Zanyong Zhuang,Xinwen Ou,Jingyuan Li,Yuan Zhou,Zhihong Zhang,Shengfa Dong,Zhang Lin
Abundant salts and complex constituents pose challenges to the enrichment of trace-level uranyl from field water samples. On the basis of the chemical behavior of the uranyl cation in several physical–chemical conditions (in the presence of MgCl2 etc.), we developed a facile and green strategy to improve the uranyl extraction from field water samples, different from the traditional way with organic impregnation. In our systems about nano-Mg(OH)2 treating salt lake brine, when the adsorbent is pretreated with a trace amount of UO22+ ion, the ability to extract uranyl from brine can increase by 2–5 times. The molecular dynamics simulation and time-resolved laser-induced fluorescence spectroscopy analysis show that, in the preadsorption stage, UO22+ ions can steadily bind to the Mg(OH)2 (001) surface because of the interaction with surface hydroxyl groups. When pretreated Mg(OH)2 was exposed to brine, the coordination interaction between the preloaded UO22+ ion and the [UO2(CO3)x(2x–2)–] in solution engenders good selectivity and affinity for uranyl over competitive ions in brine. Besides, the coordination number of UO22+ by carbonate oxygen is large, which further facilitates subsequent adsorption. Such strategy does not introduce other impurities and can apply to metal-oxides-type adsorbents, e.g., TiO2. This study should shed light on further improvement of efficient uranyl extraction from field samples and give insights into the mechanism understanding of uranyl adsorption in real systems.
Tao Gai,Yingru Li,Hao Tang,Rui Li,Lang Shao,Yunfeng Du,Yiming Ren
In this paper, a kind of graphene gel loading TBP inside, named as G-TBP-Gel was prepared via by mildly reducing the graphene oxide (GO) sheets in TBP/GO/water emulsion using ascorbic acid , which is facile and time-consuming. The G-TBP-Gel was constructed by approximately spherical pores built by reduced graphene oxide (rGO) sheets disorderly. The TBP droplets are fixed in the pores, and the total volume of TBP occupies nearly 90% volume of the G-TBP-Gel. We studied the capacities and distribution ratios of G-TBP-Gel in the application of uranium extraction under different conditions. Moreover, the G-TBP-Gel could be easily separated from the aqueous phase due to the fixation of the TBP. The residual oxygenated groups on the rGO sheets construct a network of water nano-channels, via which uranyl migrates in the process of extraction or stripping. Compared with traditional liquid-liquid extraction, the rates of extraction or stripping are much slower due to the structural factors, which still need promotion in the future.
危险品化学品经营许可证（带存储）