Enhanced Cd(II) removal with simultaneous hydrogen production in biocathode microbial electrolysis cells in the presence of acetate or NaHCO3

Enhanced Cd(II) removal with simultaneous hydrogen production was achieved in biocathode microbial electrolysis cells (MECs) using carbon source of acetate or NaHCO3 at long-term bacterial community acclimation and elevated Cd(II) concentrations. Removal of Cd(II) reached 7.33 +/- 0.37 mg/L/h (acetate) and 6.56 +/- 0.38 mg/L/h (NaHCO3) whereas hydrogen production was 0.301 +/- 0.005 m(3)/m(3)/d (acetate) and 0.127 +/- 0.024 m3/m3/ d (NaHCO3) at an initial Cd(II) of 50 mg/L. Similar Cd(II) and metallic Cd were present in the precipitates of either acetate or NaHCO3 biocathodes whereas same predominant species but in different proportions were found in the acetate or, NaHCO3 biofilms. These findings demonstrate the importance of both long-term bacterial community acclimation at elevated Cd(II) concentrations and carbon source for enhanced Cd(II) removal with simultaneous hydrogen production in the biocathode MECs. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.