H2 production by the thermoelectric microconverter coupled with microbial electrolysis cell

Microbial electrolysis cell (MEC) is a kind of environmental methods to produce H-2. However, extra voltages are always supplied to overcome the energy barrier. In this study, the thermoelectric microconverter-MEC coupled system for H2 production from acetate was first investigated. The results showed that the thermoelectric microconverter could directly convert waste heat energy to electricity, even at relative low temperature difference as 5 degrees C. In the elevated hot side temperatures, the hydrogen yield and coulombic efficiency were gradually increased from 1.05 to 2.7 mol/mol acetate and from 27 to 83%, respectively. Meanwhile, the hydrogen production rate and current density were also increased with hot side of the thermoelectric microconverter ranging from 35 to 55 degrees C. A relatively high cathodic hydrogen recovery (RH2) (81-95%) was obtained during the whole experimental period. The community analysis revealed that Geobacter accounted for over 29% of total genus in the anode biofilm, which matched the MEC performance well. Therefore, waste heat is a great potential power source and it could effectively help MEC produce hydrogen via using the thermoelectric microconverter. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.