Integrating Sulfate with Crown Ether To Construct Supramolecular Radium Traps in an Anionic Zirconium Metal-Organic...

Area of Science:

• Materials Science
• Radiochemistry
• Supramolecular Chemistry

Background:

• Radiotoxic ²²⁶Ra²⁺ poses environmental and health risks due to complex coordination chemistry.
• Effective sequestration requires precise molecular recognition strategies.

Purpose of the Study:

• To engineer a supramolecular trap for targeted ²²⁶Ra²⁺ sequestration.
• To investigate the binding mechanism and efficiency of the designed material.

Main Methods:

• Fabrication of a zirconium metal-organic framework (ZJU-X102-SO₄) integrating a 24-crown-8 ether and sulfate anchor.
• Characterization using single-crystal X-ray diffraction, solid-state NMR, XAFS, and DFT calculations.
• Validation with Ba²⁺ surrogate and testing with ²²⁶Ra²⁺ in various media.

Main Results:

• The ZJU-X102-SO₄ framework demonstrated rapid kinetics and high capacity for Ba²⁺.
• It effectively removed 70% of ²²⁶Ra²⁺ within 10 minutes with a capacity of 3.3 × 10⁴ Bq g^-1.
• High distribution coefficients (5.3 × 10⁴ mL g^-1) were observed in high-salinity media and 3 M HNO₃.

Conclusions:

• A novel supramolecular trap (ZJU-X102-SO₄) was successfully engineered for targeted ²²⁶Ra²⁺ sequestration.
• The dual-recognition design enables efficient capture of ²²⁶Ra²⁺ even in challenging conditions.
• This molecular engineering strategy offers a promising approach for developing advanced sorbents for specific cation removal.