microbial fuel cells ppt1

8/8/2019 Microbial Fuel Cells Ppt1

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Microbial Fuel Cells



MFCs

Microbial fuel cells are bio-electro-chemical

devices able to directly convert chemical

energy into electricity processing a wide range

of organic substrates.

It is a device that converts chemical energy to

electrical energy by the catalytic reaction

of microorganisms.



Working



A typical microbial fuel cell consists of anode and cathode compartments

separated by a cation (positively charged ion) specific membrane.

In the anode compartment, fuel is oxidized by microorganisms,

generating electrons and protons.

Electrons are transferred to the cathode compartment through an external

electric circuit, and the protons are transferred to the cathode compartment

through the membrane.

Electrons and protons are consumed in the cathode compartment, combining

with oxygen to form water.

In general, there are two types of microbial fuel cells: mediator and mediator-less

microbial fuel cells.



Idea of MFC

conceived

First mediator-lessMFC

(still low current output)

1912

First MFC (toxic

mediators)



Basic reactions in a Fuel cell

When micro-organisms consume a substrate

such as sugar in anaerobic conditions they

produce

Carbon dioxide

Protons and

Electrons



C12H22O11 + 13H2O ---> 12CO2 + 48H+ + 48e-



Types of MFCs

Mediator Microbial Fuel Cell

Mediator-less Microbial Fuel Cell

Microbial Electrolysis Cell



Mediator Microbial Fuel Cell

Most of the microbial cells are

electrochemically inactive.

The electron transfer from microbial cells to

the electrode is facilitated by mediators such

as methyl viologen, methyl blue, neutral

red and so on.



Mediator-less Microbial Fuel Cell

A mediator-less microbial fuel cell does not

require a mediator but uses electrochemically

active bacteria to transfer electrons to the

electrode.

Electrons are carried directly from the

bacterial respiratory enzyme to the electrode.



Microbial Electrolysis Cell

Whilst MFC's produce electric current by the

bacterial decomposition of hydrocarbons in

water, in a reverse of the process MEC's

generate hydrogen or methane directly by

applying an electric current to bacteria



Principle involved

Fuel cells have attracted interest due to their

low degree of pollution and high (theoretical)

efficiency.

Since the chemical energy of the fuel is

directly converted to electricity, fuel cells are

not influenced by the Carnot efficiency limit

like combustion and heat engines.



Principle involved

The theoretical efficiency is expressed as the

relationship between chemical energy

available( DG) and the higher heating value of

the fuel cell reaction (enthalpy change)



Principle involved

Over a large

temperature and power

range fuel cells have a

potentially higherefficiency than Carnot

technology.



Papers Read

Electricity generation and modeling of microbial fuel cell from continuous beerbrewery waste water.

Modelling and simulation of two-chambermicrobial fuel cell.

Effect of temperature on the performance of

microbial fuel cells. A review of the substrates used in MFCs for

sustainable energy production.



Make a Microbial Fuel Cell



Materials Required

Tools:

Drill or drill press

Razor knife or scissors

Hot glue gun

Funnel - Optional for filling bottles

Soldering ironLead Solder



Two heavy duty plastic bottles with sealable

lids. Wide mouth bottles are best choice for

ease of inserting broad surface area

electrodes.

Low power aquarium air pump



Agar - 100g per Liter of water

Salt - 400g per Liter of water ( 14 oz/Qt ).

Carbon cloth or carbon paper



Things to be Studied

Nernst Equation

Reaction Kinetics

Biofilm and Material of electrode.

microbial fuel cells ppt1

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