of the process, whereas the positive values of ΔH and ΔS confirmed endothermic nature and increased randomness during the adsorption process respectively. The removal of Th+4 ions from spiked tap water was checked by employing the optimized experimental parameters which indicated that rice husk is a good adsorbent for thorium ions and may be used for waste management of radionuclides.

  15. Carbon ion and high intensity acceleration test of TIT heavy ion RFQ linac

    International Nuclear Information System (INIS)

    The RFQ Linac at Tokyo Institute of Technology (TIT-RFQ) was constructed and acceleration test of ion beams 4He+ and 12C2+ was performed. The linac was designed to accelerate particles with charge to mass ratio(q/A) of 1-1/16 injected at 5 keV/u up to 214 keV/u. As the result of acceleration test, beam transmission was 89% for a low beam current. It is nearly design data 91% and the acceleration characteristic agrees well with a computer simulation. (author)

  16. The use of new modified poly(acrylamide chelating resin with pendent benzothiazole groups containing donor atoms in the removal of heavy metal ions from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Semmedu Selvaraj Kalaivani

    2014-03-01

    Full Text Available The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide (PEBTA, for Cu(II and Zn(II metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II and Zn(II ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II and Zn(II ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II and Zn(II ions can be easily removed. The adsorption–desorption process is reversible, and this indicates that PEBTA is an effective adsorbent for the removal of heavy metal ions from an aqueous medium.

  17. Metaldehyde removal from aqueous solution by adsorption and ion exchange mechanisms onto activated carbon and polymeric sorbents

    International Nuclear Information System (INIS)

    Highlights: ► First detailed analysis and study on metaldehyde removal by physical adsorbents. ► Adsorption performance of current method studied to probe reasons for failure of removal. ► Sorption performances of proposed alternative materials studied and mechanism proposed. ► Mechanism explains full sorption and degradation of metaldehyde. ► Results are of marked significance to the water treatment industries. -- Abstract: Metaldehyde removal from aqueous solution was evaluated using granular activated carbon (GAC), a non-functionalised hyper-cross-linked polymer Macronet (MN200) and an ion-exchange resin (S957) with sulfonic and phosphonic functional groups. Equilibrium experimental data were successfully described by Freundlich isotherm models. The maximum adsorption capacity of S957 (7.5 g metaldehyde/g S957) exceeded those of MN200 and GAC. Thermodynamic studies showed that sorption of metaldehyde onto all sorbents is endothermic and processes are controlled by entropic rather than enthalpic changes. Kinetic experiments demonstrated that experimental data for MN200 and GAC obey pseudo-second order models with rates limited by particle diffusion. Comparatively, S957 was shown to obey a pseudo-first order model with a rate-limiting step of metaldehyde diffusion through the solid/liquid interface. Results obtained suggest that metaldehyde adsorption onto MN200 and GAC are driven by hydrophobic interactions and hydrogen bonding, as leaching tendencies were high since no degradation of metaldehyde occurred. Conversely, adsorption of metaldehyde onto S957 occurs via ion-exchange processes, where sulfonic and phosphonic functionalities degrade adsorbed metaldehyde molecules and failure to detect metaldehyde in leaching studies for S957 supports this theory. Consequently, the high adsorption capacity and absence of leaching indicate S957 is promising for metaldehyde removal from source water

  18. Hydration of the trivalent lanthanide ion 152Eu (III) in aqueous solutions at 298 K and similarity with the trivalent transplutonium element ion 241Am (III)

    International Nuclear Information System (INIS)

    Ionic self-diffusion coefficients data for 152Eu (III) and 241Am (III) are reported for concentrations of a supporting electrolyte of Gd(NO3)3-HNO3 or Nd(ClO4)3-HClO4 aqueous solutions up to 1.14 mol.L-1 at 2 C. The open-end capillary method (O.E.C.M.) is used for the determination of the ionic self-diffusion coefficients at pH = 2.50 labelled with tracers 152Eu (III) and 241Am (III). The fitting in polynomial forms of the experimental self-diffusion coefficients versus the square root of the ionic strength : - permits a comparison between the limiting diffusion coefficient value against the square root of the ionic strength and the limiting coefficients at infinite dilute solutions taken from conductimetric measurements in the literature using the Nernst-Einstein expression. - shows that the variation of D versus the square root of supporting electrolyte concentration is not linear in dilute solution. The divergence to the Onsager limiting law starts from 10-3 M and we aim to extend the validity range up to 0.2 M or more, by proposition of semi-empirical model with one adjustable parameter b. A study of Walden's law behaviour at variable concentrations can provide an interesting discussion for an eventual expression if the parameter b. The similarity in the ionic transport process (4f and 5f elements) leads us to conclude as a further consequence, it may be argued that of 152Eu (III) and 241Am (III) ions have the same hydration as a tripositive ion (with a comparable ionic radius) in the absence of hydrolysis, association and complexing (by choice of an acidic medium at pH 2.50)

  19. Three-dimensional printed knotted reactors enabling highly sensitive differentiation of silver nanoparticles and ions in aqueous environmental samples.

    Science.gov (United States)

    Su, Cheng-Kuan; Hsieh, Meng-Hsuan; Sun, Yuh-Chang

    2016-03-31

    Whether silver nanoparticles (AgNPs) persist or release silver ions (Ag(+)) when discharged into a natural environment has remained an unresolved issue. In this study, we employed a low-cost stereolithographic three-dimensional printing (3DP) technology to fabricate the angle-defined knotted reactors (KRs) to construct a simple differentiation scheme for quantitative assessment of Ag(+) ions and AgNPs in municipal wastewater samples. We chose xanthan/phosphate-buffered saline as a dispersion medium for in situ stabilization of the two silver species, while also facilitating their extraction from complicated wastewater matrices. After method optimization, we measured extraction efficiencies of 54.5 and 32.3% for retaining Ag(+) ions and AgNPs, respectively, in the printed KR (768-turn), with detection limits (DLs) of 0.86 and 0.52 ng L(-1) when determining Ag(+) ions and AgNPs, respectively (sample run at pH 11 without a rinse solution), and 0.86 ng L(-1) when determining Ag(+) ions alone (sample run at pH 12 with a 1.5-mL rinse solution). The proposed scheme is tolerant of the wastewater matrix and provides more reliable differentiation between Ag(+)/AgNPs than does a conventional filtration method. The concept and applicability of adopting 3DP technology to renew traditional KR devices were evidently proven by means of these significantly improved analytical performance. Our analytical data suggested that the concentrations of Ag(+) ions and AgNPs in the tested industrial wastewater sample were both higher than those in domestic wastewater, implying that industrial activity might be a main source of environmental silver species, rather than domestic discharge from AgNP-containing products. PMID:26965333

  20. Thermal Development Test of the NEXT PM1 Ion Engine

    Science.gov (United States)

    Anderson, John R.; Snyder, John S.; VanNoord, Jonathan L.; Soulas, George C.

    2010-01-01

    NASA's Evolutionary Xenon Thruster (NEXT) is a next-generation high-power ion propulsion system under development by NASA as a part of the In-Space Propulsion Technology Program. NEXT is designed for use on robotic exploration missions of the solar system using solar electric power. Potential mission destinations that could benefit from a NEXT Solar Electric Propulsion (SEP) system include inner planets, small bodies, and outer planets and their moons. This range of robotic exploration missions generally calls for ion propulsion systems with deep throttling capability and system input power ranging from 0.6 to 25 kW, as referenced to solar array output at 1 Astronomical Unit (AU). Thermal development testing of the NEXT prototype model 1 (PM1) was conducted at JPL to assist in developing and validating a thruster thermal model and assessing the thermal design margins. NEXT PM1 performance prior to, during and subsequent to thermal testing are presented. Test results are compared to the predicted hot and cold environments expected missions and the functionality of the thruster for these missions is discussed.

  1. Sequestering of thorium ions from aqueous media on rice husk. Equilibrium, kinetic and thermodynamic studies

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, Shagufta; Mirza, Muhammad Latif [The Islamia University of Bahawalpur (Pakistan). Dept. of Chemistry; Khalid, Nasir [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2015-07-01

    The adsorption behaviour of thorium on rice husk has been studied by optimizing different parameters like nature of electrolyte, amount of adsorbent, equilibration time, metal concentration, and temperature, employing batch method and radiotracer technique. Maximum adsorption was observed at 0.0001 mol L{sup -1} HNO{sub 3}, using 0.1 g of adsorbent for 4 cm{sup 3} of 5.19 x 10{sup -5} mol L{sup -1} of Th{sup +4} solution in fifteen minutes equilibration time. The adsorption phenomenon was verified by FTIR, SEM and EDX techniques. The adsorption data was well fitted to Freundlich, Langmuir and Dubinin-Radushkevich isotherm equations. The characteristic Freundlich constants i.e. 1/n = 0.528 ± 0.019 and K = 4.88 x 10{sup -4} ± 1.29 x 10{sup -5} mol g{sup -1} whereas the Langmuir constants Q{sub m} = (4.159 ± 0.234) x 10{sup -6} mol g{sup -1} and K{sub L} = (3.627 ± 0.328) x 10{sup 4} dm{sup 3} mol{sup -1} have been computed for the sorption system. The sorption free energy was found to be 11.24 ± 0.211 kJ mol{sup -1} showing chemisorption nature of interaction between thorium and rice husk. The results showed that thorium adsorption on rice husk follows pseudo 2{sup nd} order with rate constant = 1.448 g mg{sup -1} min{sup -1}. The determined negative values of ΔG indicated spontaneity of the process, whereas the positive values of ΔH and ΔS confirmed endothermic nature and increased randomness during the adsorption process respectively. The removal of Th{sup +4} ions from spiked tap water was checked by employing the optimized experimental parameters which indicated that rice husk is a good adsorbent for thorium ions and may be used for waste management of radionuclides.

  2. Pengaruh Temperatur Hydrothermal Terhadap Performa Elektrokimia Lifepo4 Sebagai Katoda Baterai Ion Lithium Type Aqueous Elektrolit

    Directory of Open Access Journals (Sweden)

    Hendro Waluyo

    2014-09-01

    Full Text Available Katoda yang biasa digunakan produsen baterai lithium saat ini adalah LiCoO2. Dimana LiCoO2 memilki beberapa kekurangan beracun, tidak stabil, dan harganya mahal. Bahan katoda yang sangat menjanjikan adalah lithium iron phosphate (LiFePO4 untuk bisa menggantikan LiCoO2 .Dalam proses sintesis katoda LiFePO4 pada penelitian ini menggunakan metode hydrothermal dengan variasi temperatur 1500C,1750C dan 2000C selama 12 jam untuk waktu holdingnya. Dari hasil pengujian XRD menunjukkan terbentuknya fase LiFePO4 pada semua sampel, namun masih ditemukan zat pengotor. Untuk hasil uji SEM, serbuk LiFePO4 memiliki bentuk bulat tidak beraturan dan terjadi aglomerasi. Serbuk LiFePO4 dengan variasi temperatur 2000C memiliki performance yang paling baik dengan nilai kapasitas sebesar 109.32 mA/g hal ini karena dari hasil CV menunjukkan kinetik tranfer ion Lithium yang baik akibat distribusi ukuran partikel yang merata dan juga tingkat kristanilitas yang tinggi.

  3. The effect of salinity on the sorption of cadmium ions from aqueous medium on Fe(III-sepiolite

    Directory of Open Access Journals (Sweden)

    Habish Amal Juma

    2015-01-01

    Full Text Available In this study, the sorption of cadmium ions onto sepiolite modified with hydrated iron(III oxide, Fe(III-sepiolite, has been investigated in natural seawater, artificial seawater, aqueous solution of NaCl of the same ionic strength as the seawater and distilled water. The sorption experiments were performed as a function of the initial solution pH value, the initial metal concentration and the equilibration time, using the batch method. The equilibrium sorption data were analyzed by the Langmuir, Freundlich and Sips isotherm models and the kinetics of sorption was analyzed using the pseudo-first-order and the pseudo-second-order kinetic models. The maximum sorption capacity and the strength of the sorbate-sorbent bonds at initial pH = 7 were found to decrease in the following order: distilled water > NaCl solution > artificial seawater > natural seawater. The values of parameter nS in the Sips model, which fitted the equilibrium sorption results best, showed that heterogeneity of the sorbent surface was the highest in distilled water and the lowest in natural seawater. The sorption kinetic data fitted well with the pseudo-second-order kinetic model, which suggests that the rate-limiting step in Cd2+ sorption onto Fe(III-sepiolite could be chemisorption. The low desorption percentage in both distilled water and 0.001 M HNO3 indicated that sorption occurred mainly by chemisorption mechanisms. [Projekat Ministarstva nauke republike srbije, br. III 45019

  4. Thermodynamic studies on the interaction between some amino acids with some rare earth metal ions in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, AbdAllah A.; Bakr, Moustafa F.; Abd El-Fattah, Khaled A

    2003-11-06

    The interactions between the amino acids (glycine and L-threonine) with some rare earth metal ions (Pr{sup 3+}, Nd{sup 3+}, Eu{sup 3+}, Gd{sup 3+}, Dy{sup 3+}, Ho{sup 3+} and Yb{sup 3+}) were studied at a wide range from ionic strengths (0.07-0.32 M KNO{sub 3}) and temperatures (25-45 deg. C) in aqueous solutions by using Bjerrum potentiometric method. The stoichiometric and thermodynamic stability constants were calculated as well as the standard thermodynamic parameters ({delta}G deg., {delta}H deg. and {delta}S deg. ) for all possible reactions that occur. The degree of formation (n-bar) for all studied systems was determined and discussed. The thermodynamic parameters differences ({delta}{delta}G deg., {delta}{delta}H deg. and {delta}{delta}S deg. ) were calculated and discussed to determine the factors which control these complexation processes from the thermodynamic point of view.

  5. Simultaneous removal of acid green 25 and mercury ions from aqueous solutions using glutamine modified chitosan magnetic composite microspheres.

    Science.gov (United States)

    Tao, Xue; Li, Kun; Yan, Han; Yang, Hu; Li, Aimin

    2016-02-01

    In this current work, the magnetic composite microsphere containing glutamine modified chitosan and silica coated Fe3O4 nanoparticles (CS-Gln-MCM) has been successfully prepared and extensively characterized, which is a kind of biodegradable materials. CS-Gln-MCM shows enhanced removal efficiency for both acid green 25 (AG25), an amphoteric dye, and mercury ions (Hg(2+)) from water in the respective while measured pH range compared with chitosan magnetic composite microsphere (CS-MCM) without modification. It is due to the fact that the grafted amino acid provides a variety of additional adsorption active sites and diverse adsorption mechanisms are involved. In AG25 and Hg(2+) aqueous mixture, the modified adsorbents bear preferential adsorption for AG25 over Hg(2+) in strong acidic solutions ascribed to multiple interactions between AG25 and CS-Gln-MCM, such as hydrogen bonding and electrostatic interactions. While, in weak acidic conditions, an efficient simultaneous removal is observed for different adsorption effects involved in aforementioned two pollutants. Besides, CS-Gln-MCM illuminates not only short equilibrium time for adsorption of each pollutant less than 20.0 min but also rapid magnetic separation from water and efficient regeneration after saturated adsorption. Therefore, CS-Gln-MCM bears great application potentials in water treatment. PMID:26618263

  6. Biosorption kinetic studies of heavy metal ions from aqueous solution by a mixture of vegetable waste (abstract)

    International Nuclear Information System (INIS)

    Biosorption potential of a new bio sorbent prepared from vegetable waste composed of mixture of potato and carrot peels for the removal of heavy metals such as Ni (II) and Cu (II) from aqueous solution was determined. Batch experiments were conducted to optimize parameters i.e. initial pH, temperature, contact time, initial metal concentration and bio sorbent dose and it was observed that maximum adsorption of nickel (78%) was achieved by stirring the contents for 75 min at pH 4 and 35 deg. C by using 3.0 g of bio sorbent while in the case of copper maximum removal of copper occurred at pH 2, temperature of 50 deg. C, contact time of 45 minutes, metal concentration of 30 ppm and bio sorbent dose of 2.5 g. Kinetic studies of these reactions showed that they follow a pseudo-second order reaction, while these systems fit well in the Langmuir isotherm model and Freundlich isotherm model for Ni (II) and Cu (II) ions respectively. Both neat and metal loaded bio sorbent samples were analyzed using FT-IR spectrophotometer and X-Ray Florescence spectrometer in order to confirm the bio sorption of Ni (II) and Cu (II) and results have revealed that the metals are present in the spent bio sorbent. (author)

  7. The removal of phosphate ions from aqueous solution by fly ash, slag, ordinary Portland cement and related blends

    Energy Technology Data Exchange (ETDEWEB)

    N.M. Agyei; C.A. Strydom; J.H. Potgieter [University of Venda, Thohoyandou (South Africa). Department of Chemistry

    2002-12-01

    Phosphate ions have been removed from aqueous solution by fly ash, slag, ordinary Portland cement (OPC) and related cement blends. The rate and efficiency of PO{sub 4}{sup 3-} removal were found to increase in the order: fly ash, slag, OPC, apparently mimicking the order of increasing percent CaO in the adsorbents. Blending OPC with fly ash or slag evidently results in diminished PO{sub 4}{sup 3-} removal efficiency. Better removal was obtained at higher solute concentration, acidic pH and higher temperature. The effect of particle size and the speed of mixing were found not to be significant. A first-order kinetic model was used to obtain values for overall sorption rate constants and intraparticle diffusion constants. The Frumkin isotherm was found to be the appropriate equation for modelling isotherms from the experimental adsorption data, and values have been obtained for the isotherm constants. A 400-mg/l PO{sub 4}{sup 3-} (as P) solution was fed at a steady velocity of 2.0 cm/min through a 2.0-cm fixed-bed column (at pH 9.0 and 25{sup o}C), and breakthrough curves were constructed to obtain estimated adsorption capacity values of 32, 60, 75, 78 and 83 mg PO{sub 4}{sup 3-}/g adsorbent for fly ash, slag, OPC+fly ash, OPC+slag and OPC, respectively.

