Rice husk cellulose/sodium alginate/gelatin hydrogels: Sustainable high-performance trapping and immobilization of iodine vapor.

Efficient capture of radioactive iodine vapor during nuclear fuel reprocessing remains a critical challenge in nuclear cycle operations. To address this challenge, a hydrogel adsorbent (designated CSAG) has been synthesized via an aqueous-phase process using cellulose derived from agricultural waste (rice husks), sodium alginate, and gelatin as precursors. The optimized CSAG-50 formulation, with a 5:5 mass ratio, exhibits exceptional iodine adsorption performance, achieving a remarkable capacity of 2485.5 mg/g at 85 °C. Comprehensive characterization reveals that CSAG-50 possesses a distinctive wrinkled microstructure, which significantly enhances iodine retention efficiency. Kinetic analyses indicate that the adsorption process involves both physical diffusion and chemical interactions. The superior adsorption performance arises from enhanced capillary forces and mechanical resilience. Thermogravimetric analysis confirms the material's satisfactory thermal stability under moderate temperature conditions. Cycling performance tests demonstrate that CSAG-50 retains 42.5% of its initial adsorption capacity after three consecutive adsorption-desorption cycles, indicating robust reusability. The successful development of this fully bio-based CSAG hydrogel system represents a significant advancement in sustainable materials for nuclear waste management, while providing an environmentally compatible solution for radioactive iodine containment in nuclear industry applications.