Cobalt Exchange Research Articles

Influence of acetate, chloride and nitrate ions on the sorption of cobalt by zeolite ZSM-5

Many factors affect the ion exchange process in zeolites. In this work the influence of different anions such as acetate, chloride and nitrate on the ion exchange of cobalt in zeolite ZSM-5 is discussed. After the ion exchange in the presence of those anions no change was found in the zeolite structure, by X ray diffraction and IR spectroscopy. The retention of cobalt by zeolite ZSM-5 at low concentrations (from 0.001 to 0.3N) was higher when the exchange was done with cobalt nitrate and chloride. This behavior was different in the case of 1N cobalt salts, since the highest sorption uptake was found when working with cobalt acetate and its sorption was directly proportional to its concentration.

Catalyst effectiveness factor of cobalt-exchanged mordenites for the selective catalytic reduction of NO with hydrocarbons

The influence of intracrystalline diffusion on the selective catalytic reduction of NO was examined by using cobalt-exchanged mordenites with different crystal sizes. In the NO-CH 4-O 2 reaction, the reaction rate increased with cobalt exchange level, but the rate over a large crystal mordenite was slightly lower than that over a small crystal mordenite. In the NO-C 3H 8-O 2 reaction, where the reaction rate was higher than that of the NO-CH 4-O 2 reaction, the effect of crystal size was more significant. Furthermore, the reaction rate over the small crystal increased with increasing cobalt exchange level, whereas the rate over the large crystal decreased with increasing cobalt exchange level. The effectiveness factor calculated from these results was below unity, indicating that the volume of zeolite crystal was not fully utilized because of the diffusion limitations.

Uptake of copper and cobalt in a complexing resin: shrinking-core model with two reaction fronts

The kinetics of simultaneous ion exchange of copper and cobalt with iminodiacetic chelating resins has been studied. Microscopic studies of the ion-exchange process clearly show two different reaction fronts allowing the use of shrinking-core type models. The influence of system parameters is studied both theoretically and experimentally. Experimental results obtained at different total ion concentrations for various copper-cobalt ratios and particle diameters are reasonably predicted by the shrinking-core model, allowing diffusivity calculations.

The influence of a specific microelemental environment in alginate gel beads on the course of propionic acid fermentation

In this work the exchange of calcium, cobalt, iron, magnesium, zinc and manganese ions between alginate gel beads and casein medium was investigated. The high release of calcium ions from alginate to the medium and the biosorption of some metal ions were observed. The pure alginate gel adsorbed all the metal ions examined, from a fermentative medium. Gel with immobilized cells of two strains of Propionibacterium freudenreichii subsp. shermanii showed an active ability to adsorb only cobalt, iron and zinc ions. In this way, a special microelemental environment was created in the alginate gel. This resulted in an increase of propionic acid production and a decrease of vitamin B12 biosynthesis.

The competitive exchange of hydrogen and cobalt ions on calcium-montmorillonite

The sorption of cobalt ion on calcium-montmorillonite was studied by the radioisotopic tracer method at different pH values. In dilute solutions the reaction has to be treated as a ternary exchange of cobalt, calcium, and hydrogen ions because of the high affinity of hydrogen ion to montmorillonite. Equilibrium constant for calcium-hydrogen exchange was determined.

Nitrogen-14 NMR Study on Solvent Exchange of the Octahedral Cobalt(II) Ion in Neat 1,3-Propanediamine and n-Propylamine at Various Temperatures and Pressures. Tetrahedral-Octahedral Equilibrium of the Solvated Cobalt(II) Ion in n-Propylamine As Studied by EXAFS and Electronic Absorption Spectroscopy.