  8. Retention behavior of nickel, copper, cadmium and zinc ions from aqueous solutions on silico-titanate and silico-antimonate used as inorganic ion exchange materials

    International Nuclear Information System (INIS)

    Silico-titanate (SiTi) and silico-antimonate (SiSb) have been synthesized and characterized using X-ray diffraction patterns, infrared and thermal analysis techniques. Divalent cations such as Ni2+, Cd2+, Zn2+ and Cu2+ in the pH range 2 to 8 have been exchanged with the exchangeable active sites of the exchangers using a batch technique. From the results obtained, the equilibrium capacities and distribution coefficient values were calculated indicating high selectivity values for Ni2+, Cd2+, Zn2+ and Cu2+ ions on silico-titanate and silico-antimonate compared to other titanates and antimonates. Also SiTi and SiSb show high chemical stability in H2O, nitric and hydrochloric acids. All these results support the suitability of the prepared materials for the removal of the toxic metals concerned from waste waters. Based on the results obtained, practical separation experiments for the above mentioned cations on SiTi and SiSb columns from aqueous waste solutions were carried out. (author)

  9. Results of formate ion additive tests at EPRI's High Sulfur Test Center

    International Nuclear Information System (INIS)

    This paper presents the results of a two-part test program conducted on the 0.4-MWe mini-pilot wet limestone FGD system at the Electric Power Research Institute's (EPRI) High Sulfur Test Center (HSTC). The primary objectives of the tests were to evaluate the effects of the formate ion on FGD system operation and performance and to measure the formate consumption rates for a variety of operating conditions. Tests were run under natural-, inhibited-, and forced-oxidation conditions. Results are presented which show how system performance varied with formate ion concentrations up to 4500 ppm. Other independent test variables included recycle slurry pH, process liquor chemistry, limestone grind, and reaction tank volume. Process performance results include the effects of formate on SO2 removal efficiency, limestone utilization, sulfite oxidation, and waste solids properties. These results show that significant enhancement of SO2 removal efficiency can be achieved at relatively low formate concentrations for a wide range of test conditions. Total formate consumption results are presented along with estimates of the relative losses attributable to the three primary consumption mechanisms vaporization, coprecipitation, and chemical degradation. In the mini-pilot tests, the lowest consumption rates were measured when formate was used in combination with the thiosulfate ion (i.e., under inhibited-oxidation conditions), while the highest consumption rates were measured under forced-oxidation conditions

  10. Equilibrium, thermodynamic and kinetic studies for the biosorption of aqueous lead(II) ions onto the seed husk of Calophyllum inophyllum

    International Nuclear Information System (INIS)

    Biosorption of lead(II) ions from aqueous solution onto the seed husk of Calophyllum inophyllum was investigated in a batch system. Equilibrium, thermodynamics and kinetic studies were conducted by considering the effects of pH, initial metal ion concentration, contact time, and temperature. The results showed that the uptake of the metal ions increased with increase in initial metal ion concentration. The pH for optimum adsorption was 4 for the Pb(II) ions (q = 4.86 mg/g and 97.2% adsorption). Langmuir isotherm described the biosorption of Pb(II) ions onto the biomass (R2 = 0.9531) better than the Freundlich model (R2 = 0.7984), and the Temkin model (R2 = 0.8761). Biosorption kinetics data obtained for the metal ions sorption were fitted using pseudo-first-order and pseudo-second-order. It was found that the kinetics data fitted well into the pseudo-second-order kinetics. Thermodynamic parameters such as Gibbs free energy (ΔG), standard enthalpy (ΔH) and standard entropy (ΔS) were evaluated. The result showed that biosorption of the metal ion onto C. inophyllum biomass was spontaneous and endothermic in nature. The results of FTIR (Fourier-transform infrared spectroscopy) revealed that carboxyl, amine, and hydroxyl groups on the biomass surface were involved in the adsorption of Pb(II) ions.

  11. Ion Exchange Testing with SRF Resin FY 2012

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

    2014-07-02

    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.01, which was prepared and approved in response to the Test Specification 24590-PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590-PTF-TEF-RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

  12. Testing the semi-explicit assembly model of aqueous solvation in the SAMPL4 challenge.

    Science.gov (United States)

    Li, Libo; Dill, Ken A; Fennell, Christopher J

    2014-03-01

    Here, we test a method, called semi-explicit assembly (SEA), that computes the solvation free energies of molecules in water in the SAMPL4 blind test challenge. SEA was developed with the intention of being as accurate as explicit-solvent models, but much faster to compute. It is accurate because it uses pre-simulations of simple spheres in explicit solvent to obtain structural and thermodynamic quantities, and it is fast because it parses solute free energies into regionally additive quantities. SAMPL4 provided us the opportunity to make new tests of SEA. Our tests here lead us to the following conclusions: (1) The newest version, called Field-SEA, which gives improved predictions for highly charged ions, is shown here to perform as well as the earlier versions (dipolar and quadrupolar SEA) on this broad blind SAMPL4 test set. (2) We find that both the past and present SEA models give solvation free energies that are as accurate as TIP3P. (3) Using a new approach for force field parameter optimization, we developed improved hydroxyl parameters that ensure consistency with neat-solvent dielectric constants, and found that they led to improved solvation free energies for hydroxyl-containing compounds in SAMPL4. We also learned that these hydroxyl parameters are not just fixing solvent exposed oxygens in a general sense, and therefore do not improve predictions for carbonyl or carboxylic-acid groups. Other such functional groups will need their own independent optimizations for potential improvements. Overall, these tests in SAMPL4 indicate that SEA is an accurate, general and fast new approach to computing solvation free energies. PMID:24474161

  13. Fixed-bed column study for the removal of cadmium (II) and nickel (II) ions from aqueous solutions using peat and mollusk shells

    International Nuclear Information System (INIS)

    The study was conducted to examine the effectiveness of 4.0-4.75 mm crushed shells and Sphagnum peat moss as low-cost natural adsorbent filter materials for the removal of cadmium and nickel ions from binary aqueous solutions. The effects of column depth and flow rate on effluent metal breakthrough, metal removal and pH were investigated as a function of throughput volume (TPV). Metal removal efficiencies and adsorption capacities for each of the columns were estimated to identify the better filter material and operational conditions for the treatment of cadmium and nickel. During the column testing, a flow rate of 1.5 mL/min (surface loading of 27.5 cm3/cm2 day) and bed depth of 15 cm were found to represent the better operational conditions, where 47.9% and 42.7% cadmium and nickel cumulative removals were obtained under these operational conditions, respectively. The results will be valuable in the development of a mixed-media adsorption system for the treatment of metal-rich wastewaters such as municipal landfill leachate.

  14. Evaluation of carbon-based nanosorbents synthesised by ethylene decomposition on stainless steel substrates as potential sequestrating materials for nickel ions in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    X.J.Lee; L.Y.Lee; L.P.Y.Foo; K.W.Tan; D.G.Hassell

    2012-01-01

    The present work covers the preparation of carbon-based nanosorbents by ethylene decomposition on stainless steel mesh without the use of external catalyst for the treatment of water containing nickel ions (Ni2+).The reaction temperature was varied from 650 to 850℃,while reaction time and ethylene to nitrogen flow ratio were maintained at 30 min and 1:1 cm3/min,respectively.Results show that nanosorbents synthesised at a reaction temperature of 650℃ had the smallest average diameter (75 nm),largest BET surface area (68.95m2/g) and least amount of impurity (0.98 wt.% Fe).A series of batch sorption tests were performed to evaluate the effects of initial pH,initial metal concentration and contact time on Ni2+ removal by the nanosorbents.The equilibrium data fitted well to Freundlich isotherm.The kinetic data were best correlated to a pseudo second-order model indicating that the process was of chemisorption type.Further analysis by the Boyd kinetic model revealed that boundary layer diffusion was the controlling step.This primary study suggests that the prepared material with Freundlich constants compared well with those in the literature,is a promising sorbent for the sequestration of Ni2+ in aqueous solutions.

  15. Fixed-bed column study for the removal of cadmium (II) and nickel (II) ions from aqueous solutions using peat and mollusk shells

    Energy Technology Data Exchange (ETDEWEB)

    Li Chenxi [Civil Engineering Department, Queen' s University, 58 University Avenue, Kingston, Ontario, K7L 3N6 (Canada); Champagne, Pascale, E-mail: champagne@civil.queensu.ca [Civil Engineering Department, Queen' s University, 58 University Avenue, Kingston, Ontario, K7L 3N6 (Canada)

    2009-11-15

    The study was conducted to examine the effectiveness of 4.0-4.75 mm crushed shells and Sphagnum peat moss as low-cost natural adsorbent filter materials for the removal of cadmium and nickel ions from binary aqueous solutions. The effects of column depth and flow rate on effluent metal breakthrough, metal removal and pH were investigated as a function of throughput volume (TPV). Metal removal efficiencies and adsorption capacities for each of the columns were estimated to identify the better filter material and operational conditions for the treatment of cadmium and nickel. During the column testing, a flow rate of 1.5 mL/min (surface loading of 27.5 cm{sup 3}/cm{sup 2} day) and bed depth of 15 cm were found to represent the better operational conditions, where 47.9% and 42.7% cadmium and nickel cumulative removals were obtained under these operational conditions, respectively. The results will be valuable in the development of a mixed-media adsorption system for the treatment of metal-rich wastewaters such as municipal landfill leachate.

  16. Cytogenotoxicity of Cymbopogon citratus (DC) Stapf (lemon grass) aqueous extracts in vegetal test systems

    OpenAIRE

    Saulo M. Sousa; Pâmela S. Silva; Lyderson F. Viccini

    2010-01-01

    The lemon grass, Cymbopogon citratus (DC) Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce) root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous...

  17. Kinetic study of heavy metal ions removal from aqueous solutions using activated pumice stone

    Directory of Open Access Journals (Sweden)

    Naseh Babakhani

    2016-05-01

    Full Text Available Background: The presence of heavy metals in aquatic and terrestrial ecosystems causes harmful effects to living organisms in the environment. This research aimed to determine the potential of activated pumice stone (APS as a sorbent for the removal of Cd, Cu, and Zn from wastewater. Methods: This research was conducted during 2013 on a laboratory scale. The study was performed using batch experiments with synthetic wastewater having Cd, Cu, and Zn concentrations of 10, 20, 40, and 80 mg/L. Various isotherm models, including Langmuir and Freundlich, were used to evaluate the sorption data. The influence of contact time and amount of sorbent on the removal of Cd, Cu, and Zn from wastewater was studied. All experiments were done at pH = 7 and at room temperature (20 ± 1°C. The solution pH was adjusted using 1N NaOH or 1N HCl solutions, and the pH value was determined by a pH meter. Results: The results showed that the adsorption of Cd, Cu, and Zn approaches equilibrium after about 2 hours, while the rates of removal efficiency for Cd, Cu, and Zn at equilibrium were 91.6%, 91.8%, and 82.9%, respectively. Kinetic studies showed that the sorption of Cd, Cu, and Zn onto APS were fitted to the pseudo-second order kinetic models. Conclusion: The results indicate that the APS is a good choice, because it is a low-cost and effective sorbent. The sorption capacity of APS as a sorbent was considerably affected by the initial concentration of metal ions in the solution and by contact time.

  18. Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium

    International Nuclear Information System (INIS)

    The extraction properties of octa-phosphinoylated para-tert butyl calix[8]arene (prepared in the laboratory) in chloroform towards uranyl ions from an aqueous-acidic-salty medium (HNO3-3.5 NaNO3) containing uranyl nitrate salt, was investigated. Two spectroscopic techniques UV/Vis and Luminescence were used for this study. The latter permitted analyze the fluorescence from the uranyl ions influenced by the surrounding medium. Both permitted to learn about the power of this calixarene as extractant towards the mentioned ions. Its extraction ability or capability using this calixarene at 5.91 x 10-4 M towards the uranyl ions was 400% as determined by UV/Vis while fluorescence revealed 100% of uranyl ion extraction. A closed analysis of the results obtained by using these techniques revealed that the stoichiometry of the main extracted species was 1calixarene:2 uranyl ions. The loading capacity of the calixarene ligand towards the uranyl ions was also investigated using both techniques. UV/Vis resulted to be inadequate for quantifying exactly the loading capacity of the calixarene whereas luminescence was excellent indeed, using a 5.91 x 10-4 M calixarene concentration, its loading capacity was 0.157 M of free uranyl ions from 0.161 M of uranyl ions present in the aqueous-acidic-salty medium. The extracts from the ability and capacity studies were concentrated to dryness, purified and the dried extracts were analyzed by infrared and neutron activation analysis. By these techniques it was demonstrated that during the extraction of the uranyl ions by the calixarene ligand they form thermodynamically and kinetically stable complexes, since in the solid state, the 1:2, calixarene; uranyl ions stoichiometry was kept with the minimum formula: (UO2)2B8bL8(NO3)4(H2O)4CHCl3(CH3OH)3 the methanol molecules come from its purification. It is proposed that B8bL8 calixarene in chloroform medium is a good extractant for the treatment of nuclear wastes or radioactive wastes containing

  19. Remediation of alkaline intermediate level radioactive aqueous liquid waste stored along with organic waste at PREFRE Tarapur for ion exchange process: a laboratory scale study

    International Nuclear Information System (INIS)

    Dibutyl phosphate (DBP) and monobutyl phosphate (MBP) are formed during reprocessing of spent fuel as degradation products of Tributyl phosphate (TBP). To maintain the efficiency of TBP solvent during its repeated use, the degraded products are removed by sodium carbonate washing of the solvent. This radioactive sodium carbonate solution is stored in a separate tank along with the exhausted TBP solvent. The presence of degraded products of TBP and their complexes, ion exchange treatment of this waste is creating problems during alpha decontamination step. The present paper deals with the remediation of the aqueous phase of the above waste. For the treatment of the aqueous phase of waste, first the TBP degraded products are required to be removed so that the normal ion exchange treatment can be adopted. (author)

  20. Separation and Preconcentration of Ag(1) in Aqueous Samples by Flotation as an Ion-Associate Using Iodide and Ferroin Followed the Determination by Flame Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    A simple method for separation/preconcentration and determination of Ag (1) in aqueous samples is described. The method is based on formation of an ion-associate between Ag (1)-iodide complex and ferroin, which can be floated at the interface of the aqueous/n-heptane phases. The flotation process was carried out using 500-ml aliquot of the aqueous solution and the floated layer was dissolved in 5 ml of 1 M HNO3 containing methanol (50% v/v) as the solvent. The Ag (1) content was then determined by flame atomic absorption spectrometry (FAAS). The method so could be considered as an enrichment process, was achieved to a quantitative feature, when the pH of the solution was adjusted to 4 and the concentrations of iodide and ferroin were about 3.2x10-4 M and 6.25x10-5 M, respectively. The LOD and RSD (n=7) were obtained 1.0x10-8 M and 2.4%, respectively. It was found that a large number of cations and anions even at high considerably foreign ion/Ag(1) ratios were not interfered. The method was applied satisfactorily to recovery of Ag(I) from different aqueous samples

  1. Kinetic modeling of the biosorption of Cd2+ ions from aqueous solutions onto Eichhornia crassipes roots using potentiometry: low-cost alternative to conventional methods

    Directory of Open Access Journals (Sweden)

    Carolina Martínez-Sánchez

    2013-01-01

    Full Text Available This work presents the use of potentiometric measurements for kinetic studies of biosorption of Cd2+ ions from aqueous solutions on Eichhornia crassipes roots. The open circuit potential of the Cd/Cd2+ electrode of the first kind was measured during the bioadsorption process. The amount of Cd2+ ions accumulated was determined in real time. The data were fit to different models, with the pseudo-second-order model proving to be the best in describing the data. The advantages and limitations of the methodology proposed relative to the traditional method are discussed.

  2. Adsorption Kinetics of Cd(ll) and Pb(ll) Ions from Aqueous Solutions by Bamboo-Based Activated Charcoal and Bamboo Dust

    OpenAIRE

    Stevens Azubuike Odoemelam; Francis Kalu Onwu; Christopher Uchechukwu Sonde; Mgbeahuruike A. Chinedu

    2015-01-01

    The use of bamboo dust (BD) and bamboo-based activated charcoal for adsorption of Pb(ll) and Cd(ll) ions from aqueous solutions were assessed in this work. The effect of contact time on the uptake of these metal ions was studied in batch process. The adsorption data were correlated with pseudo first-order, pseudo second-order and diffusivity kinetic models. Results show that pseudo second-order kinetic model gave the best description for the adsorption process. Kinetic studies further showed ...

  3. Equilibrium and kinetic studies for the biosorption system of copper(II) ion from aqueous solution using Tectona grandis L.f. leaves powder

    International Nuclear Information System (INIS)

    The biosorption of copper(II) ions from aqueous solution by Tectona grandis L.f. was studied in a batch adsorption system as a function of pH, metal ion concentration, adsorbent concentration and adsorbent size. The biosorption capacities and rates of copper(II) ions onto T. grandis L.f. were evaluated. The Langmuir, Freundlich, Redlich-Peterson and Temkin adsorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data could be well interpreted by the Langmuir model with maximum adsorption capacity of 15.43 mg/g of copper(II) ion on T. grandis L.f. leaves powder. The kinetic experimental data properly correlated with the second-order kinetic model. Various thermodynamic parameters such as ΔGo, ΔHo, and ΔSo were calculated indicating that this system was a spontaneous and exothermic process

  4. Development of timing system for RF ion source and RFQ III test stand

    International Nuclear Information System (INIS)

    J-PARC LINAC is scheduled for installation of cesium seeded RF-driven H- ion source (RF ion source) and 50 mA RFQ (RFQ III) for achieving high current beam in 2014. Therefore, we were implemented beam test at RF ion source and RFQ III test stand since 2013. The control system for RF ion source and RFQ III test stand was designed considering compatibility to the control system in J-PARC LINAC. But the timing parameter for RF ion source is different from the timing parameter for H- ion source is operating in J-PARC, because method of generating H- plasma is different. Therefore, we develop the timing system for RF ion source using the timing parameter of RF ion source, and were used it at RF ion source and RFQ III test stand. This report is described mainly the timing system. (author)

  5. Electroanalytical tools to investigate the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium

    Institute of Scientific and Technical Information of China (English)

    Jignasu P Mehta; Himanshu M Pandya; Kahan I Pandya

    2012-01-01

    The divalent state of Ln(Ⅲ) ions has attracted much interest because of their ability to serve isomorphously in many biological system of divalent Ca(Ⅱ) ion.Therefore,present paper deals with the study of divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium.In present study,cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions.The cyclic voltammetric technique showed two-step reduction process at cathode for both Ln(Ⅲ) ions under specified experimental conditions and chronopotentiomeuic method also showed two different transition times (τ).Looking to the shape of cyclic voltammogram we calculated heterogeneous forward rate constant (K0fh,cm/s) and diffusion coefficient (D,cm2/s) for both ions,which suggested that sweep rate had great effect on the shape of cyclic voltammogram of Eu(Ⅲ) and Nd(Ⅲ) ions.The result of chronopotentiometry also suggested that stable divalent states of Eu(Ⅲ) and Nd(Ⅲ) ions existed with chronopotenuogram with two distinct transition times.The diffusion coefficients (D,cm2/s)were calculated from Sand equation.The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.

