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This is a microbial
reverse electrodialysis fuel cell (MRC). When a high salt
and low salt solutions are placed into alternating membrane
pairs the reverse electrodialysis (RED) stack produces
additional voltage. This allows the combined MRC to produce
a higher voltage and power density than that possible by
either the MFC or RED stack. The salt solutions can be
natural (freshwater and seawater) or regenerable solutions
using waste heat (such as ammonium bicarbonate). You can
read about the MRC in our paper in Science by
Cusick et al. (2011). |
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Extracting energy at
higher voltages from MFCs can be challenging. We developed a
capacitor circuit system that efficiently increases the
voltages produced by MFCs. You can read about it in
Kim et al. (2011), or visit
our YouTube page.
[High resolution
image] |
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This is a small (5 mL)
microbial electrolysis cell (MEC). It is very inexpensive
and can be made for only about $1.50 each. They can be
autoclaved, and one power source can run thousands of
reactors. Read more about how to make them in
Call and Logan (2011a), or results using them in
Call and Logan (2011b). Visit our YouTube page to see
how these are made and used (3 videos).
www.youtube.com/user/MFCTechnology |
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This is the largest
bioelectrochemical system we ever built. It is 1000 liters,
and it is a microbial electrolysis cell (MEC) that was used
to treat winery wastewater. The system is no longer running,
but you can read about it in
Cusick et al. (2011).
[High resolution image] |
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Here the water is flowing
through a series of 4 MDCs, so that the extent of
desalination is increased. To read more, see
Kim & Logan (2011).
[High resolution image] |
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This is a microbial
desalination cell (MDC) with a stack of ion exchange
membranes. The efficiency of the desalination is greatly
improved compared to the 3-chamber (single pair of ion
exchange membrane) systems shown below. To read more, see
Kim & Logan (2011).
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A microbial desalination
cell (MDC) can also be made to produce hydrogen gas, by
adding voltage as done in a microbial electrolysis cell (MEC),
and by using ion exchange membranes. We can this a microbial
electrolysis desalination cell (MEDC). You can read
more about this in the paper paper by
Mehanna et al. (2011).
[High resolution
image] |
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Tsinghua University and
Penn State recently developed a new type of
bioelectrochemical system called a microbial desalination
cell (MDC). This reactor contains two membranes, and three
chambers, with the water in the middle chamber desalinated
when current is generated by bacteria. The paper can be
found on the publications page (see Cao et al. 2009).
Additional images are available for our new systems at:
http://live.psu.edu/album/2110 |
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This is the same type of
cube reactor, but here we have replaced the flat anode with
a graphite fiber brush anode. See the paper by
Logan et al.
(2007). |
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This is our most
frequently used reactor, which holds 28-ml and is usually
operated in fed-batch mode. We have used this system to
examine a variety of factors that affect power generation,
such as electrode spacing, solution chemistry, electrode
materials, substrates and pure vs mixed cultures. This
reactor has a flat anode and a flat cathode. See publication
by
Liu and Logan (2004). |
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In order to scale up MFCs,
we need to provide more surface area for the cathode. This
is a reactor we tested using tubular cathodes made of
ultrafiltration membranes that were coated on the inside
with catalyst and a carbon conductive paint and a Pt
catalyst. See the publication by Zuo et al. (2007). |
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This is a single chamber
MFC that uses a very large brush anode and a flat cathode.
This reactor is red due to the growth of Rhodopseudomonas
palustris DX-1. Power is very much limited by the cathode
surface area, but it is a nice easy design that can be made
out of glass, plastic or just about any material. See Logan
et al. (2007) for performance data of a glass bottle system. |
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This is the same cube
reactor as above with a brush anode, but this one has a pure
culture of Rhodopseudomonas palustris DX-1. See paper by
Xing et al. (2008). |
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This is a two-chamber
reactor modified to have a crimp top on the reactor top and
a crimp top side access port. The brush is suspended in the
solution. |
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This flat plate microbial
fuel cell, that operates in continuous flow mode, has a
proton exchange membrane sandwiched between two carbon paper
electrodes. Channels are drilled to that the flow follows a
serpentine path through the system. See paper by Min & Logan
(2004). |
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This is a conventional
two-chamber microbial fuel cell. In this setup, both
chambers are gas sparged: one with nitrogen to maintain
anaerobic conditions in the chamber where the bacteria grow
(anode); the other with air to provide oxygen in solution
(cathode). |
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Same as the above cell,
except the anode chamber is filled with a wastewater
solution. |
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This is the Single Chamber
Microbial Fuel Cell (SCMFC) described in our ES&T paper (Liu
et al. 2004, ES&T). Here is the SCMFC is empty-- note the
central cathode tube running down the center. |
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Same as above, but filled
with wastewater. |
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A data logging multimeter
is used to monitor voltage in the circuit containing a
resistor. From the voltage and resistor information, we can
calculate total power output by the system. |