Decantation and filtration differ in the manner through which the methods separate substances in a mixture. In decantation, the separation of two substances, either of a solid and liquid or two immiscible liquids, occurs by allowing the mixture to settle and separate.
Once the substances have separated, the lighter substance is poured out, leaving the heavier substance behind.
The filtration process is mainly used for the separation of solids from liquids or gases. Separating a solid substance from a liquid is done by pouring out the liquid through a filter. The filter can either be paper, cotton wool, sand, cloth or other porous material.
While filtration is a more efficient method of separating mixtures than decantation, it is much more time consuming. The decantation process can also be slow and tedious without the aid of a centrifuge.
The main purpose of a centrifuge or separator is that it increases the rate of separation by simulating an increase in the force of gravity. It is described as a machine that separates substances of different densities using centrifugal force. This process is known as centrifugation and is an alternative to filtration.
Decantation is used in the separation of mixtures such as oil and water, gasoline and water, cream and milk, dirt and water, and wine and sediment. The filtration process is used in various processes and industries. For example, filters are used to extract precious metals in mining and in air conditioning to remove particles from air.