  6. Functionalized macroporous copolymer of glycidyl methacrylate: The type of ligand and porosity parameters influence on Cu(II ion sorption from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Sandić Zvjezdana P.

    2009-01-01

    Full Text Available The removal of heavy metals from hydro-metallurgical and other industries' wastewaters, their safe storage and possible recovery from waste- water streams is one of the greater ecological problems of modern society. Conventional methods, like precipitation, adsorption and biosorption, electrowinning, membrane separation, solvent extraction and ion exchange are often ineffective, expensive and can generate secondary pollution. On the other hand, chelating polymers, consisting of crosslinked copolymers as a solid support and functional group (ligand, are capable of selectively loading different metal ions from aqueous solutions. In the relatively simple process, the chelating copolymer is contacted with the contaminated solution, loaded with metal ions, and stripped with the appropriate eluent. Important properties of chelating polymers are high capacity, high selectivity and fast kinetics combined with mechanical stability and chemical inertness. Macroporous hydrophilic copolymers of glycidyl methacrylate and ethylene glycol dimethacrylate modified by different amines show outstanding efficiency and selectivity for the sorption of precious and heavy metals from aqueous solutions. In this study poly(GMA-co-EGDMA copolymers were synthesized with different porosity parameters and functionalized in reactions with ethylene diamine (EDA, diethylene triamine (DETA and triethylene tetramine (TETA. Under non-competitive conditions, in batch experiments at room temperature, the rate of sorption of Cu(II ions from aqueous solutions and the influence of pH on it was determined for four samples of amino-functionalized poly(GMA-co-EGDMA. The sorption of Cu(II for both amino-functionalized samples was found to be very rapid. The sorption half time, t1/2, defined as the time required to reach 50% of the total sorption capacity, was between 1 and 2 min. The maximum sorption capacity for copper (2.80 mmol/g was obtained on SGE-10/12-deta sample. The sorption

  7. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Mohd F., E-mail: faisalt@petronas.com.my; Shaharun, Maizatul S. [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia); Shuib, Anis Suhaila, E-mail: anisuha@petronas.com.my; Borhan, Azry [Chemical Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia)

    2014-10-24

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  8. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    International Nuclear Information System (INIS)

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m2/g and 0.17 cm2/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models

  9. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    Science.gov (United States)

    Taha, Mohd F.; Shuib, Anis Suhaila; Shaharun, Maizatul S.; Borhan, Azry

    2014-10-01

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m2/g and 0.17 cm2/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  10. Comparison of the toxicity of aqueous and ethanol fractions of Angelica keiskei leaf using the eye irritancy test

    OpenAIRE

    SON, HYEONG-U; YOON, EUN-KYUNG; CHA, YONG-SOO; Kim, Min-A; SHIN, YONG-KYU; KIM, JONG-MYUNG; CHOI, YONG-HEE; Lee, Sang-Han

    2012-01-01

    To determine whether aqueous and ethanol fractions of the Angelica keiskei leaf exert toxicity when used for cosmetic purposes, we performed the acute eye irritancy test. Animals were treated with sample fractions (100 mg/dose) according to standard procedure guidelines. No significant changes or damage was detected in the fraction-treated groups in terms of ocular lesions in the cornea, the size of the cornea with turbidity, swelling of the eyelid and emission discharge. However, sodium dioc...

  11. Investigation of sorption of Hg(II) ions onto coconut husk from aqueous solution using radiotracer technique

    International Nuclear Information System (INIS)

    The sorption of Hg(II) ions onto coconut (Cocos nucifera) husk has been studied using radiotracer technique. Maximum sorption (96%) of Hg(II) ions (7.39 x 10-6 M) onto sorbent surface is achieved from 10-3 M HNO3 solution in 30 min agitation time using 100 mg of coconut husk. The sorption data follow the Freundlich and Dubinin-Radushkevich (D-R) isotherms. Sorption capacity (6.84±0.45 mmol g-1) and sorption energy (10.6±0.13 kJ mol-1) have been evaluated using these isotherms. Among the ions tested to monitor their influence on the sorption, Ba(II), fluoride and tartarate increased the sorption, while thiosulfate, bromide and thiocyanate reduced ( 26%) the sorption. The cations K(I), Ce(III), Cr(III), Fe(III) and Zr(IV) partially suppressed the sorption. The variation of sorption with temperature yields thermodynamic parameters ΔH = -37.4±2 kJ mol-1 ΔS = -105±7 J mol-1 K-1 and ΔG = -2.58±0.05 kJ mol-1 at 298 K. The negative values of enthalpy and free energy reflect the spontaneous and exothermic nature of sorption, respectively. The selectivity studies of sorbent show that the coconut husk column can be used to separate Hg(II) ions from Se(IV), Zn(II), I(I) and Tc (VII). The sorbent has a potential in radiochemistry to separate gamma energies of 203Hg (279 keV) from 75Se (265 and 280 keV). (orig.)

  12. Carbon-coated Na{sub 3}V{sub 2}(PO{sub 4}){sub 3} nanocomposite as a novel high rate cathode material for aqueous sodium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ludan; Huang, Tao, E-mail: huangt@fudan.edu.cn; Yu, Aishui, E-mail: asyu@fudan.edu.cn

    2015-10-15

    Aqueous rechargeable sodium ion batteries has attracted a lot of interests because of its low cost, huge abundance of sodium resources and promising application for large-scale electric energy storage. Herein, we proposed the carbon-coated Na{sub 3}V{sub 2}(PO{sub 4}){sub 3} nanocomposite (Na{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C) as a cathode material, which was prepared using a simple sol–gel method. The structure and morphology analyses showed that the highly crystalline Na{sub 3}V{sub 2}(PO{sub 4}){sub 3} nanoparticle with an average size of 350 nm is well coated by a carbon layer with a thickness of 3 nm. Electrochemical tests showed that at high current rates, the Na{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode exhibited excellent electrochemical performance. Impressively, it delivered a discharge specific capacity of 94.5 mAh/g at 10C (1176 mA/g), 90.5 mAh/g at 15C (1764 mA/g) and 71.7 mAh/g at 20C (2352 mA/g). To the best of our knowledge, the notable rate capability has never been reported before for aqueous sodium ion batteries. The enhanced electrochemical behavior could be attributed to the combined advantages of Na{sub 3}V{sub 2}(PO{sub 4}){sub 3} nanoparticles and carbon layer in the unique core–shell structure, which improved the intrinsic poor electronic conductivity of Na{sub 3}V{sub 2}(PO{sub 4}){sub 3} greatly. Our results confirmed the prepared Na{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C nanocomposite should be a promising cathode candidate for aqueous sodium ion batteries. - Highlights: • NVP/C nanocomposite is a novel cathode material for aqueous sodium ion battery. • NVP/C nanocomposite delivered a high discharge specific capacity at high rate. • The characteristics of the unique core–shell structure are discussed in detail.

  13. Acceleration test of heavy-ion with TIT RFQ linac

    International Nuclear Information System (INIS)

    A heavy-ion acceleration system with the TIT-RFQ has been developed. The TIT-RFQ was designed to accelerate particles with a charge to mass ratio ε ≥ 1/16, as it was, the kind of particles was limited because of the insufficient withstanding voltage of the beam injection equipment. In order to solve this problem, the development of the new system was planed, and the work has been carried out since last year. By using this system, the first acceleration of N+ beam was observed in January this year; however, the beam intensity was insufficient. Some problems were pointed out, and the synchronous circuit of a RF pulse was constructed up to now. By using this circuit, the increase of the beam intensity was observed in the second acceleration test in this summer. (author)

  14. Stability studies of some fluoroquinolonyl-3′-penicillin amides in aqueous DMF solution in presence of Cu(ic-Ions

    Directory of Open Access Journals (Sweden)

    Chatterjee N

    2007-01-01

    Full Text Available Stability studies of some novel dual action fluoroquinolonyl-3′-penicillin amides (1a-e in aqueous DMF (1:1 solution has been carried out in presence of Cu (ic or Hg (ic ions and their degradation rate was monitored by UV/Vis spectrophotometric method. The results thus obtained indicate that ciprofloxacin moiety offered greater stability to the β-lactam moiety of the hybrid (1d or 1e than norfloxacin (1a or 1b in the presence of heavy metal ion degradation; whereas the degradation pattern of β-lactam moiety in the hybrids under investigation (1a-e was found to be in agreement with the previously reported heavy metal ion degradation profile of the penicillins.

  15. Sorption of Some Heavy Metal Ions from Aqueous Solutions by Polypropylene Fibers Grafted with Acrylic Acid under the Effect of Gamma Irradiation

    International Nuclear Information System (INIS)

    Polypropylene Fibers (PP) grafted with poly acrylic acid (PAAc) were prepared under the effect of gamma irradiation to be used as an adsorbent matrix for Co2+ and Ni2+ ions from aqueous solutions. The different factors which affect the grafting process such as grafting solution, inhibitor concentration, irradiation dose and the monomer concentration were investigated. The grafted PP fibers were characterized by using Fourier-transform infrared (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Differential scanning calorimetery (DSC) and Scanning electron microscopy (SEM). The effect of grafting yield on the mechanical properties of grafted PP fibers was also studied. The different conditions which affect the adsorption capacity of grafted PP fibers towards the metal ions, such as solution pH and contact time were investigated. The adsorption isotherm was studied according to the Langmuir isotherm model. The effect of regeneration cycles on the adsorption capacity of grafted PP fibers was investigated. Keywords: Polypropylene, γ-rays, Metal ions, adsorption.

  16. PVDF-ErGO-GRC electrode: A single setup electrochemical system for separation, pre-concentration and detection of lead ions in complex aqueous samples.

    Science.gov (United States)

    Hamsawahini, Kunashegaran; Sathishkumar, Palanivel; Ahamad, Rahmalan; Yusoff, Abdull Rahim Mohd

    2016-02-01

    An effective electrode was developed based on electromembrane extraction (EME) and square wave voltammetry (SWV) for simultaneous separation, pre-concentration and determination of lead (II) (Pb(II)) ions in complex aqueous samples. Electrochemically reduced graphene oxide-graphite reinforced carbon (ErGO-GRC) was utilized in conjunction with the SWV. Pb(II) ions were extracted from an aqueous sample solution into an acidic acceptor phase (1M HCl) in the lumen of the polyvinylidene fluoride (PVDF) membrane bag by the application of voltage of maximum 6 V across the supported liquid membrane (SLM), consisting of organic solvent and di-(2-ethylhexyl)phosphoric acid (D2EHPA). The parameters affecting the EME were optimized for Pb(II) ions. The optimum EME conditions were found to be 20% D2EHPA in 1-octanol impregnated in the wall of PVDF membrane (PVDF17) as the SLM, extraction time of 20 min, pH of sample solution of 8 and a voltage of 5 V. The PVDF-ErGO-GRC electrode system attained enrichment factors of 40 times and 80% of extraction with relative standard deviations (n=5) of 8.3%. Good linearity ranging from 0.25 to 2 nM with coefficients correlation of 0.999 was obtained. The Pb(II) ions detection limit of PVDF-ErGO-GRC electrode was found to be 0.09 nM. The newly developed single setup electrochemical system was applied to complex aqueous samples such as tap, river and sea water to evaluate the feasibility of the method for applications. PMID:26653429

  17. Production of a fluorescence probe in ion-beam radiolysis of aqueous coumarin-3-carboxylic acid solution-2: Effects of nuclear fragmentation and its simulation with PHITS

    Energy Technology Data Exchange (ETDEWEB)

    Maeyama, Takuya [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Yamashita, Shinichi; Taguchi, Mitsumasa [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Baldacchino, Gerard [CEA Saclay, IRAMIS, UMR 3299 CEA-CNRS SIS2M, Laboratoire de Radiolyse, F-91191 Gif sur Yvette Cedex (France); Sihver, Lembit [Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Department of Nuclear Engineering, Texas A and M University, TX 77843-3133 (United States); Department of Roanoke College, Salem, VA 24153 (United States); Department of Nuclear Engineering, Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Murakami, Takeshi [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nuclear Professional School, School of Engineering, University of Tokyo, 2-22 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)

    2011-12-15

    The G(OH) values in aqueous coumarin-3-carboxylic-acid (3-CCA) solutions irradiated with {sup 12}C{sup 6+} beams having the energies of 135, 290 and 400 MeV/u were measured by a fluorescent method around the Bragg peak, with 0.6 mm intervals, and quartz cells of 1 cm optical lengths, at the Heavy Ion Medical Accelerator in Chiba, National Institute of Radiological Sciences (NIRS). For each ion, the G(OH) has been calculated as a function of dose average LET and position. The calculated results have been compared to measurements, and the results, reproducibility and reliability of the calculations are discussed in the paper. - Highlights: > Therapeutic ion beam has energy of several hundred MeV/u because it is necessary for a few tens cm range. > With such high energy, nuclear fragmentations of carbon ions occur resulting in production of lighter ions. > In this study, OH yield in water radiolysis near the Bragg peak of therapeutic ion beams was measured. > Measured yields are discussed considering nuclear fragmentation by PHITS code.

  18. Monolayer g-C3N4 Fluorescent Sensor for Sensitive and Selective Colorimetric Detection of Silver ion from Aqueous Samples.

    Science.gov (United States)

    Cao, Yujuan; Wu, Wei; Wang, Song; Peng, Hong; Hu, Xiaogang; Yu, Ying

    2016-03-01

    Rapid and sensitive detection of heavy-metal ions in natural water environments worldwide is urgently needed because of their severe threats to human health. In the present work, monolayer graphite-like flake C3N4 (g-C3N4) materials were applied as a new fluorescent sensor for the detection of trace silver ion in aqueous solution. The thickness of synthesized g-C3N4 was 0.45 nm and obtained by exfoliating twice with ultrasonic. With the presence of ethylene diamine tetraacetic acid as a screening agent, the highly sensitive sensor reached a low detection limit of 52.3 nmol/L for silver (I) ion and there was no disturbance when silver (I) ion coexisted with other metal ions in water samples. Under the optimal conditions, the monolayer g-C3N4 was successfully used to detect trace silver (I) ion in different environmental water and drinking water samples. PMID:26753758

  19. A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models

    DEFF Research Database (Denmark)

    Flores Alsina, Xavier; Kazadi Mbamba, Christian; Solon, Kimberly;

    2015-01-01

    There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico-chemical processes after many years of mainly focusing on biokinetics. Indeed, future modelling needs, such as a plant-wide phosphorus (P) description, require a major, but...... unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems. In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation/pairing is presented and interfaced with industry...... different cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated, by implementing the aqueous phase chemistry module in some of the most frequently used WWTP process simulation models. Finally, it is shown how traditional wastewater modelling...

  20. Electrochemical stability of non-aqueous electrolytes for sodium-ion batteries and their compatibility with Na(0.7)CoO2.

    Science.gov (United States)

    Bhide, Amrtha; Hofmann, Jonas; Dürr, Anna Katharina; Janek, Jürgen; Adelhelm, Philipp

    2014-02-01

    The present study compares the physico-chemical properties of non-aqueous liquid electrolytes based on NaPF6, NaClO4 and NaCF3SO3 salts in the binary mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC). The ionic conductivity of the electrolytes is determined as a function of salt concentration and temperature. It is found that the electrolytes containing NaClO4 and NaPF6 exhibit ionic conductivities ranging from 5 mS cm(-1) to 7 mS cm(-1) at ambient temperature. The electrochemical stability window of the different electrolytes is studied by linear sweep voltammetry (LSV) and cyclic voltammetry (CV) measurements with respect to a variety of working electrodes (WE) such as glassy carbon (GC), graphite and a carbon gas diffusion layer (GDL). Electrolytes containing NaPF6 and NaClO4 are found to be electrochemically stable with respect to GC and GDL electrodes up to 4.5 V vs. Na/Na(+), with some side reactions starting from around 3.0 V for the latter salt. The results further show that aluminium is preferred over different steels as a cathode current collector. Copper is stable up to a potential of 3.5 V vs. Na/Na(+). In view of practical Na-ion battery systems, the electrolytes are electrochemically tested with Na0.7CoO2 as a positive electrode. It is inferred that the electrolyte NaPF6-EC : DMC is favorable for the formation of a stable surface film and the reversibility of the above cathode material. PMID:24336408

  1. Removal of low levels of uranium from aqueous solutions by coprecipitation and ion exchange (Preprint no. SST-02)

    International Nuclear Information System (INIS)

    Coprecipitation of uranium(VI) from aqueous solutions with ferric hydroxide has been evaluated as a means of removing uranium from aqueous effluents. Experiments with different amounts of uranium and added carbonate showed that it was possible to remove better than 95% of uranium in a single precipitation at low concentrations of uranium. Sorption on weak acid cation exchange resin has also been studied and can be used if the uranium is to be recovered. (author)

  2. ANALYSIS OF SULFONATES IN AQUEOUS SAMPLES BY ION-PAIR LC/ESI-MS/MS WITH IN-SOURCE CID FOR ADDUCT PEAK ELIMINATION

    Energy Technology Data Exchange (ETDEWEB)

    OUYANG,S.; VAIRAVAMURTHY,M.A.

