Achieving efficient uranium extraction by in situ ultrasonic texturization of commercial Fe powder

Abstract

The widespread presence of fluorinated nuclear effluent (F⁻) in the nuclear fuel cycle encourages the efficient extraction of hexavalent uranium (U(VI)) under interference by F⁻. Nano zero-valent iron (n-ZVI) is a promising material for U(VI) extraction but it suffers from labor-intensive production and storage procedures. Herein, we reported on the in situ ultrasonic texturization of commercial Fe powder for U(VI) extraction in F⁻-containing wastewater to replace n-ZVI. At various molar ratios of F⁻/U(VI), the uranium extraction efficiency of commercial Fe powder under ultrasonic conditions remained at a high value of >90% within 120 min. Moreover, the ultrasonic texturization of commercial Fe powder made it applicable in a wide pH range from 2 to 9, which remarkably outperformed a reported n-ZVI sample at pH < 4. Mechanistic studies revealed that the Kirkendall effect of the reduction reaction and mechanical disturbance by the ultrasonication induced the surface texturization of the commercial Fe powder, leading to the in situ construction of n-ZVI and thus continually providing reduction sites for U(VI).