Frontiers of Environmental Science & Engineering
>> 2016,
Volume 10,
Issue 3
doi:
10.1007/s11783-015-0793-y
RESEARCH ARTICLE
Mechanisms behind the accelerated extracellular electron transfer in
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China
Accepted: 2015-06-02
Available online: 2016-04-05
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Abstract
Modification of electrode surface with carboxylic acid terminated alkanethiol self-assembled monolayers (SAMs) has been found to be an effective approach to improve the extracellular electron transfer (EET) of electrochemically active bacteria (EAB) on electrode surface, but the underlying mechanism behind such enhanced EET remains unclear. In this work, the gold electrodes modified by mercapto-acetic acid and mercapto-ethylamine (Au-COOH, Au-NH ) were used as anodes in microbial electrolysis cells (MECs) inoculated with DL-1, and their electrochemical performance and the bacteria-electrode interactions were investigated. Results showed that the redox reaction occurred on the Au-NH with a higher rate and a lower resistance than that on the Au or the Au-COOH. Both the MECs with the Au-COOH and Au-NH anodes exhibited a higher current density than that with a bare Au anode. The biofilm formed on the Au-COOH was denser than that on bare Au, while the biofilm on the Au-NH had a greater thickness, suggesting a critical role of direct EET in this system. This work suggests that functional groups such as –COOH and-NH could promote electrode performance by accelerating the direct EET of EAB on electrode surface.
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