Studies on extraction of In(Ⅲ) with 8-hydroxyquinoline

The equilibrium molalities of In3 in extraction reaction: In3 (aq) 3HOx(org) = In(Ox)3(org) 3H (aq) were measured at ionic strengths from 0.13 to 2.54 mol-kg-1 in the aqueous phase containing Na2SO4 as the supporting electrolyte and at constant initial molality of extractant, HOx, in the organic phase at temperatures from 278.15 to 308.15 K, where HOx and Ox mean 8-hydroxy-quinoliue and its anion, respectively. The standard extraction constants K0 at various temperatures were obtained by two methods proposed in our previous paper.     

The chloroform extraction of nickel with oxine from perchlorate and sulfate solutions

Nickel-oxine complexes extracted from perchlorate and sulfate solutions with chloroform were isolated and their compositions were determined. They were Ni₂(Ox)₃(HOx)₃ClO₄ from perchlorate solution at low pH and Ni₂(Ox)₄(HOx)₂ from perchlorate solution at high pH or from sulfate solution. The extraction equilibria, 2Ni²⁺+6HOx(o)+ClO^-₄?Ni₂(Ox)₃(HOx)₃ClO₄(o)+3H⁺, 2Ni²⁺+ 6HOx(o)?Ni₂(Ox)₄(HOx)₂(o)+4H⁺ and Ni₂(Ox)₃(HOx)₃ClO₄(o)?Ni₂(Ox)₄ (HOx)₂(o)+H⁺+ClO^-₄, were proposed and the equilibrium constants were determined to be 10^7.58,10^-0.82 and 10^-8.75, respectively, at ionic strength 0.1 and 20°.     

Extraction of silver from water into nitrobenzene using sodium dicarbollylcobaltate in the presence of valinomycin

Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the Ag⁺(aq) + NaL⁺(nb)?AgL⁺(nb) + Na⁺(aq) equilibrium in the two-phase water-nitrobenzene system (L=valinomycin; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log K_ex(Ag⁺,NaL⁺)=-0.6±0.1. The stability constant of the valinomycin-silver complex in nitrobenzene saturated with water was calculated: log b_nb(AgL⁺)=4.6±0.1. The stability constants of complexes of some univalent cations with valinomycin were summarized and discussed.     

Extraction of lead from water into nitrobenzene by using strontium dicarbollylcobaltate in the presence of benzo-15-crown-5

Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the equilibrium Pb²⁺(aq)+SrL(nb)?PbL(nb)+Sr²⁺(aq)taking place in the two-phase water-nitrobenzene system (L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated aslog K_ex(Pb²⁺,SrL)=0.1±0.1. Further, the stability constant of the benzo-15-crown-5-lead complex in nitrobenzene saturated with water was calculated for a temperature of25 °C:log b_nb(PbL)=13.2±0.1.     

Solvent extraction of barium picrate by p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide)

Summary From extraction experiments andg-activity measurements, the extraction constant of the Ba²⁺(aq)+2A^-(aq)+L(nb)?BaL²⁺(nb)+2A^-(nb) equilibrium in the two-phase water-nitrobenzene system (L = p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as logK_ex(BaL²⁺,2A^-)=6.5±0.1. Furthermore, the stability constant of the p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide)̵barium complex in nitrobenzene saturated with water was calculated for at 25 °C as logb_nb(BaL²⁺)=15.4±0.1.     

Solvent extraction of lead using a nitrobenzene solution of strontium dicarbollylcobaltate in the presence of polyethylene glycol PEG 400

Summary From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Pb²⁺(aq)+SrL²⁺ (nb)↔PbL²⁺ (nb)+Sr²⁺ (aq) taking place in the two-phase water-nitrobenzene system (L=PEG 400; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as logK_ex(Pb²⁺, SrL²⁺)=2.0±0.1. Further, the stability constant of the PEG 400 - lead complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β_nb(PbL²⁺)=12.9±0.1.     

