Articles de revues : « Ioni zinco »

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Riss, H., K. Testa, K. Betiatto, Elton Mendes, R. Piletti, Márcio Antônio Fiori et Humberto Gracher Riella. « Biocidal Glasses with High Performance : Comparison of the Antimicrobial Action Obtained by Use of Different Metal Ions ». Materials Science Forum 869 (août 2016) : 963–68. http://dx.doi.org/10.4028/www.scientific.net/msf.869.963.

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The development of antimicrobial materials and its use have shown an effective way to reduce the risks posed to human life by fungi, bacteria and other pathogenic microorganisms. This work presents preliminary results about the development of powder biocidal vitreous, applying the ionic exchange process between the sodium ions, present in the glass matrix, and ionic oligodynamic species, present in the ionic exchange medium. The magnitude of the oligodynamic effect was modified with the use of different metal ions, providing significant difference in antimicrobial performance. Three samples were prepared incorporating different ionic metal in its glass matrix during the ionic exchange process, Ag+, Zn2+ and Cu2+. These precursors of cations were used: AgNO3 for the silver ions, ZnSO4 for the zinc ions and Cu (NO3)2 for the cooper ions. Samples were submitted to microbiological analysis – Agar Diffusion Test for Escherichiacoli and Staphylococcusaureus bacterial species, and fungus species Candidaalbicans – and atomic absorption techniques. Results showed higher microbiological magnitude to the silver-glass, followed by the cooper-glass and zinc-glass.

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Mendes, Elton, Elidio Angioletto, Erlon Mendes, Raquel Ternus, Kelly Regina Betiatto, Riss Heloisa, Karine Testa, Raquel Piletti, Humberto Gracher Riella et Márcio Antônio Fiori. « Kinetics Modelling of the Adsorption Process of Zinc Ions by Glass Microparticles ». Materials Science Forum 930 (septembre 2018) : 556–61. http://dx.doi.org/10.4028/www.scientific.net/msf.930.556.

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The oligodynamic property is a lethal effect which some atoms exert over bacteria, fungi and other microorganisms. The oligodynamic property can be promoted by glass microparticles doped by zinc ionic specimens utilizing the ionic exchange processes. This study is aimed at modelling the behavior of adsorption mechanisms of the zinc ions on glass microparticles absorbent, with potential use as antimicrobial material. Aqueous solutions of zinc nitrate were used as the ionic supplying of zinc ions. The amount of zinc adsorbed on the glass was determined by spectroscopy of atomic absorption and with a mass balance analysis for each adsorption conditions. The experimental data were modeled by three Eq.s employed in adsorption kinetics studies: pseudo first order, pseudo second order and Elovich Eq.. The pseudo second order data model presented the better adjust condition. A sample of zinc glass microparticles, prepared at the finest conditions established by the kinetic model of pseudo second order, was submitted to microbiological analysis: agar diffusion test with Pseudomonas aeruginosa and Staphylococcus aureus and with Candida albicans. The glass doped with ionic zinc inhibited the growth of microorganisms in every conducted analysis.

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Kravchenko, Aleksandr, Denis Dyachenko, Dmitriy Polikarpov et Valeriy Fomichev. « Electrochemical deposition of zinc coatings from the ionic liquid based on choline chloride ». E3S Web of Conferences 121 (2019) : 02008. http://dx.doi.org/10.1051/e3sconf/201912102008.

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Galvanic zinc coatings were obtained by using of electrolytes based on ionic liquid choline chloride – urea. Zinc chloride, zinc sulphate and zinc acetate were used as a sources of Zn2+ ions. Influence of zinc salt anion on morphology of deposited coatings shown. Anodic dissolution of obtained zinc coatings investigated in chloride containing aqueous solution.

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Vieira, Daniela, Jérôme Allard, Kathleen Taylor, Edward J. Harvey et Geraldine Merle. « Zincon-Modified CNTs Electrochemical Tool for Salivary and Urinary Zinc Detection ». Nanomaterials 12, n^o 24 (13 décembre 2022) : 4431. http://dx.doi.org/10.3390/nano12244431.

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Recently, the abnormal level of zinc emerged as a powerful indicator or risk factor for metabolic, endocrine, neurodegenerative and cardiovascular diseases, including cancer. Electrochemical detection has been explored to quantify zinc in a precise, rapid, and non-expensive way; however, most of the current electrochemical systems lack in specificity. In this work we studied a highly selective and sensitive electrochemical method to detect quickly and reliably free zinc ions (Zn2+). The surface of the working electrode was modified with zincon electropolymerized on carbon nanotube (CNT) to enable the binding of zinc in complex body fluids. After being physicochemically characterized, the performances of the zincon-CNT complex was electrochemically assessed. Square Wave Voltammetry (SWV) was used to determine the calibration curve and the linear range of zinc quantification in artificial saliva and urine. This zincon- CNT system could specifically quantify mobile Zn2+ in salivary and urinary matrices with a sensitivity of ~100 ng·mL−1 and a limit of detection (LOD) of ~20 ng·mL−1. Zincon-modified CNT presented as a desirable candidate for the detection and quantification of free zinc in easily body fluids that potentially can become a diagnostic non-invasive testing platform.

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Pulletikurthi, Giridhar, Maryam Shapouri Ghazvini, Tong Cui, Natalia Borisenko, Timo Carstens, Andriy Borodin et Frank Endres. « Electrodeposition of zinc nanoplates from an ionic liquid composed of 1-butylpyrrolidine and ZnCl2 : electrochemical, in situ AFM and spectroscopic studies ». Dalton Transactions 46, n^o 2 (2017) : 455–64. http://dx.doi.org/10.1039/c6dt04149c.

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Abdolmohammad-Zadeh, Hossein, Sima Hassanlouei et Monireh Zamani-Kalajahi. « Preparation of ionic liquid-modified SiO2@Fe3O4nanocomposite as a magnetic sorbent for use in solid-phase extraction of zinc(ii) ions from milk and water samples ». RSC Advances 7, n^o 38 (2017) : 23293–300. http://dx.doi.org/10.1039/c7ra02126g.

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Ismail, W. M. I. W., N. S. W. Zulkefeli et M. N. Masri. « A Sight of Zinc Corrosion in Various Alkaline Media ». Journal of Tropical Resources and Sustainable Science (JTRSS) 4, n^o 2 (13 août 2021) : 95–97. http://dx.doi.org/10.47253/jtrss.v4i2.614.

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This review concentrates on corrosion properties that expose to zinc by various alkaline media. The assumption has been advanced that zinc corrodes electrochemically in the first stage of exposition, but the chemical corrosion prevails after a longer time. Different types of electrolyte had been tested on zinc such as sodium chloride, sodium hydroxide and potassium hydroxide. Each of alkaline media can produced corrosion product such as zinc hydroxide chloride, zinc hydroxide carbonate, zinc oxide, and zinc hydroxide. The production of corrosion products is depending on the carbon dioxide content that introduced to the air. Potassium hydroxide is the highest and active alkaline where it contains the highest ionic conductivity potassium ions, K+ after hydronium, H3O+ among the cations and hydroxide, OH ? has the highest ionic conductivity among the anions.

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Ishida, Tsuneo. « Thrombosis prevention and anti-thrombus formation by zinc (Ⅱ) ions against COVID-19 infection ». Journal of Clinical Case Reports and Studies 3, n^o 6 (28 juin 2022) : 01–08. http://dx.doi.org/10.31579/2690-8808/114.

