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.