Interaction between environmental contaminant PFOA and PAMAM in water: 19F and 1H NMR studies

Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant with serious negative health effects, and removal of it from water is therefore highly relevant for environmental safety. In this paper, poly(amidoamine) (PAMAM) dendrimers have been proposed as hosts for the PFOA in order to remove it from aqueous solutions. The different aggregate structures for PAMAM-PFOA complexes with increase of -COO-/-NW3+ molar ratios were proposed on the basis NMR titrations using F-19 NMR and further analyzed by the relaxation and diffusion measurements. It is suggested that PFOA micelles are transferred to the bilayer with increasing PAMAM concentration. Moreover, the protonated surface amine groups of PAMAM contribute to reduce the critical aggregation concentration (CAC) of PFOA. The study shows that the main driving force for interaction between PAMAM and PFOA is ionic interaction. This research will serve as a starting-point for removing the fluorinated contamination by using PAMAM dendrimers. (C) 2019 Elsevier B.V. All rights reserved.