Biomedical Engineering Reference
In-Depth Information
electricity generation [
101
]. However, the acid nature of the fermentation liquor
may be detrimental to anodic microorganisms, and the feasibility of MFCs for
anaerobic effluent polishing are yet to be experimentally demonstrated.
In most of the above cases, the electricity produced by the microbes is trivial
compared to the increased rates of contaminant degradation and bioremediation.
These extended values and potentials of MFC are worth pursuing, but need further
exploration.
3.2 Other Potential Applications
3.2.1 Power Sources for Low-Power Devices
Despite the great promise of MFC technologies for power generation and waste-
water treatment at large scales, most of these envisaged applications are currently
still unfeasible and significant improvements are required. One of the most likely
areas to see practical application of MFCs in the near future, if any, would be
utilizing the limited MFC-derived electricity for low-power devices.
One most attractive attribute of MFCs is powering off-grid devices at remote
locations, such as in lakes and seas. The first demonstration that an MFC could
power a practical device was a meteorological buoy for remote monitoring, which
continuously obtained its entire power from a benthic MFC [
102
]. Another case is
a benthic MFC that powered an ultrasonic receiver for real-time tracking of
acoustically tagged green sea turtles and collected data on their behavior [
103
],
which successfully operated for several years with no power decrease. To further
optimize the configuration of benthic MFCs, Li et al. [
104
] recently investigated
the impacts of electrode shape on power generation performance, and found that
the column-type electrode offered superior properties and enabled a lower internal
resistance.
Another unusual but quite possible application of MFCs is to power implanted
medical devices, which may hopefully provide indefinite power and remove the
need for surgery to replace batteries. For example, Siu and Mu [
105
] developed a
microfabricated polydimethylsiloxane MFC with flexible and biocompatible
structure. This MFC could use glucose and oxygen in the blood for power gen-
eration, and thus could serve as a potential power source for implanted chemical
devices. However, implanting an MFC into the blood might carry risks of
thrombosis and body rejection reactions. Considering that the large intestine might
be a more suitable site for MFC implantation, Han et al. [
106
] managed to develop
an MFC that simulated the environmental features of the transverse colon. Stable
power generation with an average voltage of 308 mV (at 500 X internal resistance)
was obtained, and the maximum power density reached 73.3 mW/m
2
(normalized
to anode surface) in this system. This demonstrated that an MFC located in the
large intestine could be a promising power source for implanted medical devices.
Search WWH ::
Custom Search