Synergistic dual-layer active interface Ag⁰-HA@ACF composite for highly efficient and specific capture and immobilization of iodine vapor

Dual-layer Ag 0 -HA@ACF enables rapid iodine capture and durable immobilization. • HA-driven in situ reduction achieved 21.58 wt% uniformly dispersed Ag 0 loading. • Ag 0 -HA@ACF achieves 1934.7 mg/g iodine uptake, surpassing most Ag-based adsorbents. • DFT revealed strong chemisorption of I 2 on Ag 0 (−3.880 eV) with AgI formation. A dual-layer active interface synergistic strategy was innovatively developed to address the critical challenge of efficient capture and immobilization of radioactive iodine vapor during spent fuel reprocessing. Humic acid (HA)-grafted activated collagen fiber (ACF) was constructed as a rapid induced adsorption layer, while nanoscale zero-valent silver (21.58 wt%) was in situ immobilized through HA-assisted chelation/double reduction combined with NaBH 4 reduction, forming a specific chemical immobilization layer. The resulting Ag 0 -HA@ACF composite exhibited an outstanding iodine-vapor uptake of 1934.7 mg/g and achieved 81.2% of its saturated capacity within 6 h, outperforming most reported silver-based adsorbents. FT-IR, XPS, and DFT analyses systematically revealed the synergistic “induced adsorption–specific immobilization” mechanism, where phenolic hydroxyl and amino groups promoted rapid I 3 ⁻ formation, while nanoscale Ag 0 converted iodine into thermally stable AgI. Moreover, DFT calculations revealed a strong chemisorption interaction between Ag 0 and I 2 , with an adsorption energy of − 3.880 eV. Owing to its facile preparation and scalability, this material provides a promising strategy for radioactive iodine management. Download: Download high-res image (124KB) Download: Download full-size image