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1.
Summary The effect of pH on the sorption of ruthenium-97 on Fe2O3, Fe(OH)3 and Fe(OH)2 precipitates was studied by radiotracer technique. The sorption characteristics of Fe2O3, Fe(OH)3 and Fe(OH)2 sorbents have been established. Iron(II) hydroxide can be used for the preconcentration of ruthenium-97 or generally of trace amounts of ruthenium, without regard to the oxidation state of ruthenium. The effect of duration of the contact between the hydroxide sorbent and ruthenium-97 in solution was also studied.
Zusammenfassung Der Einfluß des pH auf die Adsorption von97Ru an Fe2O3,- Fe(OH)3-und Fe(OH)2-Niederschlägen wurde radiochemisch untersucht. Die Sorptionsmerkmale der erwähnten Adsorptionsmittel wurden festgestellt. Eisen-(II)hydroxid kann für die Anreicherung von97Ru oder allgemein von Rutheniumspuren ohne Rücksicht auf deren Oxydationsstufe verwendet werden. Der Einfluß der Berührungsdauer zwischen adsorbierendem Hydroxid und97Ru in der Lösung wurde gleichfalls untersucht.相似文献
2.
《Polyhedron》2002,21(12-13):1299-1304
The crystal structure of a trinuclear iron monoiodoacetate complex was determined. Although it has been incorrectly characterized as [Fe3O(O2CCH2I)6(H2O)3], the correct chemical formula turned out to be [Fe(III)2Fe(II)O(O2CCH2I)6(H2O)3]-[Fe(III)3O(O2CCH2I)6(H2O)3]I (1). The two kinds of Fe3O molecules (Fe(III)2Fe(II)O and Fe(III)3O) are crystallographically indistinguishable. All the Fe atoms are crystallographically equivalent because of a crystallographic threefold symmetry. Heat capacities of 1 seem to exhibit no thermal anomaly in the temperature range 5.5–309 K, although the valence detrapping phenomenon has been observed in this temperature range. This fact indicates that the valence-detrapping phenomenon in 1 occurs without any phase transition, leading 1 to a glassy state, probably because the crystal of 1 is just like a solid solution of distorted mixed-valence Fe(III)2Fe(II)O molecules and permanently undistorted Fe(III)3O molecules which may act as an inhibitor for a cooperative valence-trapping. 相似文献
3.
Uheida A Iglesias M Fontàs C Hidalgo M Salvadó V Zhang Y Muhammed M 《Journal of colloid and interface science》2006,301(2):402-408
The adsorption of palladium(II), rhodium(III), and platinum(IV) from diluted hydrochloric acid solutions onto Fe(3)O(4) nanoparticles has been investigated. The parameters studied include the contact time and the concentrations of metals and other solutes such as H(+) and chloride. The equilibrium time was reached in less than 20 min for all metals. The maximum loading capacity of Fe(3)O(4) nanoparticles for Pd(II), Rh(III), and Pt(IV) was determined to be 0.103, 0.149, and 0.068 mmol g(-1), respectively. A sorption mechanism for Pd(II), Rh(III), and Pt(IV) has been proposed and their conditional adsorption equilibrium constants have been determined to be logK=1.72, 1.69, and 1.84, respectively. Different compositions of eluting solution were tested for the recovery of Pt(IV), Pd(II), and Rh(III) from Fe(3)O(4) nanoparticles. It was found that 0.5 mol L(-1) HNO(3) can elute all of the metal ions simultaneously, while 1 mol L(-1) NaHSO(3) was an effective eluting solution for Rh(III), and 0.5 mol L(-1) NaClO(4) for Pt(IV). In competitive adsorption, the nanoparticles showed stronger affinity for Rh(III) than for Pd(II) and Pt(IV). 相似文献
4.
