Effect of salts and pH on the removal of perfluorooctanoic acid (PFOA) from aqueous solutions through precipitation and electroflocculation

Abstract

This study shows that salt type and pH affect the removal of perfluorooctanoic acid (PFOA) from water through flocculation and electro-enhanced flocculation. PFOA concentrations decreased by approximately 80% with 20 mM FeCl 3 and initial pH = 3–10. Electro-enhanced flocculation at pH = 3 reduced PFOA concentrations in water by approximately 70% with CaCl 2 and KCl, and by 50% with NaCl. At alkaline pH, PFOA removal was approximately 20% with CaCl 2 and KCl. PFOA removal was negligible without salts or with AlCl 3 , and with NaCl at alkaline pH. Differences in PFOA removal are likely due to the settling behaviour of the cation-PFOA complexes formed.