<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>MFC (Microbial fuel cell)<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Several technologies have been studied as
alternatives to petroleum-based fuels. Among these stands out the technology of
fuel cells due to their diverse field of application extends from portable
devices to generate stationary, including automotive use. Although the high
cost still prevents the application of such devices on a large scale, reduced
cost, weight and increase efficiency, will provide a rapid growth in the use of
fuel cells. The technology of fuel cells is divided into two categories
electrochemical fuel cells (also called conventional) and biocells
fuel (or fuel cell biological - MFC), the latter having received extensive
attention in the past three years. For the production of electricity, the
MFC operates with two sections (one cathode-anode-aerobic and anaerobic),
separated by an ion selective membrane H. Micro-organisms are used to catalyze
the oxidation of organic matter, generating electricity by transfer of
electrons to an external circuit, introduced before the step of reducing an electron
acceptor. In the anaerobic compartment is the oxidation of organic material,
with formation of CO2, protons and electrons. The generated protons migrate to
the aerobic compartment (cathodic chamber) permeating
through the proton exchange membrane. The produced electrons are transferred to
the cathode through the external circuit, and this surface is the reduction of
oxygen to water. This flow of electrons through the external circuit generates
an electrical current that can be measured and used to do work. The overall
cell reaction is the conversion of biodegradable organic material to carbon
dioxide and water, generating electricity in the process. The electrodes can not colonized by a few species of bacteria. Electroactive bacteria can transfer electrons to the
electrode surface without the need for redox mediators. Some of the micro-organisms known more electrochemical active Shewanella putrefaciens
and Shewanella oneidensis, the Gamma-proteobacteria,
Geobacter sulfurreducens,
Geobacter metallireducens
and Desulfuromonas acetoxidans
all Deltaproteobacteria and Rhodoferax ferrireducens the Betaproteobacteria. The MFCs form
a promising technology for sewage treatment, as a method of recovering energy
in the form of hydrogen or electricity. In 2004, there was a change in the
relationship between electricity production and sewage treatment, when it was
shown that wastewater can be treated at practical levels parallel to power
generation. The amount of energy generated in the study, although low, can be
considered high compared to previous studies. Reimers,
2001, demonstrated that inorganic and organic materials present in marine
sediments could be used in a new type of MFC, with the use of variety of
substrates, new materials and structural arrangements in the construction of
the MFCs. <o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>MFC CONSTRUCTION<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Materials<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>4 PLATES
ACRYLIC 120x120mm, 5mm thick<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>2 PLATES
ACRYLIC 100X75mm, 5mm thick<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>2 PLATES
