Hydrophilic compound removal method and odor removal method
The disclosure provides a method for removing a C4-C20 hydrophilic compound. The method for removing a hydrophilic compound includes step (a) of exposing a composition containing a C4-C20 hydrophilic compound to 0.1 to 500 kGy of radiation to remove the hydrophilic compound.
1 . A method for removing a hydrophilic compound comprising:
step (a) of exposing a composition containing perfluorooctanoic acid and salts thereof (PFOA) to 1.0 to 15 kGy of radiation in the air at room temperature, thereby removing the PFOA from the composition,
wherein the composition is a polytetrafluoroethylene (PTFE) powder or pellet containing the PFOA,
the PFOA content of the composition before exposure to said radiation in the step (a) is more than 1 ppm to 1% by mass, and
the PFOA content of the composition after exposure to said radiation in the step (a) is less than 25 ppb by mass.
2 . The method according to claim 1 ,
wherein the PTFE in the PTFE powder is PTFE consisting of tetrafluoroethylene units only or the PTFE including a tetrafluoroethylene unit and 0.0001 to 0.5% by mass of a modifying monomer unit based on mass of all the monomer units.