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Zinc induced COVID-19 thrombosis prevention and anti-thrombus formation have been established by that zinc promotes COVID-19 thrombosis prevention and anti-thrombus formation and zinc ions-induced activated anti-thrombus activity is proceeded to prevent acute ischemic stroke among COVID-19 patients Zinc can reduce neurological outcomes in COVID-19 patients that Zn2+ promotes inflammatory cytokine as a neurodegenerative disorder and the coronaviruses can affect the nervous system through blood circulation, causing neuro-inflammation. Zinc supplementation affects bronchial mucosal epithelial integrity, both under normal and zinc deficient conditions. The other, zinc ions inhibit COVID-19 lung inflammation that zinc ions promote platelet activation function that inhibits pulmonary thromboembo-lism, in which platelets could respond to changes in extracellular and intracellular Zn2+ concentration. Zn2+ plays a major role in the regulation of coagulation that zinc inhibit blood coagulation against COVID-19 infection, in which Zn2+ can modulate platelet and coagulation activation pathways, including fibrin formation that the release of ionic Zn2+ store from secretory granules upon platelet activation contributes to the procoagulant role of Zn2+ in platelet-dependent fibrin formation. Zinc-induced platelet aggregation, low concentrations of ZnSO4 and zinc chelation involve platelet activation and potentiated platelet aggregation. Persistent zinc intake for severe aggravation of COVID-19 has been suggested to be 8–11 mg/day for adults (tolerable upper intake level 40 mg/day) and suggesting that a zinc intake of 30–70 mg/day might aid in the RNA viruses control. Thus, zinc ions can inhibit inflammation, platelet behaviour function, blood coagulation, and neurological thrombus formation during ROS production and excessive oxidative stress against COVID-19 infection. Zn2+ ions-binding with many proteins-molecular mechanism has been clarified that Zn2+ ions may be bound with COVID-19 inflammatory, platelet, coagulation, thrombus proteins by Zn2+ ions-centered tetrahedrally binding protein molecular coordination pattern.

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Ishida, Dr Sci Tsuneo. « Zinc (Ⅱ)-Induced Anti-Thrombus Formation against Severe COVID-19 Infection ». SAR Journal of Medical Case Reports 3, n^o 2 (7 juin 2022) : 8–16. http://dx.doi.org/10.36346/sarjmcr.2022.v03i02.001.

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Zinc(Ⅱ) induced neurological COVID-19 anti-thrombus formation has been established by that zinc induced inhibitive bronchial thrombosis and modulatory pulmonary thromboembolism are attained, causing COVID-19 activated anti-thrombus activity and leading to COVID-19 anti-thrombus formation. Zinc supplementation affected bronchial mucosal epithelial integrity, both under normal and zinc deficient conditions that there was an interaction between the individual zinc status. The other, zinc ions inhibit COVID-19 lung inflammation and promote platelet activation function that inhibits pulmonary thromboembolism, in which platelets could respond to changes in extracellular and intracellular Zn2+ concentration. Zinc-induced platelet aggregation, low concentrations of ZnSO4 and zinc chelation involve platelet activation and potentiated platelet aggregation, in which Zn2+ plays a major role in the regulation of coagulation that zinc inhibit blood coagulation against COVID-19 infection. Zn2+ can modulate platelet and coagulation activation pathways, including fibrin formation that the release of ionic Zn2+ store contributes to the procoagulant role of Zn2+ in platelet-dependent fibrin formation. Further, zinc may reduce neurological resultings in COVID-19 patients that Zn2+ promotes inflammatory cytokine as a neurodegenerative disorder and the coronaviruses can affect the nervous system through blood circulation, causing neuro-inflammation. Zinc ions can inhibit inflammation, platelet behaviour function, and blood coagulation. Hence, zinc ions promote neurological anti-thrombosis formation during ROS production and excessive oxidative stress against COVID-19 infection. Persistent zinc intake for severe aggravation of COVID-19 has been suggested to be 8–11 mg/day for adults (upper intake level 40 mg/day) and suggesting that a zinc intake of 30–70 mg/day might aid in the RNA virus control. Accordingly, Zn2+ ions-binding molecular mechanism has been clarified that Zn2+ ions may be bound with COVID-19 inflammatory, platelet, coagulation, and thrombus various proteins by Zn2+ ions-centered tetrahedrally binding protein molecular coordination pattern.

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Silva, AB, Jorge-E. Rueda-P et Q. Gomes K. « Effect of zirconia in the density and ionic conductivity properties of Bi4V1.8Cu0.1Zn0.1O10.7 compound ». BISTUA REVISTA DE LA FACULTAD DE CIENCIAS BASICAS 13, n^o 1 (28 juin 2015) : 27. http://dx.doi.org/10.24054/01204211.v1.n1.2015.1665.

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Ceramics based bismuth vanadate are conductors of oxygen ions and they are used as solid electrolytes in pressure sensors and fuel cells. These materials operate at temperatures above 700 °C. At high temperatures, the bismuth-vanadium oxide (Bi4V2O11) has a g-phase with a large number of oxygen vacancies that favors the ionic conductivity. The g-phase of the Bi4V2O11 was stabilized at room temperature by partial substitution of vanadium (V5+) ions by cuprum (Cu2+) and zinc (Zn2+) ions to provide high ionic conductivity values between 100 and 400oC. Thus, polycrystalline samples of Bi4V1.8Cu0.1Zn0.1O10.7 were obtained after 4h sintering at 800 °C. Investigations were made about densification process and ionic conductivity related to the effect of addition of the yttria-stabilized zirconia (Zr0.88Y0.12O1.94).

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Coolbear, T., J. M. Whittaker et R. M. Daniel. « The effect of metal ions on the activity and thermostability of the extracellular proteinase from a thermophilic Bacillus, strain EA.1 ». Biochemical Journal 287, n^o 2 (15 octobre 1992) : 367–74. http://dx.doi.org/10.1042/bj2870367.

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The proteinase from the extremely thermophilic Bacillus strain EA.1 exhibits maximum stability at a pH of approx. 6.5. In the presence of calcium ions the half-life at 95 degrees C of the enzyme at this pH was 17 min, and loss of activity followed first-order decay kinetics. The role of metal ions in the activity and stability of the enzyme was studied using the holoenzyme, the metal-depleted apoenzyme, and a zinc-enriched apoenzyme preparation. Zinc and calcium ions were the preferred bivalent cations for the active site and stabilization site(s) respectively. Stabilization by metal ions was not in itself a highly stringent process, but ions other than calcium which stabilized the enzyme generally had a concomitant inhibitory effect on activity. Inhibition and stabilization of the enzyme by cations were concentration-dependent effects and certain ions activated the apoenzyme but not the holoenzyme. Manganese(II) ions conferred some stability and also activated the enzyme, but in the latter case were not as effective as zinc ions. The results are discussed with reference to the ionic radii, co-ordination number and preferred ligand donors of the ions. Mercury(II) ions severely compromised enzyme activity and stability, and the effects of thiol-reactive agents suggest that thiol groups also have a role in enzyme integrity.

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Nishikawa, Masanobu, et Ken'ichi Ogawa. « Antimicrobial Activity of a Chelatable Poly(Arginyl-Histidine) Produced by the Ergot Fungus Verticillium kibiense ». Antimicrobial Agents and Chemotherapy 48, n^o 1 (janvier 2004) : 229–35. http://dx.doi.org/10.1128/aac.48.1.229-235.2004.

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ABSTRACT We have recently developed a convenient method of screening a broad range of microorganisms that produce ε-poly-l-lysine (M. Nishikawa and K. Ogawa, Appl. Environ. Microbiol. 68:3575-3581, 2002). Using this method, we found an ergot fungus that secretes a charged polypeptide other than ε-poly-l-lysine. It was identified as a new species on the basis of its 28S rRNA sequence and was named Verticillium kibiense (formerly Epichloe kibiensis). Peptide sequencing and mass spectrometry revealed that the polypeptide is a linear peptide composed of repeated units of arginyl-histidine. The numbers of repeated units were in most cases five and in some cases four or six. This peptide showed activity against a broad range of bacteria and fungi but lost its activity under conditions of high ionic strength. Zinc and copper ions specifically changed the circular dichroism spectra of the peptide and restored the antimicrobial activity from abrogation under high ionic conditions, although these ions had no reinforcing effect on antimicrobial activity when they were added to solutions at a low ionic strength. The peptide labeled with fluorescein was able to permeate the cell membranes of target microbes, but its ability to permeate cell membranes decreased under conditions of high ionic strength. This decreased ability was partially recovered specifically by the addition of zinc and copper ions. These results indicate that poly(arginyl-histidine) is a cationic polypeptide characterized by specific metal binding and resistance to salts.

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BAIRAGI, SUKHDEV, et GHIZAL F. ANSAR. « A Review on Physical and Optical Properties of Zinc Tellurite Glasses Co-doped with different rare earth ions ». Journal of Ultra Scientist of Physical Sciences Section B 33, n^o 6 (20 décembre 2021) : 48–56. http://dx.doi.org/10.22147/jusps-b/330601.

