Speculation of feasible interaction between tri-n-octyl amine and Di-2-ethylhexylphosphoric acid from volumetric measurements

Abstract

Solvent extraction serves as one of the most proven hydrometallurgical techniques for recycling and recovery of various metal values This extraction practice is based on the shuttling of the solute molecules between two non-miscible liquid phases. The affinity of the solute is motivated by the nature of the extracting agent to initiate the transference of the solute from the feed solution to the organic phase. Therefore, choice of suitable extractants plays a crucial role in solvent extraction systems. Binary extractant systems have been more effective with improved separation ability and have drawn more attention in the field of solvent extraction. The investigation of interaction between the extracting agent and diluent, two main components of the organic phase, has immense impact on the extraction efficiency. Scrutiny of physicochemical properties like molar volume, partial molar volume apparent molar volume and excess molar volume, is essential in order to obtain more insight about the synergistic extractant mixtures. The present work reports the volumetric properties of binary mixtures of a basic extractant, tri-n-octyl amine (TOA) and an acidic extractant, di-2-ethylhexylphosphoric acid (D2EHPA) at T = 298 K-318 K to predict the possible interaction existing between these two at different mole fractions. By rising the mole fraction of TOA in the mixture, the density of the binary mixture gradually decreases. Enhancement in temperature resulted an increase in molar volume of the binary mixture.