A new μ3-O triiron(III) complex [Fe3O(OBz)6(CH3OH)3](NO3)(CH3OH)2 (HOBZ = benzoic acid) has been synthesized, its structure has been determined and variable temperature magnetic susceptility has also been measured. In the molecule, three iron atoms formed an equilateral triangle with μ3-O in center. The fitting to the magnetic susceptibility showed that an intramolecular antiferromagnetic exchange interaction occurred between iron atoms with J=-25.51 cm?1, and a weaker intermolecular autiferromagnetic exchange interaction occurred with zJ' = ?2.30 cm?1. 相似文献
5.
R L Frost R A Wills J T Kloprogge W N Martens 《Journal of Thermal Analysis and Calorimetry》2006,83(1):213-218
Thermogravimetry combined
with mass spectrometry has been used to study the thermal decomposition of
a synthetic hydronium jarosite. Five mass loss steps are observed at 262,
294, 385, 557 and 619°C. The mass loss step at 557°C is sharp and
marks a sharp loss of sulphate as SO3 from the hydronium
jarosite. Mass spectrometry through evolved gases confirms the first three
mass loss steps to dehydroxylation, the fourth to a mass loss of the hydrated
proton and a sulphate and the final step to the loss of the remaining sulphate.
Changes in the molecular structure of the hydronium jarosite were followed
by infrared emission spectroscopy. This technique allows the infrared spectrum
at the elevated temperatures to be obtained. Infrared emission spectroscopy
confirms the dehydroxylation has taken place by 400 and the sulphate loss
by 650°C. Jarosites are a group of minerals formed in evaporite deposits
and form a component of the efflorescence. The minerals can function as cation
and heavy metal collectors. Hydronium jarosite has the potential to act as
a cation collector by the replacement of the proton with a heavy metal cation. 相似文献
6.
Bi LH Kortz U Nellutla S Stowe AC van Tol J Dalal NS Keita B Nadjo L 《Inorganic chemistry》2005,44(4):896-903
The iron(III)-substituted tungstogermanate [Fe6(OH)3(A-alpha-GeWO34(OH)3)2]11- (1) has been synthesized and characterized by IR, elemental analysis, SQUID magnetometry, electron paramagnetic resonance (EPR), and electrochemistry. Single-crystal X-ray analysis was carried out on Cs4Na7[Fe6(OH)3(A-alpha-GeW9O34(OH)3)2] x 30H2O, which crystallizes in the monoclinic system, space group C2/m, with a = 36.981(4) A, b = 16.5759(15) A, c = 16.0678(15) A, beta = 95.311(3) degrees, and Z = 4. Polyanion 1 consists of two (A-alpha-GeW9O34) Keggin moieties linked via six Fe3+ ions, leading to a double-sandwich structure. The equivalent iron centers represent a trigonal prismatic Fe6 fragment, resulting in virtual D3h symmetry for 1. Electrochemistry studies revealed that 1 is stable in solution from pH 3 to at least pH 7. In pH = 3 media the reduction of the six Fe3+ centers was featured by a single voltammetric wave for most supporting electrolytes used. In that case, whatever the scan rate from 1000 mV x s(-1) down to 2 mV x s(-1), no splitting of the single Fe-wave of 1 was observed. The acetate medium induced a partial splitting of the wave, and this separation is enhanced with increasing pH. Remarkable efficiency of 1 in the electrocatalytic reduction of nitrite, nitric oxide, and nitrate is demonstrated. Magnetic susceptibility (chi) measurements indicate a diamagnetic (S(T) = 0) ground state, with an average J = -12 cm(-1) and g = 2.00. EPR studies confirm that the ground state is indeed diamagnetic, since the EPR signal intensity steadily decreases without any line broadening as the temperature is lowered and becomes unobservable below about 50 K. The signal is a single broad peak at all frequencies (90-370 GHz), ascribed to the thermally accessible excited states. Its g(iso) is 1.992 51, as expected for a high-spin Fe3+-containing species, and supports the chi data analysis. 相似文献
7.