Solvated cobalt(II) ions in neat 1,3-propanediamine (tn) and n-propylamine (pa) have been characterized by electronic absorption spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. The equilibrium between tetrahedral and octahedral geometry for cobalt(II) ion has been observed in a neat pa solution, but not in neat diamine solutions such as tn and ethylenediamine (en). The thermodynamic parameters and equilibrium constant at 298 K for the geometrical equilibrium in pa were determined to be DeltaH degrees = -36.1 +/- 2.3 kJ mol(-1), DeltaS degrees = -163 +/- 8 J mol(-1) K(-1), and K(298) = 6.0 x 10(-3) M(-2), where K = [Co(pa)(6)(2+)]/{[Co(pa)(4)(2+)][pa](2)}. The equilibrium is caused by the large entropy gain in formation of the tetrahedral cobalt(II) species. The solvent exchange of cobalt(II) ion with octahedral geometry in tn and pa solutions has been studied by the (14)N NMR line-broadening method. The activation parameters and rate constants at 298 K for the solvent exchange reactions are as follows: DeltaH() = 49.3 +/- 0.9 kJ mol(-1), DeltaS() = 25 +/- 3 J mol(-1) K(-1), DeltaV() = 6.6 +/- 0.3 cm(3) mol(-1) at 302.1 K, and k(298) = 2.9 x 10(5) s(-1) for the tn exchange, and DeltaH() = 36.2 +/- 1.2 kJ mol(-1), DeltaS() = 35 +/- 6 J mol(-1) K(-1), and k(298) = 2.0 x 10(8) s(-1) for the pa exchange. By comparison of the activation parameters with those for the en exchange of cobalt(II) ion, it has been confirmed that the kinetic chelate strain effect is attributed to the large activation enthalpy for the bidentate chelate opening and that the enthalpic effect is smaller in the case of the six-membered tn chelate compared with the five-membered en chelate.

60Co retention by Mexican montmorillonites

Radioactive elements may be retained by clays. The ability of natural Mexican clays to retain radioactive Co from aqueous solutions, is discussed. Experiments were performed with solutions containing labeled cobalt. The effect of contact time on Co2+ retention was studied. It was found that the Co2+ uptake value in dehydrated montmorillonites is between 0.30 and 0.70 meq g−1 of clay. A sorption sequence was obtained for the various clays. The samples were characterized, before and after cobalt exchange, by X-ray diffraction.

60Co sorption-desorption in Mexican montmorillonites

The ability of some antural Mexican clays to sorb radioactive Co from aqueous solution and then desorb it has been measured. The clay cations seem to be exchanged with cations present in the solution. It was observed that the amount of sorbed Co2+ depends nearly linearly on the Na++K+ content in the montmorillonites. It was found that the crystallinity was not altered after Co2+ sorption. Crystallinity of clays, before and after cobalt exchange, was determined by X-ray diffraction.

Variable-Temperature and -Pressure Multinuclear Magnetic Resonance Studies on Solvent Exchange of Cobalt(II), Iron(II), and Manganese(II) Ions in Ethylenediamine. Kinetic Chelate Effect and Chelate Strain Effect

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVariable-Temperature and -Pressure Multinuclear Magnetic Resonance Studies on Solvent Exchange of Cobalt(II), Iron(II), and Manganese(II) Ions in Ethylenediamine. Kinetic Chelate Effect and Chelate Strain EffectSen-ichi Aizawa, Kayoko Matsuda, Tomomi Tajima, Machiyo Maeda, Takashi Sugata, and Shigenobu FunahashiCite this: Inorg. Chem. 1995, 34, 8, 2042–2047Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://doi.org/10.1021/ic00112a015RIGHTS & PERMISSIONSArticle Views165Altmetric-Citations20LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (702 KB) Get e-AlertsSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts

Effects of catalyst composition on dual site zeolite catalysts used in chlorinated hydrocarbon oxidation

Cobalt exchanged and chromia impregnated Y zeolite catalysts (Co-Y/CA ) have been found to show good activity and selectivity for low-molecular-weight chlorohydrocarbon (CH 2Cl 2, C 2HCl 3, CCl 4, etc.) oxidation in the range of 250–350°C. For such dual site catalysts, the effects of cobalt and chromia composition on the catalytic properties were investigated. Higher cobalt exchange increased the acidity and the oxygen adsorption capacity of the Co-Y zeolite without affecting the surface area, whereas increasing Cr 2O 3 impregnation caused increased dealumination and consequent loss of acidity. Higher loading of Cr 2O 3 also reduced catalyst surface area by combination of structural loss and pore/channel blockage. Increasing cobalt exchange produced improved conversion of methylene chloride (CH 2Cl 2) while higher loading of impregnated Cr 2O 3 was detrimental for methylene chloride conversion due to the associated loss of surface area and acidity. Methylene chloride conversion appeared to be primarily controlled by carbonium ion formation at the acidic sites followed by oxidation with the oxygen adsorbed at the cationic sites. Conversely, trichloroethylene (C 2HCl 3) oxidation was primarily determined by the impregnated Cr 2O 3 sites; low or no Cr 2O 3 produced poor conversion while increasing Cr 2O 3 loading increased the conversion. However, an optimum impregnation level (⋍5%) seemed to be necessary to avoid poor activity either due to lack of sites or due to structural damage by overloading. Additionally, increasing cobalt exchange level in the Co-Y/CA catalysts also showed improved TCE conversion probably due to the increasing acidity. Therefore, TCE conversion seemed to be controlled by the initial adsorption at the Cr 2O 3 sites with subsequent reactions which may involve the acidic and/or cationic sites.

