Hierarchical porous cellulose monolith prepared by thermally induced phase separation for high-efficiency uranium adsorption

The development and application of new and efficient adsorption materials are key issues in the treatment of nuclear wastewater. This paper introduces a novel hierarchical porous amidoxime cellulose monolith synthesized through thermally induced phase separation (TIPS). The inherent hydrophilicity of cellulose, combined with the graded porous structure achieved through TIPS (with a specific surface area of 10.36 m2/g), endows the material with strong mass transfer ability. The adsorption properties of this amidoxime cellulose monolith for uranyl ions were evaluated in both batch and flow-through column adsorption scenarios. Remarkably, the adsorption saturation was achieved within a concise period of 13 h in batch adsorption. The hierarchical porous structure of the amidoxime cellulose monolith exhibited exceptional adsorption performance for uranyl ion, achieving a removal rate of 99.99 %. Moreover, this removal rate was sustained for 200 min, and the monolith proved recyclable for at least 5 cycles in flow-through column adsorption tests involving nuclear wastewater. When used for adsorption in real wastewater environments, the material achieved the removal of over 99.96 % of total α and β radioactivity. These findings underscore the high efficiency of the newly developed hierarchical porous amidoxime cellulose monolith in uranyl ion adsorption. They emphasize its substantial potential for the efficient adsorption and removal of uranyl ion from nuclear wastewater.