Sponge-inspired reassembly of 3D hydrolyzed collagen aerogel with polyphenol-functionalization for ultra-capturing iodine from airborne effluents

Abstract

The efficient capture of radioactive iodine (I-129, I-131) and radon (Rn-222) is crucial to the development of nuclear energy in spent fuel treatment. Herein, we successfully synthesized a new type of three-dimensional hydrolyzed collagen aerogel immobilized with catechin (Catechin@3DCF aerogel) as an effective adsorbent to remove iodine and radon through enzymatic hydrolysis, dialysis, freeze-drying, immobilization, and cross-linking. The as-prepared adsorbent was systematically characterized by FE-SEM, EDX, FT–IR, and XPS, showing that the adsorbent possesses ultra-high porosity, high content flake structure, and abundant adsorption sites on the surface of adsorbent. The results show that Catechin@3DCF aerogel exhibited excellent capture capacity for iodine and radon, with the maximum capture capacity of 222.67 wt% (88.5 wt% for 3DCF aerogel) and 44,877.9 Bq/Kg, respectively. Through the active group-shielding experiment analysis, the phenolic hydroxyl groups on the surface of adsorbent played a major role in iodine capture, followed by the -NHR group. In addition, mechanism studies have shown that the capture of iodine is mainly by chemical adsorption, while the capture of radon is mainly through physical adsorption, which is related to the numerous mesopores and flake structure of the adsorbent. Furthermore, Catechin@3DCF aerogel still maintains excellent adsorption capacity for iodine and radon under 60Co γ-ray irradiation at a total dose ranging from 10 to 350 kGy, indicating that it has excellent radiation resistance stability. Advantages such as novelty, ultra-high porosity, high-radiation stability, ultra-high capture capacity, environment-friendly, and low-cost indicate that biomass-derived Catechin@3DCF aerogel plays a role in the capture of radioactive iodine and radon from airborne effluents.