Irradiation-stable hydrous titanium oxide-immobilized collagen fibers for uranium removal from radioactive wastewater

Developing efficient adsorbents with radiation stability for uranium removal from nuclear wastewater is greatly important for resource sustainability and environmental safety in manufacturing nuclear fuel. A novel adsorbent of hydrous titanium oxide-immobilized collagen fibers (HTO/CFs) with good radiation stability for UO₂²⁺ removal was developed. Results showed that the adsorption capacity of HTO/CFs for UO₂²⁺ was 1.379 mmol g^-1 at 303 K and pH 5.0 when the initial concentration of UO₂²⁺ was 2.5 mmol L^-1. Moreover, HTO/CFs showed high selectivity for U(VI) in bilateral mixed solution including UO₂²⁺ with another coexisting ion, such as Cl^-, NO₃^-, Zn²⁺, and Mg²⁺. The adsorption behavior of UO₂²⁺ from radioactive wastewater on HTO/CF column was also investigated, and the breakthrough point was approximately 250 BV (bed volume). Notably, the HTO/CFs column can be rapidly regenerated by using only 4.0 BV of 0.1 mol L^-1 HNO₃ solution. The regenerated HTO/CFs column exhibited slight change in the breakthrough curve, suggesting its excellent reapplication ability. Furthermore, after irradiation under ⁶⁰Co γ-ray at total doses of 10-350 kGy, HTO/CFs still preserved fibrous morphology and adsorption capacity, indicating significant radiation stability. These results demonstrate that HTO/CFs are industrial scalable adsorbents for the adsorptive recovery of uranium.