Efficient recovery of Y³⁺ from aqueous media using MDLM technique: transport behavior and kinetic modeling

This study investigates the extraction behavior of Y³⁺ ions using a Multi-Dropped Liquid Membrane (MDLM) system that employs di(2-ethylhexyl) phosphoric acid (D₂EHPA) as the carrier ligand. The focus is on the system's ability to transport ions between aqueous phases selectively. The extracted complex was analyzed spectrophotometrically via ultraviolet-visible (UV-Vis) measurements after complexation with 0.05% Arsenazo III. The aim of this study was to determine the influence of the optimum D₂EHPA carrier concentration, together with the pH and temperature conditions of the donor and acceptor phases, on the system's extraction performance. Accordingly, a series of extraction experiments was performed at different D₂EHPA concentrations, pH values, and temperatures to assess their combined effects on transport kinetics. The MDLM system achieved a maximum transport efficiency of 99.90% for Y³⁺ ions at a D₂EHPA concentration of 0.0045 mol/L, with a corresponding extraction time of 160 min. The shortest transport time of 120 min was observed at a carrier concentration of 0.0075 mol/L, confirming the strong influence of carrier concentration on extraction kinetics. The calculated low activation energy of 31.446 kJ/mol suggests that the transport of Y³⁺ ions through the MDLM system into the organic phase containing D₂EHPA is diffusion-controlled.