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.

---

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 small amounts of cobalt(II) on iron(III) oxide

Summary The sorption of small amounts of cobalt(II) on iron (III) oxide has been studied as a function of pH. The mechanism of sorption is discussed. Iron (III) oxide carrier can be used for the preconcentration of small or trace amounts of cobalt(II). The influence of EDTA, glycine,L(+)-arginine andL(+)-cysteine on the sorption yields of cobalt(II) has also been studied.

---

Zusammenfassung Die Abhängigkeit der Adsorption geringer Mengen Co (II) an Eisen (III)-hydroxid vom pH wurde untersucht und der Mechanismus der Adsorption erörtert. Eisen (III) oxidträger kann für die Anreicherung kleiner Mengen oder Spuren Co(II) verwendet werden. Der Einfluß von ÄDTA, Glycin, L(+)-Arginin und L(+)-Cystein auf die sorbierte Menge Co(II) wurde gleichfalls geprüft.

     

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.     

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.     

Studying the sorption properties of a clinoptilolite-containing tuff with respect to europium(III) ions

The kinetic laws of sorption of europium(III) ions from sulfate solutions by a clinoptilolite-containing tuff are studied. The kinetic parameters of sorption process are determined and absorption isotherms are constructed for europium ions. It is found that both external and internal diffusion are rate-limiting steps, and europium is completely extracted from dilute solutions (<0.0025 m).     

Flow-Injection Methods for Determining Europium in Mixtures of Lanthanides(III)

Possible approaches to the flow-injection determination of europium(III) in the presence of other lanthanides are studied. One of the approaches is based on the direct amperometric detection of europium(III) in a flow-injection system with a glassy-carbon electrode at a potential of –0.85 V (against a saturated calomel electrode). The linear calibration range is 5.0 × 10^–5–5.0 × 10^–4M of europium, and the limit of detection is 1.8 × 10^–5M (2.8 g/mL). The throughput capacity is 90 h^–1for a sample volume of 600 L. Another approach involves the online reduction of europium(III) to europium(II) in a flow Jones mini-reductor filled with amalgamated zinc, followed by the spectrophotometric detection of europium(II) using redox reactions between europium(II) and iron(III) in the presence of 1,10-phenanthroline, molybdophosphoric acid, or Methylene Blue. In the latter case, the calibration curve is linear in the range 0–5.0 × 10^–6M europium(III), the limit of detection is 9.0 × 10^–8M (0.014 g/mL). The throughput capacity is 180 h^–1for a sample volume of 200 L. The performance parameters of the proposed flow-injection methods are estimated using the analysis of artificial mixtures and dissolved samples of samarium(III) oxide and lanthanum(III) fluoride containing europium impurities as an example.     

Mössbauer study of quenched Fe(III) salt solutions

The Mössbauer spectra of quenched aqueous iron(III) salt solutions containing HClO₄, H₂SO₄, HCl, respectively, were measured. The magnetic hyperfine structure of the spectra was studied as a function of the change of acid and iron concentrations. In the solutions of FeCl₃ containing 8.5N HCl we suppose the presence of octahedral [FeCl₄(H₂O)₂]^? complex.     

Ionic liquid modified silica gel for the sorption of americium(III) and europium(III) from dilute nitric acid medium

The imidazolium bis(2-ethylhexyl) phosphate moiety was chemically attached on silica gel by chemical modification. The resulting product ([SG-Im]⁺ [DEHP]^?) was characterized by FT-IR spectroscopy, thermogravimetry and elemental analysis. The sorption behavior of Am(III) and Eu(III) on [SG-Im]⁺ [DEHP]^? was studied from dilute nitric acid medium for the separation of Am(III) and Eu(III) from aqueous waste. The effect of time, concentrations of nitric acid and europium in aqueous phase on the distribution coefficient (K _d) was studied. The study indicated the possibility of using modified silica for the separation of Eu(III) from Am(III) with high separation factors (>50 at 0.1 M HNO₃).     

