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Recycling urine for bioelectrochemical hydrogen production using a MoS2 nano carbon coated electrode in a microbial electrolysis cell
Citation:
Hwang, J., S. Fahad, H. Ryu, K. Rodriguez, J. SantoDomingo, A. Kushima, AND W. Lee. Recycling urine for bioelectrochemical hydrogen production using a MoS2 nano carbon coated electrode in a microbial electrolysis cell. JOURNAL OF POWER SOURCES. Elsevier Science Ltd, New York, NY, 527:231209, (2022). https://doi.org/10.1016/j.jpowsour.2022.231209
Impact/Purpose:
With regards to water-energy nexus technology in wastewater, urine has great potential to be a future sustainable energy source for water, oxygen or hydrogen generation. Microbial electrolysis cells (MECs) have attracted increasing attention due to their sustainable treatment approach using wastewater as an alternative energy source. While MECs using municipal wastewater have been widely studied, only a few studies have been reported for the recovery of nutrients from urine, but capital costs such as electrodes for water electrolyzers need to be reduced. It is shown here that a novel MoS2-nano carbon (NC) electrode for generating hydrogen in a MEC, while treating urine. MoS2-NC electrode provide a low cost, but durability similar to platinum and other nanomaterials. These results show that by using a MoS2-NC electrode, the costs of electrode catalysts can be reduced, and thus provide scale up MECs development for improving of water-energy nexus.
Description:
Urine has a great potential for energy production and nutrient recovery, and a bioelectrochemical system (BES) can provide an eco-friendly and sustainable bioremediation option for recycling urine. In this study, a novel molybdenum disulfide (MoS2) nano-carbon (NC) coated cathode was developed for urine treatment and improved hydrogen production in a microbial electrolysis cell (MEC). MoS2 nanoparticles were electrodeposited on the NC coated cathodes with -100, -150 and -200 µA/cm2 and their performance was compared to NC only and carbon cloth (CC) in the MEC. The MoS2-NC200 (electrodeposition at -200 µA/cm2) cathode produced slightly higher hydrogen (57.8 ± 0.6 µmol/L) compared to MoS2-NC100 (53.9±0.8 µmol/L). At the dilution factor of 2, the MoS2-NC200 cathode had significantly higher (~31%) hydrogen production than the carbon cloth (CC) cathode with the same dilution of urine. The reproducibility tests of the MoS2-NC cathodes after a short MEC operation period (~ 10 days) showed a stable MoS2 coating on the NC cathodes. Maximum ammonia-nitrogen (NH3-N) and phosphorus (PO43--P) removal with varying dilution factors was 68.7 ± 0.1% and 98.6 ± 0.3%, respectively. Some of the exoelectrogenic bacteria were identified as members of the Clostridia and Bacteroidetes taxa. The newly fabricated MoS2-NC cathode will be a suitable strategy for microbial acclimation to urine in a MEC for a novel biotransformation process within the water-energy nexus.
URLs/Downloads:
DOI: Recycling urine for bioelectrochemical hydrogen production using a MoS2 nano carbon coated electrode in a microbial electrolysis cell
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