Patent ID: 7795332

Claim:
Method of removing a fluorinated carboxylic acid or salt thereof from an aqueous liquid by contacting the aqueous liquid with adsorbent particles, wherein said fluorinated carboxylic acid or salt thereof is selected from the group consisting of (i) partially fluorinated carboxylic acids or salts thereof corresponding to the general formula: [PF 1 —O-L 1 -COO − ] i X i+ (I) wherein PF 1 represents a linear partially or fully fluorinated aliphatic group or a linear partially or fully fluorinated aliphatic group interrupted with one or more oxygen atoms, L l represents a linear partially fluorinated aliphatic hydrocarbon group, X i+ represents a cation having the valence i and i is 1, 2 or 3; and (ii) fully fluorinated carboxylic acids or salts thereof corresponding to one of the following general formulas: [PF 2 —O—(CF 2 ) p —COO − ] i X i+ (II) wherein PF 2 represents a linear fully fluorinated aliphatic group or a linear fully fluorinated aliphatic group interrupted with one or more oxygen atoms, p is an integer of 2 to 6 and X i+ and i have the same meaning as in formula (I), wherein the anion of said fluorinated carboxylic acids or salts thereof has a molecular weight of not more than 1000 g/mol.