Summary The results of sorption measurements for gallium (III) and iodide ion traces onto tin(II) hydroxide from aqueous heterogeneous systems are given. Since only tagged sorbate was used (67Ga and 1311), in the determination of sorption by radioactive tracer method, it was necessary to establish the pH interval of tin(II) hydroxide in/stability. This was done by a turbidimetric method and the pH region of instability between 3 and 9 was found.The sorption results indicate a difference in sorption ability of gallium(III) and iodide as it appears from the dependence of the amount sorbed on contact time between heterogeneous reactants (sorbentsorbate). The amounts sorbed increase with increasing contact times at higher pH values for Ga(III) but remain unaffected for iodide sorption. Thus the sorption of iodide ions seems to be restricted to the solid surface while the sorption results for gallium(III) indicate the diffusion of sorbate into sorbent as a possible parallel mechanism. Those processes could be taken as compatible with the porous-double-layer mechanism which has been proposed in literature for aqueous heterogeneous oxide systems.
With 4 figures 相似文献
Zusammenfassung In der Arbeit werden Ergebnisse von Sorptionsmessungen für Ga3+- und j-Spuren an Zinn(II)-Hydroxid aus wäßrigen heterogenen Systemen berichtet. Zur analytischen Erfassung wurden radioaktives67Ga und 131 J verwendet. Die Stabilität von Zinn(II)-Hydroxid wurde durch Trübungsmessungen untersucht. Im pH-Bereich von 3–9 ist das Zinn(II)-Hydroxid als kolloide Suspension instabil.Ga3+ und J– verhalten sich bei der Adsorption unterschiedlich. Die adsorbierte Menge steigt mit zunehmender Kontaktzeit bei hohen pH-Werten von Gallium, bleibt jedoch für Jod unverändert. Die Unterschiede werden gedeutet durch die Annahme, daß Jod nur an der festen Oberfläche adsorbiert wird, während die Galliumionen auch in das Sorbens diffundieren können. Man könnte die Ergebnisse als verträglich mit einem porösen Doppelschichtmechanismus ansehen; ein solcher Mechanismus ist in der Literatur für wäßrige heterogene Oxidsysteme vorgeschlagen worden.
With 4 figures 相似文献
8.
9.
Experimental data on the equilibria Fe2+/Fe3+ and SO3
2−/SO4
2− in the system Fe(OH)3(H2SO4)-Na2SO3-H2O are presented. The quantitative relations between the reduction of Fe(III) and the precipitation of FeSO3·2.5H2O as a Fe2O3 precursor have considered graphically.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 41–44.Original Russian Text Copyright © 2005 by Vasekha, Motov. 相似文献
10.
S. Y. Fredericks J. M. Pedulla K. D. Jordan T. S. Zwier 《Theoretical chemistry accounts》1997,96(1):51-55
The OH stretch IR spectrum of (H2O)3 is significantly altered upon complexation of the cluster with a benzene molecule. Theoretical calculations show that the
differences in the OH stretch spectra of (H2O)3 and benzene-(H2O)3 are primarily due to mode localization induced by the benzene molecule.
Received: 27 January 1997 / Accepted: 28 January 1997 相似文献
11.
《结构化学》1992,(1)
<正> The title compound C6H16O9Fe, Mr = 288. 13, was synthesized and crystallized in monoclinic space group P21/c, a = 9. 409(4), b = 5. 812(4), c= 22. 122(7)(?) , β=90. 80(3)°. V = 1209. 6(?)3, Z = 4, Dc=1. 572g/cm3, F(000) = 592, μ = 12. 73cm-1, R = 0. 063, Rw= 0. 068 for 1191 observed reflections. The iron atom is surrounded by O(1 - 6) in a distorted octahedron. 相似文献
12.
