Wednesday, 3 October 2018
Universal Ballroom (Expo Center)
The electrochemical techniques are useful tools for the extraction of heavy metals from aqueous effluents. Between them, studies at the interface of two immiscible electrolyte solutions (ITIES) allow to understand the fundamentals that regulate the process of ionic metal extraction through hydrophobic barriers, owing to it is possible to control the equilibrium of the metal ion across the interface by applying an electrical potential. In the present work, it was studied the kinetic process of the facilitated ionic metal transfer by dibenzo-18-Crown-6 and diciclohexane-18-Crown-6 at the water/1,2-dioclhoroetane (1,2-DCE) interface
The electrochemical experiments were carried out in a 4-electrode cell (two references and two counterelectrodes) and the interface was polarized by cyclic voltammetry (CV). The rate constant (k) for the facilitated metal transfer at the water/1,2-DCE interface was evaluated from CV data through the procedure proposed by Nicholson. The peak-to-peak separation (DEp) of the transfer from the aqueous to the organic phase and from organic to the aqueous phase wave, as well as the diffusion coefficient, were considered for the calculus of k. The results showed that k is in the range of 10-3 cms-1, which is according to the values previously obtained for ion transfers at the liquid-liquid interface.