    1999-06-13

    Determination of low-molecular-weight organic sulfonates (e.g. taurine and cysteic acid) in aqueous solutions is important in many applications of biological, environmental and pharmaceutical sciences. These compounds are difficult to be determined by commonly used reversed-phase liquid chromatographic separation combined with UV-Visible detection because of their high solubility and the lack chromophoric moieties. Here the authors report a method combining ion-pair liquid chromatography and electrospray ionization tandem mass spectrometry (IPLC/ESI-MS/MS)for determining sulfonates. The ability of low-molecular-weight sulfonates to form ion-pairs with quaternary ammonium cations in aqueous solutions allowed LC separation with a C{sub 18} column. Detection of the sulfonates was accomplished with ESI-MS that lends a universal mode of mass detection for polar, water soluble compounds. An in-source collision induced dissociation (CID) was applied to eliminate the adduct peaks in mass spectra. Characteristic marker ions showed in the second stage mass spectra lent a method for identifying sulfonates.

  3. Removal of the metal ions from aqueous solutions by nanoscaled low molecular pectin isolated from seagrass Phyllospadix iwatensis.

    Science.gov (United States)

    Khozhaenko, Elena; Kovalev, Valeri; Podkorytova, Elena; Khotimchenko, Maksim

    2016-09-15

    Pectins from sea grasses are considered as promising substances with pronounced metal-binding activity. Due to the high molecular weight and heterogeneous structure, the use of pectins for removal of metal ions is difficult. Technology of directed pectin degradation was developed and homogenous degraded nanoscaled pectin polymers were synthesized. Experimental samples of degraded pectin isolated from Phyllospadix iwatensis were tested for their metal binding activity in comparison with native pectin from this seagrass and commercial citrus pectin. The metal uptake of all pectin compounds was highest within the pH range from 4.0 to 6.0. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Results showed that depolymerized pectin exerts highest lead and cadmium binding activity with pronounced affinity. All pectin compounds were suggested to be favorable sorbents. Therefore, it can be concluded that degraded pectin is a prospective material for creation of metal-removing water treatment systems. PMID:26848015

  4. Treatment plan for aqueous/organic/decontamination wastes under the Oak Ridge Reservation FFCA Development, Demonstration, Testing, and Evaluation Program

    Energy Technology Data Exchange (ETDEWEB)

    Backus, P.M.; Benson, C.E.; Gilbert, V.P.

    1994-08-01

    The U.S. Department of Energy (DOE) Oak Ridge Operations Office and the U.S. Environmental Protection Agency (EPA)-Region IV have entered into a Federal Facility Compliance Agreement (FFCA) which seeks to facilitate the treatment of low-level mixed wastes currently stored at the Oak Ridge Reservation (ORR) in violation of the Resource, Conservation and Recovery Act Land Disposal Restrictions. The FFCA establishes schedules for DOE to identify treatment for wastes, referred to as Appendix B wastes, that current have no identified or existing capacity for treatment. A development, demonstration, testing, and evaluation (DDT&E) program was established to provide the support necessary to identify treatment methods for mixed was meeting the Appendix B criteria. The Program has assembled project teams to address treatment development needs for major categories of the Appendix B wastes based on the waste characteristics and possible treatment technologies. The Aqueous, Organic, and Decontamination (A/O/D) project team was established to identify pretreatment options for aqueous and organic wastes which will render the waste acceptable for treatment in existing waste treatment facilities and to identify the processes to decontaminate heterogeneous debris waste. In addition, the project must also address the treatment of secondary waste generated by other DDT&E projects. This report details the activities to be performed under the A/O/D Project in support of the identification, selection, and evaluation of treatment processes. The goals of this plan are (1) to determine the major aqueous and organic waste streams requiring treatment, (2) to determine the treatment steps necessary to make the aqueous and organic waste acceptable for treatment in existing treatment facilities on the ORR or off-site, and (3) to determine the processes necessary to decontaminate heterogeneous wastes that are considered debris.

  5. Treatment plan for aqueous/organic/decontamination wastes under the Oak Ridge Reservation FFCA Development, Demonstration, Testing, and Evaluation Program

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) Oak Ridge Operations Office and the U.S. Environmental Protection Agency (EPA)-Region IV have entered into a Federal Facility Compliance Agreement (FFCA) which seeks to facilitate the treatment of low-level mixed wastes currently stored at the Oak Ridge Reservation (ORR) in violation of the Resource, Conservation and Recovery Act Land Disposal Restrictions. The FFCA establishes schedules for DOE to identify treatment for wastes, referred to as Appendix B wastes, that current have no identified or existing capacity for treatment. A development, demonstration, testing, and evaluation (DDT ampersand E) program was established to provide the support necessary to identify treatment methods for mixed was meeting the Appendix B criteria. The Program has assembled project teams to address treatment development needs for major categories of the Appendix B wastes based on the waste characteristics and possible treatment technologies. The Aqueous, Organic, and Decontamination (A OE D) project team was established to identify pretreatment options for aqueous and organic wastes which will render the waste acceptable for treatment in existing waste treatment facilities and to identify the processes to decontaminate heterogeneous debris waste. In addition, the project must also address the treatment of secondary waste generated by other DDT ampersand E projects. This report details the activities to be performed under the A OE D Project in support of the identification, selection, and evaluation of treatment processes. The goals of this plan are (1) to determine the major aqueous and organic waste streams requiring treatment, (2) to determine the treatment steps necessary to make the aqueous and organic waste acceptable for treatment in existing treatment facilities on the ORR or off-site, and (3) to determine the processes necessary to decontaminate heterogeneous wastes that are considered debris

  6. Cost effective and shape controlled approach to synthesize hierarchically assembled NiO nanoflakes for the removal of toxic heavy metal ions in aqueous solution

    Indian Academy of Sciences (India)

    K Yogesh Kumar; H B Muralidhara; Y Arthoba Nayaka; H Hanumanthappa; M S Veena; S R Kiran Kumar

    2015-02-01

    Hierarchical mesoporous NiO nanoflakes (NiOs) have been synthesized in high yield via a simple, economical and environmentally friendly hydrothermal route. The as-prepared NiOs were characterized by powder X-ray diffraction (PXRD), scanning electronicmicroscopy (SEM), transmission electronmicroscopy (TEM), selected area electron diffraction patterns (SAED), X-ray energy dispersive spectroscopy (EDS) and nitrogen adsorption–desorption techniques (Brunauer–Emmett–Teller, BET). Adsorption of heavy metal ions onto the as-prepared sample from aqueous solutions was investigated using differential pulse anodic stripping voltametry (DPASV) technique and discussed. The product possesses a BET surface area of 69.27 m2 g-1. It is found that NiOs exhibited the excellent performance for the removal of Hg(II), Pb(II) and Cd(II) from aqueous solution. The equilibrium adsorption data of Hg(II), Pb(II) and Cd(II) on the as-prepared NiOs were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data. The adsorption capacities for removal of Hg(II), Pb(II) and Cd(II) were determined using the Langmuir equation and found to be 1324.5, 1428.9 and 1428.5 mg g-1, respectively. Adsorption kinetics of all the metal ions followed pseudo second-order model. Moreover, NiOs can be recycled by simple acid treatment, which could retain the high removal efficiency in three successive cycles. This study suggests that nanoflakes could be explored as a new adsorbent with high efficiency and recyclability for removing heavy metal ions from aqueous solution.

  7. Preparation and Characterization of Poly(ethyl hydrazide) Grafted Oil Palm Empty Fruit Bunch for Removal of Ni(II) Ion in Aqueous Environment

    OpenAIRE

    Siti Mariam Mohd Nor; Nor Azah Yusof; Md Jelas Haron; Ili Syazana bt Johari

    2013-01-01

    Poly(ethyl hydrazide) grafted oil palm empty fruit bunch (peh-g-opefb) fiber has been successfully prepared by heating poly(methylacrylate)-g-opefb at 60 °C for 4 h in a solution of hydrazine hydrate in ethanol. The chelating ability of peh-g-opefb was evaluated based on removal of Ni(II) ions in aqueous solution. Adsorption of Ni(II) by peh-g-opefb was characterized based on effect of pH, isotherm, kinetic and thermodynamic study. This cheap sorbent based on oil palm empty fruit bunch fiber ...

  8. Application of laser-induced breakdown spectroscopy method for elements analysis of metal ions in an aqueous solution in nuclear reprocessing process control

    International Nuclear Information System (INIS)

    Laser-induced breakdown spectroscopy (LIBS) is an attractive technique for determining elemental composition in real time, in-situ, and remotely without any sample preparation. The LIBS analysis of metal ions in an aqueous solution is available in process control and environmental monitoring. In the present paper, we reviewed LIBS methods for a liquid phase to improve detection sensitivity. We performed LIBS measurements with the sheet flow for the simultaneous determination of elements in simulated high-level radioactive waste liquid and discussed the application potential as a tool for online process monitoring. (author)

  9. The impact of functionalized CNT in the network of sodium alginate-based nanocomposite beads on the removal of Co(II) ions from aqueous solutions.

    Science.gov (United States)

    Karkeh-Abadi, Fatemeh; Saber-Samandari, Samaneh; Saber-Samandari, Saeed

    2016-07-15

    Significant efforts have been made to develop highly efficient adsorbents to remove radioactive Co(II) ion pollutants from medical and industrial wastewaters. In this study, amide group functionalized multi-walled carbon nanotube (CNT-CONH2) imprinted in the network of sodium alginate containing hydroxyapatite, and new nanocomposite beads were synthesized. Then, they were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The prepared nanocomposite beads were used as an adsorbent of Co(II) ions from an aqueous solution. The presence and distribution of Co(II) ions in the surface of the nanocomposite beads was confirmed using FESEM, EDS and metal mapping analysis. The effect of various experimental conditions such as time, pH, and initial concentration of the adsorbate solution and temperature on the adsorption capacity of the nanocomposite beads were explored. The maximum Co(II) ions adsorption capacity of the prepared nanocomposite beads with the largest surface area of 163.4m(2)g(-1) was 347.8mgg(-1) in the optimized condition. The adsorption mechanism followed a pseudo-second-order kinetic model. Furthermore, the Freundlich appears to produce better fit than the Langmuir adsorption isotherm. Finally, thermodynamic studies suggest that endothermic adsorption process of Co(II) ions is spontaneous and thermodynamically favorable. PMID:27037477

  10. Chromatographic analysis and antiproliferative potential of aqueous extracts of Punica granatum fruit peels using the Allium cepa test

    OpenAIRE

    Andrielle Wouters Kuhn; Marília Tedesco; Aline Augusti Boligon; Margareth Linde Athayde; Haywood Dail Laughinghouse IV; Solange Bosio Tedesco

    2015-01-01

    Punica granatum L., locally known as romanzeira, is native to Asia but found throughout Brazil. P. granatum is used for treating inflammatory, infectious and respiratory diseases. The aim of this study was to evaluate the chromatography and genotoxicity of an aqueous extract of P. granatum (pomegranate) fruit peel using the Allium cepa L. test. The experiment set-up entailed 7 treatments: T1-distilled water, T2-tea 5 g.L-1, T3-tea 10 g.L-1, T4-glyphosate at 9.6%, T5-glyphosate with subsequent...

  11. Antioxidant and Antifatigue Properties of the Aqueous Extract of Moringa oleifera in Rats Subjected to Forced Swimming Endurance Test

    OpenAIRE

    Bonoy Lamou; Germain Sotoing Taiwe; André Hamadou; Abene; Justin Houlray; Mahamat Mey Atour; Paul Vernyuy Tan

    2016-01-01

    The effects of the aqueous extract of Moringa oleifera on swimming performance and related biochemical parameters were investigated in male Wistar rats (130–132 g). Four groups of rats (16 per group) were fed a standard laboratory diet and given distilled water, 100, 200, or 400 mg/kg of extract, respectively, for 28 days. On day 28, 8 rats from each group were subjected to the forced swimming test with tail load (10% of body weight). The remaining 8 rats per group were subjected to the 90-mi...

  12. Mechanical characterization of several ion-implanted alloys: nanoindentation testing, wear testing and finite element modeling

    International Nuclear Information System (INIS)

    The influence of ion implantation on the mechanical properties of metal alloys has been examined using a variety of experimental and numerical techniques. Ultralow load indentation testing and finite element modeling has been used for the aluminum/oxygen to extract fundamental mechanical properties. Aluminum implanted with 20 at.% O exhibits extraordinary strength, as high as 3300 MPa. The degree of strengthening expected for this Al(O) alloy on the basis of the observed microstructure of fine (1.5-3.5 nm) oxide precipitates was estimated using several micromechanical models, and the results agree with our experimental findings. Pin-on-disk tribological characterization of aluminum implanted with 10 at.% oxygen revealed that the ion-beam treatment reduced the average friction coefficient from greater than 1.0 (for pure Al) to approximately 0.25 (for Al(O)). Large-amplitude stick-slip oscillations, which occur within the first two cycles for pure aluminum, were postponed to 30-50 cycles for the ion-implanted material. Two stainless steel which have been amorphized by implantation, 304 implanted with C and 440C implanted with Ti+C, show measurable hardening with implantation, of the order of 40 and 15%, respectively. In addition, nanoindentation within pin-on-disk wear tracks on 440C reveals that the mechanical state of the extensively deformed implanted layer is apparently unchanged from its initial state. (orig.)

  13. Mechanical characterization of several ion-implanted alloys: nanoindentation testing, wear testing and finite element modeling

    Science.gov (United States)

    Bourcier, R. J.; Follstaedt, D. M.; Dugger, M. T.; Myers, S. M.

    1991-07-01

    The influence of ion implantation on the mechanical properties of metal alloys has been examined using a variety of experimental and numerical techniques. Ultralow load indentation testing and finite element modeling has been used for the aluminum/oxygen to extract fundamental mechanical properties. Aluminum implanted with 20 at.% O exhibits extraordinary strength, as high as 3300 MPa. The degree of strengthening expected for this Al(O) alloy on the basis of the observed microstructure of fine (1.5-3.5 nm) oxide precipitates was estimated using several micromechanical models, and the results agree with our experimental findings. Pin-on-disk tribological characterization of aluminum implanted with 10 at.% oxygen revealed that the ion-beam treatment reduced the average friction coefficient from greater than 1.0 (for pure Al) to approximately 0.25 (for Al(O)). Large-amplitude stick-slip oscillations, which occur within the first two cycles for pure aluminum, were postponed to 30-50 cycles for the ion-implanted material. Two stainless steels which have been amorphized by implantation, 304 implanted with C and 440C implanted with Ti + C, show measurable hardening with implantation, of the order of 40 and 15%, respectively. In addition, nanoindentation within pin-on-disk wear tracks on 440C reveals that the mechanical state of the extensively deformed implanted layer is apparently unchanged from its initial state.

  14. Solid phase extraction using silica gel modified with azo-dyes derivative for preconcentration and separation of Th(IV) ions from aqueous solutions

    International Nuclear Information System (INIS)

    Azo-dyes derivative (HL) sorbent was synthesized according to the literature to be used in the adsorption and preconcentration of Th(IV) ions from aqueous solution and it was exposed to immobilization, and new solid support material was obtained. For this purpose, azo-dyes derivative (HL) was chemically bonded to silica gel surface immobilized 3-chloropropyl trimethoxysilane, then analyzed by FTIR, BET, SEM and elemental analysis. The influence of the solution pH, initial Th(IV) concentration, amount of sorbent, contact time, temperature and foreign ion effect was investigated. The maximum Th(IV) uptake capacity was found to be 24.85 ± 0.2 mg/g. (author)

  15. Chemical modification of silica gel with synthesized Schiff base hydrazone derivative and application for preconcentration and separation of U(VI) ions from aqueous solutions

    International Nuclear Information System (INIS)

    Schiff base hydrazone derivative (HL) sorbent was synthesized according to the literature to be used in the adsorption and preconcentration of U(VI) ions from aqueous solution and it was exposed to immobilization, and new solid support material was obtained. For this purpose, Schiff base hydrazone derivative (HL) was chemically bonded to silica gel surface immobilized 3-aminopropyl trimethoxysilane, then analyzed by Fourier transform infrared, Brunauer-Emmett-Teller, scanning electron microscopy and elemental analysis. The influence of the solution pH, amount of sorbent, contact time, temperature, foreign ion effect and initial U(VI) concentration was investigated. The maximum U(VI) uptake capacity was found to be 8.46 mg/g. (author)

  16. A plant wide aqueous phase chemistry model describing pH variations and ion speciation/pairing in wastewater treatment process models

    DEFF Research Database (Denmark)

    Flores-Alsina, X.; Mbamba, C. Kazadi; Solon, K.;

    There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico-chemical processes after many years of mainly focusing on biokinetics (Batstone et al., 2012). Indeed, future modelling needs, such as a plant-wide phosphorus (P) description...... presented and interfaced with industry standard models. The module involves extensive consideration of non-ideality by including ion activities instead of molar concentrations and complex ion pairing. The general equilibria are formulated as a set of Differential Algebraic Equations (DAEs) instead of...... cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated by implementing the aqueous phase chemistry module in some of the most frequently used WWTP process simulation models. Finally, it is shown how traditional wastewater modelling studies can be...

  17. Synthesis of Novel Polymeric Resins by Gamma Irradiation for Separation of In(III) ions from Cd(II) in Aqueous Media

    International Nuclear Information System (INIS)

    In this work, Zn(II)polymethacrylates and poly(acrylamide-acrylic acid) were prepared by gamma irradiation polymerization technique of the corresponding monomer at 30 kGy. The polymeric resins were mixed with Indium ions to determine its capacity in aqueous solutions using batch experiment. The adsorption efficiency of obtained polymeric resins toward In(III) and Cd(II) in different experimental conditions was established. Batch and column methods were applied for separation of indium and cadmium. The effects of various eluants such as H2SO4, NH4NO3, HNO3 and HCl on the recovery of both metal ions were studied. The polymeric resins may be regenerated using 3M HCl solutions.

