The simultaneous removal and selective separation of U(VI) and Th(IV) via adsorption remain challenging due to their strong mobility, reactivity, and similar chemical properties. Thus, a surface-functioned lignin nanoparticle (AL-PEI) was synthesized to adsorb U(VI)/Th(IV) in a unitary system via a pH-dependent process. In alkaline solution, AL-PEI exhibited excellent adsorption performance, and the maximum adsorption capacities for U(VI) and Th(IV) reached 392 and 396 mg/g, respectively. Discrepantly in acidic solution, the adsorption performance of AL-PEI for U(VI) could still reach a high capacity (332 mg/g), whereas highly limited adsorption capacity (less than 40 mg/g) for Th(IV) was obtained, and the separation factor of U(VI) from U(VI)-Th(IV) matrix significantly reached 6662 in 3 M of the HNO₃ medium. The simultaneously efficient adsorption in alkaline solution and highly selective separation performance in acidic solution of AL-PEI also showed excellent anti-ions interference capacities, high reusability, and strong stability. This study is the first to apply lignin fabricating radiation-resistant adsorbent material, and the adsorbent displays good performance for U(VI)/Th(IV) removal and selective separation via a novel pH-dependent process, which is important to the green and sustainable development of nuclear energy and environmental protection.

由于 U(VI) 和 Th(IV) 具有很强的流动性、反应性和相似的化学性质，因此通过吸附同时去除和选择性分离 U(VI) 和 Th(IV) 仍然具有挑战性。因此，合成了表面功能化的木质素纳米颗粒 (AL-PEI)，以通过 pH 依赖性过程在单一系统中吸附 U(VI)/Th(IV)。在碱性溶液中，AL-PEI表现出优异的吸附性能，对U(VI)和Th(IV)的最大吸附容量分别达到392和396 mg/g。不同的是，在酸性溶液中，AL-PEI 对 U(VI) 的吸附性能仍然可以达到高容量 (332 mg/g)，而对 Th(IV) 的吸附容量非常有限（小于 40 mg/g） , 并且 U(VI) 与 U(VI)-Th(IV) 基质的分离因子在 3 M 的 HNO _{3中显着达到 6662}中等的。同时，AL-PEI在碱性溶液中的高效吸附和酸性溶液中的高选择性分离性能也表现出优异的抗离子干扰能力、高重复使用性和强稳定性。该研究首次应用木质素制备耐辐射吸附材料，该吸附剂通过一种新型的 pH 依赖性工艺去除 U(VI)/Th(IV) 和选择性分离表现出良好的性能，这对绿色和可持续发展具有重要意义。核能可持续发展与环境保护。