Interfacial formations in extraction systems with HDEHP and TBP

Abstract

The kinetics of the accumulation of Er(III), Ho(III), Pr(III), Nd(III), and Yb(III) in the interfacial layer of the extraction system with HDEHP or TBP in a nonaqueous diluent (heptane, toluene, tetrachloromethane), responsible for the appearance of interfacial formations, was studied, and the process mechanism was suggested. Up to 30% of the initial amount of the extractable element in the aqueous phase can be accumulated in the dynamic interfacial layer (DIL) when using HDEHP as extractant, and up to 15%, in the systems with TBP. The time dependences of the accumulation of lanthanide di(2-ethylhexyl) phosphates are characterized by the presence of a horizontal plot, i.e., the process in this period is steady-state. The accumulation in DIL depends on the initial concentration of the extractable element, extraction reagent, and solution acidity. In systems with the more polar diluent, the accumulation of the rare earth element in DIL is smaller.