In situ chemical oxidation-grafted amidoxime-based collagen fibers for rapid uranium extraction from radioactive wastewater

The development of an amidoxime (AO)-based biomass adsorbent offers a solution for uranium extraction from radioactive wastewater and seawater. It also provides a strategy for realizing environmental safety and resource sustainability. Here, an AO-based collagen fiber (CF) adsorbent (AO-CF) was fabricated via in situ oxidative grafting. The fibrous morphology enables AO-CF to realize faster adsorption rate and higher adsorption capacity. During batch adsorption, the adsorption capacity of AO-CF was 0.877 mmol g−1 (234.16 mg g−1) at 318 K and pH 5.0 when the initial concentration of UO22+ was 2.5 mmol/L, while the adsorption capacity of AO-CF at pH 8.2 was 1.128 mmol g−1 (301.18 mg g−1). Moreover, AO-CF exhibited high selectivity for UO22+ in bilateral mixed solutions, including NH4+, Zn2+, Cr3+, Mg2+, Al3+, Ca2+, Ni2+, Ba2+, and Sr2+. Furthermore, AO-CF demonstrated higher adsorption capacity of UO22+ than its major competing element, namely, VO2+, in seawater. The adsorption behavior of UO22+ in the nuclear fuel preparation wastewater on the AO-CF column showed that the breakthrough point was approximately 175.0 bed volume (BV), and the AO-CF column could be rapidly regenerated by using only 3.0 BV of 0.1 mol/L HCl solution, indicating excellent reapplication ability. This work presents a new technology for the synthesis of highly efficient adsorbents for the recovery of UO22+ from radioactive wastewater.