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Title: Excess Surface Area in Bioelectrochemical Systems Causes ion Transport Limitations

Abstract

We investigated ion transport limitations on 3D graphite felt electrodes by growing Geobacter sulfurreducens biofilms with advection to eliminate external mass transfer limitations. We characterized ion transport limitations by: (i) showing that serially increasing NaCl concentration up to 200mM increased current linearly up to a total of þ273% vs. 0mM NaCl under advective conditions; (ii) growing the biofilm with a starting concentration of 200mM NaCl, which led to a maximum current increase of 400% vs. current generation without NaCl, and (iii) showing that un-colonized surface area remained even after steadystate current was reached. After accounting for iR effects, we confirmed that the excess surface area existed despite a non-zero overpotential. The fact that the biofilm was constrained from colonizing and producing further current under these conditions confirmed the biofilms under study here were ion transport-limited. Our work demonstrates that the use of high surface area electrodes may not increase current density when the system design allows ion transport limitations to become dominant.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1184917
Report Number(s):
PNNL-SA-107829
48569
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Biotechnology and Bioengineering, 112(5):858-866
Additional Journal Information:
Journal Name: Biotechnology and Bioengineering, 112(5):858-866
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Harrington, Timothy D., Babauta, Jerome T., Davenport, Emily K., Renslow, Ryan S., and Beyenal, Haluk. Excess Surface Area in Bioelectrochemical Systems Causes ion Transport Limitations. United States: N. p., 2015. Web. doi:10.1002/bit.25500.
Harrington, Timothy D., Babauta, Jerome T., Davenport, Emily K., Renslow, Ryan S., & Beyenal, Haluk. Excess Surface Area in Bioelectrochemical Systems Causes ion Transport Limitations. United States. doi:10.1002/bit.25500.
Harrington, Timothy D., Babauta, Jerome T., Davenport, Emily K., Renslow, Ryan S., and Beyenal, Haluk. Fri . "Excess Surface Area in Bioelectrochemical Systems Causes ion Transport Limitations". United States. doi:10.1002/bit.25500.
@article{osti_1184917,
title = {Excess Surface Area in Bioelectrochemical Systems Causes ion Transport Limitations},
author = {Harrington, Timothy D. and Babauta, Jerome T. and Davenport, Emily K. and Renslow, Ryan S. and Beyenal, Haluk},
abstractNote = {We investigated ion transport limitations on 3D graphite felt electrodes by growing Geobacter sulfurreducens biofilms with advection to eliminate external mass transfer limitations. We characterized ion transport limitations by: (i) showing that serially increasing NaCl concentration up to 200mM increased current linearly up to a total of þ273% vs. 0mM NaCl under advective conditions; (ii) growing the biofilm with a starting concentration of 200mM NaCl, which led to a maximum current increase of 400% vs. current generation without NaCl, and (iii) showing that un-colonized surface area remained even after steadystate current was reached. After accounting for iR effects, we confirmed that the excess surface area existed despite a non-zero overpotential. The fact that the biofilm was constrained from colonizing and producing further current under these conditions confirmed the biofilms under study here were ion transport-limited. Our work demonstrates that the use of high surface area electrodes may not increase current density when the system design allows ion transport limitations to become dominant.},
doi = {10.1002/bit.25500},
journal = {Biotechnology and Bioengineering, 112(5):858-866},
number = ,
volume = ,
place = {United States},
year = {2015},
month = {5}
}