120X75mm, 5mm de thick<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>24
screw-nut M6<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>24
washer/bezant M6<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>6 tubes
of 20g of cyanoacrylate (superglue)<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>6
connectors 1/4<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>Hose
1/8<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>Straight
connectors 1/8<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>3 valves
d<o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>carbon fiber <o:p></o:p></p>
<p class=MsoNormal style='margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;
margin-left:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:
36.0pt;line-height:150%;mso-list:l0 level1 lfo1;mso-layout-grid-align:none;
text-autospace:none'><![if !supportLists]>á<![endif]>10x10cm
de NAFION¨ MEMBRANE117<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Procedures<o:p></o:p></p>
<p class=MsoListParagraphCxSpFirst style='margin-left:0cm;mso-add-space:auto;
text-align:justify;text-justify:inter-ideograph;text-indent:36.0pt;line-height:
150%;mso-list:l1 level1 lfo2'><![if !supportLists]>1)
<![endif]>Machining of acrylic pieces.<o:p></o:p></p>
<p class=MsoListParagraphCxSpMiddle style='margin-left:0cm;mso-add-space:auto;
text-align:justify;text-justify:inter-ideograph;text-indent:36.0pt;line-height:
150%'>The acrylic pieces were cut according to the
specifications.<o:p></o:p></p>
<p class=MsoListParagraphCxSpMiddle style='margin-left:0cm;mso-add-space:auto;
text-align:justify;text-justify:inter-ideograph;text-indent:36.0pt;line-height:
150%'><o:p> </o:p></p>
<p class=MsoListParagraphCxSpMiddle style='margin-left:0cm;mso-add-space:auto;
text-align:justify;text-justify:inter-ideograph;text-indent:36.0pt;line-height:
150%'>Assembly<o:p></o:p></p>
<p class=MsoListParagraphCxSpMiddle style='margin-left:0cm;mso-add-space:auto;
text-align:justify;text-justify:inter-ideograph;text-indent:36.0pt;line-height:
150%'><o:p> </o:p></p>
<p class=MsoListParagraphCxSpMiddle style='margin-left:0cm;mso-add-space:auto;
text-align:justify;text-justify:inter-ideograph;text-indent:36.0pt;line-height:
150%;mso-list:l2 level1 lfo3'><![if !supportLists]>á
<![endif]>Plates were united
in order to form a rectangle with cyanoacrylate based glue as shown below: <o:p></o:p></p>
<p class=MsoListParagraphCxSpMiddle style='text-align:justify;text-justify:
inter-ideograph;line-height:150%'><o:p> </o:p></p>
<p class=MsoListParagraphCxSpLast style='text-align:justify;text-justify:inter-ideograph;
line-height:150%'>https://igem.org/File:8.png<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Electrode:<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Aluminum wire was wound and coated with a
carbon fiber for the anode.<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>A heat sink
aluminum was used as the counter electrode to the cathode <o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>SETUP OF MEASUREMENT DEVICE<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>The electrodes were connected to a resistor
of 0.9620 K½, and then connected to an Agilent U1252A multimeter.
The potential was measured at intervals of 15 minutes by 9hrs30min, and stored.
