Filtration
A separation technique that removes suspended solid particles from a fluid by passing the mixture through a porous medium.
Unit
Dimensionless
In depth
The retained solid is the residue and the liquid passing through is the filtrate. Gravity filtration through fluted paper suits fast-draining mixtures, while vacuum filtration through a Büchner funnel is faster and gives a drier cake. Pore size determines what is retained, from coarse precipitates down to bacteria.
Examples in the real world
Recovering a barium sulfate precipitate from solution, or clarifying tap water through a sand bed at a treatment works.