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In this work we review the effect of physical and optical properties with different ion zinc contents of tellurite base glass. The physical properties of the glasses were evaluated and the change in density, molar volume and ionic packing density in these glasses indicates the effect of ZnO different content show on the glasses structure. The study of optical properties such as the optical band gap and refractive index of zinc tellurite glass were studied. Zinc Tellurite glasses doped with Er3+ ions were synthesized by varies researcher. The glasses were characterized by X- ray diffraction, optical absorption and photoluminescence spectra. The glassy nature of zinc Tellurite host glass has been confirmed through XRD measurements. The glasses doped or co-doped with rare-earth ions have generated much interest due to the possibility of several promising applications such as optical data storage, visible laser, fibre amplifier, optical communication and sensor devices

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Eysseltová, Jitka. « Ionic Processes in Saturated Solutions of MgCl2·6H2O in Solutions of Other Divalent Metals ». Collection of Czechoslovak Chemical Communications 66, n^o 1 (2001) : 89–98. http://dx.doi.org/10.1135/cccc20010089.

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Solubility isotherms of MgCl2·6H2O at 25 °C in solutions of chlorides of bivalent beryllium, calcium, manganese, iron, cobalt, zinc and mercury were treated by the hydration analysis. In addition to the usual procedure, the recently developed modified transfer energy Ξ was used to characterize the situation in saturated solutions. As a result, the following ionic processes were established in the saturated solutions under consideration: competition for water in solutions of MgCl2·6H2O containing beryllium and calcium chloride, complex formation in solutions of MgCl2·6H2O containing manganese, cobalt, zinc and mercury ions and formation of ions with heterogeneous coordination sphere in solutions of MgCl2·6H2O containing iron or copper ions. In the last case, the ability of the formed ions to crystallize from solution was found to be reduced in comparison with the other cases. Activity coefficients of MgCl2 were calculated along the solubility curves under consideration.

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KUMANO, MASAMI, TOMOKI YABUTANI, JUNKO MOTONAKA et YUJI MISHIMA. « RECOVERY AND EXTRACTION OF HEAVY METAL IONS USING IONIC LIQUID AS GREEN SOLVENT ». International Journal of Modern Physics B 20, n^o 25n27 (30 octobre 2006) : 4051–56. http://dx.doi.org/10.1142/s0217979206040842.

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Ionic liquids are expected to replace conventional organic solvents in organic synthesis, solvent extraction and electrochemistry due to their unique characters such as low volatility, high stability and so on. In this work, N , N ,-diethyl- N -methyl- N -(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide was used as an alternative solvent to extract heavy metal ions. As the extracting conditions, the additional effect of 8-hydroxyquinoline (8-HQ) as metal chelating agent into ionic liquids, shaking time and volume ratio were investigated. As extraction efficiency depended on 8-HQ concentration significantly, in order to extract high concentrated metal ions the solubility of 8-HQ into ionic liquid was tested. N , N ,-diethyl- N -methyl- N -(2-methoxyethyl) ammonium bis(trifluoromethansulfonyl)imide had good solubility of 8-HQ. Consequently, 5 μmol of copper, zinc, cadmium and manganese could be completely recovered with 100 μl of ionic liquid.

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Shimabuku, Quelen Letícia, Flávia Sayuri Arakawa, Franciele Camacho, Letícia Nishi, Carole Silveira et Rosangela Bergamasco. « APLICAÇÃO DE CARVÃO ATIVADO IMPREGNADO COM ÍONS DE ZINCO PARA REMOÇÃO DE CISTOS DE GIARDIA SPP. » e-xacta 6, n^o 1 (6 juin 2013) : 145. http://dx.doi.org/10.18674/exacta.v6i1.1000.

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Este trabalho teve como objetivo o estudo de filtros de carvão ativado impregnado com zinco para remoção do protozoário parasita Giardia. Para a impregnação dos íons metálicos na superfície do carvão ativado foi utilizado o método de impregnação por excesso de solvente, para a caracterização textural do material produzido foram analisados os parâmetros: área superficial específica BET, área de microporos (método t), volume e diâmetro de microporos (método HK). A caracterização estrutural foi feita através de medidas de Difração de Raios-X (DRX). Os filtros de carvão ativado impregnado com zinco foram testados com água sintética (água deionizada contaminadas com cistos de Giardia, em uma concentração na ordem de 105 cistos/L). Os resultados desse trabalho mostraram que filtros de carvão ativado impregnados com zinco atingiram uma remoção de aproximadamente 100%, trazendo resultados promissores na remoção do protozoário parasita Giardia.AbstractThis work aimed to study the activated carbon filters impregnated with zinc for removal of protozoan parasite Giardia. For impregnation of the metal ions on the surface of activated charcoal was used the method of impregnation by excess of solvent, for textural characterization of the materials produced were analyzed parameters: BET specific surface area, area of micropores (method t), diameter and volume micropores (HK method). Structural characterization was made through measurements of X-ray diffraction (XRD). The activated carbon filters impregnated with zinc were tested with synthetic water (water contaminated with Giardia cysts, with a concentration on the order of 105 cysts / L). The results of this study showed that activated carbon filters impregnated with zinc reached a removal of approximately 100%, bringing promising results in the removal of the protozoan parasite Giardia.

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Zampardi, Giorgia, et Richard G. Compton. « Fast electrodeposition of zinc onto single zinc nanoparticles ». Journal of Solid State Electrochemistry 24, n^o 11-12 (14 mars 2020) : 2695–702. http://dx.doi.org/10.1007/s10008-020-04539-9.

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Abstract The zinc deposition reaction onto metallic zinc has been investigated at the single particle level through the electrode-particle collision method in neutral solutions, and in respect of its dependence on the applied potential and the ionic strength of a sulphate-containing solution. Depending on the concentration of sulphate ions in solution, different amounts of metallic zinc were deposited on the single Zn nanoparticles. Specifically, insights into the electron transfer kinetics at the single particles were obtained, indicating an electrically early reactant-like transition state, which is consistent with the rate-determining partial de-hydration/de-complexation process. Such information on the reaction kinetics at the nanoscale is of vital importance for the development of more efficient and long-lasting nanostructured Zn-based negative electrodes for Zn-ion battery applications.

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Dhiman, R. L., S. P. Taneja et V. R. Reddy. « Structural and Mössbauer Spectral Studies of Nanosized Aluminum Doped Manganese Zinc Ferrites ». Advances in Condensed Matter Physics 2008 (2008) : 1–7. http://dx.doi.org/10.1155/2008/839536.

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Nanoparticles of aluminum-substituted manganese zinc ferrites,Mn1.05Zn0.05AlxFe1.9−xO4with0.4≤x≤1.0were synthesized by solid-state reaction route and characterized by XRD, TEM, and Mössbauer spectroscopy measurements. The particle size is found to very from 46 to 28 nm with increase of aluminum ions concentration. The unit cell parameter “aO” is found to decrease linearly with aluminum ions concentration due to smaller ionic radius of aluminum. The cation distributions were estimated from X-ray diffraction intensities of various planes. The theoretical lattice parameter, bulk density, porosity, X-ray density, oxygen positional parameter, ionic radii, jump length, as well as bonds and edges lengths of the tetrahedral (A-) and octahedral (B-) sites were determined.Fe57Mössbauer spectra recorded at room temperature were fitted with two sextets corresponding toFe3+ions at tetrahedral (A-) and octahedral (B-) sites. The magnetic hyperfine fields at A- and B-sites show a gradual decrease with increase ofAl3+ion concentration, which has been explained on the basis of supertransferred hyperfine field. The cation distribution obtained from X-ray intensities and Mössbauer data indicates a decrease inFe3+(B)/Fe3+(A)ratio with increasing aluminum concentration thereby suggesting a decrease in ferrimagnetic behavior.

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Djebbar, Mustapha, et Fatiha Djafri. « Adsorption of Zinc Ions in Water on Natural and Treated Clay ». Chemistry & ; Chemical Technology 12, n^o 2 (25 juin 2018) : 272–78. http://dx.doi.org/10.23939/chcht12.02.272.

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Gîlcă, Emilia, Andrada Măicăneanu et Petru Ilea. « Removal of zinc ions as zinc chloride complexes from strongly acidic aqueous solutions by ionic exchange ». Open Chemistry 12, n^o 8 (1 août 2014) : 821–28. http://dx.doi.org/10.2478/s11532-014-0504-8.

