CKO-Purple 8% is an aluminium oxide chemisorption medium impregnated with at least 8% potassium permanganate. By means of a chemisorption process, gases are removed from the air stream and converted into solids that remain in the grain. CKO-Purple 8% is often used as a polishing filter following a more specialised high-capacity filter medium for a specific gas.

Gases that can be removed include:

• Hydrogen sulphide (H2S)
• Sulphur dioxide (SO2)
• Nitric oxide (NO)
• Formaldehyde (HCHO)
• Methyl mercaptan (CH4S)

It is often used to improve indoor air quality but also as a polishing filter in both industrial corrosion control and sewage removal. Mixing CKO-Purple 8% with CKV-3 increases the amount of gases that can be removed.