Search results for "ionic medium"

showing 4 items of 4 documents

Hydrolysis and chemical speciation of dioxouranium(VI) ion in aqueous media simulating the major ion composition of seawater

2004

Abstract The hydrolysis and chemical speciation of the dioxouranium(VI) ion at 25 °C was studied in a number of binary electrolytes (LiCl, NaCl, MgCl2, CaCl2, Na2SO4) and some mixtures (NaCl–Na2SO4, NaNO3–Na2SO4, CaCl2–MgCl2) as well as artificial seawater (SSWE) as a function of ionic strength. The results in LiCl, CaCl2 and MgCl2 solutions confirmed the formation of (UO2)2(OH)22+, (UO2)3(OH)42+, (UO2)3(OH)5+ and (UO2)3(OH)7− species (at I=0 mol l−1: log Tβ22=−5.76, log Tβ34=−11.82, log Tβ35=−15.89 and log Tβ37=−29.26). For NaNO3, NaCl and artificial seawater the hydrolysis constant for the formation of the UO2(OH)+ species was also determined (at I=0 mol l−1: log Tβ11=−5.19). The results …

Activity coefficientHydrolysis constantUranium speciationAqueous solutionChemistryHydrolysisInorganic chemistryPitzer parametersIonic bondingArtificial seawaterGeneral ChemistryDependence on ionic strengthOceanographyUranylIon pair formationIonDioxouranium(VI)chemistry.chemical_compoundIonic strengthEnvironmental ChemistryChemical speciationHydrolysis; Dioxouranium(VI); Chemical speciation; Seawater; Dependence on ionic strength; Dependence on ionic medium; Pitzer parameters; Ion pair formationSeawaterDependence on ionic mediumWater Science and Technology
researchProduct

The Formal Redox Potential of the Ti(IV, III) Couple at 25 °C in 1 M HCl 2 M NaCl Medium

2007

The formal redox potential of the Ti(IV, III) couple has been determined at 25 degrees C in 1 M HCl, 2 M NaCl aqueous medium, by emf measurements of a junction-free cell with glass and mercury electrodes. Ti(III) and Ti(IV) concentrations were changed by controlled electrolysis. The mean value of the searched formal potential, in a large range of total titanium concentration, is 9 +/- 1 mV against the molar hydrogen electrode in the same ionic medium.

TitaniumElectrolysisStandard hydrogen electrodeInorganic chemistryTemperaturechemistry.chemical_elementIonic bondingSodium ChlorideTitanium redox equilibria Formal redox potentials Junction-free cells Electrolysis Constant ionic mediumEMF measurementElectrochemistryRedoxAnalytical Chemistrylaw.inventionchemistrylawElectrodeElectrochemistryHydrochloric AcidOxidation-ReductionGeneral Environmental ScienceTitaniumAnnali di Chimica
researchProduct

The formal redox potential of the Yb(III,II) Couple at 0°C in 3.22 molal NaCl medium

2004

Following our previous investigations on aqueous solutions of hypooxidized and iperoxidized species, we managed, by lowering the temperature of the solutions to 0 degrees C, to obtain, by electrochemical methods, Yb(II) and Yb(III) mixtures, enough stable to determine by a potentiometric method the formal redox potential of the Yb(IlI, II) couple. Its value, in a large range of total Ytterbium concentration, is -1233 +/- 3 mV against the molal hydrogen electrode in the 3.22 m NaCl medium.

YtterbiumMolalityAqueous solutionStandard hydrogen electrodeChemistryInorganic chemistryvanadium amino acids ionic mediumTemperaturechemistry.chemical_elementLarge rangeSodium ChlorideElectrochemistryRedoxAnalytical ChemistryElectrochemistryElectroanalytical methodYtterbiumOxidation-ReductionGeneral Environmental Science
researchProduct

Modelling the dependence on medium and ionic strength of molybdate acidbase properties, and its interactions with phytate

2016

The importance of molybdenum from a biological, environmental and technological point of view is very well known since many decades [15]. In particular, it is mainly present in aqueous solutions as molybdate (MoO42), which is the biologically active form, entering in the cells by active transport systems. Though molybdate is the major species in neutral to basic pH conditions, at lower pH it undergoes protonation and, chiefly, polymerization, even at millimolar concentration levels [2]. Consequently, the modelling of its speciation and acidbase properties is not very simple, as demonstrated by the nonhomogeneity of available literature data. In this light, our group has started a systematic…

molybdatephytateSettore CHIM/01 - Chimica Analiticaacid-base propertieionic strengthionic medium
researchProduct