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AbstractThe aim of this study was to compare several anion exchangers and to investigate the capacity of Amberlite IRA410 to remove zinc as chloride [ZnCl3]− from hydrochloric solutions (1 M). Influence of the process parameters such as stirring rate, resin quantity and zinc initial concentration over the removal process, was considered. The highest experimental ionic exchange capacity between the considered anionic exchangers, in the same working conditions (500 rpm, 5 g resin and 500 mg L−1), was obtained for Amberlite IRA410, 8.34 mg g−1. With an increase of zinc ions concentration, ionic exchange capacity increased up to 19.31 mg g−1 (1100 mg L−1). The experimental data were analysed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The results were also analyzed using sorption kinetics models, pseudo-first-, pseudo-second-order, intra-particle and film diffusion models. From the Dubinin-Radushkevich and Temkin isotherm models the mean free energy and heat of sorption were calculated to be 7.45 kJ mol−1, respectively 1×10−4 kJ mol−1, which indicates that zinc sorption is characterized by a physisorption process. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model.

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Asnawi, Ahmad S. F. M., Shujahadeen B. Aziz, Muaffaq M. Nofal, Yuhanees M. Yusof, Iver Brevik, Muhamad H. Hamsan, Mohamad A. Brza, Rebar T. Abdulwahid et Mohd F. Z. Kadir. « Metal Complex as a Novel Approach to Enhance the Amorphous Phase and Improve the EDLC Performance of Plasticized Proton Conducting Chitosan-Based Polymer Electrolyte ». Membranes 10, n^o 6 (25 juin 2020) : 132. http://dx.doi.org/10.3390/membranes10060132.

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This work indicates that glycerolized chitosan-NH4F polymer electrolytes incorporated with zinc metal complexes are crucial for EDLC application. The ionic conductivity of the plasticized system was improved drastically from 9.52 × 10−4 S/cm to 1.71 × 10−3 S/cm with the addition of a zinc metal complex. The XRD results demonstrated that the amorphous phase was enhanced for the system containing the zinc metal complex. The transference number of ions (tion) and electrons (te) were measured for two of the highest conducting electrolyte systems. It confirmed that the ions were the dominant charge carriers in both systems as tion values for CSNHG4 and CSNHG5 electrolytes were 0.976 and 0.966, respectively. From the examination of LSV, zinc improved the electrolyte electrochemical stability to 2.25 V. The achieved specific capacitance from the CV plot reveals the role of the metal complex on storage properties. The charge–discharge profile was obtained for the system incorporated with the metal complex. The obtained specific capacitance ranged from 69.7 to 77.6 F/g. The energy and power densities became stable from 7.8 to 8.5 Wh/kg and 1041.7 to 248.2 W/kg, respectively, as the EDLC finalized the cycles.

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Augusto, Laura Gianni. « Intranasal Zinc in the Management of the Common Cold ». Journal of Pharmacy Practice 19, n^o 6 (décembre 2006) : 395–400. http://dx.doi.org/10.1177/0897190006297066.

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Because zinc ions may prevent rhinovirus from attaching to and infecting cells in the nasal cavity, it has been recently hypothesized that direct application of ionic zinc to the nasal mucosa would be effective in reducing the duration of rhinovirus-associated colds. Five studies that compare intranasal zinc to placebo were identified in the medical literature. These studies provide conflicting results and are reviewed in detail. In the clinical trials that found efficacy, intranasal zinc was administered within the first 24 to 48 hours of the onset of cold symptoms. Adverse effects reported in clinical trials include nasal stinging or burning, epistaxis, headache, dry nose, dry mouth, nasal irritation, throat irritation, and nasal pain. Also of importance, case reports of intranasal zinc—induced persistent anosmia (complete loss of the sense of smell) have been reported in the literature. It is important that pharmacists inform their patients who want to use intranasal zinc of this possible complication.

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Wardak, Cecylia. « Solid contact Zn2+ -selective electrode with low detection limit and stable and reversible potential ». Open Chemistry 12, n^o 3 (1 mars 2014) : 354–64. http://dx.doi.org/10.2478/s11532-013-0390-5.

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AbstractA new solid contact Zn2+ polyvinylchloride membrane sensor with 2-(2-Hydroxy-1-naphthylazo)-1,3,4 -thiadiazole as an ionophore has been prepared. For the electrode construction, ionic liquids, alkylmethylimidazolium chlorides are used as transducer media and as a lipophilic ionic membrane component. The addition of ionic liquid to the membrane phase was found to reduce membrane resistance and determine the potential of an internal reference Ag/AgCl electrode. The electrode with the membrane composition: ionophore: PVC: o-NPOE: ionic liquid in the percentage ratio of (wt.) 1:30:66:3, respectively, exhibited the best performance, having a slope of 29.8 mV decade−1 in the concentration range 3×10−7–1×10−1 M. The detection limit is 6.9×10−8 M. It has a fast response time of 5–7 s and exhibits stable and reproducible potential. It has a fast response time of 5–7 s and exhibits stable and reproducible potential, which does not depend on pH in the range 3.8–8.0. The proposed sensor shows a good and satisfactory selectivity towards Zn2+ ion in comparison with other cations including alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for direct determination of zinc ions in tap water and as an indicator electrode in potentiometric titration of Zn2+ ions with EDTA.

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Asghari, Alireza, Mehri Ghazaghi, Maryam Rajabi, Mahdi Behzad et Mehrorang Ghaedi. « Ionic liquid-based dispersive liquid-liquid microextraction combined with high performance liquid chromatography-UV detection for simultaneous preconcentration and determination of Ni, Co, Cu and Zn in water samples ». Journal of the Serbian Chemical Society 79, n^o 1 (2014) : 63–76. http://dx.doi.org/10.2298/jsc062212081a.

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Ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) coupled with high performance liquid chromatography (HPLC)-UV detection was developed for simultaneous extraction and determination of nickel, cobalt, copper and zinc ions. In the proposed approach, salophen (N,N'-bis(salisyliden)-1,2-phenylenediamine) was used as a chelating agent; the ionic liquid, 1-hexeyl-3-methylimidazolium hexafluorophosphate, and acetone were selected as extracting and dispersive solvents, respectively. After extraction, phase separation was performed by centrifugation and the sedimented phase (ionic liquid) was solubilized in acetonitrile and directly injected into the HPLC for subsequent analysis. Baseline separation of metal ion complexes was achieved on a RP-C18 column using a gradient elution of the mixtures of methanol-acetonitrile-water as the mobile phase at a flow rate of 1.0 mL min-1. The influence of variables such as sample pH, concentration of the chelating agent, amount of ionic liquid (extraction solvent), disperser solvent volume, extraction time, salt effect and centrifugation speed were studied and optimized. Under the optimum conditions, the enrichment factor of 222 was obtained. The detection limits for Ni, Co, Cu and Zn were 0.8, 1.6, 1.9 and 2.8 ?g L?1, respectively. The relative standard deviations (RSDs) were in the range of 3.6-5.0 % for all of the investigated metal ions. The proposed procedure was successfully applied to the determination of the studied metal ions in water samples.

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Garrison, C. C., et E. I. Garcia-Meitin. « Silver staining of fluorocarbon copolymer membranes for contrast enhancement ». Proceedings, annual meeting, Electron Microscopy Society of America 49 (août 1991) : 1062–63. http://dx.doi.org/10.1017/s0424820100089627.

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Fluorocarbon copolymer membranes will replace conventional diaphragms in new generation chlorine cell designs. One design of such membranes is a bilayer material consisting of barrier (carboxylic) and support (sulfonic) layers which allow transport of sodium ions and inhibit transfer of other species. While the two layers can be distinguished without staining in the transmission electron microscope (TEM), resolution at the interface is typically 50 nanometers. Resolution can be improved to 5 nanometers after staining the membranes with silver ions.Previous work on staining sulfonic copolymers has been published. Xue et al. obtained excellent staining with vapor phase ruthenium tetraoxide. However, our lab was unsuccessful in applying this technique in the current study. Chryssikos et al. obtained good results using silver ions to stain by ion exchange. Since the membrane is designed to transport sodium ions, similarities between silver ions and sodium ions (+1 charge, similar ionic radii) point toward silver as a good choice. Staining experiments were carried out using silver ions, zinc ions, and ruthenium tetraoxide vapor.