Extraction of lithium with nitrobenzene solution of strontium bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium 2Li⁺(aq)+SrL₂ ²⁺(nb) 2LiL⁺(nb)+Sr²⁺(aq) taking place in the two-phase water-nitrobenzene system (L=15-crown-5; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logK _ex (2Li⁺;SrL₂ ²⁺)=−3.7. Further, the stability constant of the 15-crown-5—lithium complex in nitrobenzene saturated with water was calculated: log β_nh(LiL⁺)=7.0.     

Stability of the valinomycin - strontium complex in water saturated nitrobenzene

Summary From extraction experiments and<span style='font-size:12.0pt;font-family:Symbol; mso-bidi-font-family:Symbol'>g-activity measurements, the extraction constant corresponding to the equilibrium Ba²⁺(aq)+SrL²⁺(nb)?BaL²⁺(nb)+Sr²⁺(aq) taking place in the two-phase water-nitrobenzene system (L= valinomycin; aq= aqueous phase,</o:p>nb= nitrobenzene phase) was evaluated as logK_ex(Ba²⁺, SrL²⁺)=1.3. Furthermore, the stability constant of the valinomycin-strontium complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: logb_nb(SrL²⁺)=5.4.     

Thermodynamics of Aqueous Diethylenetriaminepentaacetic Acid (DTPA) Systems: Apparent and Partial Molar Heat Capacities and Volumes of Aqueous H2DTPA3−, DTPA5−, CuDTPA3−, and Cu2DTPA− from 10 to 55°C

Apparent molar heat capacities and volumes have been determined for aqueous solutions of the mixed electrolytes Na₅DTPA + NaOH, Na₃CuDTPA + NaOH, and NaCu₂DTPA + NaOH, and the single electrolyte Na₃H₂DTPA (DTPA=diethylenetriaminepentaacetic acid) at temperatures from 10 to 55°C. The experimental results have been analyzed in terms of Young's rule with the Guggenheim form of the extended Debye–Hückel equation and the Pitzer ion-interaction model. These calculations led to standard partial molar heat capacities and volumes for the species H₂DTPA^3–(aq), DTPA^5–(aq), CuDTPA^3–(aq), and Cu₂DTPA^–(aq) at each temperature. The partial molar properties at 0.1 m ionic strength were also calculated. The standard partial molar properties were extrapolated to elevated temperatures with the revised Helgeson–Kirkham–Flowers (HKF) model. Values for the partial molar heat capacities from the HKF model have been combined with the literature data to estimate the ionization constants of H₂DTPA^3–(aq) and the formation constant of the CuDTPA^3–(aq) copper complex at temperatures up to 300°C.     

Extraction of barium picrate into nitrobenzene in the presence of benzo-15-crown-5

From extraction experiments with ¹³³Ba as a tracer, the extraction constant corresponding to the equilibrium Ba²⁺(aq) + 2A^-(aq) + 2L(nb) BaL₂ ²⁺(nb) + 2A^-(nb) in the two-phase water-nitrobenzene system (A^- = picrate, L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex (BaL₂ ²⁺, 2A^-) = 5.7. Furthermore, the stability constant of the benzo-15-crown-5 - barium complex in nitrobenzene saturated with water was calculated: log b_nb (BaL₂ ²⁺) = 14.6.     

Stability of the 15-crown-5-sodium complex in water saturated nitrobenzene

From extraction experiments with²²Na as a tracer, the extraction constant corresponding to the equilibrium Ba²⁺(aq)+2NaL⁺(nb)⇄ ⇄BaL₂ ²⁺(nb)+2Na⁺(aq) taking place in the two-phase water-nitrobenzene system (L=15-crown-5; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logK _ex (Ba²⁺,2NaL⁺)=3.3±0.1. Further, the stability constant of the complex BaL₂ ²⁺ in nitrobenzene saturated with water was calculated: log β_nh(BaL ₂ ²⁺ )=16.4±0.1.     

