Extraction and recovery of Hg(II) from the aqueous, alkaline nuclear wastes stored in the Savannah River site (SRS) is a challenging issue. Although not a fission product, Hg is present in the high level nuclear waste because it is used as a catalyst for the dissolution of U-Al alloy. We have synthesized a highly lipophilic, tripodal pyrazolyl ligand (C42H42N6), stable in alkaline medium, with three soft pyrazole N-donor atoms expecting that this ligand will be highly effective for the extraction of Hg out of the aqueous solution in both high activity and low activity radioactive waste. A 1D polymer of the tripodal ligand with Hg(II) was synthesized by reaction in ambient conditions and an appropriate solvent, such as CH2Cl2 or acetone, and characterized by single crystal X-ray diffraction and standard spectroscopic techniques. Other pyrazole-based ligands (pzH) can also be effectively used to bind/extract Hg from different sources: three new mercury-pyrazolato compounds, [pndp-pzHgCH2COCH3]; C18H11N7HgO11, [Hg2Cl2(3,5-Me2-4-NO2-pz)3(Et3NH)]; C21H34N10Hg2O6, and [Hg2(3-NO2-pz)3; C5H4N3Cl2Hg2.5O4 were synthesized and characterized by single crystal X-ray diffraction and standard spectroscopic techniques. The results of Hg(II) extraction by these ligands into an organic phase will be discussed.

Pyrazole-based ligands for complexation, extraction and recovery of Hg(II) from nuclear waste

255th National Meeting (2018)

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