Transport dynamics of atenolol in an electrodialysis cell: Membrane sorption and electric field-driven effects

Abstract

Electrooxidation has proven to be an effective technique to remove pharmaceutical from water and wastewater. However, the low concentration of pharmaceuticals in the environment affects the process, becoming a drawback that needs solution. A new system coupling electrooxidation and electrodialysis was recently proposed for micropollutants removal, since ionic interactions between micropollutants and ion-exchange membranes were already proven. Despite this, the transport of pharmaceutical through ion-exchange membranes under the application of an electric field is still unclear and pathless. To fill this gap, the transport of atenolol (ATL) at under- and overlimiting current conditions was evaluated in an electrodialysis cell for the first time as an initial step to the application of the hybrid process. This study focused on the interaction and transport of ATL through the cation-exchange membrane (CEM), considering ATL cationic aspect. Different current densities (5, 10, 15, 25 mA/cm2) were applied and ion uptake experiments were done. It was found that the transport is mostly driven by this parameter: by applying 15 mA/cm2, ≈98% removal rate was achieved, while applying 5 mA/cm2 only 7% of ATL was removed. Part of the ATL remained into the CEM structure can be desorbed by applying an electric field at inverse polarity. It occurs because ATL seems to be linked by electrostatic interactions with the functional groups on the CEM matrix. Thus, a hybrid process would be feasible allowing to concentrate and degrade ATL simultaneously, reducing the consumption of chemicals, energy, unitary processes, besides operational costs.