Studies of the ionic transport through ion exchange membranes and in their adjacent electrolyte films have become a topic of great importance, due to their different applications in environmental problems [1]. A better understanding of the phenomena and processes involved in the mass transport in devices with ion exchange membranes allows designing cells with higher performance and lower energy consumption. There are few studies about of transport of ions in membranes, Wang et al. (1990) studied the mass transport of monovalent cations across a polypyrrole membrane [2], Oulmi, (2012) [3] analyzed the transport of Na⁺ in cation-exchange membrane (CEM), in both previous work CEM are used, studies on anion-exchange membrane (AEM) are scarce, and the transport mechanism may be different from the one observed in a CEM. Therefore, in the present work, the transport of HSO₄^- through AEM is studied. The system used consists of a cell of four electrodes, where anode and cathode are separated by an anionic-exchange membrane (Selemion) with an exposed area of 0.28 cm² on each side. Two platinized titanium plates with an area exposed to the 10.8 cm² are used as anode and cathode; two saturated calomel with Luggin capillaries were used as reference electrodes. The electrochemical studies were: open circuit potential, chronoamperometry of sampled current and cyclic voltammetry at different scan rate, H₂SO₄ concentration and different potential range.

The cyclic voltammograms at different H₂SO₄ concentrations are shown in the Figure 1. It exhibits that HSO₄^- can transfer across the Selemion membrane due to a peak current. The peak current increases as the HSO₄^- concentration increases, but when the species HSO₄^- is depleted at the interface of the membrane, the intensity of current decreases until a limiting current is reached, similar to the phenomenon that occurs when a species depletes at the interface of an electrode/electrolyte [2]. By continuing to increase the potential, the current intensity begins to increase. The water splitting supplying new current carriers and giving rise to the so-called exaltation effect [4]. This phenomenon appears at all the HSO₄^- concentration. On the other hand, electrochemical studies show that the transfer of the anions in the anion-exchange membrane (Selemion) is through a migration process and the adjacent films by migration and diffusion.