Efficient uptake of uranium(VI) by a layered manganese thiophosphite intercalated with NH4+

Abstract

Uranium (U), as a basic raw material for the nuclear industry, poses long-term strong chemical toxicity and radiological hazard to the living system if not properly treated. Herein, the efficient separation of U(VI) has been achieved by a layered manganese thiophosphite intercalated with NH4+, namely (NH4)0.48Mn0.76PS3·H2O (N-MPS). N-MPS has good pH durability and β/γ irradiation resistance, and exhibits an outstanding capacity (qmU = 854.36 mg/g), fast kinetics, and superb selectivity towards U(VI). Impressively, the obtained KdU values in U(VI)-contaminated tap water and lake water are up to 2.23 × 104 mL/g. We further find that the adsorbent can be completely regenerated by a mild and eco-friendly method and reused for at least five cycles. By using various characterizations (Raman, XPS, TEM, Zeta potential and EXAFS) and batch adsorption experiments, the adsorption mechanism of N-MPS for U(VI) has been revealed, that is, the synergy of ion exchange between U(VI) ions and interlayered NH4+ ions and surface adsorption of N-MPS. This work not only confirms that N-MPS has excellent application potential for highly efficient incarceration of U(VI) from wastewater, but also paves the way to develop new high-performance adsorbents by intercalation.