Interfacial Engineering Improved the Selective Extraction of Uranyl from Saline Water by Nano-Mg(OH)2 and the Underlying Mechanism

Abstract

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 engender...