Microbial fuel cell for simultaneous removal of uranium (VI) and nitrate

Nuclear wastes contain high nitrate concentration along with radionuclides like U (VI). Also, several reports suggest the presence of U (VI) and nitrate as co-contaminants in groundwater. The denitrifying bacteria consortia at MFC cathode produced phosphatase enzyme, which catalyzed the controlled release of phosphate from glycerol 3 phosphate. The inorganic phosphate combined with U (VI) resulting in insoluble uranyl phosphate. Ninety percent of initial U (VI) added in the biocathode could be recovered as Uranyl phosphate. XRD analysis confirmed the presence of uranyl phosphate precipitating at the cathode. Nitrate acted as an electron acceptor at the cathode, enabling completion of the MFC circuit and simultaneous nitrate and U (VI) removal. Since the process was performed in the MFC; the remediation was accompanied by power output. The power density of 2.91 Wm−3 and nitrate removal rate of 0.130 kg NO3−-N m−3 d−1 was achieved. The 16S rDNA based community analysis revealed a high abundance of Pseudomonas species in biocathode. This study demonstrates the applicability of MFC for simultaneous nitrate and U (VI) removal while producing electrical energy.