Cross-linked polymeric ammonium salts and their use in absorbing organic contaminants

A method for absorbing at least one or more PFAS molecules from an aqueous medium wherein said at least one or more PFAS molecules comprise water soluble fluorinated amphiphilic structures with carbon chain lengths ranging from 4 to 14 carbon atoms which comprises contacting said PFAS molecules with at least one crosslinked polymeric ammonium salt, or a mixture of said crosslinked polymeric ammonium salts, wherein in said salts about 25% or more of the groups which link ammonium nitrogen atoms are group Y, wherein Y is an n-alkylene group or alkyl substituted n-alkylene aroup, wherein said n-alkylene group or said alkyl substituted n-alkylene group has from 2 to about 20 carbon atoms;

• from zero to about 75% of the groups which link ammonium nitrogen atoms are group Z, wherein Z is a hydrocarbylene radical containing from 2 to 50 carbon atoms, said hydrocarbylene radical optionally containing or substituted with one or more hydroxyl, ether, amino. thioether, keto, ester, silyl group or heterocyclic rings;
• and about 25% or more of the ammonium nitrogen atoms are secondary ammonium nitrogen atoms with the result that said PFAS molecules are absorbed into said at least one crosslinked polymeric ammonium salt, or into a mixture of said crosslinked polymeric ammonium salts.