Extraction of natural radionuclides from aqueous solutions by novel maltolate-based task-specific ionic liquids

Two novel maltol-based ionic liquids, namely [A336][Mal] and [C101][Mal], were synthesized as potential extracting agents for radionuclides from water. These two room temperature task-specific ionic liquids could be easily prepared by anion metathesis starting from commercially available materials. The isolated compounds were characterized by standard analytical methods. Their application as extraction agent for U_nat., ²³⁴Th, ²¹⁰Pb, ²¹⁰Bi, ²¹⁰Po and ²²⁶Ra was elucidated by liquid–liquid extraction and scintillation counting. Uranium was totally extracted by both ionic liquids over a broad pH range (2–8), while the other radionuclides were removed with differing efficacies depending on the respective pH value.