Sorption of small amounts of europium(III) on iron(III) hydroxide and oxide

The sorption of small amounts of europium(III) on iron(III) hydroxide and oxide has been studied as a function of pH. The mechanism of sorption is discussed. Optimum conditions have been found for the preconcentration of small or trace amounts of europium(III) by iron(III) hydroxide and oxide. The influence of complexing agents (EDTA, oxalate, tartrate and 5-sulfosalicylic acid) on the sorption of small amounts of europium(III) on iron(III) oxide has also been studied.     

Sorption of trace amounts of ruthenium,manganese and europium on iron(III) hydroxide

Summary The effect of pH on the sorption of trace amounts of ruthenium, manganese and europium on iron(III) hydroxide was studied by radiotracer techniques. The effect of amount of sorbent and duration of the contact between the sorbate and the sorbent were also studied. The results indicate that an iron(III) hydroxide precipitate can be used for the preconcentration of traces of ruthenium, manganese and europium.

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Zusammenfassung Der Einfluß des pH auf die Adsorption von Spuren Ruthenium, Mangan und Europium an Eisen (III) hydroxid wurde untersucht. Die Wirkung der Menge Adsorptionsmittel und die Dauer des Kontaktes zwischen diesem und dem Adsorbat wurden gleichfalls geprüft. Die Ergebnisse zeigen, daß Eisen(III)hydroxidniederschläge für die Anreicherung der erwähnten Spuren geeignet sind.

     

Sorption of iron(III) in ionic and colloidal states on iron(III) oxide deposited on a silica gel sufrace

The sorption of iron(III) in ionic and colloidal states on iron(III) oxide deposited on a silica gel surface has been studied as a function of pH of aqueous solution by batch equilibrations. The behaviour of Fe³⁺ and colloidal Fe(III) on the sorbent column has also been investigated. Conditions for sorption of iron from aqueous solutions are given. The colloidal iron(III) can be quantitatively separated from Fe³⁺ on the sorbent column under given experimental conditions.     

Determination of metallic iron, iron(II) oxide, and iron(III) oxide in a mixture

A procedure is described for the estimation of metallic iron, ferrous oxide, and ferric oxide when present together. The sample is treated with bromine dissolved in ethanol, and filtered. Iron in the filtrate is titrated iodometrically, and corresponds to the metallic iron present in the mixture. The oxide residue is dissolved in hydrochloric acid under a carbon dioxide atmosphere. The iron(II) formed, equivalent to FeO present, is titrated with a standard vanadate solution, and the total iron(III) (FeO + Fe₂O₃) in the titrated solution is then estimated iodometrically.     

Sorption thermodynamics of cobalt(II) cations on iron-manganese concretions

Isotherm of ion exchange of Co²⁺ and Na⁺ cations on iron-manganese concretions is thermodynamically described using a modified Langmuir equation. The thermodynamic characteristics of the ion exchange are determined.     

Preconcentration of iron (III), cobalt (II) and copper (II) nitroso-R complexes on tetradecyldimethylbenzylammonium iodide-naphthalene adsorbent

Iron, cobalt and copper form coloured water soluble anionic complexes with disodium 1-nitroso-2-naphthol-3-6-disulphonate (nitroso R-salt). The anionic complex is retained quantitatively as a water insoluble neutral ion associated complex (M-nitroso R-TDBA) on tetradecyldimethylbenzylammonium iodide on naphthalene (TDBA(+)I(-)-naphthalene) packed column in the pH range of: Fe(III): 3.1-6.5, Co: 3.4-8.5 and Cu 5.9-8.0 when their solutions are passed individually over this adsorbent at a flow rate of 0.5-5.0 ml/min. The solid mass consisting of an ion associated metal complex along with naphthalene is dissolved out of the column with 5 ml dimethylformamide/chloroform and metals are determined spectrophotometrically. The absorbance is measured at 710 nm for iron, 425 nm for cobalt and 480 nm for copper. Beers law is obeyed in the concentration range 9.2-82 mug of iron, 425 nm for cobalt cobalt and 3.0-62 mug of copper in 5 ml of final DMF/CHCl(3) solution. The molar absorptivities are calculated to be Fe: 7.58 x 10(3), Co: 1.33 x 10(4) and Cu: 4.92 x 10(4)M(-1)cm(-1). Ten replicate determinations containing 25 mug of iron, 9.96 mug of cobalt and 3.17 mug of copper gave mean absorbances 0.677, 0.450 and 0.490 with relative standard deviations of 0.88, 0.98 and 0.92%, respectively. The interference of large number of metals and anions on the estimations of these metals has been studied. The optimized conditions so developed have been employed for the trace determination of these metals in standard alloys, waste water and fly ash samples.     

Microscopic investigation of iron (III), cobalt (II), and nickel(II) in mixtures

Summary The complex FeI₃·3 C₉H₇N has been verified through topochemical reactions leading to known microcrystalline products. Using the same technique, Fe(III), Co(II), and Ni(II) can be detected in mixtures at concentrations of 1 to 0.01% within an hour.

