Tyhjösuodatus

Tyhjösuodatus, also known as vacuum filtration, is a laboratory technique used to separate a solid from a liquid using a vacuum. It is a common method for collecting precipitates or drying solids. The process involves drawing the liquid through a filter paper or membrane using a vacuum source, leaving the solid particles behind on the filter.

The basic apparatus for vacuum filtration typically includes a Buchner funnel or Hirsch funnel, a filter flask, filter paper, and a vacuum source such as a vacuum pump or a water aspirator. The filter paper is placed in the funnel, and the solid-liquid mixture is poured onto the filter paper. When the vacuum is applied, the liquid is rapidly drawn through the filter paper and into the filter flask, while the solid is retained on the filter.

Vacuum filtration is generally faster and more efficient than gravity filtration, especially for fine precipitates or large volumes of liquid. It is also useful for washing the collected solid by rinsing it with a small amount of solvent while the vacuum is still applied, ensuring that impurities are washed away. The collected solid can then be dried in the filter flask or transferred to an oven. This technique is widely used in organic chemistry, analytical chemistry, and various industrial processes where solid-liquid separation is required.