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Uranium extraction from radioactive nuclear waste is vital for sustainable energy supply and ecological security. Herein, a polyethyleneimine-chitosan composite microspheres n-PEI/ECH-CTS (n = 0.1, 0.2, 0.3, 0.4, 0.5) were synthetized for efficient and selective uranium adsorption. The prepared chitosan microspheres with uniform size, uniform dispersion and good mechanical strength combine cost-effectiveness and environmental benefits. The 0.4-PEI/ECH-CTS exhibits the highest adsorption capacity of 380.65 mg g

The increasing demand for rare-earth elements (REEs) due to their extensive high-tech applications has encouraged the development of new sustainable approaches for REE recovery and separation. In this work, a series of acrylic acid-functionalized metal–organic framework materials (named as y-AA-x@MIL-101s) were prepared and used for selective adsorption of Sc(III). The adsorbent was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, nitrogen adsorption, X-ray photoelectron spectroscopy, and zeta potential and surface functional-group titration. The adsorption isotherm and kinetics data were accurately described by the Langmuir and pseudo-second-order models. The adsorption capacity of the material for Sc(III), Nd(III), Gd(III), and Er(III) was 90.21, 104.59, 58.29, and 74.94 mg g–1, respectively. Importantly, the adsorbent was better for selective recovery of Sc(III) not only from the 16 REE mixed system but also the Cu(II), Zn(II), Mn(II), Co(II), a...

Imidazolium-based ionic liquids (ILs) are a promising candidate for efficient separation of radioactive pertechnetate (TcO4-) from nuclear waste. However, their effective fixation, availability of active sites and slow adsorption kinetics remain challenges. Here, we incorporated the bisimidazolium-based ILs into porous metal-organic frameworks (MOFs) via a combination of immersion grinding and in-situ polymerization. 3,3′-divinyl-1,1′(1,4-butanediyl) diimidazolium dichloride is tightly bound inside and outside the porous MOFs matrix by uniform immersion grinding, which facilitates the exposure of more adsorption sites and provides channels for the anions to travel through quickly. Solvent-free polymerization reduces environmental pollution and energy consumption. Notably, the composite P[C4(VIM)2]Cl2@MIL-101 possesses an admirable removal efficiency (673 mg g−1) compared with the pristine poly(ionic liquid)s (215 mg g−1). Meanwhile, it exhibits fast sorption kinetics (92% in 2 min), good β and γ radiation-resistance, excellent regeneration and eminent removal efficiency in high alkaline conditions (83%). These superior traits endow that P[C4(VIM)2]Cl2@MIL-101 effectively separated TcO4- from simulated Hanford Low-activity Waste (LAW) Melter off-gas scrubber solution tested in this work. DFT density functional theory confirms that the strong electrostatic attraction and minimum Gibbs free energy (−6.2 kcal mol−1) achieve high selective adsorption for TcO4-. P[C4(VIM)2]Cl2@MIL-101 demonstrates the considerable potential to remove TcO4- from radioactive contaminants.

99Technetium (99Tc) is one of the most dangerous radioactive isotopes in the legacy nuclear waste, and harmful to the environment and human health. Effectively removing it remains a long-term challenge. Herein a resin-like imidazolium-based ionic liquid polymer (DVB-2C8VEIMBr) was prepared for selective adsorption of TcO4− (ReO4− as an alternative for laboratory operation). It is manifested that DVB-2C8VEIMBr integrates high adsorption capacity (313.28 mg·g−1) and selectivity (90.68% in 6000 times excess of SO42− ions). A real-scenario experiment exhibits DVB-2C8VEIMBr can remove up to 93% of TcO4− from the simulated Hanford LAW scrubber solution. More importantly, DVB-2C8VEIMBr displays super acid and alkaline resistance and stability after immersing for 8 months under extreme conditions of 3 M HCl and 2 M NaOH. It can also effectively separate rhenium from molybdenum solution in the range of 3 M HCl - pH 2. Additionally, it still showed perfect regeneration performance after 10 cycles. In particular, this work demonstrates the feasibility of imidazolium-based ionic liquid adsorbents in the TcO4− or ReO4− immobilization process, which can be applied to capture these radioactive oxygen anions under high acid and high alkali conditions.

Technetium (99Tc), a radionuclide generated from uranium fission in nuclear reactors, has posed a major threat to humans due to its long half-life and radioactivity. Therefore, it is urgent to develop a strategy of selectively and efficiently capturing of 99Tc. In this work, a series of solid copolymers (denoted as DVB-[CxClVim][Cl]) were synthesized for efficient adsorption of perrhenate (ReO4−, a surrogate for TcO4−) from mixed ions solution. The adsorbents with vinylimidazolium-based ionic liquid as functional group and divinylbenzene (DVB) as the basic framework exhibited stable structure and good ReO4−adsorption performance. The influences of the linear n-alkyl chain length on the morphology and adsorption property of the copolymers were discussed in detail. The maximum uptake of Re(VII) on DVB-[C4ClVim][Cl] was 517.61 mg·g−1. Rhenium could be separated from molybdenum in the presence of co-anions and co-cations by DVB-[C6ClVim][Cl], which demonstrated its good adsorption selectivity. The kinetic studies showed that pseudo-second-order model was more suitable for describing the behavior of Re(VII) adsorption. The adsorption mechanism was ion-exchange between Cl− and ReO4− confirmed by FI-IR, IC and XPS analysis. Additionally, DVB-[CxClVim][Cl] remained effective Re(VII) capture ability after eight adsorption/elution cycles, demonstrating their good reusability.