Thermodynamics of Extraction of Selenium by Tri‐iso‐octyl Amine (TIOA) from Chloride Medium

Abstract

The equilibrium distribution of selenium in hydrochloric acid medium and with the chloride salt of tri‐iso‐octylamine (TIOA) in xylene was studied. Experimental data were analyzed graphically and numerically to determine the stoichiometry of the extraction species. It was found that the extraction reaction is endothermic (ΔH = +17.060 KJ/mol). Selenium was extracted by the reaction:

The effect of extractant concentration, equilibration period, diluents, and diverse ion and stripping agents on the extraction of selenium were studied. The distribution constant and the thermodynamic parameters enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) were evaluated.

Keywords:

• Selenium
• Extraction
• TIOA
• Thermodynamic parameters
• Xylene

Acknowledgments

The authors thank Henkel Corporation, USA, for sending us the reagent TIOA and also thank the Department of Metallurgical Engineering, Jadavpur University, for laboratory facilities. Authors are thankful to Ms. Kasturi Mitra for her contribution.