What is Filtration?
Filtration is the techniques of separation of solid from liquid by using a medium that allows the passage of liquid but not the solid is called filtration. The medium used for the process of filtration is known as filter (which consists of membrane of fine pores). The fluid that passes through the filter is called filtrate and the solid particles that cannot pass through
the filter medium are oversized particles. The maximum sized particle that can pass through the filter paper is said to be the pore size of the filter. There are three forms of filtration, which are biological, geological and
industrial forms.
Filtration Example:
Filtration is one of the most important separation techniques used in day-to-day life. One of the most common example is preparation of tea.
1. After the tea is prepared we separate the tea leaves using a sieve. Through sieve only liquid will pass, leaving behind the tealeaves (oversized particles).This process of separation of tea leaves from the fluid is nothing but filtration.
2. The filtration of blood in kidneys is example of biological filtration in
which reabsorption of the substances required for body takes place.
3.Vacuum cleaners and air conditioners also use filtration process for removal of dust, and particles from the environment.
4. Canisters or cartridges are often used for the separation of oil.
Filtration Process:
Filtration is a very important process used in the field of chemistry for the separation of materials that have different composition. Filtration is not
similar to sieving, as in sieving only large sized particle will be collected on the sieve, but in filtration solid particles of small sized can be collected on the filter.
Various types of filtration are used depending upon the size of
particles or dissolved in the fluid.
1. General Filtration: In this method the mixture is poured on the medium (filter paper) and force of gravity will act upon the liquid and will pull the liquid down. As a result, the solid is left on the filter and the liquid flows below it.
2. Vacuum Filtration: In laboratories, Buchner funnel and hose are used for the creation of vacuum. This vacuum is used to suck the fluid through the filters and this method is used for the separation of dry solids.
3. Cold Filtration: This technique is used to cool a solution at faster
speed, resulting to the formation of small crystals. It is used when the
solid is firstly dissolved in the liquid. Therefore, the container with the solution is placed in the ice bath before carrying out the filtration.
4. Hot Filtration: This process is used for the solutions, which crystallize on cooling. The funnel is usually kept hot during filtration by coming in contact with hot solvent.
Application of Filtration:
1.Filtration plays a vital role in our day-to-day life as it is used in the
production of sterile materials like membrane filters.
2. Bacteria proof filters are used for the filtration of thermo-labile substances.
3. The production of bulk drugs is also carried out by filtration, which involve removal of impurities from the fluid.
4. The one of the most important
application of filtration is in the effluent and waste water treatment.
5. Filtration plays very important role in the formation of liquid orals and other clear solutions like syrups, eye-drops, and aromatic water
preparation.
Palak Budhiraja 