TY - JOUR
T1 - Magnetite/zeolite nanocomposite-modified cathode for enhancing methane generation in microbial electrochemical systems
AU - Vu, Mung Thi
AU - Noori, Md Tabish
AU - Min, Booki
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea [ 2018R1A2B6001507 ].
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/8/1
Y1 - 2020/8/1
N2 - In this study, magnetite/zeolite (MZ) was successfully synthesized to use as a feasible and cost-effective cathode catalyst for enhancing methane generation in a microbial electrochemical system (MES). The novel MZ catalyst consists of hydrophilic zeolite cores and conductive magnetite nanoparticles for enhanced electroactive biofilm development on the cathode by facilitating micro-channels for nutrient diffusion, increased surface area, and reduced charge transfer resistance. The MES using an MZ cathode (MES-MZ) achieved a maximum methane yield of 0.38 ± 0.010 LCH4/gCOD, which was significantly higher than that of the control operation without a catalyst (0.33 ± 0.008 LCH4/gCOD). The methane production rate was increased by almost 21% from 196 mL/(L.d) in the control MES to 238 mL/(L.d) in the MES-MZ, along with an improvement in the methane percentage from 73% to 79%. In addition, the maximum current generation was recorded using the MES-MZ at 9.29 ± 0.16 mA, which was about 16% higher than that of 8.0 ± 0.13 mA observed in the control reactor and is consistent with about a 36.2% improvement of the Coulombic efficiency. The CV and EIS analyses revealed that MZ lowered the overpotential losses during the electron transfer process, and revealed a more positive cathode potential with the MES-MZ (−0.48 V vs. Ag/AgCl), which possibly suggests direct electron transfer for the dominant pathway for the conversion of carbon dioxide to methane.
AB - In this study, magnetite/zeolite (MZ) was successfully synthesized to use as a feasible and cost-effective cathode catalyst for enhancing methane generation in a microbial electrochemical system (MES). The novel MZ catalyst consists of hydrophilic zeolite cores and conductive magnetite nanoparticles for enhanced electroactive biofilm development on the cathode by facilitating micro-channels for nutrient diffusion, increased surface area, and reduced charge transfer resistance. The MES using an MZ cathode (MES-MZ) achieved a maximum methane yield of 0.38 ± 0.010 LCH4/gCOD, which was significantly higher than that of the control operation without a catalyst (0.33 ± 0.008 LCH4/gCOD). The methane production rate was increased by almost 21% from 196 mL/(L.d) in the control MES to 238 mL/(L.d) in the MES-MZ, along with an improvement in the methane percentage from 73% to 79%. In addition, the maximum current generation was recorded using the MES-MZ at 9.29 ± 0.16 mA, which was about 16% higher than that of 8.0 ± 0.13 mA observed in the control reactor and is consistent with about a 36.2% improvement of the Coulombic efficiency. The CV and EIS analyses revealed that MZ lowered the overpotential losses during the electron transfer process, and revealed a more positive cathode potential with the MES-MZ (−0.48 V vs. Ag/AgCl), which possibly suggests direct electron transfer for the dominant pathway for the conversion of carbon dioxide to methane.
KW - Direct electron transfer
KW - Electromethanogenesis
KW - Magnetite/zeolite nanocomposites
KW - Methane yield
KW - Microbial electrochemical system
UR - http://www.scopus.com/inward/record.url?scp=85081258043&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2020.124613
DO - 10.1016/j.cej.2020.124613
M3 - Article
AN - SCOPUS:85081258043
VL - 393
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
SN - 1385-8947
M1 - 124613
ER -