Extraction of lead with nitrobenzene solution of strontium bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Pb²⁺(aq)+SrL₂ ²⁺(nb)⇆PbL₂ ²⁺(nb)+Sr²⁺(aq) taking place in the two-phase water-nitrobenzene system (L=15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated: logK _ex (Pb²⁺,SrL₂ ²⁺)=3.0. Further, the stability constant of the PbL₂ ²⁺ complex in nitrobenzene saturated with water was calculated: log β_nb(PbL ₂ ²⁺ )=17.8     

Solvent extraction of sodium from water into nitrobenzene by using strontium dicarbollylcobaltate in the presence of benzo-15-crown-5

Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the 2Na⁺(aq)+SrL(nb)?2NaL⁺(nb)+Sr²⁺(aq) equilibrium taking place in the two-phase water-nitrobenzene system (L=benzo-15-crown-5; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log K_ex(2Na⁺,SrL)=1.0±0.1. Further, the stability constant of the benzo-15-crown-5-sodium complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log b_nb(NaL⁺)=7.8±0.1.     

Solvent extraction of calcium and strontium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of polypropylene glycol PPG 425

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M⁺(aq) + Cs⁺(org) ⟺ M⁺(org) + Cs⁺(aq) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (M⁺ = Li⁺, H₃O⁺, Na⁺, NH₄⁺ \hbox{NH}_{4}{}^{+} , Ag⁺, Tl⁺, K⁺, Rb⁺; aq = aqueous phase, org = FS 13 phase) were evaluated. Furthermore, the individual extraction constants of the M⁺ cations in the mentioned two-phase system were calculated; they were found to increase in the series of Li⁺ < H₃O⁺ < Na⁺< NH₄ ⁺ \hbox{NH}_{4}{}^{ + } < Ag⁺ < Tl⁺ < K⁺ < Rb⁺ < Cs⁺.     

Natural radioactivity traces in South-Brazilian cereal flours by gamma-ray spectrometry

Summary Cereal flours are the major component of the Brazilian diet and are also important exportation products. Radioactivity concentrations of ²³² Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were determined in commercial samples of South-Brazilian cereal flours (soy, wheat, corn, manioc, rye and oat flour) to verify the radiological security of these foodstuffs. The measurements were carried out by gamma-ray spectrometry using a 66% relative efficiency HPGe detector. The ⁴⁰K flour activities, at 95% of confidence level were in: soy 474±3 Bq ^. kg^-1; corn 30.0±0.3 Bq ^. kg^-1; rye 94±1 Bq ^. kg^-1; manioc 67±1 Bq ^. kg^-1; oat 76±1 Bq ^. kg^-1 and wheat 36.2±0.4 Bq ^. kg^-1. The lower limit of detection for ⁴⁰K ranged from 0.54 to 1.43 Bq ^. kg^-1. The ¹³⁷Cs activities in flour samples were: soy ￡0.07 Bq ^. kg^-1, corn ￡0.01 Bq ^. kg^-1, oat ￡0.03 Bq ^. kg^-1 and in wheat, manioc and rye ￡0.02 Bq ^. kg^-1. The highest concentrations levels of ²³² Th and ²²⁶Ra were 0.69±0.04 Bq ^. kg^-1 and 0.44±0.03 Bq ^. kg^-1, respectively, in soy flour.     

Studies on the thermodynamics of solvent extraction of indium (III) with HDEHMTPCA

The equilibrium molalities In³⁺ in {In₂(SO₄)₃ + Na₂SO₄ + HDEHMTPCA + n-C₈H₁₈ + water} were measured at ionic strength from (0.1 to 2.0) mol · kg⁻¹ containing Na₂SO₄ as supporting electrolyte in aqueous phase and at constant molality extractant at temperatures from (278.15 to 303.15) K in organic phase. The standard extraction constants K⁰ at various temperatures were obtained by methods of extrapolation and polynomial approximation. Thermodynamic quantities for the extraction process were calculated.     

