Extraction/transportation of Co2+ metal ions with bis(2-ethylhexyl) phosphate dissolved in kerosene using a multidropped liquid membrane technique.

The transport properties of Co²⁺ ions from the aqueous donor phase to aqueous acceptor phase with the recently developed multidroplet liquid membrane (MDLM) extraction system were studied. This system serves as a continuous process for the transportation of ions and requires fewer reagents for starting and conducting the procedure. Moreover, the procedure results in fewer waste chemicals and mixtures in comparison to traditional extraction methods. During extraction, bis(2-ethylhexyl) phosphate (D2EHPA) was used as a carrier material and 5% potassium thiocyanate (KSCN) solution was used to obtain a colored complex for UV-Vis detection. By means of several experiments, the optimum D2EHPA concentration, pH range for both donor and acceptor phases, and temperature range effect on transport kinetics were investigated. In the extraction of cobalt ions with the MDLM system, the activation energy was calculated as E_a = 13.80 kcal mol^-1, and it was found that the extraction was chemically controlled since it was greater than 10 kcal mol^-1.