New dendritic ionic liquids (DILs) for the extraction of metallic species from water

Abstract

Four dendritic ionic liquids (DILs) have been easily synthesized from 3rd generation PAMAM and PPI: PAMAM G3 NH₃⁺ Tf₂N⁻ (1), PPI G3 NH₃⁺ Tf₂N⁻ (2), PPI G3 NH₂ Me⁺ BF₄⁻ (3) and PAMAM G3 NH₂ Me⁺ BF₄⁻ (4). These DILs are fully characterized by spectroscopic methods (¹H, ¹³C and ¹⁹F NMR) and elemental analysis. Compound 1 is hydrophobic while compounds 2–4 are hydrophilic. In order to apply these DILs for the extraction of aqueous metallic cations (Cu²⁺, Ni²⁺, Pb²⁺, Cd²⁺, and Ag⁺), liquid–liquid extraction and dialysis were performed. ICP technology has been used to reveal the amount of metallic cation that has been extracted. Compound 1 shows the best results especially for the extraction of Cu²⁺, Pb²⁺ and Ag⁺ cations (up to 98%). Two processes have been employed: liquid–liquid extraction and dialysis.