The extraction of Ga3+ and Al3+ with the liquid cation-exchangers di-n-butyldithiophosphoric acid (DBTPA) and di-(2-ethylhexyl)dithiophosphoric acid (DETPA) in kerosene, in the presence and absence of alcohols and tri-n-butyl phosphate (TBP) has been studied. Both Ga3+ and Al3+ can be extracted in the form of a neutral complex, MA3, but the distribution coefficient of Ga3+ is the higher by about two orders of magnitude, which can be the basis of the solvent extraction separation of gallium and aluminium. The differences can be explained by the interaction between the sulphur donor atoms of the extractants and the d10 electronic shell of Ga3+ as well as by the lower steric hindrance of ligands co-ordinated to Ga3+. 相似文献
13.
14.
The title compound is formed by controlled hydrolytic polymerization in nonaqueous solution of simple oxo-bridged binuclear ferric salts under the presence of carboxylate ligands. The rhombohedral crystalline form of the cluster with six imidazole molecules, which has crystallographically required C3y symmetry, will be reported. The largest Fe—Fe distance in the undecairon oxo-hydroxo cluster is about 0.68 nm and the cluster has a diameter near 2 nm, which implies that this cluster reach- a nanometer-sized dimension. 相似文献
15.
M. Földesová P. Dillinger P. Lukáč 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(1):227-230
The Fe(III) uptake from aqueous solutions by natural and chemically modified zeolites was investigated using a gradual radioexchange
method and AAS technique. The leachability of Fe(III) from loaded zeolites was studied too. The Fe-uptake reached the value
of 60 mg·g−1 for the zeolite chemically treated with 6 mol·l−1 solution of NaOH and it is more than twelve times higher than that of the raw zeolite. The leachability of the loaded zeolite
samples in water and alkaline solution was up 5%. The leachability of the same zeolites in acid solution depended on the concentration
of modifying solution. The leachability at pH=2.6 in the range 2–20% at pH=1.9 was many times higher. The results of the radioexchange
and AAS methods were compared. 相似文献
16.
Mbomekalle IM Keita B Nadjo L Berthet P Hardcastle KI Hill CL Anderson TM 《Inorganic chemistry》2003,42(4):1163-1169
Reaction of the trivacant lacunary complex, alpha-Na(12)[As(2)W(15)O(56)], with an aqueous solution of Fe(NO(3))(3).9H(2)O yields the sandwich-type polyoxometalate, alphabetabetaalpha-Na(12)(Fe(III)OH(2))(2)Fe(III)(2)(As(2)W(15)O(56))(2) (Na1). The structure of this complex, determined by single-crystal X-ray crystallography (a = 13.434(1) A, b = 13.763(1) A, c = 22.999(2) A, alpha = 90.246(2) degrees, beta = 102.887(2) degrees, gamma = 116.972(1) degrees, triclinic, Ponemacr;, R1 = 5.5%, based on 25342 independent reflections), consists of an Fe(III)(4) unit sandwiched between two trivacant alpha-As(2)W(15)O(56)(12)(-) moieties. UV-vis, infrared, cyclic voltammetry, and elemental analysis data are all consistent with the structure determined from X-ray analysis. Magnetization studies confirm that the four Fe(III) centers are antiferromagnetically coupled. A cyclic voltammogram of Na1 reveals that a three-wave W(VI) system replaces the two-wave W(VI) system found in the precursor alpha-As(2)W(15)O(56)(12)(-) complex. The observed modifications in the CV patterns of Na1 and alpha-As(2)W(15)O(56)(12)(-) are most likely due to subsequent changes in the acid-base properties of two reduced POMs that occur as a result of Fe(III) incorporation. Na1 is shown to be more efficient than the monosubstituted complex alpha(2)-As(2)(Fe(III)OH(2))W(17)O(61)(7)(-) in the electrocatalytic reduction of dioxygen. This is attributed to cooperativity effects among the adjacent Fe(III) centers in Na1. 相似文献
17.
