Final answer:
Vacuum filtration employs a vacuum to quickly filter larger volumes, whereas gravity filtration uses gravity. Membrane filters with a pore size of 0.2-µm can remove bacteria, but smaller pores are needed for viruses, and HEPA filters are widely used to purify air in various settings.
Step-by-step explanation:
Filtration is a technique to remove solids from liquids or gases using a porous medium. In the context of liquids, the filtration process separates a heterogeneous mixture, allowing the liquid to pass through while retaining the solid particles.
In vacuum filtration, a vacuum pump generates a pressure differential, drawing the liquid through the filter. This method is effective for filtering larger volumes of liquid and is especially useful when a rapid filtration is desired. For example, vacuum filtration units are connected to the filter, and the solution is drawn through by the vacuum pressure.
Gravity filtration, on the other hand, relies on the earth's gravitational force to drive the liquid through the filter. It is a simpler method and does not require any special equipment aside from a funnel and filter medium. Gravity filtration is generally used when the filtrate, rather than the residue, is required, and when the filtration process does not need to be expedient.
Various applications include using membrane filters to sterilize liquids, such as antibiotic solutions in laboratories, as well as the use of HEPA filters to clean air by capturing bacteria, viruses, and other particles. For instance, a 0.2-µm membrane filter would effectively remove bacteria from solutions but may not be small enough to capture all viruses. In clinical settings, HEPA filters are commonplace in air purifiers and vacuum cleaners to maintain a clean environment.