Hierarchically Porous Poly(ionic liquid) - Organic Cage Composite Membrane for Efficient Iodine Capture

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Iodine capture is critical for spent nuclear fuel reprocessing due to iodine's volatility and toxicity.
• Existing methods face challenges in achieving high efficiency and capacity for iodine vapor removal.

Purpose of the Study:

• To develop a hierarchically porous composite membrane for enhanced iodine vapor capture.
• To investigate the structure-performance relationship of the composite membrane for iodine adsorption.

Main Methods:

• Fabrication of a poly(ionic liquid)-organic cage composite membrane (PIL@CC3) with gradient CC3 crystal distribution.
• Characterization of the membrane's porous structure and iodine uptake capacity.
• Evaluation of iodine adsorption performance compared to pristine materials.

Main Results:

• The PIL@CC3 membrane achieved an exceptional iodine uptake capacity of 980 mg/g, significantly outperforming pristine PIL membranes (99 mg/g) and CC3 powder (662 mg/g).
• The hierarchically porous structure (micro-meso-macroporous) facilitated efficient mass transfer and diffusion of iodine molecules.
• Asymmetric distribution of CC3 crystals enhanced the interception of trace iodine.

Conclusions:

• The PIL@CC3 composite membrane offers a highly effective solution for capturing volatile iodine vapor.
• This study presents a novel strategy for designing advanced porous membranes for toxic vapor remediation.