Conjugated microporous polymers bearing phosphonate ligands as an efficient sorbent for potential uranium extraction from high-level liquid wastes
Conjugated microporous polymers bearing phosphonate ligands as an efficient sorbent for potential uranium extraction from high-level liquid wastes
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DOI：
10.1039/c8ta02875c
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发表时间：
2018-07
影响因子：
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通讯作者：
Meiyun Xu;Xiaoli Han;Tao Wang;Shenhua Li;D. Hua
中科院分区：
文献类型：
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作者：
Meiyun Xu;Xiaoli Han;Tao Wang;Shenhua Li;D. Hua
从高放废液中回收铀对可持续核能至关重要。然而，固有的高酸度、强放射性和大量的核裂变产物是高效从高放废物中提取铀的主要挑战。在这项工作中，报告了一种新的方法，潜在的从高放废物中提取铀，使用含乙基磷酸酯配体的共轭微孔聚合物(CMPS)作为吸附剂。以1，3，5-tris(4，4，5，5-tetramethyl-1，3，2-dioxaborolan-2-yl)benzene和2，7-二溴-9，9‘-二(丙基膦酸二乙酯)荧烷为原料，经Suzuki偶联反应制得比表面积为58.2m2 g−1的化学机械抛光电极。高分辨电子显微镜和扫描电子显微镜表征表明，化学机械抛光-极压片具有重叠的片状形貌。吸附前后CMP-EP的XPS深度剖面图证实，铀的吸附发生在材料的孔内。在6M HNO3溶液中，MP-EP对铀(VI)离子表现出良好的结合选择性，吸附能力高达73mgU/g，且在碱性溶液中再生时具有良好的吸附重复使用性能。由于其刚性的π共轭骨架，γ-EP在6M HNO3中经1000kGy射线照射后，其结构、吸附容量和选择性没有显著变化。通过XPS和FTIR研究了吸附机理，发现铀酰离子在6M HNO3中形成UO2(NO3)2等络合物，并与膦酸类配体上的PO基团结合。这项工作是第一个使用功能性CMP作为吸附剂从高放废物中有效地回收铀的例子。
Recovery of uranium from high-level liquid wastes (HLWs) is of vital importance for sustainable nuclear energy. However, inherent high acidity, strong radioactivity and massive nuclear fission products are the major challenges for efficient extraction of uranium from HLWs. In this work, a new approach is reported for potential uranium extraction from HLWs using conjugated microporous polymers (CMPs) bearing ethylphosphate ligands (CMP-EP) as sorbents. CMP-EP with a BET surface area of 58.2 m2 g−1 is prepared by the Suzuki coupling reaction of 1,3,5-tris(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene and 2,7-dibromo-9,9′-bis(diethyl propylphosphonate)fluorene. HRTEM and SEM characterization shows that CMP-EP sheets possess an overlapping flaky morphology. The uranium sorption arises inside the pores of the material as confirmed by depth-profiling XPS of CMP-EP before and after adsorption. CMP-EP exhibits excellent binding selectivity for uranium(VI) ions with a high sorption capability of 73 mg U per g in 6 M HNO3 solutions, and outstanding reusability for adsorption when regenerated with alkaline solutions. Thanks to its rigid π-conjugated skeleton, the CMP-EP after γ-ray irradiation of 1000 kGy in 6 M HNO3 shows no dramatic changes in structure, sorption capacity and selectivity. The sorption mechanism is studied by XPS and FTIR measurements revealing that uranyl ions tend to form complexes such as UO2(NO3)2 in 6 M HNO3, and then bind to PO groups of phosphonate ligands. This work represents the first example for effective recovery of uranium from HLWs using functional CMPs as sorbents.