Temperature effect on the solvent extraction of copper(II), cobalt(II) and nickel(II) with salicylideneaniline from sulphate media

Abstract

The temperature effect on the solvent extraction of copper(II), cobalt(II) and nickel(II) by Schiff base salicylideneaniline (SAN) in chloroform from sulfate aqueous medium of constant ionic strength was studied. The temperature dependence of the extraction equilibrium constants were investigated to estimate the variation of enthalpy (ΔH) and entropy (ΔS). These thermodynamic functions were, as a result, calculated and discussed in conjunction with the structure of the extracted species. It was found that the extraction of each metal increased with increase in temperature. Besides ΔH and ΔS have been discussed in connection with the nature of bonding and also the symmetry of the metal complexes. It was established through this study that the types of bonding in the complexes formed in the aqueous solution are clearly reflected by the values of ΔH and ΔS for the complex formation reaction.