Functional Dendrimeric “Nanosponges” for the Removal of Polycyclic Aromatic Hydrocarbons from Water

A series of poly(propylene imine) dendrimers functionalized with long aliphatic chains has been prepared and characterized. The property of these dendrimers to encapsulate polycyclic aromatic hydrocarbons from water down to a few ppb level has been established. The inclusion formation constants are orders of magnitude higher than those reported for activated carbon (from 1.4 × 10 4 to 3.4 × 10 5 M - 1 ) or cyclodextrins (10−10 3 M - 1 ) while they are comparable to those of cyclodextrin polymers (from 1 × 10 8 to 5 × 10 9 ). Furthermore, the loading capacities depend on polycyclic aromatic compounds and the type of alkylated dendrimeric derivatives, that is, 6−19 mg/g for fluoanthrene, 44−67 mg/g for phenanthrene, and 34−57 mg/g for pyrene. Regeneration is also feasible using nonpolar solvents.