Stability of Ba2+-15-crown-5 complex in water saturated nitrobenzene

From extraction experiments and γ-activity measurements, the extraction constant of the Ba²⁺ (aq)+SrL₂/²⁺(nb)⇆⇆BaL₂/²⁺ (nb)+Sr²⁺(aq) equilibrium taking place in a two-phase water-nitrobenzene system (L=15-crown-5; aq-aqueous phase, nb=nitrobenzene phase) was evaluated as logK _ex(Ba²⁺,SrL₂/²⁺)=1.8. Further, the stability constant of the BaL₂/²⁺ complex in water saturated nitrobenzene was calculated to be log β_nh(BaL₂ ²⁺)=16.5.     

Apparent molar volumes of aqueous sodium trifluoromethanesulfonate and trifluoromethanesulfonic acid from 283 K to 600 K and pressures up to 20 MPa

Relative densities of NaCF₃SO₃(aq) at molalities 0.073 ≤ m/(mol-kg^-1) ≤ 1.68 were measured with vibrating-tube densimeters from 283 K to 600 K and from 0.1 MPa to 20 MPa. Relative densities of HCF₃SO₃(aq) at molalities 0.12 < m/(mol-kg^-1) < 2.1 were determined at temperatures from 283 K to 328 K at 0.1 MPa. Apparent molar volumes calculated from the measured densities were represented by the Pitzer ion-interaction treatment. The temperature and pressure dependence of the standard partial molar volume and the second virial coefficients in the Pitzer equation were expressed by empirical expressions in which the compression coefficient of water and temperature were used as independent variables. The conventional standard partial molar volumes V‡(CF₃SO ₃ ^- , aq) fromT = 283 K to 573 K were calculated from the experimental values for V‡(NaCF₃SO₃, aq) and known values for V‡(Na⁺, aq). The values of V‡(CF₃SO_3/-, aq) at temperatures from 283 K to 328 K obtained from the values of V‡(NaCF₃SO₃, aq) and V‡(HCF₃SO₃, aq) agree to within 1.2 cm³-mol^-1.     

Stability of the valinomycin - lithium complex in nitrobenzene saturated with water

Summary From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Li⁺(aq)+NaL⁺(nb) ↔LiL⁺(nb)+Na⁺(aq) taking place in the two-phase water-nitrobenzene system (L = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as logK_ex(Li⁺,NaL⁺)=-1.1. Further, the stability constant of the valinomycin-lithium complex species in nitrobenzene saturated with water was calculated: logβ_nb(LiL⁺)=6.3.     

Interaction Between the Low Molecular Mass Components of Blood Serum and the Vanadium(III)–2,2′-Bipyridine System

The complex species formed between vanadium(III)?C2,2??-bipyridine (Bipy) and the small blood serum bioligands lactic (HLac), oxalic (H₂Ox), citric (H₃Cit) and phosphoric (H₃PO₄) acids were studied in aqueous solution by means of electromotive forces measurements emf(H) at 25?°C and 3.0?mol?dm^?3 KCl as the ionic medium. The data were analyzed using the least-squares computational program LETAGROP, taking into account the hydrolytic products of vanadium(III) and the binary complexes formed. Formation of the complexes [V(Bipy)(Lac)]²⁺, [V(Bipy)(Lac)₂]⁺, [V(OH)₂(Bipy)(Lac)] and [V₂O(Bipy)₂(Lac)₂]^? were observed in the vanadium(III)?CBipy?CHLac system. Also, the species [V(Bipy)(HOx)]²⁺, [V(Bipy)(Ox)]⁺, [V(OH)(Bipy)(Ox)], [V(OH)₂(Bipy)(Ox)]^? and [V(OH)₃(Bipy)(Ox)]^2? were found in the vanadium(III)?CBipy?CH₂Ox system, the complexes [V(Bipy)(HCit)]⁺, [V(Bipy)(Cit)], [V(OH)(Bipy)(Cit)]^? and [V(OH)₂(Bipy)(Cit)]^2? were found in the vanadium(III)?CBipy?CH₃Cit system, and the species [V(Bipy)(H₂PO₄)]²⁺ and [V(Bipy)(HPO₄)]⁺ were detected in the vanadium(III)?CBipy?CH₃PO₄ system. The stability constants of these complexes were determined.