Cellulose-Derived Nanomaterials for Affordable and Rapid Remediation of Uranium in Water

Due to its long half-life of 4.5 billion years and inherent toxicity, uranium is an important radioactive pollutant, necessitating effective methods for its removal from water, although its chemical toxicity is more significant. Adsorption using advanced materials is emerging as an affordable and sustainable approach for the removal of soluble uranium, principally in the form of UO22+, a major concern in several water sources in India and other parts of the world. This study is a comparative investigation of the adsorption capabilities of two phosphorylated cellulose-reinforced iron oxyhydroxide composites, namely, nano- and microstructures and their potential use in removing UO22+ from water. Results indicate that cellulose nanostructures exhibit superior efficiency compared to the corresponding microstructures for UO22+ adsorption, with equilibrium achieved within 2 min of exposure. Green synthesis of the composite produces particulate media with excellent structural integrity. Furthermore, it exhibits rapid adsorption dynamics despite the presence of competing ions in water. It also exhibits high uranium extraction efficiency over a broad pH range and exhibits outstanding regeneration performance. Various analytical techniques, including XRD, SEM, HRTEM, XPS, TGA, and FT-IR, were employed to investigate the structure of the composites and their interactions with uranium. We find that UO22+ binds through oxygen and phosphorus functional groups of the material. We evaluated various sustainability metrics to assess the ecological impact of the composite and its synthesis process. We demonstrate the potential of the developed adsorbent as a highly efficient and sustainable method for uranium removal from water.