Hydrogen Production from Acetate in a Sleeve Shape Microbial Electrolysis Cell with a Mipor Cathode

A sleeve-shape microbial electrolysis cell (MEC) was designed by making the anode surround the cathode. A mipor titanium tube coated with platinum was employed as the cathode, and seven pieces of graphite felts with exoelectrogens absorbing on surface piled up together served as the anode. Sodium acetate was used as a feed. Larger cathode surface area, shorter electrode spacing, greater system capacity and more reasonable structure design were contributed to enhance this system's performance. In 24 h batch tests, the hydrogen production rate increased from 0.14 to 2.36 L/L/d and the hydrogen recovery increased significantly from 40.15% to 86.13%, as the applied voltage increased from 0.2 to 1.0 V. And the chemical oxygen demand (COD) removal rate ranged from 0.23% (at 0.2 V) to 31.44% (at 1.0 V). The results demonstrated that high overall energy recovery and hydrogen production could be obtained by a relative higher applied voltage (>0.5 V).