PURPOSE: To produce the relatively stiff filter effective in deodorizing and collecting ozone by mixing a phenolic binder into powdered activated carbon made from coconut husk and press-forming the mixture into a porous plate which is then heat-treated.

CONSTITUTION: Coconut husk is carbonized to form activated carbon in the activated carbon producing stage 1, and the activated carbon is powdered. In the second binder mixing stage 2, several percent of a phenolic binder is mixed into the powdered activated carbon produced in the stage 1. The mixture is press-formed into a porous plate in which many through-holes are formed in the stage 3. The porous plate is heat-treated at ≤850°C for several ten hr in the stage 6. Consequently, a relatively stiff filter effective in deodorizing and collecting ozone is produced.