UPSC Prelims 2011 · Question 47 of 100

UPSC Prelims 2011 question on Microbial Fuel Cells

Microbial fuel cells are considered a source of sustainable energy. Why?

1. They use living organisms as catalysts to generate electricity from certain substrates.

2. They use a variety of inorganic materials as substrates.

3. They can be installed in waste water treatment plants to cleanse water and produce electricity.

Which of the statements given above is/are correct?

  1. 1 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer

Answer: C. 1 and 3 only

Verdict

Correct Answer: 1 and 3 only

Analysis

Microbial Fuel Cells are considered a source of sustainable energy because they use microorganisms to generate electricity from organic matter and can also help in wastewater treatment.

Statement by statement

1. They use living organisms as catalysts to generate electricity from certain substrates — Correct
Microbial Fuel Cells use bacteria or other microorganisms as biocatalysts. These microbes break down organic substances and release electrons, which flow through an external circuit to produce electricity.

2. They use a variety of inorganic materials as substrates — Incorrect
MFCs mainly use organic substrates such as glucose, acetate, sewage, agricultural waste or other biodegradable organic matter. Their sustainability comes from using renewable organic waste, not mainly inorganic materials.

3. They can be installed in wastewater treatment plants to cleanse water and produce electricity — Correct
Wastewater contains organic pollutants. In MFCs, microbes break down these pollutants, helping clean the water while simultaneously generating electricity.

Extra UPSC info

MFCs usually have an anode, cathode and proton exchange membrane.
At the anode, microbes oxidise organic matter and release electrons.
They are useful for waste-to-energy, wastewater treatment and green technology.
Their main limitation is low power output, which makes large-scale commercial use difficult.
They are different from hydrogen fuel cells because MFCs use microbes and organic waste as the energy source.

How to crack it

Microbial Fuel Cells generate electricity using living microorganisms and can be used in wastewater treatment. Therefore, statements 1 and 3 only are correct.

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