The hexaammine cobalt (2+/3+) exchange reaction: ground-state versus thermally excited pathways

The hexaammine cobalt (2+/3+) exchange reaction: ground-state versus thermally excited pathways

Proton exchange and epimerization of cobalt(III) chelated amino acids via carbanion intermediates

Proton exchange and epimerization of cobalt(III) chelated amino acids via carbanion intermediates

Heterogeneous isotopic exchange of oxygen with cobalt forms of high-silica zeolites

1. The mobility of the structural oxygen in the zeolites increases in substitution of sodium and potassium ions by cobalt in Y, L, erionite, mordenite, and TsVM zeolites. 2. Nonequivalence of the structural oxygen atoms is observed in NaKE zeolite with an increase in the degree of exchange of cobalt to 0.25. 3. Nonequivalence of the structural oxygen atoms is found on introduction of 2.9 wt.% cobalt in TsVM zeolite.

Oxygen-17 nuclear magnetic resonance studies on the acetic acid exchange of manganese(II), iron(II), cobalt(II), nickel(II), and copper(II) perchlorates in acetic acid

Oxygen-17 nuclear magnetic resonance studies on the acetic acid exchange of manganese(II), iron(II), cobalt(II), nickel(II), and copper(II) perchlorates in acetic acid

Progressive ion exchange of lithium and cobalt(II) in sodium mordenite and its effect on the enthalpy of sorption of O 2 and N 2

The effects of progressive replacement of sodium ions in mordenite with lithium and cobalt(II) ions on the initial enthalpies of sorption of O 2 and N 2 have been studied. Zeolites, like mordenite, demonstrate higher enthalpies of sorption of N 2 than of O 2 and consequently are employed as selective sorbents in pressure swing adsorption (PSA) systems to separate O 2 and N 2 from air. Lithium exchange produced little effect on the enthalpy of sorption of N 2 up to an exchange level of 41% on an equivalent basis. As the level of lithium exchange increased from 41% to 49%, a sharp increase (from 5.7 to 6.2 kcal/mole, i.e., 23.8 to 25.9 kJ/mole) in the enthalpy of sorption of N 2 was exhibited. Cobalt(II) exchange produced a significant increase in the enthalpy of sorption of N 2 even at low levels of exchange. At an exchange level of 15% cobalt(II), the enthalpy of sorption of N 2 increased from 5.6 kcal/mole (23.4 kJ/mole) for sodium mordenite to 6.6 kcal/mole (27.6 kJ/mole). Cobalt(II) exchange also produced the same type of effect on the enthalpy of sorption of O 2 increasing that value from 4.3 to 4.9 kcal/mole (18.0 to 20.5 kJ/mole) at a 15% exchange level. However, lithium exchange little affected the enthalpy of sorption of O 2 regardless of the extent of exchange. The different effects of progressive lithium and cobalt(II) ion exchange on the enthalpies of sorption of O 2 and N 2 are explained in terms of the position the respective cations occupy in the outgassed mordenite structure.

Progressive ion exchange of lithium and cobalt(II) in sodium mordenite and its effect on the enthalpy of sorption of O2 and N2

The effects of progressive replacement of sodium ions in mordenite with lithium and cobalt(II) ions on the initial enthalpies of sorption of O2 and N2 have been studied. Zeolites, like mordenite, demonstrate higher enthalpies of sorption of N2 than of O2 and consequently are employed as selective sorbents in pressure swing adsorption (PSA) systems to separate O2 and N2 from air. Lithium exchange produced little effect on the enthalpy of sorption of N2 up to an exchange level of 41% on an equivalent basis. As the level of lithium exchange increased from 41% to 49%, a sharp increase (from 5.7 to 6.2 kcal/mole, i.e., 23.8 to 25.9 kJ/mole) in the enthalpy of sorption of N2 was exhibited. Cobalt(II) exchange produced a significant increase in the enthalpy of sorption of N2 even at low levels of exchange. At an exchange level of 15% cobalt(II), the enthalpy of sorption of N2 increased from 5.6 kcal/mole (23.4 kJ/mole) for sodium mordenite to 6.6 kcal/mole (27.6 kJ/mole). Cobalt(II) exchange also produced the same type of effect on the enthalpy of sorption of O2 increasing that value from 4.3 to 4.9 kcal/mole (18.0 to 20.5 kJ/mole) at a 15% exchange level. However, lithium exchange little affected the enthalpy of sorption of O2 regardless of the extent of exchange. The different effects of progressive lithium and cobalt(II) ion exchange on the enthalpies of sorption of O2 and N2 are explained in terms of the position the respective cations occupy in the outgassed mordenite structure.

