title: Efficient and Selective Uptake of TcO4-by a Cationic Metal-Organic Framework Material with Open Ag+Sites.
abstract: 99Tc is one of the most problematic radioisotopes in used nuclear fuel owing to its combined features of high fission yield, long half-life, and high environmental mobility. There are only a handful of functional materials that can remove TcO4-anion from aqueous solution and identifying for new, stable materials with high anion-exchange capacities, fast kinetics, and good selectivity remains a challenge. We report here an 8-fold interpenetrated three-dimensional cationic metal-organic framework material, SCU-100, which is assembled from a tetradentate neutral nitrogen-donor ligand and two-coordinate Ag+cations as potential open metal sites. The structure also contains a series of 1D channels filled with unbound nitrate anions. SCU-100 maintains its crystallinity in aqueous solution over a wide pH range from 1 to 13 and exhibits excellent β and γ radiation-resistance. Initial anion exchange studies show that SCU-100 is able to both quantitatively and rapidly remove TcO4-from water within 30 min. The exchange capacity for the surrogate ReO4-reaches up to 541 mg/g and the distribution coefficient Kdis up to 1.9 × 105mL/g, which are significantly higher than all previously tested inorganic anion sorbent materials. More importantly, SCU-100 can selectively capture TcO4-in the presence of large excess of competitive anions (NO3-, SO42-, CO32-, and PO43-) and remove as much as 87% of TcO4-from the Hanford low-level waste melter off-gas scrubber simulant stream within 2 h. The sorption mechanism is well elucidated by single crystal X-ray diffraction, showing that the sorbed ReO4-anion is able to selectively coordinate to the open Ag+sites forming Ag-O-Re bonds and a series of hydrogen bonds. This further leads to a single-crystal-to-single-crystal transformation from an 8-fold interpenetrated framework with disordered nitrate anions to a 4-fold interpenetrated framework with fully ordered ReO4-anions. This work represents a practical case of TcO4-removal by a MOF material and demonstrates the promise of using this type of material as a scavenger for treating anionic radioactive contaminants during the nuclear waste partitioning and remediation processes.
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Daopeng
authors.initials: D
authors.lastname: Sheng
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Nuclear Chemistry and Chemical Engineering Division, Institute of Nuclear and New Energy Technology, Tsinghua University , Beijing 100084, China.
authors.forename: Chao
authors.identifier: 0000-0001-5539-4754
authors.initials: C
authors.lastname: Xu
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Xiao
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Yaxing
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Lanhua
authors.initials: L
authors.lastname: Chen
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Juan
authors.initials: J
authors.lastname: Diwu
authors.affiliation: Nuclear Chemistry and Chemical Engineering Division, Institute of Nuclear and New Energy Technology, Tsinghua University , Beijing 100084, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Chai
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , 95 Chieftain Way, Tallahassee, Florida 32306, United States.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Albrecht-Schmitt
authors.affiliation: School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University , 215123, Suzhou, P. R. China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123, Suzhou, P. R. China.
authors.forename: Shuao
authors.identifier: 0000-0002-1526-1102
authors.initials: S
authors.lastname: Wang
mesh_terms: D000838:Anions; D002412:Cations; D008670:Metals; D009566:Nitrates / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000838:Anions; D002412:Cations; D008670:Metals; D009566:Nitrates