Aqueous Solutions of Cr(III) Sulfate: Modeling of Equilibrium Composition and Physicochemical Properties
Tóm tắt
Chemical equilibria in aqueous solutions of chromium sulfate are studied and the mathematical model of chromium complexation is developed in a wide range of concentrations (0.001–1.2 mol/l). The results of calculations satisfactorily agree with the experimental data, which confirms the adequacy of the suggested mathematical model of the equilibrium composition of an aqueous chromium sulfate solution. The nature of “green” modification of Cr2(SO4)3 is established. This modification occurs in its diluted solutions (c < 0.1 mol/l) due to predominant polynuclear chromium hydroxo complexes, whereas in the concentrated solutions (c > 0.1 mol/l), it forms due to prevailing chromium sulfate complexes. The diagram was plotted that shows the regions with different prevailing forms of the complexes in the equilibrium system H2O–Cr2(SO4)3 at different concentrations and pH and explains the experimental data on the basis of some physicochemical properties (electric conductivity, viscosity, light absorption) of chromium sulfate solutions within a wide range of concentrations.
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