Preparation of polyacrylonitrile-based nanofiber mats by electrospinning for uranium recovery

BACKGROUND: Seawater mining of uranium in a sustainable manner is an emerging approach to meet long-term nuclear energy requirements. Amidoxime-functionalized polymers are of particular interest because of their high binding affinity for uranyl ions. Nevertheless, their low reusability and low mechanical stability make them impractical. This study discusses the preparation and performance evaluation of amidoxime-functionalized electrospun polyacrylonitrile (PAN) and polyurethane (PU) nanofiber mats as adsorbents for uranium (VI) adsorption. RESULTS: PAN and PU blends were electrospun into composite nanofiber mats, which were amidoximated for nitrile groups. Structural, morphological, and thermal analyses were carried out by FT-IR, SEM, XRD, TGA, and DSC analyses. Amidoxime conversion was established by FT-IR with 94% efficiency. Uranium adsorption experiments in pH 4.1 and 25 °C conditions showed the maximum capacity of 435 mg g⁻¹ for PU-PAO nanofibers. Although pure PAO mats had a slightly higher capacity (495 mg g⁻¹), they could not be recycled easily. This contrasts with PU-PAO mats, which did not lose their integrity and could be cycled up to six times without losing their performance substantially. CONCLUSION: PU addition improved mechanical stability and handleability without compromising the high adsorption capability of amidoxime-functionalized nanofibers. These findings validate the use of PU-PAO composite nanofibers as efficient and sustainable adsorbents for uranium recovery from aqueous systems, like seawater. Their performance vs. durability ratio presents a promising direction towards industrially viable and scalable uranium recovery technologies.