We investigate the adsorption of hexavalent uranium, U(VI), on phosphorylated cellulose nanofibers (PHO-CNF) and compare the results with those for native and TEMPO-oxidized nanocelluloses. Batch adsorption experiments in aqueous media show that PHO-CNF is highly efficient in removing U(VI) in the pH range between 3 and 6. Gelling of nanofiber hydrogels is observed at U(VI) concentration of 500 mg/L. Structural changes in the nanofiber network (scanning and transmission electron microscopies) and the surface chemical composition (X-ray photoelectron spectroscopy) gave insights on the mechanism of adsorption. The results from batch adsorption experiments are fitted to Langmuir, Freundlich, and Sips isotherm models, which indicate a maximum adsorption capacity of 1550 mg/g, the highest value reported so far for any bioadsorbent. Compared to other metals (Zn, Mn, and Cu) and typical ions present in natural aqueous matrices the phosphorylated nanofibers are shown to be remarkably selective to U(VI). The results suggest a solution for the capture of uranium, which is of interest given its health and toxic impacts when present in aqueous matrices.

我们研究了六价铀U（VI）在磷酸化纤维素纳米纤维（PHO-CNF）上的吸附，并将结果与​​天然和TEMPO氧化的纳米纤维素的结果进行了比较。在水性介质中的分批吸附实验表明，PHO-CNF在3至6的pH范围内能高效去除U（VI）。在500 mg / L的U（VI）浓度下观察到纳米纤维水凝胶的凝胶化。纳米纤维网络的结构变化（扫描和透射电子显微镜）和表面化学成分（X射线光电子能谱）提供了有关吸附机理的见解。批吸附实验的结果适用于Langmuir，Freundlich和Sips等温模型，表明最大吸附容量为1550 mg / g，这是迄今为止任何生物吸附剂的最高值。与天然水基质中存在的其他金属（锌，锰和铜）和典型离子相比，磷酸化纳米纤维对U（VI）的选择性显着。结果提出了一种铀捕获的解决方案，考虑到它在水性基质中的健康和毒性影响，因此引起人们的关注。