From the same may construct the table below, where the MFC produced watts /
hour.<o:p></o:p></p>
Time<o:p></o:p>
|
Potential with
charge (mV)<o:p></o:p>
|
Resistence ½<o:p></o:p>
|
Current(mA)<o:p></o:p>
|
Potencia (uW)<o:p></o:p>
|
Energy (uW-h)<o:p></o:p>
|
1<o:p></o:p>
|
65,00<o:p></o:p>
|
153,38<o:p></o:p>
|
0,424<o:p></o:p>
|
27,546<o:p></o:p>
|
6,886<o:p></o:p>
|
2<o:p></o:p>
|
121,29<o:p></o:p>
|
153,38<o:p></o:p>
|
0,791<o:p></o:p>
|
95,914<o:p></o:p>
|
23,978<o:p></o:p>
|
3<o:p></o:p>
|
222,90<o:p></o:p>
|
153,38<o:p></o:p>
|
1,453<o:p></o:p>
|
323,930<o:p></o:p>
|
80,983<o:p></o:p>
|
4<o:p></o:p>
|
120,89<o:p></o:p>
|
153,38<o:p></o:p>
|
0,788<o:p></o:p>
|
95,282<o:p></o:p>
|
23,821<o:p></o:p>
|
5<o:p></o:p>
|
161,97<o:p></o:p>
|
153,38<o:p></o:p>
|
1,056<o:p></o:p>
|
171,041<o:p></o:p>
|
42,760<o:p></o:p>
|
6<o:p></o:p>
|
139,97<o:p></o:p>
|
153,38<o:p></o:p>
|
0,913<o:p></o:p>
|
127,732<o:p></o:p>
|
31,933<o:p></o:p>
|
7<o:p></o:p>
|
124,67<o:p></o:p>
|
153,38<o:p></o:p>
|
0,813<o:p></o:p>
|
101,334<o:p></o:p>
|
25,333<o:p></o:p>
|
8<o:p></o:p>
|
96,71<o:p></o:p>
|
153,38<o:p></o:p>
|
0,631<o:p></o:p>
|
60,978<o:p></o:p>
|
15,245<o:p></o:p>
|
9<o:p></o:p>
|
67,01<o:p></o:p>
|
153,38<o:p></o:p>
|
0,437<o:p></o:p>
|
29,276<o:p></o:p>
|
7,319<o:p></o:p>
|
10<o:p></o:p>
|
172,65<o:p></o:p>
|
153,38<o:p></o:p>
|
1,126<o:p></o:p>
|
194,341<o:p></o:p>
|
48,585<o:p></o:p>
|
11<o:p></o:p>
|
212,42<o:p></o:p>
|
153,38<o:p></o:p>
|
1,385<o:p></o:p>
|
294,186<o:p></o:p>
|
73,547<o:p></o:p>
|
12<o:p></o:p>
|
320,00<o:p></o:p>
|
153,38<o:p></o:p>
|
2,086<o:p></o:p>
|
667,623<o:p></o:p>
|
166,906<o:p></o:p>
|
13<o:p></o:p>
|
358,00<o:p></o:p>
|
153,38<o:p></o:p>
|
2,334<o:p></o:p>
|
835,598<o:p></o:p>
|
208,899<o:p></o:p>
|
14<o:p></o:p>
|
147,53<o:p></o:p>
|
153,38<o:p></o:p>
|
0,962<o:p></o:p>
|
141,903<o:p></o:p>
|
35,476<o:p></o:p>
|
15<o:p></o:p>
|
333,00<o:p></o:p>
|
153,38<o:p></o:p>
|
2,171<o:p></o:p>
|
722,969<o:p></o:p>
|
180,742<o:p></o:p>
|
16<o:p></o:p>
|
357,00<o:p></o:p>
|
153,38<o:p></o:p>
|
2,328<o:p></o:p>
|
830,936<o:p></o:p>
|
207,734<o:p></o:p>
|
17<o:p></o:p>
|
293,00<o:p></o:p>
|
153,38<o:p></o:p>
|
1,910<o:p></o:p>
|
559,714<o:p></o:p>
|
139,929<o:p></o:p>
|
18<o:p></o:p>
|
260,95<o:p></o:p>
|
153,38<o:p></o:p>
|
1,701<o:p></o:p>
|
443,962<o:p></o:p>
|
110,991<o:p></o:p>
|
18<o:p></o:p>
|
150,40<o:p></o:p>
|
153,38<o:p></o:p>
|
0,981<o:p></o:p>
|
147,478<o:p></o:p>
|
36,869<o:p></o:p>
|
20<o:p></o:p>
|
178,94<o:p></o:p>
|
153,38<o:p></o:p>
|
1,167<o:p></o:p>
|
208,759<o:p></o:p>
|
52,190<o:p></o:p>
|
21<o:p></o:p>
|
177,45<o:p></o:p>
|
153,38<o:p></o:p>
|
1,157<o:p></o:p>
|
205,297<o:p></o:p>
|
51,324<o:p></o:p>
|
22<o:p></o:p>
|
95,06<o:p></o:p>
|
153,38<o:p></o:p>
|
0,620<o:p></o:p>
|
58,915<o:p></o:p>
|
14,729<o:p></o:p>
|
23<o:p></o:p>
|
97,04<o:p></o:p>
|
153,38<o:p></o:p>
|
0,633<o:p></o:p>
|
61,395<o:p></o:p>
|
15,349<o:p></o:p>
|
24<o:p></o:p>
|
50,00<o:p></o:p>
|
153,38<o:p></o:p>
|
0,326<o:p></o:p>
|
16,299<o:p></o:p>
|
4,075<o:p></o:p>
|
25<o:p></o:p>
|
167,00<o:p></o:p>
|
153,38<o:p></o:p>
|
1,089<o:p></o:p>
|
181,829<o:p></o:p>
|
45,457<o:p></o:p>
|
26<o:p></o:p>
|
155,85<o:p></o:p>
|
153,38<o:p></o:p>
|
1,016<o:p></o:p>
|
158,360<o:p></o:p>
|
39,590<o:p></o:p>
|
27<o:p></o:p>
|
108,30<o:p></o:p>
