Study of di-hydrogen (Na; K or NH4) orthophosphates in aqueous solutions at temperatures from 298.15 K to 353.15 K
| Autor: | Mohamed El Guendouzi, Asmaa Benbiyi |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Activity coefficient
Molality Aqueous solution Chemistry General Chemical Engineering Inorganic chemistry Analytical chemistry General Physics and Astronomy 02 engineering and technology 010402 general chemistry 01 natural sciences 0104 chemical sciences Gibbs free energy Dilution Solvent symbols.namesake 020401 chemical engineering symbols 0204 chemical engineering Physical and Theoretical Chemistry Solubility Dissolution |
| Zdroj: | Fluid Phase Equilibria. 408:223-231 |
| ISSN: | 0378-3812 |
| DOI: | 10.1016/j.fluid.2015.08.035 |
| Popis: | In this investigation, the thermodynamic properties of aqueous solutions Na, K or NH4 dihydrogenphosphate were determined at various temperatures ranging from 298.15 K to 353.15 K. The measurements of water activity were performed in the molality range from dilution to saturation using the hygrometric method. The modeling approach based on the ion interaction model was developed to determine the thermodynamic properties. From these measurements of phosphate salts, mixing parameters in binary solutions were evaluated at various temperatures, without considering formation of aqueous complexes. The osmotic and activity coefficients were determined for these aqueous solutions of orthophosphate salts. The measurements of the binary systems were combined with reference pure water, NaH2PO4(s), KH2PO4(s) and (NH4)H2PO4(s) solubility data to construct a chemical model that calculates solute and solvent activities from dilute to saturated solution concentration from 298.15 to 353.15 K respectively up to mmax(NaH2PO4(s)) = 7.90–18.29 mol kg−1; mmax(KH2PO4(s)) = 1.83–5.10 mol kg−1; and mmax((NH4)H2PO4(s)) = 4.93–12.62 mol kg−1. The thermodynamic characteristics, solubility products K s p ° and the standard molar Gibbs energy of dissolution Δ G d i s s ° were also given. |
| Databáze: | OpenAIRE |
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