Method for recovering fluorinated emulsifier
View Patent ↗To provide a method for recovering, from a liquid to be treated containing a fluorinated polymer and a fluorinated emulsifier, the fluorinated emulsifier easily and efficiently. A liquid to be treated containing a fluorinated polymer and a fluorinated emulsifier, and a strongly basic anion exchange resin having an ion exchange capacity of at most 1.0 eq/L and a water content of at least 60 mass %, are brought into contact with each other, so that the fluorinated emulsifier is adsorbed on the strongly basic anion exchange resin, whereby the fluorinated emulsifier is recovered from the liquid to be treated.
1. A method comprising:
bringing a liquid comprising a fluorinated polymer and a fluorinated emulsifier and a strongly basic anion exchange resin having an ion exchange capacity of at most 1.0 eq/L and a water content of at least 60 mass % into contact with each other, so that the fluorinated emulsifier is adsorbed on the strongly basic anion exchange resin, to recover the fluorinated emulsifier from the liquid.
2. The method according to claim 1 , further comprising: eluting the fluorinated emulsifier from the strongly basic anion exchange resin after the fluorinated emulsifier is adsorbed on the strongly basic anion exchange resin.
3. The method for according to claim 1 , wherein the liquid is a waste water, obtained by coagulating the fluorinated polymer in the aqueous dispersion comprising the fluorinated polymer and the fluorinated emulsifier to form coagulum and removing the coagulum.
4. The method according to claim 1 , wherein the concentration of the fluorinated emulsifier in the liquid is from 10 to 5,000 ppm.
5. The method according to claim 1 , wherein the ratio of the strongly basic anion exchange resin to the liquid (the strongly basic anion exchange resin/the liquid) is from 1/100 to 1/5,000 by mass.
6. The method according to claim 1 , wherein the fluorinated emulsifier is a fluorinated carboxylic acid, a fluorinated sulfonic acid, a salt of a fluorinated carboxylic acid, or a salt of a fluorinated sulfonic acid.
7. The method according to claim 6 , wherein the fluorinated carboxylic acid is a perfluoroalkylcarboxylic acid or a compound in which an etheric oxygen atom is inserted between carbon atoms in a perfluoroalkylcarboxylic acid.
8. The method according to claim 1 , wherein the counter ion of the strongly basic anion exchange resin is OH − or Cl − .
9. The method according to claim 1 , wherein the strongly basic anion exchange resin has quaternary ammonium groups on its side chains as ion exchange groups.
10. The method according to claim 1 , wherein the average particle size of the strongly basic anion exchange resin is from 0.1 to 5 mm.
11. The method according to claim 1 , wherein the concentration of the fluorinated emulsifier in the liquid is from 10 to 1,000 ppm.
12. The method according to claim 1 , wherein the ratio of the strongly basic anion exchange resin to the liquid (the strongly basic anion exchange resin/the liquid) is from 1/100 to 1/2,000 by mass.
13. The method according to claim 1 , wherein the average particle size of the strongly basic anion exchange resin is from 0.3 to 5 mm.
14. The method according to claim 1 , wherein the ion exchange capacity of the strongly basic anion exchange resin is from 0.7 to 1.0 eq/L.
15. The method according to claim 1 , wherein the ion exchange capacity of the strongly basic anion exchange resin is from 0.8 to 1.0 eq/L.
16. The method according to claim 1 , wherein the water content of the strongly basic anion exchange resin is from 63 to 80 mass %.
17. The method according to claim 1 , wherein the water content of the strongly basic anion exchange resin is from 63 to 75 mass %.
18. The method according to claim 1 , wherein the strongly basic anion exchange resin is a styrene/divinylbenzene crosslinked resin having trimethylammonium groups on a side chain thereof.
19. The method according to claim 1 , wherein the liquid further comprises a suspended solid component.
20. The method according to claim 19 , wherein a treatment of reducing an amount of the suspended solid component in the liquid is not conducted before bringing the liquid and the strongly basic anion exchange resin into contact with each other.