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In the fields of spent fuel reprocessing and nuclear environmental remediation, it is important to design and synthesize adsorbent materials with high efficiency and selectivity for separating TcO4- and its analog ReO4-. The porous and crystalline covalent organic framework (COF) materials show unique advantages in radionuclide separation. In this work, a vinyl-rich two-dimensional COF material (TbDa-COF) was synthesized firstly. The ionic liquid 1-vinyl-3-ethyl imidazolium bromide (C2vimBr) as a monomer was successfully grafted onto TbDa-COF by using γ-ray pre-irradiation induced grafting polymerization. The crystallinity and porosity of the TbDa-COF remains after grafting with ionic liquid. The effect of concentration of ionic liquid monomer on the grafting is the most important. The grafting yield increases with the rising of monomer content, and solvent has slight effect on the grafting yield of products. The prepared ［C2vimBr］-TbDa-COF material shows excellent adsorption performance for ReO4-. The adsorption equilibrium can be reached within 2 min, and the maximum adsorption capacity is up to 420 mg/g. The introduction of long hydrophobic alkyl groups on the graft chain in ［C2vimBr］-TbDa-COF is conducive to improving the adsorption selectivity towards ReO4-. This work demonstrates the great potential of ionic liquid modified COF for spent fuel reprocessing and nuclear environmental remediation.

Wang et al. report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy for efficient capture of 99TcO4−, where tunable ReO4− uptake up to 952 mg g−1 can be achieved by simply adjusting the γ-ray dose. The COFs feature high porosity, ultra-robust nanofiber structure, and fast adsorption kinetics, thus emphasizing their advantages in terms of column experiments.

The main factors affecting the safety of underground structures are groundwater chemical corrosion and water level fluctuations. To investigate the mechanical properties of marble and the energy evolution pattern during the failure process under the coupled effects of chemical corrosion and dry-wet cycling, samples were subjected to 5, 10 and 20 cycles of dry-wet ageing in chemical solutions with pH values of 4, 7 and 10, respectively, followed by mechanical property testing. The energy evolution pattern during the failure process of the specimens was also studied. It was found that there is a strong correlation between number of dry-wet cycles and pH value of chemical solution. Chemical corrosion at the early stage of dry-wet cycling has the greatest effect on the deterioration of the rock. As the number of dry-wet cycles increases, the degree of corrosion in acidic solutions is most evident, with the uniaxial compressive strength and elastic modulus decreasing by 27.88% and 33.52% respectively, followed by alkaline solutions, and the degree of corrosion in neutral solutions is the lowest. In addition, dry-wet cycling and chemical corrosion lead to an increase in the internal pores of the rock samples and a decrease in the energy storage capacity. Nevertheless, the proportion of energy loss increases with the number of dry and wet cycles, with the proportion of energy loss in acidic media increasing from 35.61% to 41.63%, indicating that the plastic deformability of marble increases under the action of chemical corrosion and dry and wet cycles. The research results have certain guiding significance for the design, construction and maintenance reinforcement of underground structures under the conditions of chemical corrosion and dry-wet cycling. [ABSTRACT FROM AUTHOR]

Hierarchically porous silica was alkylated with trimethylchlorosilane, and a novel quaternary phosphonium modified hierarchically porous silica (HPS-C-P) was prepared by radiation-induced grafting of quaternary phosphonium. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and specific surface area (BET) analysis results indicated that alkyl and quaternary phosphonium groups were uniformly grafted on the surface of hierarchically porous silica. It was found that the adsorption of HPS-C-P for ReO4- could reach equilibrium within 4 min, and the adsorption capacity was 140.5 mg/g, which was higher than that of hierarchically porous silica modified with quaternary phosphonium by a chemical method (74.4 mg/g). The maximum separation factor (SF) of HPS-C-P relative to NO3-, SO42-, Cl-, CO32-- and PO43- toward ReO4- could reach 159, 827, 557, 681, 1 905, which was higher than those of most recently reported adsorbents. Moreover, HPS-C-P exhibited high radiation resistance and cyclic adsorption performance. FTIR spectroscopy and XPS analysis results showed that ReO4- was adsorbed by HPS-C-P through the ion exchange mechanism.

Platinum-decorated Ketjen Black supported MoSx (Pt-MoSx/KB) catalysts were synthesized using a two-step γ-ray radiation-induced reduction method in an ethylene glycol medium. The content of amorphous MoSx, the ratio of high activity sulfur, and the size and quantity of Pt nanoparticles (NPs) in Pt-MoSx/KB nanocomposites can be effectively controlled by adjusting the absorbed dose, as well as the concentrations of ammonium tetrathiomolybdate and chloroplatinic acid hydrate precursors. The formation mechanism of Pt NPs with different sizes is related to the underlying principles of radiation-induced reduction reactions and nanocrystal growth. Remarkably, Pt-MoSx/KB-III, with a Pt loading of only 5.7% and an NP size of 3.50 nm, exhibited impressive electrocatalytic properties in acidic media, achieving overpotentials of 107 mV and 185 mV at current densities of 10 mA cm−2 and 100 mA cm−2, respectively. These performance levels are comparable to those of commercial 20% Pt/C catalysts. The intrinsic activity of Pt, the electronic metal–support interaction effect between Pt and MoSx, and the fine-tuning of hydrogen adsorption free energy by Pt atoms located on top of the Mo atoms lead to the high catalytic performance. The beneficial impact stemming from the incorporation of Pt into MoSx/KB on the catalytic performance for the hydrogen evolution reaction was elucidated via DFT calculations. The Pt-MoSx/KB catalysts produced in this manner hold great promise as a novel class of cathode catalysts for applications in water electrolysis. [ABSTRACT FROM AUTHOR]