Nuclear chemistry

Yield (engineering)

Metallurgy

Materials science

Solubility

Crystal structure

Radiochemistry

Inorganic chemistry

Physical chemistry

Organic chemistry

Crystallization

Technetium

Aqueous solution

Denticity

Pertechnetate

Crystallography

Chemistry

Benzene

Inorganic Chemistry

99Tc is one of the most abundant radiotoxic isotopes in used nuclear fuel with a high fission yield and a long half-life. Effective removal of pertechnetate (TcO4–) from an aqueous solution is important for nuclear waste separation and remediation. Herein, we report a series of facilely obtained benzene-linked guanidiniums that could precipitate TcO4– and its nonradioactive surrogate ReO4– from a high-concentration acidic solution through self-assembly crystallization. The resulting perrhenate and pertechnetate solids exhibit exceptionally low aqueous solubility. The benzene-linked guanidiniums hold one of the highest TcO4– removal capacities (1279 mg g–1) among previously reported materials and possess a removal percentage of 59% for ReO4– in the presence of Cl– over 50 times. The crystallization mechanism was clearly illustrated by the single-crystal structures and density functional theory calculations, indicating that TcO4– is captured through a charge-assisted hydrogen bonding interaction and stabilized by π–π stacking layers. In addition, the removal process is easily recycled and no toxic organic reagents are introduced. This work provides a green approach to preliminarily separate TcO4– from high-level nuclear wastes.

99TcO4– Separation through Selective Crystallization Assisted by Polydentate Benzene-Aminoguanidinium Ligands