TY - JOUR
T1 - Enhancing hydrogen production in microbial electrolysis cells by in situ hydrogen oxidation for self-buffering pH through periodic polarity reversal
AU - Yang, Yuli
AU - Qin, Mohan
AU - Yang, Xiaoli
AU - He, Zhen
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017
Y1 - 2017
N2 - Successful pH control plays a key role in hydrogen production in microbial electrolysis cells (MECs). Herein, periodic polarity reversal (PPR) is applied to a dual-cathode MEC and achieves the enhanced hydrogen production. The MEC with PPR produces 1.3 ± 0.1 m3H2m−3d−1with 50-mM NaCl as the catholyte, much higher than 0.9 ± 0.1 m3H2m−3d−1from the MEC with dual-working cathodes or 0.8 ± 0.1 m3H2m−3d−1from the MEC with one working cathode. Such enhancement benefits from a slower increase in the catholyte pH, for example, it takes 15.3 h to increase the 10-mM NaCl pH from 7.00 to 12.00 in the MEC with PPR, 1.7–3.6 times that of the MECs without PPR, which is due to the decrease in the catholyte pH of the reversed cathode during PPR. The potential of the reversed electrode is more positive than the anode, suggesting that the reversed electrode acts as a second anode electrode using residue hydrogen gas as an electron source. Thus, a mechanism of in situ oxidation of hydrogen gas for pH buffering is proposed and discussed. These findings have provided a simple but effective pH control strategy for enhancing hydrogen production in MECs.
AB - Successful pH control plays a key role in hydrogen production in microbial electrolysis cells (MECs). Herein, periodic polarity reversal (PPR) is applied to a dual-cathode MEC and achieves the enhanced hydrogen production. The MEC with PPR produces 1.3 ± 0.1 m3H2m−3d−1with 50-mM NaCl as the catholyte, much higher than 0.9 ± 0.1 m3H2m−3d−1from the MEC with dual-working cathodes or 0.8 ± 0.1 m3H2m−3d−1from the MEC with one working cathode. Such enhancement benefits from a slower increase in the catholyte pH, for example, it takes 15.3 h to increase the 10-mM NaCl pH from 7.00 to 12.00 in the MEC with PPR, 1.7–3.6 times that of the MECs without PPR, which is due to the decrease in the catholyte pH of the reversed cathode during PPR. The potential of the reversed electrode is more positive than the anode, suggesting that the reversed electrode acts as a second anode electrode using residue hydrogen gas as an electron source. Thus, a mechanism of in situ oxidation of hydrogen gas for pH buffering is proposed and discussed. These findings have provided a simple but effective pH control strategy for enhancing hydrogen production in MECs.
KW - Bioenergy
KW - Hydrogen production
KW - Microbial electrolysis cells
KW - Periodic polarity reversal
KW - pH control
UR - http://www.scopus.com/inward/record.url?scp=85013078304&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2017.02.046
DO - 10.1016/j.jpowsour.2017.02.046
M3 - Article
AN - SCOPUS:85013078304
SN - 0378-7753
VL - 347
SP - 21
EP - 28
JO - Journal of Power Sources
JF - Journal of Power Sources
ER -