Efficient capture of Tc/Re(VII, IV) by a viologen-based organic polymer containing tetraaza macrocycles
Efficient capture of Tc/Re(VII, IV) by a viologen-based organic polymer containing tetraaza macrocycles
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DOI：
10.1016/j.cej.2019.122581
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发表时间：
2020-01-15
影响因子：
15.1
通讯作者：
Xia, Chuanqin
中科院分区：
文献类型：
--
作者：
Ding, Mu;Chen, Lang;Xia, Chuanqin
TC-99是一种裂变产额高、半衰期长的β放射性核素，由于其对人体的潜在毒性，迫切需要从液体放射性废物中去除TC。因此，我们提出了一种基于紫精的阳离子有机聚合物(VBCOP)，作为一种新型的具有阳离子中心和官能团的吸附剂，可以有效地从水介质中捕获Re/Tc(VII，IV)。结果表明，该材料能在5min内快速去除水溶液中的TcO4-/ReO4-，对Re(Vi)的最大吸附容量可达444 mg g(-1)，对Re(Vi)和Tc(Vi)的分配系数(K-d)分别为4.0×10(5)和7.2×10(5)mLg(-1)。用X射线光电子能谱(XPS)、能谱仪(EDS)和离子色谱仪(IC)对吸附机理进行了研究，结果表明材料中的氯离子被ReO4-取代。此外，我们还研究了它对用NaBH4还原ReO4-制备的低价Re的吸附机理，并通过X射线光电子能谱(XPS)和扩展X射线吸收精细结构(EXAFS)分析证实了与Re(IV)络合的材料中引入的柔性四氮杂大环。总体而言，本研究展示了一种既能去除TeO4/ReO4-，又能去除低价Tc/Re的新型吸附材料，为处理不同价态的含Tc放射性废物提供了一种新的策略。
Tc-99 is a beta-emitting radionuclide with high fission yield, long half-time and it is urgent to remove Tc from liquid radioactive waste due to its potential toxicity for human. Herein, we presented a viologen-based cationic organic polymer (VBCOP) as a novel adsorbent with cationic sites and functional groups for efficient capture of Re/Tc (VII, IV) from aqueous medium. The results showed that this material could rapidly remove TcO4-/ReO4- from aqueous solution within 5 min and the maximum sorption capacity for Re(VII) could reach up to 444 mg g(-1), and the distribution coefficient (K-d) towards Re(VII) and Tc(VII) reached 4.0 x 10(5) and 7.2 x 10(5) mL g(-1), respectively. And more, the adsorption mechanism was also studied by X-ray photoelectron spectroscopy (XPS), Energy dispersive spectrometer (EDS) mapping and Ion chromatography (IC), the results suggested an ion-exchange process in which the Cl- in this material was replaced by ReO4-. Additionally, we investigated its adsorption mechanism towards low-valent Re which was prepared by reducing ReO4- with NaBH4, and the flexible tetraaza macrocycle introduced in the material chelated with Re(IV) was confirmed by X-ray photoelectron spectroscopy (XPS) and Extended X-ray absorption fine structure (EXAFS) analysis. In general, the research exhibits a new sorbent material that can remove both TeO4/ReO4- and the low-valent Tc/Re, and provide a new strategy to treat radioactive waste containing Tc with different valences.