Research Library
Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
• 2014
• 2017
• 2014
sequestration.
• 2013
• 2015
• 2020
In this study, the effect of external resistance on the microbial reverse-electrodialysis cell (MRC) performance using organic-rich wastewater as an electron donor was examined. The optimum of external resistance was determined to be 300 Ω. In such condition, the power density of 1.53 ± 0.198 W/m 2 , substrate removal of 52 ± 2.3%, Coulombic efficiency of 70 ± 2.6%, energy recovery of 3.0 ± 0.4%, and energy efficiency of 53 ± 7.1% were obtained in the MRC. The differences in power density at different external resistances were mainly due to the changes in internal resistance and ion flux efficiency in the MRC. The external resistance affected substrate removal and Coulombic efficiency through the length of batch cycle time, and current density exchanged as well as the Tafel slope. Furthermore, the proper external resistance applied to the reactor created high power production; thus, high energy efficiency and energy recovery were achieved. These results demonstrated that selecting proper external resistance was an essential key for a successful MRC operational.
• 2011
There is a tremendous source of entropic energy available from the salinity difference between river water and seawater, but this energy has yet to be efficiently captured and stored. Here we demonstrate that H(2) can be produced in a single process by capturing the salinity driven energy along with organic matter degradation using exoelectrogenic bacteria. Only five pairs of seawater and river water cells were sandwiched between an anode, containing exoelectrogenic bacteria, and a cathode, forming a microbial reverse-electrodialysis electrolysis cell. Exoelectrogens added an electrical potential from acetate oxidation and reduced the anode overpotential, while the reverse electrodialysis stack contributed 0.5-0.6 V at a salinity ratio (seawater:river water) of 50. The H(2) production rate increased from 0.8 to 1.6 m(3)-H(2)/m(3)-anolyte/day for seawater and river water flow rates ranging from 0.1 to 0.8 mL/ min. H(2) recovery, the ratio of electrons used for H(2) evolution to electrons released by substrate oxidation, ranged from 72% to 86%. Energy efficiencies, calculated from changes in salinities and the loss of organic matter, were 58% to 64%. By using a relatively small reverse electrodialysis stack (11 membranes), only ~1% of the produced energy was needed for pumping water. Although Pt was used on the cathode in these tests, additional tests with a nonprecious metal catalyst (MoS(2)) demonstrated H(2) production at a rate of 0.8 m(3)/m(3)/d and an energy efficiency of 51%. These results show that pure H(2) gas can efficiently be produced from virtually limitless supplies of seawater and river water, and biodegradable organic matter.