How to Build a Plant Microbial Fuel Cell
Most microbial fuel cells are made using marine or pond bacteria, but it is still possible to produce a fuel cell which operates using a plant fuel, rather than a bacteria. Although most plants cannot be used for this type of fuel production, as they lack the enzymes which can control electrons and power electricity, it is still possible to manage to make a fuel cell out of plant life.
Step 1 - Create Your Anode and Cathode
Open up the ends of the compression fitting, and ensure that the ends are roughened enough to fit neatly over the tubes of the fitting. Then, make a mark on one side of your plastic containers, and then measure across to the other container. Make a hole on each of the lids of your containers, and then place a hole the same size as your air pump tubing. Drill a hole on each of the marks on your plastic containers. Place acrylic cement around one of the endcaps, and then place it over the hole you have just drilled. Place the 2 pieces together, and hold the cap on until it dries. Add more cement to create an airtight seal. Add the compression fitting tube onto the end, and then place the remaining cap on the other end of the tube. Add a layer of cement over the second container, and place the hole over the edge of the cap. Ensure that your two boxes sit flat side-by side before continuing. Leave to dry.
Step 2 - Make the Electrodes
Cut your cloth into equal squares of around 2 inches each side. Take a piece of wire, ad remove 1/2 inch from each end except one. From the remaining end, take off 5 or 6 inches. Add a layer of nickel epoxy to the stripped wire, and place it along the 2 inch edges of your square cloth. Leave to dry overnight. Once dry, test with an multimeter to ensure that there is a low resistance.
Step 3 - Make the Salt Membrane
Take the tube from your compression fitting, and wrap one end with aluminum foil. Place a 1/2 pint of water into a saucepan, and bring to a point. Add 1 ounce of agar. Wait until this is dissolved, and then add a teaspoon of salt. Allow to cool slightly, and then pour into the tube. Leave for 10 minutes, and then place in the refrigerator overnight. Once you are ready to begin using the fuel cell, you can screw the tube into position.
Step 4 - Adding the Plants
You will need a fast-acting water plant such as a reed or water-weed variety. Place a little bit of soil in one part of the container with 2 holes, and fill up with suitable water from a river. Add the plants to the soil, and allow to grow for a little before creating the fuel cell. Once the plants are grown, add the electrodes to either side of the water, install the air pump, and add your tube connecting the 2 tubes.