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Liu, Zhen, Guozhu Li, Tong Cui, Abhishek Lahiri, Andriy Borodin et Frank Endres. « Tuning the electronic environment of zinc ions with a ligand for dendrite-free zinc deposition in an ionic liquid ». Physical Chemistry Chemical Physics 19, n^o 38 (2017) : 25989–95. http://dx.doi.org/10.1039/c7cp05345b.

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Morais, Inês P. A., M. Renata S. Souto et António O. S. S. Rangel. « A Double-Line Sequential Injection System for the Spectrophotometric Determination of Copper, Iron, Manganese, and Zinc in Waters ». Journal of AOAC INTERNATIONAL 88, n^o 2 (1 mars 2005) : 639–44. http://dx.doi.org/10.1093/jaoac/88.2.639.

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Abstract A double-line sequential injection system was developed for the spectrophotometric determination of several metal ions in waters. The proposed double-line configuration was used to enable adding sample and chromogenic reagents as merging zones. The methodology was applied to the spectrophotometric determination of copper, iron, manganese, and zinc in samples of diverse origins at the range of 0.15–5.00, 0.10–10.0, 0.48–4.00, and 0.11–5.00 mg/L, respectively. Different chromogenic reagents and detection wavelengths were used. The chromogenic reagents for iron and manganese were 1,10-phenanthroline and formaldoxime, respectively. Copper and zinc were both determined using the analytical reagent zincon. Analytical characteristics of the methodology, such as manifold parameters, buffer pH, and reagent concentrations were optimized, and interference of some of the metal ions commonly present in water sample was assessed. Results of the analysis were in agreement with those obtained by atomic absorption spectrometry. Repeatability, expressed as the relative standard deviation for 10 consecutive injections of water samples, was lower than 6%. The determination rate was approximately 36/h.

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Song, Yixiao, Jingwen Qin, Lei Li, Naveed Mushtaq, M. A. K. Yousaf Shah et Jun Xie. « Introducing Fuel Cell Application Using Sodium Vacancies in Hexagonal Wurtzite Structured ZnO Nanorods for Developing Proton–Ion Conductivity ». Crystals 12, n^o 11 (9 novembre 2022) : 1594. http://dx.doi.org/10.3390/cryst12111594.

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Zinc oxide, a direct band gap semiconductor of ≥3.30 eV, is prevalent in potential requests for energy devices. The early-stage demonstration of ZnO provides a new method of developing high ionic conductivity in multifunctional semiconductors for electrolyte applications in ceramic fuel cells (CFCs). In the present work, we successfully synthesized Na-doped ZnO nanorods by a hydrothermal method and employed them as an electrolyte in CFCs. The synthesized Na-doped-ZnO nanorods showed an effective ionic conductivity of 8.75 × 10−2 S cm−1 along with an excellent power density of 609 mWcm−2 ± 5% when the fuel cell was operating at 550 °C. The enhanced ionic conductivity could be due to Na+ doping into Zn2+ and the high ionic radius of Na ions producing bulk oxygen vacancies in the ZnO structure to conduct oxygen ions or protons. Furthermore, we used experimental analysis, such as X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), ultraviolet–visible (UV–visible), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS), to evaluate the change in structural properties and mechanism of ionic transport in ZnO nanorods with sodium doping. The presented work provides insight into a novel approach of developing the high ionic conductivity of electrolytes in a low-cost ZnO semiconductor material.

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Westerhausen, Matthias, Tobias Bollwein et Kurt Polborn. « Synthese, Struktur und Reaktivität von Aminomethylpyridin- zinkdihalogeniden / Synthesis, Structure and Reactivity of Aminomethylpyridine Zinc Dihalides ». Zeitschrift für Naturforschung B 55, n^o 1 (1 janvier 2000) : 51–59. http://dx.doi.org/10.1515/znb-2000-0110.

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Zinc dichloride reacts with aminomethylpyridine (AMP) to the corresponding 1:1 adduct 1, whereas ZnBr2 forms an ionic 1:2 complex of the type [(AMP)2ZnBr]+ Br- 2, which loses one neutral coligand upon heating in Me-C (O)OEt to yield nearly insoluble (AM P)ZnBr2 3. The condensation reaction of these compounds with acetone yields propylideneaminomethylpyridine zinc dichloride (4) and dibromide (5), respectively. The reaction of ZnI2 with AMP and acetone gives propylideneaminomethylpyridine zinc dichloride (6) in quantitative yield. The structures of 3, 4, and 6 confirm the linear relationship between the Zn-N distance and the X-Zn-X angle in compounds of the type (L2)ZnX2 with L2 being a bidentate amino base, whereas short Zn-N bonds enforce small X-Zn-X angles. Compound 2 consists of separated ions in the solid state with a five coordinate zinc atom in a distorted trigonal bipyramidal coordination sphere

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Wright, David A. « Trace Metal Uptake and Sodium Regulation in Gammarus Marinus From Metal Polluted Estuaries in England ». Journal of the Marine Biological Association of the United Kingdom 66, n^o 1 (février 1986) : 83–92. http://dx.doi.org/10.1017/s0025315400039667.

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The regulation of major ions in aquatic Crustacea has been extensively studied, and it is hardly surprising that ever-present ionic constituents of sea water such as sodium, potassium, chloride, calcium and magnesium have been incorporated into highly efficient regulatory mechanisms. On the other hand, we know little of the mechanisms governing the uptake and regulation of trace elements, despite the fact that metals such as zinc and copper may be important constituents of enzymes and blood pigment.

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Smolik, Marek. « Distribution of microamounts of some M2+ ions during ZnSO4·7H2O crystallization ». Canadian Journal of Chemistry 78, n^o 7 (1 juillet 2000) : 993–1002. http://dx.doi.org/10.1139/v00-054.

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Distribution coefficients (D) of trace amounts of Ni2+, Co2+, Mg2+, Cd2+, Cu2+, Mn2+, Ca2+, and Fe2+ have been determined during crystallization of ZnSO4·7H2O. Their dependencies on the ionic radii of M2+ ions, solubilities and structures of the corresponding sulfates as well as their abilities to form solid solutions with ZnSO4·7H2O have been analyzed. The D values are in the range <0.006 (DCa) - 1.61 (DNi) and depend mainly on similarity of the structures of the corresponding sulfates and the ability of MSO4·nH2O to form solid solutions with ZnSO4·7H2O. The order of lowering some of the determined distribution coefficients (DNi > DMg > DCo > DFe > Dcu) exactly agrees with increase of the deformation trend of octahedral coordination of corresponding ions resulting from their electronic configuration. The D coefficients do not depend on similarity of size of ionic radii of microcomponent (rM2+) to macrocomponent (rZn2+), however for ions forming monoclinic sulfate hydrates at 20°C (Co2+, Fe2+, Cd2+, Ca2+) this dependence of distribution coefficients on rM2+ is linear in a plot of log D against ionic radius. The effect of solubilities of corresponding sulfates in water on the D coefficients is complex and clouded by crystal-chemical factors.Key words: crystallization, zinc(II) sulfate heptahydrate, cocrystallization, distribution coefficients D (Henderson-Kracek, Khlopin), distribution of trace impurities.

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Li, Jinpeng, Naveed Mushtaq, Naila Arshad, M. A. K. Yousaf Shah, Muhammad Sultan Irshad, Rong Yan, Senlin Yan et Yuzheng Lu. « Proton-Ion Conductivity in Hexagonal Wurtzite-Nanostructured ZnO Particles When Exposed to a Reducing Atmosphere ». Crystals 12, n^o 11 (26 octobre 2022) : 1519. http://dx.doi.org/10.3390/cryst12111519.

