An impingement filter can be used to purify a polluted solution, be it gas or liquid.

The impingement filter acts by inducing the solution to change direction and the particles to adhere to the filter medium. In many cases this filter medium is designed to contain apertures of specific size which will absorb the impurities in the solution. The gas or liquid, less impurities, is permitted free passage through the medium.

Common examples of impingement filters are air filter

Air filter

A particulate air filter is a device composed of fibrous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. A chemical air filter consists of an absorbent or catalyst for the removal of airborne molecular contaminants such as volatile organic compounds...

s, fuel filter

Fuel filter

A fuel filter is a filter in the fuel line that screens out dirt and rust particles from the fuel, normally made into cartridges containing a filter paper. They are found in most internal combustion engines....

s and oil filters used in cars, trucks etc.