  18. Design and test of the ion mobility spectrometer with corona discharge ion source

    International Nuclear Information System (INIS)

    In the present paper we describe in detail the design and construction of a home built ion mobility spectrometer with corona discharge as an ionization source. The ion mobility spectra have been recorded using the corona discharge in two different modes: i) chemical ionization and ii) direct ionization in the corona discharge. The chemical ionization of the organic compounds resulted in less fragmented ion mobility spectra in comparison to the direct ionization of the compounds in the corona discharge. The measured positive ion mobility spectra of several organic compounds including acetone, methanol, ethanol and benzene are presented. (Authors)

  19. Influence of NO2 and metal ions on oxidation of aqueous-phase S(IV in atmospheric concentrations

    Directory of Open Access Journals (Sweden)

    Cláudia R. Martins

    2008-06-01

    Full Text Available An investigation was made of the influence of atmospheric concentrations (15 or 130 ppbv of NO2 on the aqueous-phase oxidation rate of S(IV in the presence and absence of Fe(III, Mn(II and Cr(VI metal ions under controlled experimental conditions (pH, T, concentration of reactants, etc.. The reaction rate in the presence of the NO2 flow was slower than the reaction rate using only clean air with an initial S(IV concentration of 10-4 mol/L. NO2 appears to react with S(IV, producing a kind of inhibitor that slows down the reaction. Conversely, tenfold lower concentrations of S(IV ([S(IV]º = 10-5 mol/L caused a faster reaction in the presence of NO2 than the reaction using purified air. Under these conditions, therefore, the equilibrium shifts to sulfate formation. With the addition of Fe(III, Mn(II or Cr(VI in the presence of a NO2 flow, the reaction occurred faster under all the conditions in which S(IV oxidation was investigated.A reação de oxidação de S(IV em fase aquosa foi estudada em laboratório em presença de NO2 dos íons metálicos Fe(III, Mn(II, e Cr(VI sob condições experimentais controladas (pH, T, concentração dos reagentes, etc.. Na presença de corrente de ar com NO2 (15 ou 130 ppbv a reação de oxidação de S(IV ocorreu mais lentamente do que na presença de ar purificado, para uma concentração inicial de S(IV de 10-4 mol/L. Ao contrário, para concentração inicial de S(IV dez vezes menor ([S(IV]° = 10-5 mol/L a reação ocorreu mais rapidamente na presença de NO2. A explicação está relacionada com o equilíbrio envolvendo a formação de espécies intermediárias de longa vida, que impedem o prosseguimento da reação, porém a depender das concentrações relativas de S(IV e NO2, essas espécies se decompõem deslocando o equilíbrio no sentido de formação de sulfato. A adição dos íons Fe(III, Mn(II ou Cr(VI em presença de corrente de ar com NO2 indicou atividade catalítica para esses íons, em todas

  20. Acceleration test of heavy ion RFQ linac at TIT

    International Nuclear Information System (INIS)

    An 80 MHz heavy ion RFQ linac at Tokyo Institute of Technology (TIT) has been constructed for research on inertial fusion and plasma experiments. Equipment for beam acceleration has been fabricated and assembled to confirm the performance with low currents of the RFQ. The linac successfully accelerated He+ and C2+ ion beams to their final energies of 219 keV/u. The obtained beam transmission was more than 89% with currents of a few tens μA. (orig.)

  1. Synthesis of aqueous suspensions of magnetic nanoparticles with the co-precipitation of iron ions in the presence of aspartic acid

    Science.gov (United States)

    Pušnik, Klementina; Goršak, Tanja; Drofenik, Miha; Makovec, Darko

    2016-09-01

    There is increasing demand for the production of large quantities of aqueous suspensions of magnetic iron-oxide nanoparticles. Amino acids are one possible type of inexpensive, nontoxic, and biocompatible molecules that can be used as the surfactants for the preparation of stable suspensions. This preparation can be conducted in a simple, one-step process based on the co-precipitation of Fe3+/Fe2+ ions in the presence of the amino acid. However, the presence of this amino acid changes the mechanism of the magnetic nanoparticles' formation. In this investigation we analyzed the influence of aspartic amino acid (Asp) on the formation of magnetic iron-oxide nanoparticles during the co-precipitation. The process of the nanoparticles' formation was followed using a combination of TEM, x-ray diffractometry, magnetic measurements, in-situ FT-IR spectroscopy, and chemical analysis, and compared with the formation of nanoparticles without the Asp. The Asp forms a coordination complex with the Fe3+ ions, which impedes the formation of the intermediate iron oxyhydroxide phase and suppresses the growth of the final magnetic iron-oxide nanoparticles. Slower reaction kinetics can lead to the formation of nonmagnetic secondary phases. The aspartic-acid-absorbed nanoparticles can be dispersed to form relatively concentrated aqueous suspensions displaying a good colloidal stability at an increased pH.

  2. Effect of magnesium carbonate on the uptake of aqueous zinc and lead ions by natural kaolinite and clinoptilolite

    OpenAIRE

    Shahwan, Talal; Zünbül, B.; Eroğlu, Ahmet E.; S. Yılmaz

    2005-01-01

    Adsorption behavior of Zn2+ and Pb2+ ions on kaolinite and clinoptilolite, originating from natural resources, was studied as a function of contact time and concentration. Zn2+ and Pb2+ ions are quickly adsorbed on both minerals and the uptake of the latter is more favored. The uptake of both ions was then examined on kaolinite–MgCO3 and clinoptilolite–MgCO3 mixtures over a metal ions range from 1 to 10 000 mg/L. The sorption behavior of Zn2+ and Pb2+ on pure MgCO3 was also studied. MgCO3 is ...

  3. Synthesis and evaluation of different thio-modified cellulose resins for the removal of mercury (II) ion from highly acidic aqueous solutions.

    Science.gov (United States)

    Takagai, Yoshitaka; Shibata, Atsushi; Kiyokawa, Shigemi; Takase, Tsugiko

    2011-01-15

    Seven different types of thio- and/or amine-modified cellulose resin materials were synthesized and their mercury (II) ion adsorption properties determined. All seven resins showed good mercury (II) adsorption capability in the more neutral pH regions. However, the o-benzenedithiol- and o-aminothiophenol-modified cellulosic resins were found to be very effective in removing mercury (II) ions from strongly acidic media. For example, 93.5-100% mercury (II) ion recoveries from very acid aqueous solutions (nitric acid concentration ranged from 0.1 to 2.0 mol/L) were obtained using the o-benzenedithiol-modified resin while recoveries ranged from ca. 50% to 60% for the o-aminothiophenol-modified resin. An adsorption capacity of 23 mg (as Hg atoms) per gram of resin was observed for the o-benzenedithiol-modified cellulose in the presence of 1.0 mol/L nitric acid. This same resin shows very good selectivity for mercury (II) as only ruthenium (II) also somewhat adsorbed onto it out of 14 other metal ions studied (Ag(+), Al(3+), As(3+), Co(2+), Cd(2+), Cr(3+), Cu(2+), Fe(3+), Mn(2+), Ni(2+), Pt(2+), Pb(2+), Ru(2+), and Zn(2+)). PMID:20974469

  4. Luminescence quenching of [Os(bpy)3]2+ by Mn7+, Cr6+ and Ce4+ ions in acidic aqueous solution

    International Nuclear Information System (INIS)

    Luminescence quenching of [Os(bpy)3]2+ by Mn7+, Cr6+ and Ce4+ ions in acidic aqueous media are studied. Ground state interactions between [Os(bpy)3]2+ and these ions show ground state association with stoichiometric ratios in accordance with the electron transfer process. Positive deviation is observed from the linear Stern–Volmer relationship which with the ground state association is in support of static quenching mechanism. Benesi-HildEbrand equation was used to evaluate the association constant which were found to be 5×103 M−1, 6.6×104 M−1 and be 1.1×105 M−1 for association of [Os(bpy)3]2+ with Ce4+, Cr6+ and Mn7+, respectively, based on luminescence intensity measurements. Different models for static luminescence quenching were employed to discuss the results. - Highlights: • Pure luminescence static quenching of [Os(bpy)3]2+ by strong oxidizing agents are reported. • Ground state association is observed between [Os(bpy)3]2+ and Ce4+, Cr6+ and Mn7+ ions. • Interaction of [Os(bpy)3]2+ with these ions was found to depend on their stoichiometric ratios. • Emission intensity of [Os(bpy)3]2+ was found to depend on its uncomplexed concentration

  5. Removal of Pb(II) ions from aqueous solution using water hyacinth root by fixed-bed column and ANN modeling.

    Science.gov (United States)

    Mitra, Tania; Singha, Biswajit; Bar, Nirjhar; Das, Sudip Kumar

    2014-05-30

    Hyacinth root was used as a biosorbent for generating adsorption data in fixed-bed glass column. The influence of different operating parameters like inlet Pb(II) ion concentration, liquid flow rate and bed height on the breakthrough curves and the performance of the column was studied. The result showed that the adsorption efficiency increased with increase in bed height and decreased with increase in inlet Pb(II) ion concentration and flow rate. Increasing the flow rate resulted in shorter time for bed saturation. The result showed that as the bed height increased the availability of more number of adsorption sites in the bed increased, hence the throughput volume of the aqueous solution also increased. The adsorption kinetics was analyzed using different models. It was observed that maximum adsorption capacity increased with increase in flow rate and initial Pb(II) ion concentration but decreased with increase in bed height. Applicability of artificial neural network (ANN) modeling for the prediction of Pb(II) ion removal was also reported by using multilayer perceptron with backpropagation, Levenberg-Marquardt and scaled conjugate algorithms and four different transfer functions in a hidden layer and a linear output transfer function. PMID:24727010

  6. Single trapped cold ions: a testing ground for quantum mechanics

    International Nuclear Information System (INIS)

    In this article I review some results obtained during my PhD work in the group of Professor Messina, at the University of Palermo. I discuss some proposals aimed at exploring fundamental issues of quantum theory, e.g. entanglement and quantum superpositions, in the context of single trapped ions. This physical context turns out to be extremely well suited both for studying fundamental features of quantum mechanics, such as the quantum-classical border, and for technological applications such as quantum logic gates and quantum registers. I focus on some procedures for engineering nonclassical states of the vibrational motion of the centre of mass of the ion. I consider both the case in which the ion interacts with classical laser beams and the case of interaction with a quantized mode of light. In particular, I discuss the generation of Schroedinger cat-like states, Bell states and Greenberger-Horn-Zeilinger states. The schemes for generating nonclassical states stem from two different quantum processes: the parity effect and the quantum state manipulation via quantum non-demolition measurement. Finally, I consider a microscopic theory of the interaction of a quantum harmonic oscillator (the centre of mass of the ion in the trapped ion context) with a bosonic thermal environment. Using an exact approach to the dynamics, I discuss a quantum theory of heating of trapped ions able to describe both the short time non-Markovian regime and the thermalization process. I conclude showing briefly how the trapped ion systems can be used as simulators of key models of open quantum systems such as the Caldeira-Leggett model. (phd tutorial)

  7. “Turn on/off” proton transfer based fluorescent sensor for selective detection of environmentally hazardous metal ions (Zn2+, Pb2+) in aqueous media

    International Nuclear Information System (INIS)

    Sensing ability of fluorescence based chemosensor: Indole-7-carboxaldehyde (I7C) for environmentally hazardous metal ions (Xn+=Zn2+, Pb2+, Co2+, Ni2+, Cu2+, Cd2+, Cr3+, and Fe3+) has been investigated. Based on excited state proton transfer (ESPT) phenomenon, the sensing capability of I7C is verified experimentally (UV–vis, FTIR, NMR) and theoretically (DFT, TD-DFT) in aqueous media. Chemical hardness (η), electrophilicity (ω) and electronic chemical potentials (μ) confirm the selective reactivity of I7C (Nc and Nt conformers) in the presence of metal ions by the formation of (1:1) metal ion: I7C complex (MX, MX⁎). MX, MX⁎ are found to display excellent sensing capability for Zn2+ and Pb2+ ions. “Turn-On” response for Zn2+ is observed through the appearance of a new enhanced fluorescence at ~430 nm. By strong blue emission I7C establishes its strong candidature as “blue emitter”. “Turn-Off” response is observed for Pb2+ through the quenching of the existing fluorescence peak. - Highlights: • Indole-7-carboxaldehyde (I7C) shows “Turn-on” and “Turn-off” sensing for Zn2+ and Pb2+ ions. • I7C forms complex with metal ions (MX⁎). • 27-Fold strong blue fluorescence due to MZn⁎ formation indicates I7C as a good candidature to be used as blue emitter. • Computed (UV–vis absorption/emission, FTIR, NMR) data validate the experimental facts

  8. Development of a radioactive ion beam test stand at LBNL

    International Nuclear Information System (INIS)

    For the on-line production of a 14O+ ion beam, an integrated target transfer line ion source system is now under development at LBNL. 14O is produced in the form of CO in a high temperature carbon target using a 20 MeV 3He beam from the LBNL 88double-prime Cyclotron via the reaction 12C(3He,n)14O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O2 and CO are presented. Ionization efficiencies of 28% for Ar+, 1% for CO, 0.7% for O+, 0.33 for C+ have been measured. copyright 1999 American Institute of Physics

  9. Development of a radioactive ion beam test stand at LBNL

    International Nuclear Information System (INIS)

    For the on-line production of a 14O+ ion beam, an integrated target--transfer line ion source system is now under development at LBNL. 14O is produced in the form of CO in a high temperature carbon target using a 20 MeV 3He beam from the LBNL 88'' Cyclotron via the reaction 12C(3He,n)14O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O2 and CO are presented. Ionization efficiencies of 28% for Ar+, 1% for CO, 0.7% for O+, 0.33 for C+ have been measured

  10. Simultaneous adsorption of Ni(II and Mn(II ions from aqueous solution unto a Nigerian kaolinite clay

    Directory of Open Access Journals (Sweden)

    Folasegun Anthony Dawodu

    2014-04-01

    Full Text Available An unmodified Nigerian kaolinite clay (UAK was utilized as a low-cost adsorbent for the removal of Ni(II and Mn(II ions from a binary solution of both metal ions. Batch adsorption methodology was used to evaluate the effect of solution pH, initial metal ion concentration, sorbent dose, particle size, contact time, temperature and ligand on adsorption. FTIR, XRD and SEM analysis were used to characterize the adsorbent. The equilibrium isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R isotherm model. The Freundlich isotherm model provided the best fit to the experimental data for both metal ions as indicated by the values of the regression coefficient. The Langmuir monolayer maximum adsorption capacities for Ni(II and Mn(II ions are 166.67 mg/g and 111.11 mg/g, respectively. The kinetic data were analyzed using the pseudo-first order, pseudo-second order equations, the Elovich equation and intraparticle diffusion rate equation. The Elovich equation gave the best fit to the experimental data for both metal ions. The presence of intraparticle diffusion mechanism was indicated, although it was not the sole rate determining step. Thermodynamic studies indicated an endothermic, spontaneous and a physisorption process between both metal ions and UAK. The results showed that the kaolinite can be utilized as a low-cost adsorbent for the removal of Ni(II and Mn(II ions from solution.

  11. Selective chemosensor for Hg(II) ions based on tris[2-(4-phenyldiazenyl)phenylaminoethoxy]cyclotriveratrylene in aqueous samples

    NARCIS (Netherlands)

    Nuriman,; Kuswandi, Bambang; Verboom, Willem

    2009-01-01

    A novel chemosensor, based on tris[2-(4-phenyldiazenyl)phenylaminoethoxy]cyclotriveratrylene (TPPECTV) as chromophore, has been developed for the colorimetric determination and visual detection of Hg(II) ions. TPPECTV exhibits a pronounced chromogenic behavior toward Hg(II) ions by changing the colo

  12. Synthesis and characterization of a cryo gel starting from chitosan and their study as adsorbent of Cu (II) ions in aqueous solution

    International Nuclear Information System (INIS)

    The present work consisted in the synthesis of cryo gels from chitosan, which were cross-linked with ethylene glycol diglycidyl ether to obtain a stable, porous and resistant material to the interaction with aqueous solutions, in order that can be used in metal sorption processes. The performed synthesis consisted in a aqueous chitosan gel preparation crosslinked with ethylene glycol diglycidyl ether (Edge), evaluating two levels of crosslinking (1 and 2%); later to obtain the cryo gels, the aqueous gels were subjected to an ice segregation induced self-assembly process (ISISA), considering two levels of speed of materials formation. The obtained materials were characterized first determining their solubility in aqueous solutions and to the pair was determined the degree of swelling of the materials. Later, were used techniques like: the sweeping electronic microscopy to be able to observe the morphology of the obtained cryo gels, X-ray diffraction to know the crystallinity of the same, zeta potential with the aim of know the electrical potential in the materials, specific area determination, Fourier transformation infrared spectroscopy (Ftir) and X-ray photoelectrons spectroscopy (XP S), to know the functional groups and chemical interactions of the present elements in the materials before and after the copper ions sorption. The evaluation of the cryo gels as sorbents was performed obtaining the sorption kinetics for the Cu (II) ion at 25 and 30 grades C, and adjusting the experimental data obtained to the Lagergren and Ho kinetic models, as well as was performed adsorption isotherms at 25 and 35 grades C for the copper ion, adjusting the obtained data to the Langmuir, Freundlich and Langmuir-Freundlich models. In general, it was observed that the obtained materials show a macroporous structure, which presents and uniform swelling without significant deformations. Furthermore, was observed that the speed of formation of the materials affects the pores size and the

  13. RF testing of 75 MHz prototype heavy ion RFQ

    International Nuclear Information System (INIS)

    The Heavy Ion RFQ at Pelletron Accelerator Facility (PAF), Mumbai is designed (75 MHz) to accelerate ions with q/m of 1/7 from 10 keV/u to 575 keV /u over a vane length of 4.62 m. A prototype heavy ion RFQ, 1.42 m long with 1.34 m of modulated vanes is designed and fabricated to study the RF properties. Measurement of resonant frequency (f0), Quality factor (Q0), and shunt impedance Rsh was carried out using Vector Network Analyzer is reported. The vane is fabricated without any joint, significant effort was put in measuring the longitudinal and transverse field profile along the RFQ which will be discussed. The outcome of experimental measurements and simulation is compared. (author)

