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-octylamine (TOA) in kerosene from acidic chloride media has been developed. The extraction percentage was found to be 76.7 using 1.5 M TOA. 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 positive value of enthalpy change indicates that high temperature favors the formation of extractable complex (Co (II)-TOA complex) and the positive value of entropy change indicates inner sphere complexation. 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).