Efficiency of Tri-n-octylamine for the liquid-liquid extraction of Co (II) from acidic chloride medium

Abstract

Cobalt criticality is increasing as a function of time and this concern has impelled researchers to ascertain efficient recovery schemes of cobalt. In this paper, an extraction strategy for cobalt utilizing tri-n-octyl amine (TOA) in kerosene from acidic chloride media has been developed. The extraction percentage was found to be 76.7 using 1.5M TOA. The extracted species has been formulated as (R₃NH) CoCl3 based on the findings of slope analysis. Influence of various salting out agents like NH₄Cl, KCl, and NaCl on the percentage extraction has been analysed and KCl emerged as beneficial for extraction. The estimated values of enthalpy change and entropy change shows that the extraction process is enthalpy driven with formation of Co (II)-TOA inner sphere complex. Kerosene as diluent was proved to be efficient in comparison to other aromatic hydrocarbons for the extraction of Co under the present experimental conditions. In order to examine the interaction between cobalt and TOA, FTIR analysis has been carried out. The changes in absorption peak position of functional groups confirmed binding of TOA with Co (II).