  14. ADSORPTION OF CHROMIUM (VI FROM AQUEOUS SOLUTIONS BY DIFFERENT ADMIXTURES – A BATCH EQUILIBRIUM TEST STUDY

    Directory of Open Access Journals (Sweden)

    K. SHIVA PRASHANTH KUMAR

    2014-08-01

    Full Text Available Wide variety of inorganic compounds such as nutrients and trace metals, organic chemicals, radioactive contaminants and pathogens are commonly present as contaminants in the groundwater. Migration of contaminants in soil involves important mechanisms such as molecular diffusion, dispersion under physical processes, adsorption, precipitation and oxidation - reduction under chemical processes and biodegradation under biological process. Cr (VI is a major and dangerous contaminant as per the ground water is concerned. There are numerous research work carried out with concentrated efforts by the researchers towards removal of Cr (VI contaminant from aqueous solutions. There are few studies relevant to Cr (VI removal with respect to utilization of low cost admixtures and also soil type. In the present study, different low cost admixtures like rice husk (RH, shredded tyre (ST and fly ash (FA are used to understand the performance in removal of Cr (VI from aqueous solution and also two different soil types are used along with the admixture. The results are discussed in terms of sorption capacity and performance of individual admixture and combination of admixture with soil in removal of contaminant. The fly ash, rice husk and shredded tyre admixtures are used and the results revealed that the shredded tyre showed higher performance in removal of contaminant concentration. Also, the soil which has more fine particle content (size<0.075 mm IS sieve showed reasonable reduction in concentration of contaminant at the lower levels of contaminant initial concentration. The sorption capacity results of Cr (VI contaminant, treated with various admixtures are further validated with the published work of other investigators. The shredded tyre (ST showed more adsorption capacity, i.e., 3.283 mg/g at pH of 4.8. For other admixtures, adsorption capacity value is varying in the range of 0.07 mg/g to 1.7 mg/g. Only in case of activated alumina and modified saw dust

  15. Inorganic ion exchangers based on manganese and potassium for recovery and removal of pollutant metals of aqueous effluents

    International Nuclear Information System (INIS)

    This work presents a study on the synthesis, characterization and ion exchange properties of inorganic ion exchangers based on manganese and potassium. The ion exchangers were synthesized by calcination of the mixture of manganese(II) oxalate and potassium oxalate and were characterized by granulometer distribution analysis, X-ray powder diffraction, infrared spectroscopy and scanning electron microscopic. From the data obtained in characterization it was observed that exist two distinguished groups of these materials. The first group belong to ion exchangers with up to 30% w/w potassium and the second group formed by the ion exchangers with more than 30% w / w of content of potassium in their compositions. The studies of adsorption of these materials showed that the adsorption of Cd2+ is a function of the following parameters as pH, concentration of Cd2+, time of contact between the ion exchangers the concentration of the Cd2+ solution and the interference of other ions like Ni2+. The great pH of adsorption for these materials occur in pH 9, the study of the influence of the cadmium concentration in the adsorption showed that for a group of exchangers the adsorption decreases with the increase of cadmium concentration and for the other group the adsorption increases with the increase of cadmium concentration. The kinetics of adsorption occur in a contact time between the ion exchangers and the Cd2+ solutions relatively short, at about 15 minutes is necessary to establish the equilibrium. The presence of Ni2+ as interfering ion decreases the adsorption of cadmium of 99,7% to 65%. These inorganic ion exchangers showed be good exchangers for Cd2+. (author)

  16. Citrate-capped quantum dots of CdSe for the selective photometric detection of silver ions in aqueous solutions

    International Nuclear Information System (INIS)

    A simple strategy for the synthesis of water soluble, luminescent, citrate-capped CdSe quantum dots (Q-CdSe) and their applications to selective detection of silver ions are described. The steady state photoluminescence (PL) spectra show single, narrow emission band at ca. 554 nm without any contribution from the trap states. The effect of various ions including physiologically important metal ions (viz. K+, Ca2+, Fe3+, Zn2+, Mg2+, Mn2+, Cu2+, Ag+, Pb2+ and Cd2+), on the PL intensity of citrate-capped Q-CdSe has been studied. Among these, selective luminescence quenching with Ag+ ion was found to be predominant. Under the optimum conditions, the response was linear between 1.7 and 18 μM. The quenching constant KSV was found to be ca. 3.4 x 105 M-1. The mechanism of photoluminescence quenching of Q-CdSe by metal ions (Ag+) is also discussed. Based on these studies, the potential use of Q-CdSe as a luminescent probe for the selective detection of silver ion has been proposed. -- Graphical abstract: A simple strategy for the synthesis of water soluble, luminescent, citrate-capped quantum dots of CdSe (Q-CdSe) has been developed. The effect of various ions including physiologically important metal ions (viz. K+, Ca2+, Fe3+, Zn2+, Mg2+, Mn2+, Cu2+, Ag+, Pb2+ and Cd2+), on the luminescence intensity of citrate-capped Q-CdSe has been studied. Among these, a significant luminescence quenching only by Ag+ ions was observed which suggests the potential use of Q-CdSe as a luminescent sensor for the selective optical detection of silver ions in a physiological condition.

  17. Biosorption of Cd(II) and Pb(II) ions by aqueous solutions of novel alkalophillic Streptomyces VITSVK5 spp. biomass

    Science.gov (United States)

    Saurav, Kumar; Kannabiran, Krishnan

    2011-03-01

    Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution. The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species. The biosorption property of Streptomyces VITSVK5 spp. was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb). Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L-1, cadmium 3.1±0.3μg L-1, zinc 8.4±2.6μg L-1 and copper 0.3±0.1μg L-1, whereas mercury was well below the detection limit. The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated. The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively. The biosorbent dosage was optimized as 3 g L-1 for both the trace metals. Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (-COOH), hydroxyl (-CHOH) and amine (-NH2) groups of biomass with the metal ions. This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp. The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

  18. Preparation of cross-linked magnetic chitosan-phenylthiourea resin for adsorption of Hg(II), Cd(II) and Zn(II) ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Abdel-Latif, D.A. [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Chitosan was chemically modified through the reaction with phenylisothiocyanate. Black-Right-Pointing-Pointer The modified chitosan-phenylthiourea cross-linked with formaldehyde in presence of magnetite to produce modified magnetic resin. Black-Right-Pointing-Pointer The resulted resin characterized by various instrumental methods. Black-Right-Pointing-Pointer The resin was applied to remove Hg{sup 2+}, Cd{sup 2+} and Zn{sup 2+} from aqueous solutions. - Abstract: In this study, cross-linked magnetic chitosan-phenylthiourea (CSTU) resin were prepared and characterized by means of FTIR, {sup 1}H NMR, SEM high-angle X-ray diffraction (XRD), magnetic properties and thermogravimetric analysis (TGA). The prepared resin were used to investigate the adsorption properties of Hg(II), Cd(II) and Zn(II) metal ions in an aqueous solution. The extent of adsorption was investigated as a function of pH and the metal ion removal reached maximum at pH 5.0. Also, the kinetic and thermodynamic parameters of the adsorption process were estimated. These data indicated that the adsorption process is exothermic and followed the pseudo-second-order kinetics. Equilibrium studies showed that the data of Hg(II), Cd(II) and Zn(II) adsorption followed the Langmuir model. The maximum adsorption capacities for Hg(II), Cd(II) and Zn(II) were estimated to be 135 {+-} 3, 120 {+-} 1 and 52 {+-} 1 mg/g, which demonstrated the high adsorption efficiency of CSTU toward the studied metal ions.

  19. Biosorption of Cd(Ⅱ)and Pb(Ⅱ)Ions by Aqueous Solutions of Novel Alkalophillic Streptomyces VITSVK5 spp.Biomass

    Institute of Scientific and Technical Information of China (English)

    Kumar Saurav; Krishnan Kannabiran

    2011-01-01

    Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution.The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species.The biosorption property of Streptomyces VITSVK5 spp.was investigated by absorbing heavy metals Cadmium(Cd)and Lead(Pb).Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L·1,cadmium 3.1±0.3 μg L·1,zinc 8.4±2.6μg L·1 and copper 0.3±0.1μg L·1,whereas mercury was well below the detection limit.The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated.The optimum pH for maximal biosorption was4.0 for Cd(Ⅱ)and 5.0 for Pb(Ⅱ)with 41% and 84% biosorption respectively.The biosorbent dosage was optimized as 3 g L-1 for both the trace metals.Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl(-COOH),hydroxyl(-CHOH)and amine(-NH2)groups of biomass with the metal ions.This could be mainly involved in the biosorption of Cd(Ⅱ)and Pb(Ⅱ)onto Streptomyces VITSVK5 spp.The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

  20. A PEGylated fluorescent turn-on sensor for detecting fluoride ions in totally aqueous media and its imaging in live cells.

    Science.gov (United States)

    Zheng, Fangyuan; Zeng, Fang; Yu, Changmin; Hou, Xianfeng; Wu, Shuizhu

    2013-01-14

    Owing to the considerable significance of fluoride anions for health and environmental issues, it is of great importance to develop methods that can rapidly, sensitively and selectively detect the fluoride anion in aqueous media and biological samples. Herein, we demonstrate a robust fluorescent turn-on sensor for detecting the fluoride ion in a totally aqueous solution. In this study, a biocompatible hydrophilic polymer poly(ethylene glycol) (PEG) is incorporated into the sensing system to ensure water solubility and to enhance biocompatibility. tert-Butyldiphenylsilyl (TBDPS) groups were then covalently introduced onto the fluorescein moiety, which effectively quenched the fluorescence of the sensor. Upon addition of fluoride ion, the selective fluoride-mediated cleavage of the Si-O bond leads to the recovery of the fluorescein moiety, resulting in a dramatic increase in fluorescence intensity under visible light excitation. The sensor is responsive and highly selective for the fluoride anion over other common anions; it also exhibits a very low detection limit of 19 ppb. In addition, this sensor is operative in some real samples such as running water, urine, and serum and can accurately detect fluoride ions in these samples. The cytotoxicity of the sensor was determined to be Grade I toxicity according to United States Pharmacopoeia and ISO 10993-5, suggesting the very low cytotoxicity of the sensor. Moreover, it was found that the senor could be readily internalized by both HeLa and L929 cells and the sensor could be utilized to track fluoride level changes inside the cells. PMID:23197478

  1. Removal of uranium(VI) ions from aqueous solutions using Schiff base functionalized SBA-15 mesoporous silica materials.

    Science.gov (United States)

    Dolatyari, Leila; Yaftian, Mohammad Reza; Rostamnia, Sadegh

    2016-03-15

    Functionalized SBA-15 mesoporous silica particles, bearing N-propylsalicylaldimine and ethylenediaminepropylesalicylaldimine Schiff base ligands, abbreviated as SBA/SA and SBA/EnSA respectively, were prepared and characterized by FT-IR, elemental analysis, TGA, XRD, TEM and SEM techniques. The potentials of these adsorbents were examined by using them in solid phase extraction of U(VI) ions from water samples. It is shown that 20 mg of SBA/SA or SBA/EnSA can remove rapidly (∼15 min) and quantitatively uranium(VI) ions from 10 to 200 mL of water solutions (pH 4) containing 0.2 mg of the ions, at 25 °C. The adsorbed ions were stripped by 1 mL of dilute nitric acid solution (0.1 mol L(-1)). It means that the studied adsorbents are able to be used for removal and concentration of uranyl ions. This allowed achieving to a concentration factor of 200 for uranyl ions. The variation in the ionic strength in the range 0-1 mol L(-1) did not affect the extraction efficiencies of the adsorbents. The adsorbents showed selective separation of uranyl ions from Cd(2+), Co(2+), Ni(2+), Mn(2+), Cr(3+), Ba(2+), Fe(3+) and Eu(3+) ions. Thermodynamic investigations revealed that the adsorption of uranyl ions by the adsorbents was spontaneous and endothermic. The Langmuir model described suitably the adsorption isotherms. This model determined the maximum adsorption capacity of the adsorbents SBA/SA and SBA/EnSA as 54 and 105.3 mg uranyl/g adsorbent, respectively. The kinetics of the processes was interpreted by using Pseudo-second-order model. PMID:26720327

  2. Large-scale tests of aqueous scrubber systems for LMFBR vented containment

    International Nuclear Information System (INIS)

    Six large-scale air cleaning tests performed in the Containment Systems Test Facility (CSTF) are described. The test conditions simulated those postulated for hypothetical accidents in an LMFBR involving containment venting to control hydrogen concentration and containment overpressure. Sodium aerosols were generated by continously spraying sodium into air and adding steam and/or carbon dioxide to create the desired Na2O2, Na2CO3 or NaOH aerosol. Two air cleaning systems were tested: (a) spray quench chamber, educator venturi scrubber and high efficiency fibrous scrubber in series; and (b) the same except with the spray quench chamber eliminated. The gas flow rates ranged up to 0.8 m3/s (1700 acfm) at temperatures to 3130C (6000F). Quantities of aerosol removed from the gas stream ranged up to 700 kg per test. The systems performed very satisfactorily with overall aerosol mass removal efficiencies exceeding 99.9% in each test

  3. Formation of ozone in the reaction between the ozonide radical ion, O/sub 3//sup -/, and the carbonate radical ion, CO/sub 3//sup -/, in aqueous alkaline solutions. [Electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Holcman, J.; Sehested, K.; Bjergbakke, E.; Hart, E.J.

    1982-05-27

    Ozone forms in aqueous alkaline solutions by a reaction between the O/sub 3//sup -/ and CO/sub 3//sup -/ radical ions. This reaction has been demonstrated under conditions favorable for the generation of suitable concentrations of these ions by a high-pressure pulse radiolysis technique. The reaction is O/sub 3//sup -/ + CO/sub 3//sup -/ ..-->.. O/sub 3/ + CO/sub 3//sup 2 -/. Its rate constant k/sub (O/sub 3//sup -/+CO/sub 3//sup -/)/ of (6 +- 2) x 10/sup 7/ dm/sup 3/ mol/sup -1/ s/sup -1/ has been determined by computer simulation of the reactions involved.

  4. EQUILIBRIUM MODELLING AND SPECTROSCOPIC STUDIES FOR THE BIOSORPTION OF ZN+2 IONS FROM AQUEOUS SOLUTION USING IMMOBILIZED SPIRULINA PLATENSIS

    OpenAIRE

    N. Gaur ، R. Dehankhar

    2009-01-01

    Biosorption equilibrium of zinc ions to Spirulina platensis both in free and immobilized forms were studied in batch system with respect to pH, metal ion concentration, algal dosages and time. The maximum adsorption was observed at pH=8, optimum metal ion concentration and algal dose were 100 mg/L and 1g/100mL, respectively. Biosorption equilibrium was established in 90 minutes. The maximum attainable biosorption was found to be 97.1% for Spirulina platensis. The equilibrium adsorption capaci...

  5. Production and test of {sup 18}F samples in the SNICS ion source

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K.E.; Paul, M. [Hebrew Univ., Jerusalem (Israel); Roberts, A.; Nickels, J. [Univ. of Wisconsin, Madison, MO (United States)

    1995-08-01

    For experiments with {sup 18}F beams the output of the SNICS ion source for fluorine ions was investigated. {sup 18}F, which is a well-studied PET isotope, is generated at the medical cyclotron of the University of Wisconsin. Aqueous [{sup 18}F] fluoride ions are produced via the {sup 18}O(p,n){sup 18}F reaction using a 30-{mu}A, 11.4-MeV proton beam bombarding a 95% enriched [{sup 18}O] water target. In order to minimize the {sup 18}O component of the {sup 18}F material the [{sup 18}F] fluoride must be separated from the [{sup 18}O] water. For this purpose the aqueous [{sup 18}F] fluoride solution ({approximately} 0.5-1 ml) is removed from the production target and placed in a glassy carbon vessel. The vessel is heated to 115{degrees}C with He bubbling through the solution, evaporating the water while the {sup 18}F adheres to the vessel walls. When dry, the vessel is filled with 1 ml {sup 18}O-depleted 99.98% [{sup 16}O] water which is again evaporated. After this step is repeated once more the vessel is filled with 1.5 ml [{sup 16}O] water and 200-300 mole of natural KF as carrier material.

  6. Rapid and efficient removal of fluoride ions from aqueous solution using a polypyrrole coated hydrous tin oxide nanocomposite.

    Science.gov (United States)

    Parashar, Kamya; Ballav, Niladri; Debnath, Sushanta; Pillay, Kriveshini; Maity, Arjun

    2016-08-15

    Polypyrrole/hydrous tin oxide nanocomposites (PPy/HSnO NC 1, 2, 3, 4 and 5) were synthesized through encapsulating HSnO by the PPy via an in situ polymerization for fluoride removal. The optimized adsorbent i.e. PPy/HSnO NC 3 was characterized using FE-SEM, HR-TEM, ATR-FTIR, XRD, BET, TGA and zeta sizer. Microscopic images revealed the encapsulation of HSnO by precipitating PPy during polymerization. The FTIR and XRD studies confirmed the presence of both constituents. The BET surface area and pHpzc of the adsorbent were estimated to be 65.758m(2)/g and 7.6, respectively. The fluoride adsorption followed pseudo-second-order model and was commendably rapid. The monolayer adsorption capacity was found to be 26.16-28.99mg/g at pH 6.5±0.1. The thermodynamic parameters indicated the sorption of F(-) was spontaneous, endothermic and that physisorption occurred. The calculated activation energy (Ea∼20.05kJ/mol) provided further evidence of a physisorption mechanism. Moreover, the adsorbent performed very well over a considerably wide pH range of 3.5-8.5 and in the presence of other co-existing ions. The regeneration of the F(-) laden PPy/HSnO NC 3 showed a high desorption efficiency of 95.81% up to 3 cycles. Ground water tested results also demonstrate the potential utility of the PPy/HSnO NC as an effective adsorbent. PMID:27209396

  7. Robust long-distance entanglement and a loophole-free Bell test with ions and photons

    OpenAIRE

    Simon, Christoph; Irvine, William T M

    2003-01-01

    Two trapped ions that are kilometers apart can be entangled by the joint detection of two photons, each coming from one of the ions, in a basis of entangled states. Such a detection is possible with linear optical elements. The use of two-photon interference allows entanglement distribution without interferometric sensitivity to the path length of the photons. The present method of creating entangled ions also opens up the possibility of a loophole-free test of Bell's inequalities.