Luminescent properties of europium(III) and terbium(III) complexes with para- and ortho-ethoxybenzoic acids

The luminescent properties of europium(III) and terbium(III) complexes with para- and ortho-ethoxybenzoic acids are studied. The excitation energies of the triplet states of ligands are determined, a hypothesis is made about the efficient luminescence of europium(III) and terbium(III) complexes, the geometry of the coordination polyhedron of a europium complex is established, and the luminescence quantum yields of the complexes in solution are determined.     

Synthesis of arsenic sorbent by the reaction of magnesium hydroxide with aqueous iron(III) chloride solution

The reaction of magnesium hydroxide with a concentrated aqueous solution of iron(III) chloride yields a mixture of magnesium–iron layered double hydroxide and iron oxide–hydroxide in the akaganeite form. The content of these phases depends on the Mg/Fe atomic ratio in the starting reactant mixture. Iron oxide–hydroxide is the major reaction product at the Mg/Fe atomic ratio in the interval 1.5–1.75, and layered magnesium–iron layered double hydroxide, at Mg/Fe = 3–4. The ability of the synthesized products to take up As(III) from aqueous solutions was studied. These sorbents allow the arsenic concentration to be decreased from 3–5 mg L^–1 to values below MPC (0.01 mg L^–1).     

Tast polarography of europium(III)-l-histidine complex

Study of europium(III)-l-histidine complex has been made in sodium perchlorate at μ=0.1 by tast polarography. The reduction process appears to be quasi irreversible. The apparent rate constants have been determined byGellings method¹. With the knowledge ofE ₁ ^2/r and use ofLingane's method, one complex Eu(Histd)²⁺ with the instability constant 6.77×10^?5 is reported.     

Sorption of chromium(VI) and chromium(III) on aluminium hydroxide

Factors that influence the sorption of Cr(VI) and Cr(III) on aluminium hydroxide were investigated. The sorption of chromates decreases as the pH of the suspension increases. The mechanism of CrO ₄ ^2– sorption was interpreted in terms of reactions between chromates and –OH and/or H₂O groups at the hydroxide/liquid interface. It has been shown that chromates are more tightly sorbed on aluminium hydroxide compared to other anions, e.g. chlorides. On the other hand, specifically absorbed anions, such as molybdates, compete strongly with chromates for the sorption sites. The sorption of chromium(III) increases with the pH of the suspension. Also, the sorption of chromium(III) is suppressed in the presence of citrate ions. The best conditions for the fixation of Cr(VI) and Cr(III) by aluminium hydroxide are presented.     

Characterization of iron(III) oxide and oxide-hydroxide as Sr-sorbent

Iron(III) hydroxide and oxide-hydroxide samples prepared by precipitation of 0.2M iron(III) nitrate solution by 5M NaOH and subsequently aged at pH 12 for times of up to 50 h have been characterized. The sorption properties towards Sr²⁺ were characterized by radiotracer method using⁸⁵Sr, morphology of the samples was characterized by Transmission Electron Microscopy and Emanation Thermal Analysis. X-ray diffraction patterns characterized the crystallinity of the samples aged for various times. The maximum (100%) sorption capacity for⁸⁵Sr corresponding to amorphous iron(III) hydroxide decreased to 75% with the time of precipitate ageing (up to 40 h). This finding corresponds to the development in crystallinity and morphology of the sorbent.     

Surface structure of Fe(III)-containing binary hydroxide systems

A brief overview is given of recently obtained data on the surface structure and composition of various iron(III)-containing nickel hydroxide systems, as studied using transmission Mössbauer spectroscopy supplemented by atomic absorption, Auger electron and Fourier transform infrared spectroscopic data. The systems studied include coprecipitated binary Ni(II)–Fe(III) hydroxides in a wide range of compositions, ferric hydroxide precipitated on the surface of -Ni(OH)₂ crystallites, ferric hydroxo complexes adsorbed onto nickel hydroxides from alkaline electrolytes and the products of their hydrolysis.     

