Constructing of a stable Ti3C2 MXenes nano-traps with ultrahigh and selectively uranyl encapsulation capability by polyethyleneimine intercalation

Abstract

Seawater and salt lake naturally deposited abundant unconventionality uranium resource and can be harvest for long-term sustainability of nuclear power. However, recovering it from other more plentiful metal ions postulates high affinity and selectivity to dispose an enormous volume of water. Herein, we propose an effective strategy to regulate uranyl extraction capacity and selectivity via chemistry intercalation. We reported the PEI-Ti3C2 exhibited ultrahigh uranyl loading capability (qmax = 580 mg/g at 28 ℃ and 1370 mg/g at 40 ℃), high removal efficiency and remarkable sequestration selectivity (Uinitial = 1.02 ppm, ∼ 82.90 % ∼99.19 % capture efficiency and ∼3.17 × 104 ∼ 6.15 × 105 KdU value), despite the presence of a large concentration of Na+, K+, Ca2+, Mg2+ coexisting ions. Surprisingly, at 103-folds VO43−, the capture efficiency can still reached 89.17 % with 4.12 × 104 KdU value. PEI-Ti3C2 MXenes demonstrated trustworthiness stability after five successive adsorption–desorption cycles accompanied by 89.57 % average elution and soaking in the actual seawater for 35 days. Natural uranium spiked-seawater tests displayed the nano-traps reached ∼2.03 ∼ 26.37 mg/g adsorption capacity after 24 h contact in 0.503–10.064 ppm solution. FTIR and XPS analysis elucidated that the chelation of pyridine and pyrrolidine with uranyl is the main uptake mechanism, which showed a higher affinity than the surface oxygen terminal. The state-of-the-art of intercalation functionalization with its simplicity, low environmental burden and large-scale synthesis is expected to provide new insights into the development of highly efficient MXenes based uranium adsorption materials.