Efficient anion recognition is of great significance for radioactive ⁹⁹TcO₄⁻ decontamination, but it remains a challenge for traditional sorbents. Herein, we put forward a tactic using soft crystalline cationic material with anion-adaptive dynamics for ⁹⁹TcO₄⁻ sequestration. A cucurbit[8]uril-based supramolecular metal-organic material is produced through a multi-component assembly strategy and used as a sorbent for effective trapping of TcO₄⁻. Excellent separation of TcO₄⁻/ReO₄⁻ is demonstrated by fast removal kinetics, good sorption capacity and high distribution coefficient. Remarkably, the most superior selectivity among metal-organic materials reported so far, together with good hydrolytic stability, indicates potential for efficient TcO₄⁻ removal. The structure incorporating ReO₄⁻ reveals that the supramolecular framework undergoes adaptive reconstruction facilitating the effective accommodation of TcO₄⁻/ReO₄⁻. The results highlight opportunities for development of soft anion-adaptive sorbents for highly selective anion decontamination.

Electrorefining process has been widely used to separate and purify metals, but it is limited by deposition potential of the metal itself. Here we report in-situ anodic precipitation (IAP), a modified electrorefining process, to purify aluminium from contaminants that are more reactive. During IAP, the target metals that are more cathodic than aluminium are oxidized at the anode and forced to precipitate out in a low oxidation state. This strategy is fundamentally based on different solubilities of target metal chlorides in the NaAlCl₄ molten salt rather than deposition potential of metals. The results suggest that IAP is able to efficiently and simply separate components of aluminum alloys with fast kinetics and high recovery yields, and it is also a valuable synthetic approach for metal chlorides in low oxidation states.