Kinetics of iron(III) chloride extraction with n-tributyl phosphate

The equilibrium and rate of solvent extraction of FeCl₃ complexes from HCl solutions into benzene solutions of tributyl phosphate (TBP) has been studied. The extracted species was found to be FeCl₃·3TBP. The results show that the extraction is first order in both Fe(III) and TBP. The rate constant of adduct formation equals ～1.24M min^?1. The reaction order is zero for the aqueous phase acidity. The rate-controlling steps are discussed in the light of the results.     

Pectins of the familyLamiaceae (Labiatae)

The pectin substances (PSs) of members of the familyLamiaceae (Labiatae) Nepeta transcaucasica (I),Ziziphora capitata (II),Rosmarinus officinalis (III), andSalvia officinalis (IV) have been isolated, purified, and characterized. It has been shown that the PSs mainly contain residues of rhamnose, arabinose, galactose, xylose, glucose, and, in small amounts, those of fucose, mannose, and ribose, and differ in their quantitative ratios. The polymer chains are constructed D-galacturonic acid residues with a predominance of 1 → 4-α-glycosidic bonds.     

Luminescent and triboluminescent properties of europium(III) hexafluoroacetylacetonate and trifluoroacetate complexes with triphenylphosphine oxide

Crystalline and strongly luminescent complexes of europium hexafluoroacetylacetonate and trifluoroacetate with triphenylphosphine oxide of Eu(HFAA)₃ · 2TPPO and [Eu(TFA)₃ · 2TPPO(H₂O)]₂ composition are synthesized that demonstrating triboluminescent properties. It is established that the measured photoluminescence and triboluminescence spectra of these noncentrosymmetric complex compounds are identical, due to the characteristic f-f-luminescence of the europium(III) ion.     

Complex formation of thiocyanate ions with iron(III) on the solid phase of fibrous ion exchangers

Characteristics of complex formation of SCN^–-ions with iron(III) on fibrous materials filled with an AV-17 anion exchanger (PANV–AV-17) and a KU-2 cation exchanger (PANV–KU-2) are studied by diffuse reflection spectroscopy. Sorption conditions of thiocyanate ions on PANV–AV-17 in the dynamic mode and the influence of concentrations of Cl^–, SO ₄ ^2- and NO ₃ ^- on the sorption and analytical signals of thiocyanate complexes are studied. Sorption conditions of iron(III) on PANV–KU-2 and the conditions of formation of thiocyanate complexes are studied. Systems for the sorption–spectroscopic determination of 0.1–0.7 μg/mL of SCN^–-ions in aqueous solutions of pH 5 ± 1 on PANV–AV-17 and test-determination of 5–30 μg of SCN^–-ions on PANV–KU-2 are proposed.     

Sorption of chromium(III) and chromium(VI) on lead sulfide

The sorption of chromium(III) and chromium(VI) on lead sulfide has been investigated in dependence on pH, time of sorption and the concentrations of sorbate and sorbent. The mechanisms of the sorption of Cr³⁺ and CrO ₄ ^2– traces on lead sulfide are discussed; a difference between CrO ₄ ^2– sorption on PbS and -Fe₂O₃ has been found. Sulfates and molybdates affect the removal of chromates from aqueous solutions. Lead sulfide carrier prepared in this work was also used for the preconcentration of chromium(III) and chromium(VI) from tap water.     

Crystal structure and luminescence of europium(III) acrylate

The atomic structure of europium acrylate crystals [Eu₂(Acr)₅OH·3H₂O]·2(0.5H₂O) was studied by X-ray analysis (a = 24.360(3) Å, b = 18.466(2) Å, c = 8.5818(9) Å, β = 96.087(2)°, space group C2/c, Z = 6, ρ_calc = 2.036 g/cm³). The crystal structure involves chains of binuclear [Eu₂(C₃H₃O₂)₅OH·3H₂O] molecules, running infinitely in the [101] direction and having pairs of C₉H₉EuO₇H₂O molecules alternating with C₆H₆EuO₄OH·2H₂O molecules that link the pairs. The infinite chains are linked by hydrogen bonds and van der Waals interactions. The thermal behavior of luminescence of the europium(III) complex is discussed.