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Effect of surface roughness, porosity and roughened micro-pillar structures on the early formation of microbial anodes

Champigneux, Pierre and Renault-Sentenac, Cyril and Bourrier, David and Rossi, Carole and Délia, Marie-Line and Bergel, Alain Effect of surface roughness, porosity and roughened micro-pillar structures on the early formation of microbial anodes. (2019) Bioelectrochemistry, 128. 17-29. ISSN 1567-5394

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Official URL: https://doi.org/10.1016/j.bioelechem.2019.03.002

Abstract

The early formation of electroactive biofilms was investigated with gold electrodes inoculated with Geobacter sulfurreducens. Biofilms were formed under an applied potential of 0.1 V/SCE, with a single batch of acetate 10 mM, on flat gold electrodes with different random surface roughness. Roughness with arithmetical mean height (Sa) ranging from 0.5 to 6.7 μm decreased the initial latency time, and increased the current density by a factor of 2.7 to 6.7 with respect to nano-rough electrodes (Sa = 4.5 nm). The current density increased linearly with Sa up to 14.0 A·m−2 for Sa of 6.7 μm. This linear relationship remained valid for porous gold. In this case, the biofilm rapidly formed a uniform layer over the pores, so porosity impacted the current only by modifying the roughness of the upper surface. The current density thus reached 14.8 ± 1.1 A·m−2 with Sa of 7.6 μm (7 times higher than the nano-rough electrodes). Arrays of 500-μm-high micro-pillars were roughened following the same protocol. In this case, roughening resulted in a modest gain around 1.3-fold. A numerical model showed that the modest enhancement was due to ion transport not being sufficient to mitigate the local acidification of the structure bottom.

Item Type:Article
HAL Id:hal-02279662
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Agence Nationale de la Recherche
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Deposited By: Loetitia MOYA
Deposited On:05 Sep 2019 12:50

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