Microbial fuel cells (MFCs) generate current via electrochemical reactions produced
by bacteria attached to the anode that oxidize organic matter.
Due to their high volume use in household products, some concentration of
surfactant will reach wastewater treatment plants. The average surfactant
concentration in wastewater ranges from 10 to 20 mg L-1, and up to 300 mg L-1, for
domestic and industrial wastewaters, respectively.
This study aimed to demonstrate the feasibility of enhancing power production by
adding Tween 80 and SDS surfactants to air-cathode MFCs, and their effect in cell
viability at the anodic biofilm.
In order to analyze the effect of anionic and nonionic surfactants in MFCs
performance, eight MFCs were spiked with two types of surfactants, the anionic
surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant Tween® 80 at
two different concentrations 10 and 100 mg L-1. Cell viability at the anodic biofilms was examined using the LIVE/DEAD BacLight viability assay and images were
visualized with a confocal laser scanning microscope.
The electrochemical results demonstrate that, for an air-cathode MFC operating on
1 g L-1 acetate in a fed-batch mode, reactors where SDS was added show a lower
overall performance, maximum PD of 544 mW m-2, CE of 12.3%, Rint of 322 Ω (10 mg
L-1) and maximum PD of 265 mW m-2, CE of 9.4%, Rint of 758 Ω (100 mg L-1).
Reactors where Tween 80 was added show quite stable performance, maximum PD
of 623 mW m-2, CE of 15.4%, Rint of 216 Ω (10 mg L-1) and maximum PD of 591 mW
m-2, CE of 10.8%, Rint of 279 Ω (100 mg L-1), compared with reactors operating at
only acetate as a substrate, maximum PD of 574 mW m-2. Confocal microscopy
images confirm this observation and biofilm viability appeared severely
compromised in SDS reactors, especially at high concentrations.
This study has opened up a whole new research area in determining which types of
surfactants are toxic to the anodic biofilm and to further investigate the scale-up
feasibility of this technology for wastewater treatment.
|Date of Award||Jul 2011|
- Biological, Environmental Science and Engineering
|Supervisor||Pascal Saikaly (Supervisor)|