Kinetic role of diethylenetriaminepentaacetic acid added to stripping phase in permeation of rare earth metal ions through a supported liquid membrane

The effects of addition of diethylenetriaminepentaacetic acid (DTPA) to the stripping phase on the permeation rates of rare earth metal ions (Ln³⁺) through a supported liquid membrane (SLM) were investigated. It was note worthy that in the presence of DTPA Ln³⁺ permeated through the SLM even in the range of high pH in the stripping phase where permeation of these ions was not detectable without DTPA. By measurement of the concentrations of Ln in the SLM, the formation of DTPA-Ln chelates led to an improvement in the permeation rates at high pH in the stripping phase.