Proteolytic specificity and cobalt exchange of hemorrhagic toxin e, a zinc protease isolated from the venom of the western diamondback rattlesnake (Crotalus atrox).

Proteolytic specificity and cobalt exchange of hemorrhagic toxin e, a zinc protease isolated from the venom of the western diamondback rattlesnake (Crotalus atrox).

The kinetics of the exchange of cobalt(II) ions between NaCl and Na2O-SiO2-Fe2O3 melts in the temperature range 1200 to 1400 K

Studies of the equilibria and kinetics of the Co2+ ion exchange in the Na2O-SiO2-Fe2O3/NaCl system were performed over the 1200 to 1400 K temperature range by measuring the emf of galvanic cells of the following composition: $$( - )Co\left| {\frac{{NaCl - CoCl_2 }}{{Na_2 O - SiO_2 - Fe_2 O3}}} \right.\left| {NaCl - CoCl_2 } \right.\left| {Co( + )} \right.$$ Distribution coefficients α of the Co2+ ions between the salt phase and silicate melt are of the l0−2 order. Differential equations describing the transfer process of the Co2+ ions from the salt phase to the silicate phase were solved. The diffusion coefficients DCo 2+ in the Na2O-SiO2-Fe2O3 melt were determined by substituting the Co2+ ion concentration change in fused NaCI into the differential equations. The values of DCo 2+ are about 10−5 cm2S−1 and they decrease with decreasing temperature and increasing Fe−2O−3 content in slags. The diffusion coefficient of the cobalt (II) ions in slags determined in this way is consistent with that determined by the otating disk method.

ChemInform Abstract: NITROGEN‐14 MAGNETIC RESONANCE STUDIES OF THE EFFECT OF PRESSURE ON THE EXCHANGE OF ACETONITRILE SOLVENT ON NICKEL(II) AND COBALT(II)

Chemischer InformationsdienstVolume 12, Issue 5 Physical Organic Chemistry ChemInform Abstract: NITROGEN-14 MAGNETIC RESONANCE STUDIES OF THE EFFECT OF PRESSURE ON THE EXCHANGE OF ACETONITRILE SOLVENT ON NICKEL(II) AND COBALT(II) Y. YANO, Y. YANOSearch for more papers by this authorM. T. FAIRHURST, M. T. FAIRHURSTSearch for more papers by this authorT. W. SWADDLE, T. W. SWADDLESearch for more papers by this author Y. YANO, Y. YANOSearch for more papers by this authorM. T. FAIRHURST, M. T. FAIRHURSTSearch for more papers by this authorT. W. SWADDLE, T. W. SWADDLESearch for more papers by this author First published: February 3, 1981 https://doi.org/10.1002/chin.198105075AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue5February 3, 1981 RelatedInformation

ChemInform Abstract: HIGH‐PRESSURE NUCLEAR MAGNETIC RESONANCE KINETICS. 5. PROTON NUCLEAR MAGNETIC C RESONANCE STUDY OF THE EFFECT OF PRESSURE ON THE EXCHANGE OF NONAQUEOUS SOLVENTS ON NICKEL(II) AND COBALT(II)

Chemischer InformationsdienstVolume 10, Issue 45 Organoelement Compounds ChemInform Abstract: HIGH-PRESSURE NUCLEAR MAGNETIC RESONANCE KINETICS. 5. PROTON NUCLEAR MAGNETIC C RESONANCE STUDY OF THE EFFECT OF PRESSURE ON THE EXCHANGE OF NONAQUEOUS SOLVENTS ON NICKEL(II) AND COBALT(II) F. K. MEYER, F. K. MEYERSearch for more papers by this authorK. E. NEWMAN, K. E. NEWMANSearch for more papers by this authorA. E. MERBACH, A. E. MERBACHSearch for more papers by this author F. K. MEYER, F. K. MEYERSearch for more papers by this authorK. E. NEWMAN, K. E. NEWMANSearch for more papers by this authorA. E. MERBACH, A. E. MERBACHSearch for more papers by this author First published: November 6, 1979 https://doi.org/10.1002/chin.197945301Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume10, Issue45November 6, 1979 RelatedInformation