In suit establishment of Ti3C2 MXenes exchanger via Na+, K+ and NH4+ intercalation: Exceptionally UO22+ loading capability and hijacking mechanism

Abstract

Uranium naturally occurs over four billion tonnes in the seawater, which can be extracted for use as nuclear fuel. Herein, an efficient Ti3C2 MXenes catcher was constructed by a facile and environmental friendly chemistry intercalation strategy and directed at uranium capture. We demonstrate the promising loading capability of MXenes with expansion interlayer spacing due to the intercalation of Na+, K+ and NH4+. We report high sequestration capacity (qm-Na = 1099.40 mg/g and qm-K 876.05 mg/g), large KdU values (104 –105 mL/g, despite the presence of a tremendous excess of Na+, K+, Ca2+ and Mg2+ system). Remarkable, even in the 104-folds of V5+ system, the adsorption efficiency of Na+-MXenes still reached 51.98 %. Real uranium spiked seawater extraction experiments indicated that the sample exhibits promising harvesting uranium performance with ∼ 95.92 ∼ 3643.84 μg/g adsorption capacity after 24 h contact in ∼ 30.34 ∼ 1702.37 μg/L initial concentration. Importantly, the uranyl ion in the exchanged MXenes products could be easily eluted by hydrochloric acid and hydroxide during continuous adsorption–desorption cycles. HRTEM, XRD, FTIR and XPS tests confirmed that ion exchange and surface coordination were the main uptake mechanisms. These advantages of intercalation functionalization method coupled with the very high loading capacity, easy fabrication and environmentally friendly nature providing a new insight for further development of highly efficient uranium enrichment materials.