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Zinc oxide (ZnO), a direct wide band gap semiconductor (≥3.30 eV), has widespread potential for applications in energy devices and related industries. The initial physical demonstration of ZnO in ceramic fuel cells (CFCs) gave a new view of developing high ionic conductivity for multifunctional semiconductor technology. However, in the present work, we successfully synthesized highly textured nanoparticles of ZnO using a hydrothermal method followed by sintering in a reducing atmosphere. The resultant ZnO materials as electrolytes showed efficient ionic conductivity (5.28 × 10−2 S cm−1) and an excellent power density of 520 mW cm−2 ± 5% at 550 °C for low-temperature ceramic fuel cells (LT-CFCs). The achievement of enhanced ionic conductivity without any external ions or cation doping in the CFC was anticipated, since there was a rare possibility of vacancies in the bulk ZnO structure to conduct oxygen ions or protons. Therefore, we found that laterally the surfaces of the ZnO nanoparticles could be textured to become oxygen-deficient when sintered in an H2 atmosphere, which suggests a special mechanism for effective ionic transport. Furthermore, experimental analyses such as SEM, XPS, UV–visible, and EIS methods were performed to analyze the changes in the structural properties and mechanism of ionic transport in ZnO nanoparticles. The presented work provides insights into a novel approach for developing high ionic conductivity in electrolytes in low-cost semiconductor oxides such as ZnO for energy storage and conversion devices.

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Trivunac, Katarina, Zoran Sekulic et Slavica Stevanovic. « Zinc removal from wastewater by complexation-microfiltration process ». Journal of the Serbian Chemical Society 77, n^o 11 (2012) : 1661–70. http://dx.doi.org/10.2298/jsc120302037t.

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As a result of its wide industrial applications, zinc has become an important contaminant in aquatic environment since it is a toxic heavy metal and some of its compounds such as zinc arsenate and zinc cyanide, may be extremely hazardous. Therefore, there is a growing need for developing simple methods capable of separating and recovering trace zinc from environmental waters. Nowadays, the ultra and microfiltration method for trace metals removal from waters by the addition of water-soluble polymers into the aqueous solutions has become a significant research area. The choice of watersoluble macroligands remains important for developing this technology. Sodium carboxymethyl cellulose (Na-CMC) was selected as complexing agent. The microfiltration experiments were carried out in stirred dead-end cell. To separate formed polymer-metal complex Versapor membranes were used. The concentration of heavy metal ions after microfiltration in aqueous solution was determined using atomic absorption spectroscopy (AAS). Effects of amount of complexing agent, pH value, type of anion, ionic strength and operating pressure on the flux (J) and rejection coefficient (R) were investigated. Experimental results indicate a considerable influence of the pH, ionic strength and type of anion on the rejection coefficient, while effect of amount of complexing agent is relatively insignificant. The Na-CMC used in the research proved to be very effective, which may be supported by the high rejection coefficients obtained (99%).

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Jeon, Ye-Rin, Jin Yu et Soo-Jin Choi. « Fate Determination of ZnO in Commercial Foods and Human Intestinal Cells ». International Journal of Molecular Sciences 21, n^o 2 (9 janvier 2020) : 433. http://dx.doi.org/10.3390/ijms21020433.

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(1) Background: Zinc oxide (ZnO) particles are widely used as zinc (Zn) fortifiers, because Zn is essential for various cellular functions. Nanotechnology developments may lead to production of nano-sized ZnO, although nanoparticles (NPs) are not intended to be used as food additives. Current regulations do not specify the size distribution of NPs. Moreover, ZnO is easily dissolved into Zn ions under acidic conditions. However, the fate of ZnO in commercial foods or during intestinal transit is still poorly understood. (2) Methods: We established surfactant-based cloud point extraction (CPE) for ZnO NP detection as intact particle forms using pristine ZnO-NP-spiked powdered or liquid foods. The fate determination and dissolution characterization of ZnO were carried out in commercial foods and human intestinal cells using in vitro intestinal transport and ex vivo small intestine absorption models. (3) Results: The results demonstrated that the CPE can effectively separate ZnO particles and Zn ions in food matrices and cells. The major fate of ZnO in powdered foods was in particle form, in contrast to its ionic fate in liquid beverages. The fate of ZnO was closely related to the extent of its dissolution in food or biomatrices. ZnO NPs were internalized into cells in both particle and ion form, but dissolved into ions with time, probably forming a Zn–ligand complex. ZnO was transported through intestinal barriers and absorbed in the small intestine primarily as Zn ions, but a small amount of ZnO was absorbed as particles. (4) Conclusion: The fate of ZnO is highly dependent on food matrix type, showing particle and ionic fates in powdered foods and liquid beverages, respectively. The major intracellular and intestinal absorption fates of ZnO NPs were Zn ions, but a small portion of ZnO particle fate was also observed after intestinal transit. These findings suggest that the toxicity of ZnO is mainly related to the Zn ion, but potential toxicity resulting from ZnO particles cannot be completely excluded.

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Fournier, J. B., Mohamed El Hourch et Gérard J. Martin. « Zinc, copper and lead contents of wines. Comparison between the total concentrations by atomic absorption spectrometry and the concentrations of the free ions by polarography ». OENO One 32, n^o 1 (31 mars 1998) : 45. http://dx.doi.org/10.20870/oeno-one.1998.32.1.1058.

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In the introduction of this article, some examples of the use of trace element data in the characterisation of viticultural produce are reminded. This paper described the determination of zinc, copper and lead by two techniques based on radically different principles. The atomic absorption spectrometry, applied after the mineralisation of the samples by wet process, allows the determination of the total element contents in wine. The polarography allows the analysis of the concentrations of these elements that are under labile chemical forms, and which are dissolved under the ionic forms Zn++, Cu++ and Pb++. The wines analysed in this study were produced from three different parcels chosen in relation to their geological qualities. The vines implanted on these parcels are strictly identical, and three fermentation techniques were applied to each lots of grapes. The results obtained shows that the copper is only under ionic form and that the temperature of the fermentation influences the total copper level in the final wine. At the opposite, there is no ion Pb++ in the samples, but a long duration of maceration increases the lead content. Concerning zinc, only the ions Zn++ are present in the wine in case of a short duration of the maceration. When this duration increases, some other chemical forms of zinc are dissolved in addition to the ions Zn++ which are instantaneously dissociated in aqueous solutions. The problem of the contamination of grapes by the materials used, the phytosanitary treatments and the atmospheric pollution is discussed. The knowledge of the proportion of a trace element that is under ionic forms is indispensable to evaluate the bio-availability of the considered element and the toxicologic risks. The advent and the expansion of the electrochemical methods is expected as an important advance in this field of research.

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Senda, Mitsugi, Hajime Katano et Yuko Kubota. « Stripping Analysis Using Ion-Transfer Voltammetry at Liquid/Liquid Interface ». Collection of Czechoslovak Chemical Communications 66, n^o 3 (2001) : 445–55. http://dx.doi.org/10.1135/cccc20010445.

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Principles and theory of stripping ion-transfer voltammetry at the organic solvent (O)/water (W) interface are described, in which a thin O-film is used to preconcentrate an ionic substance by electroextraction followed by stripping analysis using linear sweep voltammetry or normal pulse voltammetry. For ease of handling, the thin O-film was gelled by adding poly(vinyl chloride) to make an O-gel electrode. Lead(II), cadmium(II) and zinc(II) ions behave reversibly or quasi-reversibly in voltammetric transfer at the O/W interface assisted by 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine (DPT) present in the O-phase. Thus, these ions at trace levels can be determined using stripping ion-transfer voltammetry with the O(DPT)-gel electrode. The detection limit was as low as a few tens of nmol/l of these ions. Simultaneous determination of two or more ions is possible when their half-wave potentials of ion transfer are reasonably separated.

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Kerns, Karl, Michal Zigo et Peter Sutovsky. « Zinc : A Necessary Ion for Mammalian Sperm Fertilization Competency ». International Journal of Molecular Sciences 19, n^o 12 (18 décembre 2018) : 4097. http://dx.doi.org/10.3390/ijms19124097.

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The importance of zinc for male fertility only emerged recently, being propelled in part by consumer interest in nutritional supplements containing ionic trace minerals. Here, we review the properties, biological roles and cellular mechanisms that are relevant to zinc function in the male reproductive system, survey available peer-reviewed data on nutritional zinc supplementation for fertility improvement in livestock animals and infertility therapy in men, and discuss the recently discovered signaling pathways involving zinc in sperm maturation and fertilization. Emphasis is on the zinc-interacting sperm proteome and its involvement in the regulation of sperm structure and function, from spermatogenesis and epididymal sperm maturation to sperm interactions with the female reproductive tract, capacitation, fertilization, and embryo development. Merits of dietary zinc supplementation and zinc inclusion into semen processing media are considered with livestock artificial insemination (AI) and human assisted reproductive therapy (ART) in mind. Collectively, the currently available data underline the importance of zinc ions for male fertility, which could be harnessed to improve human reproductive health and reproductive efficiency in agriculturally important livestock species. Further research will advance the field of sperm and fertilization biology, provide new research tools, and ultimately optimize semen processing procedures for human infertility therapy and livestock AI.

