Effect of Temperature on the Extraction of Chromium(III) from Alkaline Aqueous Solutions with Trioctylmethylammonium Chloride (Aliquat 336)

Abstract

The effect of temperature was examined on the equilibrium of extraction of chromium(III) from the alkaline aqueous solutions with Aliquat 336. The stoichiometry of chromium(III) complexes in the organic phase and their conditional extraction constants at temperatures from 273 to 298 K were determined. The temperature positively affected the extraction of chromium(III). Fourteen linear correlations, reflecting the influence of temperature on the equilibrium of extraction of chromium(III) under different conditions, were established. They permitted the estimation of the thermodynamic functions describing the extraction of chromium(III) at temperatures from 273 to 298 K. The values of the enthalpy change indicated endoenergic character of the extraction of Cr(III).