  8. Molecular dynamics simulation study of ionic hydration and ion association in dilute and 1 molal aqueous sodium chloride solutions from ambient to supercritical conditions

    Science.gov (United States)

    Driesner, T.; Seward, T. M.; Tironi, I. G.

    1998-09-01

    The increasing demand for accurate equations of state of fluids under extreme conditions and the need for a detailed microscopic picture of aqueous fluids in some areas of geochemistry (e.g., mineral dissolution/precipitation kinetics) potentially make molecular dynamics (MD) simulations a powerful tool for theoretical geochemistry. We present MD simulations of infinitely dilute and 1 molal aqueous NaCl solutions that have been carried out in order to study the systematics of hydration and ion association over a wide range of conditions from ambient to supercritical and compare them to the available experimental data. In the dilute case, the hydration number of the Na + ion remains essentially constant around 5.5 from ambient to supercritical temperatures when the density is kept constant at 1 g cm -3 but decreases to below 5 along the liquid-vapor curve. In both cases, the average ion-first shell water distance decreases by about 0.03 Å from ambient to near critical temperatures. The Cl - ion shows a slight expansion of the first hydration shell by about 0.02 Å from ambient to near critical temperatures. The geometric definition of the first hydration shell becomes ambiguous due to a shift of the position of the first minimum of the Cl-O radial distribution function. In the case of the 1 molal solution, the contraction of the Na + first hydration shell is similar to that in the dilute case whereas the hydration number decreases drastically from 4.9 to 2.8 due to strong ion association. The released waters are replaced on a near 1:1 basis by chloride ions. Polynuclear clusters as predicted by Oelkers and Helgeson (1993b) are observed in the high temperature systems. The hydration shell of the Cl --ion shows significant deviation from the behavior in dilute systems, that is, at near vapor saturated conditions, the expansion of the hydration shell is significantly larger (0.12 Å from ambient to near critical temperatures). Due to a very large shift of the first

  9. Immobilization of 5-aminopyridine-2-tetrazole on cross-linked polystyrene for the preparation of a new adsorbent to remove heavy metal ions from aqueous solution

    International Nuclear Information System (INIS)

    Highlights: • Novel chelating resin was prepared using pyridine-2-tetrazole as ligand. • The resin has quite high adsorption capacity for Cu(II), Pb(II) and Hg(II). • The resin shows the different selectivity from the common used IDA resin. • The preparation procedure is a two-step reaction and is easy to carry out. - Abstract: Novel 5-aminopyridine-2-tetrazole-functionalized polystyrene resin (APTZ-PS) was prepared by anchoring 5-aminopyridine-2-carbonitrile onto chloromethylated polystyrene beads (CMPS) and subsequently using the cyano-tetrazole conversion reaction. The APTZ-PS resin was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and specific surface area and pore size analyses. The adsorption experiments of the prepared resin for heavy metal ions were conducted by batch methods. The effects of the experimental conditions, such as pH, contact time and initial metal ion concentration on the adsorption properties of Cu(II), Pb(II) and Hg(II) were investigated. The results showed that the resin possessed perfect adsorption capacities for Cu(II), Pb(II) and Hg(II), and the selectivity was different from the commonly used iminodiacetic acid-chelating resin. The sorption kinetics of the three metal ions followed the pseudo-second-order equation. The adsorption isotherms for Cu(II) and Pb(II) could be better fitted by the Langmuir model than the Freundlich model, whereas the Freundlich model was the best for the Hg(II) ion. Even after five consecutive adsorption–desorption cycles, no obvious change in the adsorption capacity of the resin was found, which implied that the APTZ-PS resin was suitable for the efficient removal of heavy metal ions from aqueous solution

  10. Immobilization of 5-aminopyridine-2-tetrazole on cross-linked polystyrene for the preparation of a new adsorbent to remove heavy metal ions from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Chen, Youning; Wang, Chaozhan; Wei, Yinmao, E-mail: ymwei@nwu.edu.cn

    2014-07-15

    Highlights: • Novel chelating resin was prepared using pyridine-2-tetrazole as ligand. • The resin has quite high adsorption capacity for Cu(II), Pb(II) and Hg(II). • The resin shows the different selectivity from the common used IDA resin. • The preparation procedure is a two-step reaction and is easy to carry out. - Abstract: Novel 5-aminopyridine-2-tetrazole-functionalized polystyrene resin (APTZ-PS) was prepared by anchoring 5-aminopyridine-2-carbonitrile onto chloromethylated polystyrene beads (CMPS) and subsequently using the cyano-tetrazole conversion reaction. The APTZ-PS resin was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and specific surface area and pore size analyses. The adsorption experiments of the prepared resin for heavy metal ions were conducted by batch methods. The effects of the experimental conditions, such as pH, contact time and initial metal ion concentration on the adsorption properties of Cu(II), Pb(II) and Hg(II) were investigated. The results showed that the resin possessed perfect adsorption capacities for Cu(II), Pb(II) and Hg(II), and the selectivity was different from the commonly used iminodiacetic acid-chelating resin. The sorption kinetics of the three metal ions followed the pseudo-second-order equation. The adsorption isotherms for Cu(II) and Pb(II) could be better fitted by the Langmuir model than the Freundlich model, whereas the Freundlich model was the best for the Hg(II) ion. Even after five consecutive adsorption–desorption cycles, no obvious change in the adsorption capacity of the resin was found, which implied that the APTZ-PS resin was suitable for the efficient removal of heavy metal ions from aqueous solution.

  11. Simple optical determination of silver ion in aqueous solutions using benzo crown-ether modified gold nanoparticles

    International Nuclear Information System (INIS)

    We describe a method for the modification of gold nanoparticles (Au-NPs) with benzo-15-crown-5 that led to the development of a colorimetric assay for Ag(I) ion. The brown color of a solution of the modified Au-NPs turns to purple on addition of Ag(I) ion. The ratio of the UV-vis absorption at 600 nm and 525 nm is proportional to the concentration of Ag(I) ions in the range from 20 to 950 nM, and the detection limit is 12.5 nM. Other metal ions do not interfere if present in up to millimolar concentrations. The method enables a rapid determination of Ag(I) in lake and drinking water and is amenable to bare-eye readout. (author)

  12. The influence of metal ions on the photocatalytic oxidation of 2-chlorophenol in aqueous titanium dioxide suspensions

    International Nuclear Information System (INIS)

    This study investigated the effect of metal ions,such as Fe3+, Cu2+, Ni2+, Cr3+ and Zn2+, on the photocatalytic oxidation of 2-chlorophenol with illumination of 254 nm and 365 nm UV lights. Different metal ions have individual reduction potentials, and hence, their abilities to capture electrons also differ; the rates of 2-chlorophenol decomposition vary as well. This study was made to explore the relationships between the reduction potentials of different metal ions and their photocatalytic rates of 2-chlorophenol. Results show that when the reduction potential is greater than zero, regardless of illumination wavelength, the reaction rate increases with increasing reduction potentials of the metal ions. When the reduction potential is less than zero, the reaction rates are about the same for illumination of 365 nm or 254 nm UV lights. (author)

  13. A napthelene-pyrazol conjugate: Al(III) ion-selective blue shifting chemosensor applicable as biomarker in aqueous solution.

    Science.gov (United States)

    Mukherjee, Manjira; Pal, Siddhartha; Lohar, Somenath; Sen, Buddhadeb; Sen, Supriti; Banerjee, Samya; Banerjee, Snehasis; Chattopadhyay, Pabitra

    2014-10-01

    A newly synthesized and crystalographically characterized napthelene–pyrazol conjugate, 1-[(5-phenyl-1H-pyrazole-3-ylimino)-methyl]-naphthalen-2-ol (HL) behaves as an Al(III) ion-selective chemosensor through internal charge transfer (ICT)-chelation-enhanced fluorescence (CHEF) processes in 100 mM HEPES buffer (water–DMSO 5:1, v/v) at biological pH with almost no interference of other competitive ions. This mechanism is readily studied from electronic, fluorimetric and (1)H NMR titration. The probe (HL) behaved as a highly selective fluorescent sensor for Al(III) ions as low as 31.78 nM within a very short response time (15–20 s). The sensor (HL), which has no cytotoxicity, is also efficient in detecting the distribution of Al(III) ions in HeLa cells via image development under fluorescence microscope. PMID:25075382

  14. Molecular dynamics study of linear and comb-like polyelectrolytes in aqueous solution: effect of Ca2+ ions

    Science.gov (United States)

    Tong, Kefeng; Song, Xingfu; Sun, Shuying; Xu, Yanxia; Yu, Jianguo

    2014-08-01

    All-atom molecular dynamics simulations were employed to provide microscopic mechanism for the salt tolerance of polyelectrolytes dispersants. The conformational variation of polyelectrolytes and interactions between COO- groups and counterions/water molecules were also studied via radius of gyration and pair correlations functions. Sodium polyacrylate (NaPA) and sodium salts of poly(acrylic acid)-poly(ethylene oxide) (NaPA-PEO) were selected as the representative linear and comb-like polyelectrolyte, respectively. The results show that Ca2+ ions interact with COO- groups much stronger than Na+ ions and can bring ion-bridging interaction between intermolecular COO- groups in the NaPA systems. While in the NaPA-PEO systems, the introduced PEO side chains can prevent backbone chains from ion-bridging interactions and weaken the conformational changes. The present results can help in selecting and designing new-type efficient polyelectrolyte dispersants with good salt tolerance.

  15. Investigation of complexing reactions of terbium(3) ions with anions of salicylic and 5-sulfosalicylic acids in aqueous solutions

    International Nuclear Information System (INIS)

    Complexing of terbium(3) ions with anions of salicylic and 5-sulfosalicylic acids was investigated by luminescence-kinetic method. Values of stability and dissociation constants of formed complexes were obtained

  16. The Development of Ionophore-Selective Based optical chemical sensors for the determination of heavy metal ions in aqueous environments

    OpenAIRE

    Li, Li

    2010-01-01

    The development of optical sensors for in-situ, real-time and low-cost monitoring of heavy metal ions is a tremendously and fast growing area of research. This work presents several novel sensing strategies for developing optical chemical sensors that can be used as early warning devices for heavy metal pollution in water. The optical sensors that are comprised of metal chelating reagent, together with an ion carrier immobilised within polymeric thin films, i.e. hybrid sol-gel ...

  17. Synthesis and characterization of a surface-grafted Cd(II) ion-imprinted polymer for selective separation of Cd(II) ion from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Min [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Feng, Changgen, E-mail: cgfeng@cast.org.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Li, Mingyu; Zeng, Qingxuan; Gan, Qiang [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Yang, Haiyan [Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-03-30

    Highlights: • Cd(II) ion-imprinted polymer (Cd(II)-IIP) is prepared. • Cd(II)-IIP shows high stability, good selectivity and reusability. • Cd(II)-IIP can be used as a sorbent for selective removal of Cd(II) ion. - Abstract: A novel Cd(II) ion-imprinted polymer (Cd(II)-IIP) was prepared with surface imprinting technology by using cadmium chloride as a template and allyl thiourea (ATU) as a functional monomer for on-line solid-phase extraction of trace Cd(II) ion and selective separation Cd(II) ion in water samples. The Cd(II)-IIP exhibited good chemical performance and thermal stability. Kinetics studies showed that the equilibrium adsorption was achieved within 8.0 min and the adsorption process can be described by pseudo-second-order kinetic model. Compared to the Cd(II) non-imprinted polymer (Cd(II)-NIP), the Cd(II)-IIP had a higher adsorption capacity and selectivity for Cd(II) ion. The maximum adsorption capacities of the Cd(II)-IIP and Cd(II)-NIP for Cd(II) were 38.30 and 13.21 mg g{sup −1}, respectively. The relative selectivity coefficients of the adsorbent for Cd(II) in the presence of Cu{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Pb{sup 2+} and Zn{sup 2+} were 2.86, 6.42, 11.50, 9.46 and 3.73, respectively. In addition, the Cd(II) ion adsorbed was easy to remove from sorbent and the Cd(II)-IIP exhibited good stability and reusability. The adsorption capacity had no obvious decrease after being used six times. The accuracy of this method was verified by the standard reference material, it was then applied for cadmium ion determination in different types of water samples.

  18. Synthesis and characterization of a surface-grafted Cd(II) ion-imprinted polymer for selective separation of Cd(II) ion from aqueous solution

    International Nuclear Information System (INIS)

    Highlights: • Cd(II) ion-imprinted polymer (Cd(II)-IIP) is prepared. • Cd(II)-IIP shows high stability, good selectivity and reusability. • Cd(II)-IIP can be used as a sorbent for selective removal of Cd(II) ion. - Abstract: A novel Cd(II) ion-imprinted polymer (Cd(II)-IIP) was prepared with surface imprinting technology by using cadmium chloride as a template and allyl thiourea (ATU) as a functional monomer for on-line solid-phase extraction of trace Cd(II) ion and selective separation Cd(II) ion in water samples. The Cd(II)-IIP exhibited good chemical performance and thermal stability. Kinetics studies showed that the equilibrium adsorption was achieved within 8.0 min and the adsorption process can be described by pseudo-second-order kinetic model. Compared to the Cd(II) non-imprinted polymer (Cd(II)-NIP), the Cd(II)-IIP had a higher adsorption capacity and selectivity for Cd(II) ion. The maximum adsorption capacities of the Cd(II)-IIP and Cd(II)-NIP for Cd(II) were 38.30 and 13.21 mg g−1, respectively. The relative selectivity coefficients of the adsorbent for Cd(II) in the presence of Cu2+, Ni2+, Co2+, Pb2+ and Zn2+ were 2.86, 6.42, 11.50, 9.46 and 3.73, respectively. In addition, the Cd(II) ion adsorbed was easy to remove from sorbent and the Cd(II)-IIP exhibited good stability and reusability. The adsorption capacity had no obvious decrease after being used six times. The accuracy of this method was verified by the standard reference material, it was then applied for cadmium ion determination in different types of water samples

  19. Preparation of cross-linked magnetic chitosan-phenylthiourea resin for adsorption of Hg(II), Cd(II) and Zn(II) ions from aqueous solutions.

    Science.gov (United States)

    Monier, M; Abdel-Latif, D A

    2012-03-30

    In this study, cross-linked magnetic chitosan-phenylthiourea (CSTU) resin were prepared and characterized by means of FTIR, (1)H NMR, SEM high-angle X-ray diffraction (XRD), magnetic properties and thermogravimetric analysis (TGA). The prepared resin were used to investigate the adsorption properties of Hg(II), Cd(II) and Zn(II) metal ions in an aqueous solution. The extent of adsorption was investigated as a function of pH and the metal ion removal reached maximum at pH 5.0. Also, the kinetic and thermodynamic parameters of the adsorption process were estimated. These data indicated that the adsorption process is exothermic and followed the pseudo-second-order kinetics. Equilibrium studies showed that the data of Hg(II), Cd(II) and Zn(II) adsorption followed the Langmuir model. The maximum adsorption capacities for Hg(II), Cd(II) and Zn(II) were estimated to be 135 ± 3, 120 ± 1 and 52 ± 1 mg/g, which demonstrated the high adsorption efficiency of CSTU toward the studied metal ions. PMID:22277339

  20. Adsorption of Hg2+, Cu2+ and Zn2+ ions from aqueous solution using formaldehyde cross-linked modified chitosan-thioglyceraldehyde Schiff's base.

    Science.gov (United States)

    Monier, M

    2012-04-01

    A chitosan-thioglyceraldehyde Schiff's base cross-linked magnetic resin (CSTG) was prepared and characterized using various instrumental methods. Then, the prepared resin was used for comparative studies on the removal of toxic metal ions like: Hg(2+), Cu(2+) and Zn(2+) from aqueous solutions. The effects of the initial pH value of the solution, contact time, the initial metal ion concentration and temperature on the adsorption capacity of the composite were investigated. The kinetics data were analyzed by pseudo-first order and pseudo-second order equations. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Langmuir equation. The maximum theoretical adsorption capacities of the CSTG resin for Hg(2+), Cu(2+) and Zn(2+) were found to be 98±2, 76±1 and 52±1 mg g(-1), respectively. The negative values of Gibbs free energy of adsorption (ΔG(ads°) indicated the spontaneity of the adsorption of all metal ions on the novel resin. PMID:22155403

  1. Chemical enrichment and separation of uranyl ions in aqueous media using novel polyurethane foam chemically grafted with different basic dyestuff sorbents.

