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.
· 2024
· 2023
· 2013
Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m²-cat) and wastewater (WW: 0.3 to 1.7 W/m²), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m²; WW: 1.9 W/m²). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m²-mem; WW: 1.7 W/m²) and 2-CP (Acetate: 1.3 W/m²-mem; WW: 0.6 W/m²) reactors were much higher than previous MRCs (0.3-0.5 W/m²-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment.
· 2015
· 2012
Reverse electrodialysis allows for the capture of energy from salinity gradients between salt and fresh waters, but potential applications are currently limited to coastal areas and the need for a large number of membrane pairs. Using salt solutions that could be continuously regenerated with waste heat (≥40°C) and conventional technologies would allow much wider applications of salinity-gradient power production. We used reverse electrodialysis ion-exchange membrane stacks in microbial reverse-electrodialysis cells to efficiently capture salinity-gradient energy from ammonium bicarbonate salt solutions. The maximum power density using acetate reached 5.6 watts per square meter of cathode surface area, which was five times that produced without the dialysis stack, and 3.0 ± 0.05 watts per square meter with domestic wastewater. Maximum energy recovery with acetate reached 30 ± 0.5%.
· 2024
· 2024
· 2017
· 2021
· 2022
Microbial fuel cell (MFC) is a green innovative technology that can be employed for nutrient removal/recovery as well as for energy production from wastewater. This paper summarizes the recent advances in the use of MFCs for nutrient removal/recovery. Different configurations of MFCs used for nutrient removal are first described. Different types of nutrient removal/recovery mechanisms such as precipitation, biological uptake by microalgae, nitrification, denitrification and ammonia stripping occurring in MFCs are discussed. Recovery of nutrients as struvite or cattiite by precipitation, as microalgal biomass and as ammonium salts are common. This review shows that while higher nutrient removal/recovery is possible with MFCs and their modifications compared to other techniques as indicated by many laboratory studies, field-scale studies and optimization of operational parameters are needed to develop efficient MFCs for nutrient removal and recovery and electricity generation from different types of wastewaters.
· 2019