Difference between Molecular diffusion and Eddy diffusion

Molecular diffusion

When diffusion results from the random movement or motion of the molecules it is called molecular diffusion.

• Molecular diffusion is the slow process
• Molecular diffusion is the mechanism of mass transfer in stagnant or in fluids which are flowing in laminar flow.
• Example:- If pure water is added in a tank which is filled with brine solution without disturbing brine, and left it for some time then the salt will permeate the liquid by molecular diffusion.

Eddy diffusion

When the movement of the molecules occurs with the help of an external force that is mechanical stirring or movement of fluid then it is called eddy or turbulent diffusion.

• Eddy diffusion is a fast process
• Eddy diffusion is the mechanism of mass transfer in fluids which are highly developed the turbulent flow.
• Example:- If pure water is added in a tank which is filled with brine solution without disturbing brine, and left it for some time then the salt will permeate the liquid by molecular diffusion. But the process very slow hence mechanical agitation is used to increase the diffusion.