    Science.gov (United States)

    El-Shahat, M F; Moawed, E A; Farag, A B

    2007-01-15

    The new type of the grafted polyurethane foam sorbents were prepared by coupling polyether polyol, toluene diisocyanate and basic dyestuff (Methylene blue, Rhodamine B and Brilliant green). The Me.B-PUF, Rh.B-PUF and Br.G-PUF were characterized using UV/vis, IR and TGA. The adsorption properties and chromatographic behaviour of these new adsorbents for preconcentration and separation of uranium(VI) ions at low concentrations from aqueous thiocyanate media were investigated by a batch process. The maximum sorption of U(VI) was in the pH ranges 1-4. The kinetics of sorption of the U(VI) by the Grafted-PUF were found to be fast with half life of sorption (t(1/2)) in 2.43min. The average sorption capacity of different sorbents 0.124meqg(-1) for uranyl ions, enrichment factors approximately 40 and the recovery 98-100% were achieved (R.S.D. approximately 0.73%). The basic dyestuff Grafted-PUF could be used many times without decreasing their capacities significantly. The value of the Gibbs free energy (DeltaG) for the sorbents is -7.3kJmol(-1), which reflects the spontaneous nature of sorption process. The sorption mechanism of the metal ion onto Grafted-PUF was also discussed. PMID:19071294

  2. Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: Equilibrium, kinetic and thermodynamic study

    International Nuclear Information System (INIS)

    The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g-1 for 10 g L-1 of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 oC. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

  3. EQUILIBRIUM MODELLING AND SPECTROSCOPIC STUDIES FOR THE BIOSORPTION OF ZN+2 IONS FROM AQUEOUS SOLUTION USING IMMOBILIZED SPIRULINA PLATENSIS

    Directory of Open Access Journals (Sweden)

    N. Gaur ، R. Dehankhar

    2009-01-01

    Full Text Available Biosorption equilibrium of zinc ions to Spirulina platensis both in free and immobilized forms were studied in batch system with respect to pH, metal ion concentration, algal dosages and time. The maximum adsorption was observed at pH=8, optimum metal ion concentration and algal dose were 100 mg/L and 1g/100mL, respectively. Biosorption equilibrium was established in 90 minutes. The maximum attainable biosorption was found to be 97.1% for Spirulina platensis. The equilibrium adsorption capacities of adsorbents used for zinc ions were measured and extrapolated using Langmuir and Freundlich isotherms models. Langmuir model was found to be in better correlation with experimental data. The maximum Langmuir constants Q◦ (mg/g and b were 92.93 and 0.0012, respectively for Spirulina platensis embedded in calcium alginate matrix. The immobilized Spirulina platensis in calcium of alginate matrix was the best biosorbent. 0.1 M EDTA was used as an eluant, which allowed the reuse of biomass in three biosorption-desorption cycles without considerable loss in biosorption capacity. 89-95 % zinc ions were desorbed with EDTA. The functional groups involved in zinc biosorption were identified by using Fourier Transform Infra Red spectroscopy. Spectroscopic analysis of algae revealed the presence of carboxyl, hydroxyl, amino, amide and imine groups, which were responsible for biosorption of zinc ions.

  4. A test stand for off-line laser ion source development at TRIUMF

    International Nuclear Information System (INIS)

    A test stand for ion source development and laser resonance ionization spectroscopy was built and commissioned at TRIUMF. The test stand is needed to develop efficient ion sources that can function reliably in the hostile, high temperature, high radiation environment of TRIUMF's isotope separator on-line (ISOL) production target ion source. In addition, it enables laser resonance ionization spectroscopy to develop laser excitation schemes suitable for the solid-state laser systems used with TRIUMF's resonant ionization laser ion source . Also, it allows for possible improvement of current ion sources and validation of new designs. The test stand employs a copy of the ion optics used on-line, so that results can be transferred directly to radioactive ion beam production. Due to space restrictions and the need for rapid mass scans, a quadrupole mass spectrometer is used as a mass separator. One of the first experiments conducted on the laser ion source test stand (LIS STAND) was resonant ionization spectroscopy of gallium to improve on the ionization scheme previously used on-line, so that low yield isotopes (e.g., 62Ga) become available for experiments. Different Rydberg series in gallium were observed and autoionizing states were searched for. The overall LIS STAND system performance, characteristics, and the first resonant ionization spectroscopy are described.

  5. Acceleration test of heavy ion RFQ linac at TIT

    International Nuclear Information System (INIS)

    An 80 MHz heavy ion RFQ Linac at Tokyo Institute of Technology (TIT) was constructed for researches on inertial fusion and plasma experiments. The first acceleration was accomplished with low intensity He+ ion beam in 1993. This four vane type RFQ accelerates particles with charge to mass ratio (q/A) of 1/16 from 5 keV/amu to 214 keV/amu. Two-dimensional (2D) machining was applied for cutting of the RFQ vane-tips. The vane parameters for the RFQ were optimized considering the effects of multipole components at inter-vane field. In order to increase the acceleration efficiency synchronous phase was gradually raised from -30 degrees to -20 degrees at the open-quotes accelerator sectionclose quotes. The beam transmission is expected to be 68.4% for the beam current of 10 mA. Details of the RFQ tuning and performance will be reported

  6. Optimization of Preparation of Activated Carbon from Ricinus communis Leaves by Microwave-Assisted Zinc Chloride Chemical Activation: Competitive Adsorption of Ni2+ Ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    M. Makeswari

    2013-01-01

    Full Text Available The preparation of activated carbon (AC from Ricinus communis leaves was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted zinc chloride. Optimized parameters were radiation power of 100 W, radiation time of 8 min, concentration of zinc chloride of 30% by volume, and impregnation time of 24 h, respectively. The surface characteristics of the AC prepared under optimized conditions were examined by pHZPC, SEM-EDAX, XRD, and FTIR. Competitive adsorption of Ni2+ ions on Ricinus communis leaves by microwave assisted zinc chloride chemical activation (ZLRC present in binary and ternary mixture was compared with the single metal solution. The effects of the presence of one metal ion on the adsorption of the other metal ion were investigated. The experimental results indicated that the uptake capacity of one metal ion was reduced by the presence of the other metal ion. The extent of adsorption capacity of the binary and ternary metal ions tested on ZLRC was low (48–69% as compared to single metal ions. Comparisons with the biosorption of Ni2+ ions by the biomass of ZLRC in the binary (48.98–68.41%-~Ni-Cu and 69.76–66.29%-~Ni-Cr and ternary solution (67.32–57.07%-~Ni–Cu and Cr could lead to the conclusion that biosorption of Ni2+ ions was reduced by the influence of Cu2+ and Cr3+ ions. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The adsorption process follows the pseudo-second-order kinetic model.

  7. The synthesis of (N 2O 2S 2)-Schiff base ligands and investigation of their ion extraction capability from aqueous media

    Science.gov (United States)

    Zoubi, Wail A. L.; Kandil, Farouk; Chebani, Mohamad Khaled

    2011-09-01

    Two new Schiff bases (I) and (II) containing nitrogen-sulfur-oxygen donor atoms were designed and synthesized in a multi-step reaction sequence. The Schiff base (I) was used in solvent extraction of metal chlorides such as Cu 2+ and Cr 3+ as well as metal picrates such as Hg 2+ and UO 22+ from aqueous phase to the organic phase. The influences of the parameter functions, such as pH, solvent, ionic strength of aqueous phase, aqueous to organic phase and concentration of the extractant were investigated to shed light on their chemical extracting properties upon the extractability of metal ions. The effect of chloroform, dichloromethane and nitrobenzene as organic solvents over the metal chlorides extraction was investigated at 25 ± 0.1 °C by using flame atomic absorption and the result is that the ability of extraction in solvents as follows: C 6H 5NO 2 > CHCl 3 > CH 2Cl 2 and the compositions of the extracted species have been determined. The metal picrate extraction was investigated at 25 ± 0.1 °C by using UV-visible spectrometry. As well that the extraction of picrates metal such as UO 22+ and Hg 2+ with Schiff base(I) in absence and presence of 2-(2-aminoethyl) pyridine was investigated in chloroform. The extraction results revealed the presence of neutral donors 2-(2-aminoethyl) pyridine shifts the extraction percentage curves towards higher pH region, indicating a synergistic effect of this donors on extraction of UO 22+ and Hg 2+ by the studied Schiff base (I).

  8. Determining the acceptance of the Brookhaven EBIS Test Stand for primary ions by computer simulation

    International Nuclear Information System (INIS)

    We report on computer studies to determine the acceptance of the Electron Beam Ion Source Test Stand (EBTS) at BNL. Knowledge of the acceptance is a useful guide in selecting a source of primary ions, and in designing a transfer line which best matches the primary ion beam to the acceptance of the EBTS. In this work, an ion beam with suitable parameters is tracked out of the EBIS, to a plane where knowledge of the acceptance is wanted. The emittance of the extracted beam in this plane gives a starting point for determining a more reliable value of acceptance. The result will be compared with a theoretical estimate

  9. Test Ion Acceleration in the Field of Expanding Planar Electron Cloud

    OpenAIRE

    Basko, M. M.

    2006-01-01

    New exact results are obtained for relativistic acceleration of test positive ions in the non-Boltzmann laminar zone of a planar electron sheath evolving from an initially mono-energetic electron distribution. The electron dynamics is analyzed against the background of motionless foil ions. The limiting gamma-factor of accelerated ions is shown to be determined primarily by the values of the ion-electron charge-over-mass ratio and the initial gamma-factor of the accelerated electrons: there e...

  10. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt); Nawar, N., E-mail: nnawar@mans.edu.eg [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt); Abdel-Latif, D.A. [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt)

    2010-12-15

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO{sub 4} and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid {alpha}-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid {alpha}-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+}. The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  11. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions.

    Science.gov (United States)

    Monier, M; Nawar, N; Abdel-Latif, D A

    2010-12-15

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO(4) and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid α-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid α-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg(2+), Cu(2+) and Co(2+). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction. PMID:20810212

  12. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions

    International Nuclear Information System (INIS)

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO4 and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid α-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid α-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg2+, Cu2+ and Co2+. The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  13. Thermodynamic modeling of naringenin protonation equilibria in NaClO4 aqueous solutions by specific ion interaction theory and Pitzer equations

    Indian Academy of Sciences (India)

    Morteza Jabbari; Rahele Zhiani; Ali Farajtabar

    2015-06-01

    The protonation equilibria for the flavonoid naringenin were studied at 25°C using combined multiwavelength spectroscopic and pH-potentiometric methods as a function of the ionic strength. Over a wide range of ionic strengths, 0.10–3.00 mol dm−3, the investigation was performed in different aqueous solutions of NaClO4 as the background electrolyte. The dependence on ionic strength of protonation constants was modeled by the Brönsted–Guggenheim–Scatchard Specific Ion Interaction Theory (SIT) and Pitzer approaches. Apart from the values of SIT interaction coefficients and Pitzer parameters, the protonation constants at infinite dilution (zero ionic strength) were obtained. On the basis of these results, it was found that Pitzer mode l gives more satisfactory results rather than the SIT method.

  14. Preparation and Characterization of Poly(ethyl hydrazide Grafted Oil Palm Empty Fruit Bunch for Removal of Ni(II Ion in Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Siti Mariam Mohd Nor

    2013-07-01

    Full Text Available Poly(ethyl hydrazide grafted oil palm empty fruit bunch (peh-g-opefb fiber has been successfully prepared by heating poly(methylacrylate-g-opefb at 60 °C for 4 h in a solution of hydrazine hydrate in ethanol. The chelating ability of peh-g-opefb was evaluated based on removal of Ni(II ions in aqueous solution. Adsorption of Ni(II by peh-g-opefb was characterized based on effect of pH, isotherm, kinetic and thermodynamic study. This cheap sorbent based on oil palm empty fruit bunch fiber has a great future potential in water treatment industries based on high adsorption capacity, biodegradability and renewability.

  15. A high surface area tunnel-type α-MnO2 nanorod cathode by a simple solvent-free synthesis for rechargeable aqueous zinc-ion batteries

    Science.gov (United States)

    Alfaruqi, Muhammad Hilmy; Islam, Saiful; Gim, Jihyeon; Song, Jinju; Kim, Sungjin; Pham, Duong Tung; Jo, Jeonggeun; Xiu, Zhiliang; Mathew, Vinod; Kim, Jaekook

    2016-04-01

    Tunnel-type α-MnO2 with a nanorod morphology was prepared via a simple solvent-free synthesis method for use in aqueous zinc-ion battery (ZIB). This synthesis method produced α-MnO2 with a high BET surface area of 153 m2 g-1. α-MnO2 electrode demonstrated remarkable zinc storage properties (first and second discharge capacities of 323 and 270 mAh g-1 at 16 mA g-1) with good capacity retentions and rate capability. After charging within only 60 s, the α-MnO2 nanorod cathode delivered a considerable discharge capacity of 115 mAh g-1 when cycled at current density of 16 mA g-1.

  16. Crystalline self-assembly of organic molecules with metal ions at the air-aqueous solution interface. A grazing incidence X-ray scattering study

    DEFF Research Database (Denmark)

    Weissbuch, I.; Buller, R.; Kjær, K.; Als-Nielsen, J.; Leiserowitz, L.; Lahav, M.

    . Specular reflectivity yields the electron density profile of the film in the direction normal to the air-solution interface and, by modeling, gives independent information on the structure of both crystalline and amorphous parts of the film. In particular, we focus on the following systems: ordering of......The advent of intense X-rays from synchrotron sources made possible to probe, at the molecular level, the structural aspects of self-assemblies generated at interfaces. Here we present the two-dimensional (2-D) packing arrangements of two-, three- and multi-component organo-metallic self......-assemblies formed via interfacial reaction at the air-aqueous solution interface, as determined by grazing incidence X-ray diffraction (GIRD) and X-ray specular reflectivity techniques. GIXD yields structural information on the crystalline part of the Langmuir film, including the ions and counterions lateral order...

  17. High-Performance Olivine NaFePO4 Microsphere Cathode Synthesized by Aqueous Electrochemical Displacement Method for Sodium Ion Batteries.

    Science.gov (United States)

    Fang, Yongjin; Liu, Qi; Xiao, Lifen; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2015-08-19

    Olivine NaFePO4/C microsphere cathode is prepared by a facile aqueous electrochemical displacement method from LiFePO4/C precursor. The NaFePO4/C cathode shows a high discharge capacity of 111 mAh g(-1), excellent cycling stability with 90% capacity retention over 240 cycles at 0.1 C, and high rate capacity (46 mAh g(-1) at 2 C). The excellent electrochemical performance demonstrates that the aqueous electrochemical displacement method is an effective and promising way to prepare NaFePO4/C material for Na-based energy storage applications. Moreover, the Na2/3FePO4 intermediate is observed for the first time during the Na intercalation process through conventional electrochemical techniques, corroborating an identical two-step phase transition reaction both upon Na intercalation and deintercalation processes. The clarification of the electrochemical reaction mechanism of olivine NaFePO4 could inspire more attention on the investigation of this material for Na ion batteries. PMID:26207862

  18. Surface adsorption and self-assembly of Cu(II) ions on TEMPO-oxidized cellulose nanofibers in aqueous media.

    Science.gov (United States)

    Liu, Peng; Oksman, Kristiina; Mathew, Aji P

    2016-02-15

    TEMPO-mediated oxidized cellulose nanofibers (TOCNFs) have shown potential in the bioremediation of metal ions from contaminated water due to their interaction with positively charged metal ions via electrostatic interactions involving surface carboxyl groups. Copper is one of the most common pollutants in industrial effluents and is thus the target metal in the current study. The specific surface adsorption of Cu(II) was similar for TOCNFs with different degrees of functionalization and directly impacted the zeta potential. SEM imaging of the TOCNF after Cu(II) adsorption revealed interesting nanostructured clusters that were attributable to Cu(II) ions first being adsorbed by carboxylate groups on the TOCNF and subsequently being reduced and self-assembled to Cu(0) nanoparticles (NPs) or copper oxide NPs by microprecipitation. TOCNF turned superhydrophilic and resulted in faster water filtration after copper adsorption due to the stronger polarity of the copper ions or the self-assembled Cu(0) NPs creating voids or highly water-permeable channels at the interface between the interconnected TEMPO-oxidized nanofibers. Thus, the adsorption of Cu(II) ions and self-assembly into the Cu NPs on TOCNF favors a faster water purification process and provides a viable route to reuse/recycle TOCNFs studded with Cu nanoparticles as biocidal materials. PMID:26619127

  19. High-energy heavy ion testing of VLSI devices for single event upsets and latch up

    Indian Academy of Sciences (India)

    S B Umesh; S R Kulkarni; R Sandhya; G R Joshi; R Damle; M Ravindra

    2005-08-01

    Several very large scale integrated (VLSI) devices which are not available in radiation hardened version are still required to be used in spacecraft systems. Thus these components need to be tested for highenergy heavy ion irradiation to find out their tolerance and suitability in specific space applications. This paper describes the high-energy heavy ion radiation testing of VLSI devices for single event upset (SEU) and single event latch up (SEL). The experimental set up employed to produce low flux of heavy ions viz. silicon (Si), and silver (Ag), for studying single event effects (SEE) is briefly described. The heavy ion testing of a few VLSI devices is performed in the general purpose scattering chamber of the Pelletron facility, available at Nuclear Science Centre, New Delhi. The test results with respect to SEU and SEL are discussed.

  20. Aqueous phase oligomerization of α,β-unsaturated carbonyls and acids investigated using ion mobility spectrometry coupled to mass spectrometry (IMS-MS)

    Science.gov (United States)

    Renard, Pascal; Tlili, Sabrine; Ravier, Sylvain; Quivet, Etienne; Monod, Anne

    2016-04-01

    One of the current essential issues to unravel our ability to forecast future climate change and air quality, implies a better understanding of natural processes leading to secondary organic aerosol (SOA) formation, and in particular the formation and fate of oligomers. The difficulty in characterizing macromolecules is to discern between large oxygenated molecules from series of oligomers containing repeated small monomers of diverse structures. In the present study, taking advantage from previously established radical vinyl oligomerization of methyl vinylketone (MVK) in the aqueous phase, where relatively simple oligomers containing up to 14 monomers were observed, we have investigated the same reactivity on several other unsaturated water soluble organic compounds (UWSOCs) and on a few mixtures of these precursor compounds. The technique used to characterize the formed oligomers was a traveling wave ion mobility spectrometry coupled to a hybrid quadrupole - time of flight mass spectrometer (IMS-MS) fitted with an electrospray source and ultra-high performance liquid chromatography (UPLC). The technique allows for an additional separation, especially for large ions, containing long carbon chains. We have shown the efficiency of the IMS-mass spectrometry technique to detect oligomers derived from MVK photooxidation in the aqueous phase. The results were then compared to other oligomers, derived from ten other individual biogenic UWSOCs. The technique allowed distinguishing between different oligomers arising from different precursors. It also clearly showed that compounds bearing a non-conjugated unsaturation did not provide oligomerization. Finally, it was shown that the IMS-mass spectrometry technique, applied to mixtures of unsaturated conjugated precursors, exhibited the ability of these precursors to co-oligomerize, i.e. forming only one complex oligomer system bearing monomers of different structures. The results are discussed in terms of atmospheric