Cathodic abatement of Cr(VI) in water by microbial reverse-electrodialysis cells

For the first time a microbial reverse electrodialysis cell (MRC) was used for the treatment of water contaminatedby Cr(VI). It has been recently shown that both inorganic and organic pollutants can beremoved by reverse electrodialysis processes (RED) using water with different salinity without the supplyof electric energy. However, a high number of membrane pairs is usually necessary for the treatment ofwastewater by RED. Here, it was showed that a lower number of membranes can be used by theutilization of a MRC (i.e., a RED cell with a biotic anode) for such purposes. Indeed, the abatement ofCr(VI), chosen as model pollutant, was successfully achieved by cathodic reduction in short times usinga drastically lower number of membrane pairs with respect to that required by a conventional RED. Theeffect of the number of membrane pairs and of the salinity gradient was studied in detail and theperformances of MRC was systematically compared to that of RED.