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Zusammenfassung Die Zusammensetzung des Komplexes FeJ₃ · (C₉H₇N)₃ wurde durch topochemische Kristallfällungsreaktionen erwiesen. In gleicher Weise lassen sich Fe(III), Co(II) und Ni(II) in Konzentrationen zwischen 0,01 und 1% innerhalb 1 Stunde nebeneinander nachweisen.

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Presented at the 8th Pan-American Congress of Pharmacy and Biochemistry, November 30-December 7, 1969, Caracas, Venezuela.     

Sorption of lanthanum(III), cobalt(II) and iodide ions at trace concentrations on ferric hydroxide

Summary The sorption of lanthanum(III), cobalt(II) and iodide traces was studied in dependence on the solid-liquid contact time, pH value and the properties of the carrier (internally or externally formed). The ferric hydroxide carrier was prepared by mixing aqueous ferric chloride and ammonia solutions. The results are discussed in regard to colloidal properties of the ferric hydroxide and mechanisms of sorption.

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Zusammenfassung Die Abhängigkeit der Sorption von Lanthan(III)-, Kobalt(II)- und Jodidspuren von der Berührungsdauer zwischen fester und flüssiger Phase, vom pH-Wert und von den kolloidalen Eigenschaften des Trägers (abgesondert, oder direkt im Sorptionssystem vorbereitet) wurde untersucht. Der Eisen(III)-hydroxidträger wurde durch Mischen wässriger Eisen(III)chlorid- und Ammoniaklösung gewonnen.Die Ergebnisse wurden im Hinblick auf die kolloidalen Eigenschaften des Eisen(III)hydroxids und den Sorptionsvorgang diskutiert.

     

Studies on extraction of iron(III) and cobalt(II) chlorides by quaternary ammonium halides

Summary The extraction of iron(III) and cobalt(II) from hydrochloric acid solutions by Hyamine 1622, a quaternary ammonium halide, in dichloroethane is described. The effect of acidity, salting-out agent, metal and extradant concentrations and temperature, has been investigated. The extraction mechanism is discussed in the light of results obtained. Separation of iron(III) and cobalt(II) is also outlined.     

Synthesis and characterisation of complexes of iron(II,III), cobalt(II,III) and nickel(II) with dinitrosoresorcinol

Summary Complexes of Fe^II, Fe^III, Co^II, Co^III and Ni^II with dinitroso resercinol (DNR) have been isolated and characterised. Ni studies showed that the metals are coordinated to the oxygens of one hydroxyl and one nitroso group, the second hydroxyl and nitroso groups remaining uncoordinated. The magnetic moments of the Fe^II and Ni^II complexes are commensurate with tetrahedral (or disorted octahedral) structures, while the others are ocahedral, however, the electronic spectra suggest ocahedral stereochemistries for all the complexes.     

Spectral and magnetic studies on normal cobalt(II) planar and cobalt(III) octahedral, spin-crossover cobalt(III) octahedral and planar-tetrahedral cobalt(II) carbodithioates

Five cobalt(II) complexes, a normal complex Co(4-PPipzcdt)₂ (4-PPipzcdt = 4-phenylpiperazine-1-carbodithioate), and four zwitterionic complexes, Co(4-PPipzcdtH)₂X₂ and Co(4-MPipzcdtH)₂X₂ (X = Cl, Br; 4-PPipzcdtH = 4-phenylpiperazine-1-carbodithioic acid, 4-MPipzcdtH = 4-methylpiperazine-1-carbodithioic acid), have been synthesized. Normal cobalt(III) complexes of the type Co(4-MPipzcdt)₃ and Co₂ {2-MPipz(cdt)₂}₃ (2-MPipz(cdt)₂ = 2-methylpiperazine-1,4-dicarbodithioate) and two zwitterionic cobalt(III) complexes of the type Co(4-MPipzcdtH)₃X₃ (X = Cl, Br) have also been obtained. In addition to the room temperature IR and electronic spectra and magnetic susceptibility studies, all the complexes, except the normal Co(4-MPipzcdt)₃ and Co(4-PPipzcdt)₂ and zwitterionic Co(4-MPipzcdtH)₃Cl₃, have been investigated by variable-temperature magnetic susceptibility measurements. The results of the variable-temperature magnetic susceptibility studies suggest that two cobalt(II) carbodithioates exhibit a square planar-tetrahedral equilibrium, while two cobalt(III) octahedral carbodithioates show a spin-crossover phenomenon.     

Activation volumes for peroxodisulphate oxidation of cobalt(III), iron(II) and nickel(II) complexes

Summary Dependences of rate constants on pressure (in aqueous solution up to 1.25 kbar) are reported for peroxodisulphate oxidation of hexacyanoferrate(II), tris(2,2-bipyridyl)iron(II), tris(1,10-phenanthroline)iron(II), bis(1,4,7-triazacyclononane)nickel(II) and bis(1,2-ethanediamine)cysteinatocobalt(III) and its thioglycollato-analogue, and for periodate oxidation of the two last-named complexes. Derived activation volumes are reported and discussed in terms of intrinsic and solvational contributions. Rate laws and pressure effects on reactivity are reported for the reaction of peroxodisulphate with pentacyanoferrates(II) containing N-alkylpyrazinium ligands.     

