Résumé
The transport and separation of silver(I) ions across a bulk liquid membrane by 2-mercaptobenzothiazole (MBT) as carrier were investigated. The efficiency of Ag(I) transport was studied as a function of different parameters. The maximum of Ag(I) recovery was 85% in the presence of thiourea 0.1 M at pH 1, as complexing agent in the receiving phase, for a short extraction time of 4 h. A selective separation between Ag(I) and Mn(II) ions from equimolar mixture Ag–Cu–Mn solutions was performed. Besides, we have applied the kinetic model involving two consecutive irreversible first-order reactions to calculate the pseudo-first-order apparent membrane entrance and exit rate constants ke and ks, respectively. Under optimal conditions, the kinetic model curves of time dependence of silver concentrations (R) in the feed, membrane and receiving phases showed a good agreement with the experimental results. The apparent rate constants values were 6.93 × 10−3 min−1 for ke and 6.81 × 10−2 min−1 for ks. The transport of silver(I) is mainly controlled by the slow reaction of the formation of Ag–MBT complex at the membrane entrance.