|
153,38<o:p></o:p>
|
0,706<o:p></o:p>
|
76,469<o:p></o:p>
|
19,117<o:p></o:p>
|
28<o:p></o:p>
|
145,80<o:p></o:p>
|
153,38<o:p></o:p>
|
0,951<o:p></o:p>
|
138,595<o:p></o:p>
|
34,649<o:p></o:p>
|
29<o:p></o:p>
|
153,26<o:p></o:p>
|
153,38<o:p></o:p>
|
0,999<o:p></o:p>
|
153,140<o:p></o:p>
|
38,285<o:p></o:p>
|
30<o:p></o:p>
|
230,11<o:p></o:p>
|
153,38<o:p></o:p>
|
1,500<o:p></o:p>
|
345,225<o:p></o:p>
|
86,306<o:p></o:p>
|
31<o:p></o:p>
|
122,04<o:p></o:p>
|
153,38<o:p></o:p>
|
0,796<o:p></o:p>
|
97,104<o:p></o:p>
|
24,276<o:p></o:p>
|
32<o:p></o:p>
|
91,73<o:p></o:p>
|
153,38<o:p></o:p>
|
0,598<o:p></o:p>
|
54,860<o:p></o:p>
|
13,715<o:p></o:p>
|
33<o:p></o:p>
|
64,22<o:p></o:p>
|
153,38<o:p></o:p>
|
0,419<o:p></o:p>
|
26,889<o:p></o:p>
|
6,722<o:p></o:p>
|
34<o:p></o:p>
|
15,11<o:p></o:p>
|
153,38<o:p></o:p>
|
0,099<o:p></o:p>
|
1,488<o:p></o:p>
|
0,372<o:p></o:p>
|
35<o:p></o:p>
|
37,67<o:p></o:p>
|
153,38<o:p></o:p>
|
0,246<o:p></o:p>
|
9,252<o:p></o:p>
|
2,313<o:p></o:p>
|
36<o:p></o:p>
|
76,50<o:p></o:p>
|
153,38<o:p></o:p>
|
0,499<o:p></o:p>
|
38,155<o:p></o:p>
|
9,539<o:p></o:p>
|
37<o:p></o:p>
|
20,48<o:p></o:p>
|
153,38<o:p></o:p>
|
0,134<o:p></o:p>
|
2,734<o:p></o:p>
|
0,684<o:p></o:p>
|
38<o:p></o:p>
|
8,75<o:p></o:p>
|
153,38<o:p></o:p>
|
0,057<o:p></o:p>
|
0,499<o:p></o:p>
|
0,125<o:p></o:p>
|
39<o:p></o:p>
|
45,22<o:p></o:p>
|
153,38<o:p></o:p>
|
0,295<o:p></o:p>
|
13,330<o:p></o:p>
|
3,333<o:p></o:p>
|
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>This means that the MFC produced is necessary
to feed our own meter for approximately 5.6 minutes. The calculations below
demonstrate our conclusion:<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Current battery power meter = 2.8mA = I.<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Supply voltage meter = 7.38 V = V<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Power generated by the MFC = 1930.085 μW<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Power required by multimeter:<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>P = VXI = 7.38V x 0.0028 = nd = 0.020664W 20664μW<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>PMFC / Pmultimetro
= 0.093405 h Å 5.6 minutes<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>The electricity generated is measured as
follows:<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>The MFC electrodes are connected in
parallel with the multimeter, whose terminals are
also placed in parallel with screw terminals, so that there is overhang of the
screws engaged in the junction, in order to connect, also in parallel with a
resistor (15 k) with sole purpose of measuring its power.<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>The voltage produced by the full MFC
suffers a fall due to the consumption of the load. With a quarter of a period
of time, it is checked potential difference "up" resistor, so in the
end of 8 hours of perform the integration of the power to obtain energy.<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'>Through the knowledge of Ohm's law, we know
that the voltage produced undergoes substantial decrease before the presence of
the load, which does not affect the efficiency of the system.<o:p></o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt;line-height:150%'><o:p> </o:p></p>