Spectrophotometric determination of iron(II) with 1,10-phenanthroline in the presence of large amounts of iron(III)

A study was made to establish proper conditions for the selective determination of Fe(II) by the 1,10-phenanthroline method in the presence of large amounts of Fe(III). It was shown that fe(III) is effectively masked by fluoride. The pH of the solution to be masked should be below 2.5 in order to prevent acceleration by the fluoride of aerial oxidation of Fe(II).     

Ligational behaviour of two biologically active N−S donors towards cobalt(III), iron(III), iron(II) and rhodium(III)

Summary The chelating behaviour of two biologically active ligands, pyridine-2-carboxaldehyde(4-phenyl) thiosemicarbazone(L₁H) and pyridine-2-carboxaldehyde thiosemicarbazone(LH), towards Fe^III, Co^III, Fe^II and Rh^III has been investigated. The ligands act as tridentate N–N–S donors, resulting in the formation of bis-chelate complexes of the type M^III(A)₂X·nH₂O (A=L₁ or L; X=Cl, ClO₄; M=Co^III, Rh^III, Fe^III), Fe^II(L₁H)₂SO₄·2H₂O and Fe^II(L₁)₂·H₂O. Biological activity of the ligands and the metal complexes in the form ofin vitro antibacterial activities towardsE. coli has been evaluated and the possible reasons for enhancement of the activity of ligands on coordination to metal ion is discussed.     

Sorption of144Ce(III) and147Pm(III) on hydrated iron sesquioxide

The sorption of¹⁴⁴Ce(III) and of¹⁴⁷Pm(III) on hydrated iron sesquioxide suspension and the sorption of¹⁴⁴Ce(III) on hydrated iron sesquioxide in a laboratory column were studied. The dependence of the sorption on pH and time, the sorption isotherm, the temperature-dependence of sorption, and the effects of ionic strength on sorption and desorption were determined under static conditions. The maximum sorptions of¹⁴⁴Ce(III) and¹⁴⁷Pm(III) were reached at pH=7.4 (K_d=8.9·10⁵) and pH=9.1 (K_d=6.2·10⁵), respectively.     

Sorption of Hexacyanoferrate(II,III) Anions on Nickel(II) Hydroxide

Fe(CN)₆ ^{3 -} and Fe(CN)₆ ^{4 -} anions are sorbed from aqueous solutions of their potassium and cesium salts on -Ni(OH)2 by the mechanism of anion exchange with hydroxy groups. Alkali metal cations (K⁺, Cs⁺) are also partly sorbed on nickel(II) hydroxide in the form of anionic complexes (K,Cs) _z Fe(CN)₆ ^{(n - z)-}, where n = 3 or 4 (0 < z < n). The chemical composition of the new phase appearing in contact of nickel(II) hydroxide with aqueous potassium and cesium hexacyanoferrates(II, III) was determined by X-ray phase analysis and IR spectroscopy.     

The structural organization of oligonuclear cobalt(II,III) and cobalt(III) carboxylates

The review deals with the topology of homonuclear carboxylate complexes of cobalt(II, III) and cobalt(III) whose structures are built from the monocarboxylate anions RCOO^– (R is a radical containing no electron-donating substituents), water, and its deprotonated forms.     

Thermal studies on oxalate complexes. III. Complexes of cobalt(III) and cobalt(II)

The decomposition of K₂[Co(C₂O₄)₂] and K₃[Co(C₂O₄)₃] has been studied using TG. In the case of the latter compound, the first step involves the rupture of all the oxalates and one of the resultant carbonates to liberate CO₂ and three molecules of CO. Subsequent steps involve the loss of CO₂. In the case of K₂[Co(C₂O₄)₂], four decomposition reactions are observed. The first involves the loss of only CO. Subsequent steps involve loss of CO₂, CO₂ and CO, and CO₂, respectively. Basic carbonates appear to be the intermediate products. Kinetic parameters are presented for most of the reactions.     

Sorption of iron(II) and ruthenium(III)-triazine complexes on silica gel and its analytical applicability

2,4,6-Tri(2′-pyridyl)-s-triazine (TPTZ) complexes with iron(II) and ruthenium(III) were prepared. Their sorption and desorption features on silica gel have been investigated. Both complexes were strongly adsorbed. This has been utilized for separating and preconcentrating iron(II) and ruthenium(III) using TPTZ-impregnated silica gel. The chromatographic behavior of TPTZ on silica gel column was examined and found to be effective modifier for silica gel surface. The sorption capacity of silica gel for those metal-triazine complexes has been determined under static conditions and was found to be 5.28 × 10^–3 mM (Fe(TPTZ)₂²⁺) and 2.9 × 10^–3 mM (Ru(TPTZ)₂³⁺). Saturated methanolic solutions of KI or 25% NaClO₄ solutions desorbed both complexes quantitatively from the silica gel surface.