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Krstic, Milena, Branka Petković, Miloš Milčić, Dušan Mišić et Juan Francisco Santibanez. « Synthesis, characterization and biological study of new dinuclear zinc(II) and nickel(II) octaaza macrocyclic complexes ». Macedonian Journal of Chemistry and Chemical Engineering 38, n^o 1 (30 mai 2019) : 1. http://dx.doi.org/10.20450/mjcce.2019.1599.

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Two new nitrato complexes of zinc and nickel with 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc), have been synthesized and characterized. The IR spectral peaks showed that the coordinated and ionic nitrate ions are in agreement with the formula proposed by elemental analysis. Conductometric titrations predicted methanol to be a convenient solvent for synthesis and revealed the stoichiometry of the complexes, while molar electrical conductivities indicated a 1 : 3 complex electrolyte type for the zinc complex, and a 1 : 2 complex electrolyte type for the nickel complex. The optimized complex structure was obtained by molecular modeling and density functional theory calculations. The biological activity of the novel complexes was examined by screening eight different bacterial strains and two cancer cell lines. The zinc complex showed better antimicrobial activity against the bacterial strains, while the complexes did not show significance antiproliferative activity toward cancer cells MCF-7 and MDA-MB-231.

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Abdul Wahid, Mohamad Firdaus, C. M. Mardziah, Koay Mei Hyie et N. R. Nik Roselina. « Synthesis and Characterization of Zinc Doped Hydroxyapatite for Bone Substitute Applications ». Applied Mechanics and Materials 660 (octobre 2014) : 942–46. http://dx.doi.org/10.4028/www.scientific.net/amm.660.942.

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Hydroxyapatite was prepared by using precipitation method. The substitution of zinc ions in hydroxyapatite structure was studied by several characterization techniques. Several concentration of zinc ions were substituted into hydroxyapatite. Characterization technique such as X-ray diffraction method was used to study the phase changes and the lattice parameters with the addition of zinc. Field emission scanning electron microscopy was used to examine the influence of zinc on the crystal size and the morphology of the as-synthesized powders. Based on X-ray diffraction result, the addition of zinc affects the lattice parameters and phase. The result showed that zinc ions were substituted in the structure. As zinc substitution increased, the lattice parameters a and c decreased. The crystal shape of hydroxyapatite without zinc ions was regular shapes while hydroxyapatite with zinc ions was irregular and also tends to agglomerates with single particle was calculated about 28 - 34 nm .

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Yanga, Chao-Chen, et Hsin-Yi Hsu. « Raman Spectroscopic Study of a New Type of Room Temperature ZnCl2-DMSO2 Molten Salts ». Zeitschrift für Naturforschung A 65, n^o 8-9 (1 septembre 2010) : 745–48. http://dx.doi.org/10.1515/zna-2010-8-917.

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In this study, Raman spectra of binary zinc chloride-dimethylsulfone (ZnCl2-DMSO2) melts have been measured. The intra-molecular vibrations of group and ionic species have been confirmed and discussed. From the Raman spectrum analysis and discussions, the equilibrium reaction equation about the complex ions forming in the ZnCl2-DMSO2 melt is submitted, such as n ZnCl2+n(n−2)(CH3)2SO2 ⇔ 2ZnCln2−n +(n−2) Zn[(CH3)2SO2]n2+, (n ≧ 3). However, the Raman spectra reveal that the ZnCl42− (375 cm−1) and ZnCl3 − (290 cm−1) complexes are the major ions for the 40 - 90 mol%ZnCl2 melts; furthermore, as the DMSO2 content is increased, the binary melt advantage the forming of Zn[(CH3)2SO2]n2+ complex ion and promote its transport characteristic

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Baruah, S., Gamolwan Tumcharern et Joydeep Dutta. « Chitosan Clad Manganese Doped Zing Sulphide Nanocrystallites for Biolabeling ». Advanced Materials Research 55-57 (août 2008) : 589–92. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.589.

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The synthesis of fluorescent nanocrystals is receiving a lot of attention for potential application in biological labeling as well as phosphors for field emission devices. Zinc sulphide doped with manganese (ZnS:Mn2+) is one of the most efficient electroluminescent phosphor displaying a wide emission band centred around 590 nm resulting from the intra-ionic transition in Mn2+ ions. We report a unique synthesis of zinc sulphide nanoparticles doped with manganese using a biocompatible passivating agent ‘chitosan’, with bright luminescence peaking at 590 nm. This high luminescence efficiency of the synthesized nanocrystals are ideal for quantum dot based bio-labeling applications. Synthesis of the nanoparticles was carried out by precipitation reaction in aqueous media of zinc acetate and sodium sulphide where manganese acetate was added as the dopant. The obtained nanoparticles were around 4 to 6 nm in size and were found to be stable for months of shelf life. The photoluminescence intensity did not degrade when the colloid was heated up to 65 oC for prolonged periods.

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Ali, Azza M. M. « Determination of Trace Metal Ions in Common Salt by Stripping Voltammetry ». Journal of AOAC INTERNATIONAL 82, n^o 6 (1 novembre 1999) : 1413–18. http://dx.doi.org/10.1093/jaoac/82.6.1413.

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Abstract Sensitive voltammetric methods using cathodic and anodic differential pulse stripping techniques were applied for determination of trace ions cadmium(II), cobalt(II), copper(II), lead(II), manganese(II), nickel(II), and zinc(II), which are usually found in different grades of common salt as contaminants. The optimal conditions, i.e., deposition time, preconcentration potential, supporting electrolyte, and ionic strength, were investigated for each metal ion. Concentration of the metal ion was determined by the standard addition method. Metal content varied according to the quality of the table salt.

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Wang, Chun Rong, Xin Ren, Wen Xiu Li, Zhi Fei Hou, Chao Ke et Qin Geng. « Magnetic Flocculation Technology for Copper and Zinc Ions Removal from the Tin Smelting Wastewater ». Applied Mechanics and Materials 295-298 (février 2013) : 1284–88. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.1284.

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Magnetic flocculation technology was investigated for the removal of copper and zinc ions from simulated tin smelting wastewater, and the effects of magnetic powder dosage, flocculant dosage, and pH on the removal of copper and zinc ions were estimated. The results show that the effluent quality is poor with magnetic powder, PAC and PAM separately dosed, but when magnetic powder is combined with PAC or PAM, the excellent effluent quality is obtained with the removal rate of the copper and zinc ions of more than 90% and 70% respectively. In addition, under the condition of magnetic powder dosage of 30g/L and PAC dosage of 60mg/L, pH show more significant effect on zinc ions than copper ions with pH increased from 5 to 10, and the removal rate of zinc ions increase by about 24%, while the removal rate of copper ions only increase by about 2.5%. Compared with the system with single metal ion, the coexistent ion system has excellent heavy metal removal efficiency, namely the copper ions removal rate increase by 3.42%, and the zinc ions removal rate increase by 0.46%. Moreover, magnetic flocculation technology presents the characteristics of shorter time of flocculation and sedimentation, smaller volume of the flocs and faster separation velocity.

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Tomson, Alexey E., Inessa A. Gontcharova, Andrei M. Trigubovich, Tamara V. Sokolova, Yulian Yu Navosha, Nataliya E. Sosnovskaya et Victoriya S. Pehtereva. « SORPTION OF HEAVY METALS BY MOLD FUNGUS ASPERGILLUS CARBONARIUS MELANIZING CARDBOARD ». Nature Management, n^o 1 (30 juin 2021) : 221–28. http://dx.doi.org/10.47612/2079-3928-2021-1-221-228.

