Filtration may be defined as a process of separation of solids from a fluid by passing the same through a porous medium that retains the solids but allows the fluid to pass through. OR • It is a process used to separate solid particles from a liquid with the help of a filter or pores of filter paper. . OR • In simple words, filteration is the action or process of filtering something. • Examples The most common example is making tea.

1. Filtration
S. I MAKRANI
Assistant Professor
Department of Pharmaceutics
Ali Allana College of Pharmacy Akkalkuwa

2. Content
 Definition
 Process of filtration
 Mechanisms of filtration
 Application of filtration
 Type of filtration
 Equipment's used in filtration

3. • Filtration may be defined as a process of separation of solids from a fluid by passing the
same through a porous medium that retains the solids but allows the fluid to pass
through. OR
• It is a process used to separate solid particles from a liquid with the help of a filter or
pores of filter paper. . OR
• In simple words, filteration is the action or process of filtering something.
• Examples The most common example is making tea.
• While preparing tea, a filter or a sieve is used to separate tea leaves from the water.
• Through the sieve pores, only water will pass.
• The liquid which has obtained after filtration is called the filtrate; in this case, water is
the filtrate.
• The filter can be a paper, cloth, cotton-wool, asbestos, or glass-wool, sand, or any
other porous material.
Filtration
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4. Fig. Principle of filtration 2

5. • The mixtures are of two main types:
• Homogeneous mixtures and Heterogeneous mixtures.
• A homogeneous mixture is a mixture that is uniform throughout.
• A heterogeneous mixture is a mixture that is not uniform throughout, i.e.,
ingredients of the mixture are distributed unequally.
• Air is a homogeneous mixture of different gases, including oxygen, nitrogen,
carbon dioxide, and water vapour.
• Homogeneous mixtures are sometimes also called solutions; especially when
it is a mixture of a solid dissolved in a liquid.
• An example of a heterogeneous mixture is the mixture of sand in water.
• On shaking, sand will stay undissolved and are distributed unevenly.
Process of filtration
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6. Slurry:
• The suspension to be filtered is known as slurry.
Filter medium:
• The porous medium used to retain the solids is known as filter medium.
Filter cake:
• The accumulated solids on the filter are referred to as filter cake,
Filtrate:
• The clear liquid passing through the filter is filtrate.
Clarification:
• When solids are present in a very low concentration, i.e., not exceeding
1.0% w/v, the process of its separation from liquid is called clarification
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7. • Straining
• Sedimentation
• Impaction
• Interception
• Adhesion
• Flocculation
• Chemical and Physical adsorption
• Biological growth
Figure : Steps involved in mechanism of filtration
Mechanism of filtration
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8. • Some of the mechanisms are:
• Straining: Similar to sieving. i.e. the particles of larger size cannot pass
through the smaller pore size of the filter medium.
• Impingement: the solids are retained on the filter medium.
• Entanglement : Particles become entangled in the mass of fibres due to
smaller size of particles than the pore size. Thus the solids are retaincd on
the filter medium.
• Attractive forces: Solids are retained on the filter medium as a result of
attractive forces between particles and filter medium.
• Sedimentation: The particles within the filter settle on the filtering
medium.
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9. • Based on the mechanism,
 Surface filtration:
 Depth filtration:
 Membrane Filtration:
• Surface filtration: Surface filtration involves the removal of material
suspended in a liquid by means of sieving.
• Depth filtration: In this method, the removal of suspended material from the
liquid suspension is performed by passing the liquid through a filter bed
composed of granular or compressible Filter medium.
• Membrane Filtration: Membrane filtration is a separation process that uses
a semi Permeable membrane.
Types of filtration
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10.  During manufacturing of sterile products, it is necessary to remove
smallest particle. Therefore, air is filtered through HEPA filters (high
efficiency particulate air filters) to get sterile air.
 The solution, suspension, eye drops, elixirs etc. should be free from
suspended solids. Filtration is major step during production of such
formulations.
 Filtration methods are used in home to clarify potable water
 Filtration is necessary to separate substances of different chemical
composition
 On industrial scale filtration is used for dewaxing of oils.
 Filtration technique is used to treat sewage and waste water
treatment.
Application of filtration
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11. Plate and frame filter press
Figure . Construction of Plate and frame filter press 9

12. Filter leaf
Figure . Construction of Filter leaf 10

13. Drum filter
Figure . Construction of Drum filter 11

14. Meta filter
Figure . Construction of Meta filter 12

15. Cartridge filter
Figure . Construction of Cartridge filter 13

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