Classification Based on Rate Processes:

The separations based on rate processes take place due to differences in the kinetic properties of the components of the mixture. The separations are majorly achieved because of the following two reasons.

• Various diffusion rates through permeable barriers such as membranes,
• Various migration velocities under various fields like electrical, gravitational and thermal

Different diffusion rate through permeable barriers

The most generally used permeable barrier is semi = permeable membrane. The methods based on its use are

i)  Ultrafiltration,

ii) Reverse Osmosis,

iii) Dialysis, and

iv) Electrodyalysis.