Harben SM Mosselmans JF Ryan ÁT Whitwood AC Walton PH 《Dalton transactions (Cambridge, England : 2003)》2012,41(1):208-218
We report the syntheses of imprinted polymers using iron-oxo-hydroxo clusters as templates. Three new iron clusters, [Fe(6)O(2)(OH)(2)(O(2)CC(Cl)=CH(2))(12)(H(2)O)(2)] (1), [{Fe(O(2)CC(Cl)=CH(2))(OMe)(2)}(10)] (2) and [Fe(6)O(2)(OH)(2)(O(2)C-Ph-(CH)=CH(2))(12)(H(2)O)(2)] (3) have been prepared from commercially-available carboxylic acids. Cluster-imprinted-polymers (CIPs) of 1, 2 and 3 were prepared with ethylene glycol dimethacrylate monomer, and of 1 with methyl methacrylate monomer. The imprinted sites within the CIPs were examined using EXAFS and diffuse reflectance UV/vis spectroscopy, demonstrating that the clusters 1, 2 and 3 were incorporated intact within the polymers. Extraction of the clusters from the CIPs imprinted with 1 and 3 gave new polymers that showed evidence of an imprinting effect. 相似文献
18.
Wu R Jayasooriya UA Cannon RD 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(3):575-579
IR spectra are reported for the compounds [Fe3O(O2CC(CH3)3)6(py)3][FeCl4] and [Fe3O(O2CC(CH3)3)6(py)3]. Using isotopic substitution at the central oxygen atom, the assignments of the in-plane and out-of-plane vibrations of this atom are confirmed, and coupling is demonstrated between the in-plane modes v(as)(Fe3O) and carboxylate deformation modes rho(r)(C-CO2). 相似文献
19.
The magnetic property of μ3-oxotriiron(III) complex [Fe3O(OBz)6(CH3OH)3](NP3)-(CH3OH)2 (HOBz? benzoic acid) has been studied. We use isosceles triangle model and molecular field correction to fit the experimental magnetic susceptibility data. It shows that an intramolecular antiferromagnetic exchange interaction occurs with J = -31.27 cm?1, J'= -27.26 cm?1, and a weaker intermolecular antiferromagnetic exchange interaction occurs with zJ' = - 3.76 cm?1. We give the d5-d5-d5 energy level diagram of triiron(III) complex as a function of J'/J. From the diagram we can get the total spin ST of the complex as 1/2 in the ground state. 相似文献
20.
Two isostructural mixed-valence vanadium phosphonoacetates H2(DABCO)[V(IV)O(H2O)V(III)(OH)(O3PCH2CO2)2].2.5H2O (1) and H2(PIP)[V(IV)O(H2O)V(III)(OH)(O3PCH2CO2)2].2.5H2O (2) have been synthesized. They crystallize in the orthorhombic space group Pnna with a = 7.0479(10) A, b = 15.307(2) A, and c = 17.537(3) A for 1 and a = 7.0465(9) A, b = 15.646(2) A, and c = 17.396(2) A for 2. X-ray single-crystal diffraction reveals that 1 and 2 have a three-dimensional open framework featuring 16-ring ellipsoid channels that are filled with doubly protonated 1,4-diazabicyclo[2,2,2]octanium/piperazinium cations and water molecules. According to the classification in metal-organic frameworks, 1 and 2 contain infinite (-O-V-)(infinity) chains that are cross-linked by "metalloligand" [VO(H2O)(O3PCH2CO2)2](4-) into a 3-D net of the sra topology. The temperature dependence of the magnetic susceptibility of 1 shows that the chi(m)T value in the range of 60-320 K is constant of 1.105 cm3 K mol(-1)/V2 unit, and upon further cooling, the chi(m)T value rapidly increases to 1.81 cm3 K mol(-1) at 2 K. The corresponding effective magnetic moment (mu(eff))/V2 unit varies from 2.97 mu(B) at 320 K to 3.80 mu(B) at 2 K. The magnetic data in the range of 2-320 K follow the Curie-Weiss law with C = 1.074 cm3 K mol(-1) and Theta= -1.34 K. 相似文献