Introduction:

A microbial fuel cell (MFC) is a device that converts chemical energy into electrical energy using the metabolic activity of microorganisms. It is a bioreactor that uses bacteria to produce electricity from organic matter. The sludge contains acetate. It is produced as a byproduct of the decomposition of organic matter in wastewater. Acetic acid is a form of acetate.

Components required:

1. Anode chamber
2. Cathode chamber
3. Salt bridge
4. Perforated aluminum
5. Conducting wire
6. Voltmeter
7. Aquarium air pump

Diagram:

Chemical reaction:

At anode:

Microbial oxidation: CH₃COOH + 2H₂O     ->     2CO₂ + 8H⁺ + 8e^–

Microbes oxidize acetate (CH₃COOH) to carbon dioxide (CO₂), releasing protons (H⁺) and electrons (e^–).

In an electrolytic cell, oxidation refers to the loss of electrons, occurring at the positive anode. Oxidation occurs when a substance loses electrons.

At cathode:

Electron acceptor reduction: 8H⁺ + 8e^– + 2O₂     ->     4H₂O

Electrons travel through an external circuit, are joined by protons from the anode, and then react with oxygen (O₂) to form water (H₂O).

Reduction refers to the gain of electrons, happening at the negative cathode. Reduction occurs when a substance gains electrons.

Overall:

Complete reaction: 2CH₃COOH + 2O₂     ->     2CO₂ + 2H₂O

The overall reaction shows the oxidation of acetate and the reduction of oxygen, with the net products being carbon dioxide and water, and the generation of electricity.

Salt bridge:

In a Microbial Fuel Cell (MFC), the salt bridge is a crucial component that facilitates the transfer of ions (protons) between the anode and cathode chambers, enabling electricity generation. This connection maintains electrical neutrality and allows the electrochemical reactions within the cell to proceed effectively.

The salt bridge prevents the buildup of positive or negative charges in either chamber, which would halt the electrochemical reactions. So, it maintains electrical neutrality.

The salt bridge also helps to prevent the mixing of solutions from the anode and cathode chambers, which could interfere with the electrochemical reactions.

Advantages:

The voltage generated from the sludge (organic waste) is around 100mV.

Designer:
Er. Anil Kumar Prusty
WhatsApp: +91 9861004895