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It has been shown that the mould fungus Aspergillus carbonarius, which synthesizes extracellular melanin, is able to develop due to the degradation of cellulose inside the cardboard under conditions of low water availability. The maximum yield of melanin was noted in a slightly alkaline medium, but in the presence of copper ions, a high level of pigmentation of the medium is also observed at low pH values. Melanized mycelium and exomelanin are characterized by a high sorption capacity in relation to heavy metal ions present in printing pigments of waste paper. In the process of growth A. carbonarius decreases acidity from neutral values to pH 2.8–3.1, increases the mobility of heavy metals immobilized on cellulose fibers and binds them by functional groups via ionic or chelating pathways. The sorption capacity of biomass with respect to copper, zinc, and nickel ions increased in the order of viable mycelium < inactivated mycelium < exomelanin. Lead ions were most actively bound by inactivated mycelium. The extracellular pigment accumulated copper better than other metals. The distribution coefficient in the system melanin – Cu2+ reached 1390 ml/g.

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Abdullah, Omed, Yahya Salman, Dana Tahir, Gelas Jamal, Hawzhin Ahmed, Azhin Mohamad et Auday Azawy. « Effect of ZnO Nanoparticle Content on the Structural and Ionic Transport Parameters of Polyvinyl Alcohol Based Proton-Conducting Polymer Electrolyte Membranes ». Membranes 11, n^o 3 (26 février 2021) : 163. http://dx.doi.org/10.3390/membranes11030163.

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Proton conducting nanocomposite solid polymer electrolytes (NSPEs) based on polyvinyl alcohol/ammonium nitrate (PVA/NH4NO3) and different contents of zinc oxide nanoparticles (ZnO-NPs) have been prepared using the casting solution method. The XRD analysis revealed that the sample with 2 wt.% ZnO-NPs has a high amorphous content. The ionic conductivity analysis for the prepared membranes has been carried out over a wide range of frequencies at varying temperatures. Impedance analysis shows that sample with 2 wt.% ZnO-NPs has a smaller bulk resistance compared to that of undoped polymer electrolyte. A small amount of ZnO-NPs was found to enhance the proton-conduction significantly; the highest obtainable room-temperature ionic conductivity was 4.71 × 10−4 S/cm. The effect of ZnO-NP content on the transport parameters of the prepared proton-conducting NSPEs was investigated using the Rice–Roth model; the results reveal that the increase in ionic conductivity is due to an increment in the number of proton ions and their mobility.

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Yu, Jin, et Soo-Jin Choi. « Particle Size and Biological Fate of ZnO Do Not Cause Acute Toxicity, but Affect Toxicokinetics and Gene Expression Profiles in the Rat Livers after Oral Administration ». International Journal of Molecular Sciences 22, n^o 4 (8 février 2021) : 1698. http://dx.doi.org/10.3390/ijms22041698.

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Zinc oxide (ZnO) particles have been used as dietary supplements because zinc is an essential trace element for humans. Along with the rapid development of nanotechnology, the use of ZnO nanoparticles (NPs) is increasing in the food industry, but their oral toxicity potential still remains to be answered. In this study, the effects of particle size and biological fate of ZnO on acute toxicity, toxicokinetics, and gene expression profiles in the livers were investigated after oral administration of ZnO NPs (N-ZnO), bulk-sized ZnO (B-ZnO) or Zn ions in rats. The plasma concentration-time profiles after a single-dose oral administration of ZnOs differed depending on particle/ionic forms and particle size, showing high absorption of Zn ions, followed by N-ZnO and B-ZnO, although in vivo solubility did not differ from particle size. No significant acute toxicity was found after oral administration of ZnOs for 14 days in rats. However, transcriptomic responses in the livers were differently affected, showing that metabolic process and metal biding were up-regulated by Zn ions and N-ZnO, respectively, which were not pronounced in the liver treated with B-ZnO. These findings will be useful to predict the potential oral toxicity of ZnO NPs and further mechanistic and long-term exposure studies are required to assume their safety.

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Timofeeva, Svetlana Nikolaevna, Ilnur Ravilevich Kadikov, Andrey Aleksandrovich Korchemkin et Iskander Foatovich Vafin. « The effects of zinc and magnesium ingestion on essential trace-element accumulation in the organs of white rats upon cadmium exposure ». BIO Web of Conferences 27 (2020) : 00110. http://dx.doi.org/10.1051/bioconf/20202700110.

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Due to high athropogenic loads on the environment, issues surrounding public health and safety in consumable products are being raised with ever-increasing frequency. One toxic metal, whose consumption results in irreparable harm to the health of animals and human is cadmium. To antagonize such toxic effects to human health, magnesium and zinc are considered being essential elements and their combination effects warrant further studies. To this end, we developed a Wistar rat model to look at the combinatorial effects of cadmium with magnesium and zinc consumption on the accumulation of iron and zinc ions in kidney and liver tissues. Our findings suggested that exposure to cadmium ions reduced zinc ion levels in the liver and kidneys, reduced iron ions in the liver (but were increased in the kidneys), decreased magnesium ions in the kidneys but increased their levels within the liver. Moreover, while the consumption of magnesium and zinc ions individually, partially reduced the effects caused by cadmium consumption alone, the simultaneous consumption of zinc and magnesium ions proved to be significantly more effective.

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Zhang, Dong. « Removal of Heavy Metal Ions from Water Using Porous Nano-Barium-Stroutium Titanate as an Adsorbent ». Advanced Materials Research 148-149 (octobre 2010) : 865–68. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.865.

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The ability of porous nano-barium-stroutium titanate (PBST) to remove heavy metal (lead, nickel and zinc) ions by sorption from aqueous solution was assessed. The effects of process parameters such as pH, contacttime, regeneration conditions and the effects of common coexisting ions on heavy metal (lead, nickel and zinc) ions uptake were investigated. The results showed that the lead, nickel and zinc ions studied could be quantitatively retained at a pH value range of 5~8. The adsorption capacities of PBST for lead, nickel and zinc were found to be11 6.5mg•g-1, 4.8mg•g-1 and 8.3 mg•g-1, respectively. Desorption studies were carried out successfully with diluted HNO3 solutions. The results indicate that PBST can be used as an effective adsorbent for the treatment of wastewaters contaminated with lead, nickel and zinc ions.

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Azami, Kian, et Seyed Mojtaba Mostafavi. « Simultaneously determination of copper and zinc in human serum and urine samples based on amoxicillin drug by dispersive ionic liquid- liquid microextraction coupled to flame atomic absorption spectrometry ». Analytical Methods in Environmental Chemistry Journal 3, n^o 03 (29 septembre 2020) : 32–43. http://dx.doi.org/10.24200/amecj.v3.i03.111.

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In this work the effect of amoxicillin on copper and zinc (Cu and Zn) deficiency was evaluated by determining of Cu and Zn concentration in human serum and urine samples. By dispersive ionic liquid cloud point extraction procedure (DIL-CPE), 0.03 g of pure amoxicillin drug was added to mixture of 0.1 g of hydrophobic ionic liquid and 0.2 mL acetone which was injected to 2 mL of serum or urine samples which was diluted with DW up to 10 mL. The cloudy solution was shacked for 7 min and Cu and Zn ions was extracted based on sulfur group on amoxicillin ligand at pH of 7 by DIL-CPE. Then, the solution centrifuged and after back extraction with I mL of nitric acid (0.2 M), the remained solution was determined by flame atomic absorption spectrometry (F-AAS).

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Pajarito, Bryan B., Kayla C. Castañeda, Sofia Denise M. Jeresano et Dominique Ann N. Repoquit. « Reduction of Offensive Odor from Natural Rubber Using Zinc-Modified Bentonite ». Advances in Materials Science and Engineering 2018 (16 juillet 2018) : 1–8. http://dx.doi.org/10.1155/2018/9102825.

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Natural bentonite was modified with zinc ions and was used as a filler to reduce the offensive odor from raw natural rubber (NR). Characterization of filler shows the limited exchange of inherent calcium ions and the preferred adsorption of zinc ions on the surface of natural bentonite during modification. The modification process was also accompanied by bassanite formation due to sulfate ions brought by the zinc salt. Zinc-modified bentonite demonstrates an antimicrobial effect against microorganisms that are known to degrade or produce offensive odor from raw NR. Due to its antimicrobial and adsorption properties, zinc-modified bentonite significantly reduces the offensive odor from raw NR at loadings of 2.5–7.5 phr as shown by the olfactometry test. In terms of vulcanization characteristics, the loading of zinc-modified bentonite at 7.5 phr caused a slight decrease in elastic torque and increase in scorch and curing times of NR. The hardness and tensile properties of vulcanized NR are maintained after compounding with zinc-modified bentonite at 7.5 phr.

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