Filter paper

Filter paper and from paper-like materials are used in many areas to separate solids from liquids or gases; physically seen to separate a solid phase from an aqueous or gaseous.

Areas of application

• In the household solid / liquid: Tea from teabag paper, filter paper, coffee filters
• Solid / gas: Vacuum Cleaner Bag

• Solid / liquid: oil filter, fuel filter
• Solid / gas: air filter, pollen filter

• Solid / liquid: Numerous applications with special filter papers (see below)

Use in chemical laboratory

In the chemical laboratory filter paper is important in preparative and analytical work .. For the various uses of papers with different pore sizes were developed:

Filter shapes and pore sizes

Filter papers are designed for different funnel shapes as flat round filter or as a pre-folded pleated filter.

Depending on the application papers of different pore sizes are used, which are marked by color codes:

• Black band filters are used for coarse precipitates ( rapid filtration )
• White band filters are used for finer precipitation (medium rapid filtration )
• Blue band filter used for very fine precipitates (slow filtration)

Ashless filter paper

Ashless filter burn out during the drying and ashing of a precipitate filtered out virtually residue-free, and thus do not affect the gravimetric analytical work for the sample weight, as it is the case with ordinary filters.

Use in the biology laboratory

Here round filters are used, but not for filtering, but for moisturizing eg small cut plant parts in preparative work. As a general rule for round filters of corresponding size in petri dishes are placed.