Search results for "Ionic strength dependence"

showing 3 items of 3 documents

Modelling of proton and metal exchange in the alginate biopolymer.

2005

Acid-base behaviour of a commercial sodium alginate extracted from brown seaweed (Macrocystis pyrifera) has been investigated at different ionic strengths (0.1or=I/mol l(-1)or=1.0) and in different supporting electrolytes (Et4NI, NaCl, KCl, LiCl, NaCl+MgCl2), with the aim of examining the influence of ionic medium on the proton-binding capacity and of quantifying the strength of interaction with light metal ions in the perspective of speciation studies in natural aqueous systems. Potentiometric ([H+]-glass electrode) and titration calorimetric data were expressed as a function of the dissociation degree (alpha) using different models (Henderson-Hasselbalch modified, Högfeldt three parameter…

Alginic acid; Proton- and metal-binding capacity; Thermodynamic parameters; Ionic strength dependence; Models for medium dependence and ion associationProton bindingAlginatesIonic strength dependenceInorganic chemistryPotentiometric titrationIonic bondingProtonationElectrolytePhaeophytaBiochemistryAnalytical ChemistryBiopolymersGlucuronic Acidalginic acid proton and metal-binding capacity Thermodynamics parameters Ionic strength dependence models for medium dependence and ion associationAlginic acidMagnesium ionAqueous solutionMolecular StructureChemistryHexuronic AcidsProton- and metal-binding capacityThermodynamic parametersIonic strengthMetalsProtonsModels for medium dependence and ion associationAnalytical and bioanalytical chemistry
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Hydrolysis of dioxouranium(VI): a calorimetric study in NaClaq and NaClO4aq, at 25°C

2004

Abstract We report the results of a calorimetric study on the hydrolysis of UO 2 2+ in different ionic media (NaClO 4 aq , NaCl aq ) at 25 °C. Experiments in NaCl were performed at different ionic strength, at I ≤1 mol l −1 . The species considered in both ionic media were UO 2 (OH) + , (UO 2 ) 2 (OH) 2 2+ and (UO 2 ) 3 (OH) 5 + , and in addition (UO 2 ) 3 (OH) 4 2+ and (UO 2 ) 3 (OH) 7 − in NaCl aq . The dependence on ionic strength of enthalpy changes in NaCl aq was expressed by the simple linear equation Δ H pq =Δ H ° pq + aI 1/2 ( a , empirical parameter). Comparison with literature findings is given and some recommended values are reported.

Aqueous solutionChemistryIonic strength dependenceEnthalpyInorganic chemistryIonic bondingCalorimetryCalorimetryCondensed Matter PhysicsSodium perchlorateUranylchemistry.chemical_compoundHydrolysisReaction enthalpyIonic strengthPhysical chemistrySettore CHIM/01 - Chimica AnaliticaPhysical and Theoretical ChemistryHydrolysis of UO22+InstrumentationThermochimica Acta
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On the Complexation of Cu(II) and Cd(II) With Polycarboxyl Ligands. Potentiometric Studies With ISE-H+, ISE-Cu2+, and ISE-Cd2+

2009

The interaction of Cu2+ and Cd2+ ions with polyacrylates (PAA, 2 kDa and 100 kDa), polymetacrylate(PMA, 5.4 kDa), and alginate (AA, 70 kDa to 100 kDa) was studied by potentiometry, using ISE-Cu2+, ISE-Cd2+, and ISE-H+ electrodes. The investigations were performed in NaNO3 aqueous solutions, in the ionic strength range 0.10 e I (mol ·L-1) e 0.75, at T ) 298.15 K. The “diprotic-like model” was used to explain the acid-base behavior of the polycarboxylates under investigation (for this model, the monomeric unit of the polyelectrolyte is considered as a dicarboxylate). The results give evidence for the formation of the ML species in all the systems investigated. In addition, the MLH species was…

inorganic chemicalsAcrylate polymerchemistry.chemical_classificationSequestering abilitypolycarboxylic acidsLigandGeneral Chemical EngineeringIonic strength dependencePotentiometric titrationInorganic chemistryGeneral ChemistryUronic acidComplexation Potentiometric study polyelectrolytesPolysaccharidePolyelectrolytechemistry.chemical_compoundchemistryIonic strengthSodium nitrateSettore CHIM/01 - Chimica Analiticapolycarboxylic acids; Sequestering ability; Ionic strength dependenceNuclear chemistryJournal of Chemical & Engineering Data
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