DFT investigations of uranium complexation with amidoxime-, carboxyl- and mixed amidoxime/carboxyl-based host architectures for sequestering uranium from seawater
Guo, XJ (reprint author), Chinese Acad Sci, Shanghai Inst Appl Phys, Shanghai 201800, Peoples R China.
文章类型:
期刊文献
英文摘要:
Amidoxime-based polyethylene fiber plays an important role in sequestering uranium from seawater. Co-grafting carboxyl groups with amidoxime onto polyethylene fibers can enhance the uranium sorption efficiency. This work aims to theoretically understand the complexation of uranyl with amidoxime-, carboxyl- and mixed amidoxime/carboxyl-based host architectures within a polyethylene fiber. Using density functional theory method, we examined the geometrical structures, the electronic structures and the thermodynamic stabilities of various substitution complexes, as well as the effect of host structure on these complexes. The results showed that the affinity of amidoximate (AO ) for uranyl is similar to that of CO23 , but stronger than that of carboxyl (AA ). For the uranyl complexes with separate mixed amidoximate/carboxyl, the U-O(AO ), U-N(AO ) and U-O(AA ) bonds show the decreasing order of covalent character. However, for the uranyl complexes with mixed amidoximate/carboxyl-based host architectures, the covalent character of U-O(AO ), U-O(AA ) and U-N(AO ) bonds decrease in sequence. HAA is thermodynamically more favorable to react with UO2(CO3)(3)(4) forming a complex than HAO, which is due to the higher dissociation ability of HAA compared to HAO. The dissociated H+ from HAA is conducive for the dissociation of UO2(CO3)(3)(4), which is possibly the origin of the synergistic effects between HAO and HAA in the uranium extraction process from seawater. The host structures have a strong impact on the interaction between uranyl and the amidoxime-, carboxyl-and mixed amidoxime/carboxyl-based host architectures. Comparing all the host architectures, those with -(CH2)(4)- and -(CH2)(3)- as linkages are more appropriate for uranyl together with one CO32 group. (C) 2015 Elsevier B.V. All rights reserved.
DFT investigations of uranium complexation with amidoxime-, carboxyl- and mixed amidoxime_carboxyl-based host architectures for sequestering uranium from seawater.pdf（1169KB）
DFT investigations of uranium complexation with amidoxime-, carboxyl- and mixed amidoxime_carboxyl-based host architectures for sequestering uranium from seawater.pdf
