Latest ArticlesExploring efficient materials for capturing radioactive iodine in nuclear waste is of great significance for the progress of nuclear energy as well as the protection of ecological environment. Covalent organic frameworks (COFs) have emerged as promising adsorbents because of their predesignable and functionalizable skeleton structures. However, it remains a grand challenge to achieve large scale preparation of COFs. In this work, we developed a mild and efficient microwave irradiation method instead of the traditional solvothermal method to prepare copper phthalocyanine-based covalent organic frameworks (CuPc-COFs) within only 15 min. The nitrogen-rich 1, 2, 4, 5-tetracarbonitrilebenzene (TCNB) was selected as the solely organic ligand to construct copper phthalocyanine-based 2D conjugated COFs. The resultant CuPc-COFs exhibited excellent iodine enrichment with 2.99 g/g for volatile iodine and 492.27 mg/g for iodine-cyclohexane solution, respectively, outperforming that of many porous materials. As indicated by spectroscopic analysis and DFT calculations, this impressive adsorption performance can be attributed to the charge transfer arising from nitrogen-rich phthalocyanine structures and electron-rich π-conjugated systems with iodine molecules. Moreover, the strong electrostatic interaction between Cu(II) on chelate centers and polyiodide anions (Ix-) also play an important role in the firmly trapping radioactive iodine. Therefore, this study provides a facile and intelligent approach to implement metal-based COFs for the remediation of toxic radioactive iodine.
Based on the outstanding application advantages of nitrogen-rich materials with regular porous frameworks in the capture of gaseous radioactive iodine, a series of covalent organic frameworks (COFs) with dual channels and abundant tertiary-amine active sites were constructed herein via a unique multi-nitrogen node design. The high density of up-to-six nitrogen adsorption sites in a single structural unit of the products effectively improved the adsorption capacities of the materials for iodine. Moreover, the adsorption affinity of the active sites can be further regulated by charge-induced effect of different electron-donating groups introduced into the COFs. Adsorption experiments combined with DFT theoretical calculations confirmed that the introduction of electron-donating groups can effectively increase the electron density around the active sites and enhance the binding energy between the materials and iodine, and thus improve the iodine adsorption capacity to 5.54 g/g. The construction strategy of multi-nitrogen node and charge-induced effect proposed in this study provides an important guidance for the study of the structure-activity relationship of functional materials and the design and preparation of high-performance iodine adsorption materials.
The treatment of anionic 99TcO4- in the waste tank with high alkalinity is still very challenging. In this work, a new temperature-responsive alkaline aqueous biphasic system (ABS) based on (tri-n-butyl)-n-tetradecyl phosphonium chloride (P44414Cl) was developed to remove radioactive 99TcO4-. The phase transition mechanism was studied by cloud point titration, small-angel X-ray scattering, dynamic light scattering, and molecular dynamic simulations. As the NaOH concentration or temperature increased, the P44414+ micelle could grow and aggregate. This micelle showed a particularly high affinity toward ReO4-/99TcO4- compared to other competing anions and could directly extract more than 98.6% of 99TcO4- from simulated radioactive tank waste supernatant. Furthermore, the loaded 99TcO4- could be easily stripped by using concentrated nitric acid rather than metal salt-based reductants. This work clearly demonstrates that the alkaline ABS is a promising separation system for solving the technetium problem in the alkaline waste tank.
Soft N-donor bis-triazin bipyridines derives (R-BTBP) are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste (HLW). In addition to minor actinides, R-BTBP also holds very strong complexation ability toward fission palladium. However, few studies have been focused on the separation and complexation with the fission product Pd(Ⅱ) by R-BTBP. Herein, the complexation behaviors of Pd(Ⅱ) with four typical R-BTBP ligands were systematically studied by single crystal X-ray diffraction, 1H NMR titration and theoretical calculation. The effects of R-BTBP initial conformation and nitrate anions on the complexation behaviors of R-BTBP with Pd(Ⅱ) were thoughtfully analyzed. Both the 1:1 and 2:1 binuclear complexes could be formed between Pd(Ⅱ) and R-BTBP with initial Ⅱ conformation in the presence of nitrate anions, while only one 1:1 type Pd(Ⅱ) complex could be formed for those with initial OO conformation. Without nitrate anion, only one 1:1 type complex was formed in solution. The structure of the 1:1 Pd(Ⅱ)/R-BTBP complex was firstly characterized by single crystal crystallography. DFT calculation results showed that a significant large rotational energy barrier (21.8~22.6 kcal/mol) must be overcome to form the Ⅱ type 2:1 Pd(Ⅱ) complex for those OO type R-BTBP ligands, however which would not prevent them from forming the 1:1 type complex.
The hunt for agents that are suitable for actinide decorporation to reduce the whole-body load of actinide in accidental internal exposure is the ever-lasting goal in radiation protection and medical treatment in nuclear emergency. All current decorporation agents can be categorized as two groups, one is the molecular ligands, and the other is the nanoparticles decorated with molecular ligands. Here in this work, functional nanodiamonds (fNDs) with ssDNA (the endogenous biomacromolecule rich in phosphate groups) loaded on the NDs is reported, which poses good uranyl adsorption selectivity, high cellular uptake, fast excretion, and effective decorporation of uranyl from rat renal proximal tubular epithelial cells (NRK-52E). All those results corroborate that fNDs can potentially serve as a brand new family of chelators for actinide decorporation.
Photocatalytic removal of uranium has attracted much attention in nuclear wastewater treatment and it is highly needed to develop functional photocatalyst with excellent removal performance. In this work, seven kinds of carbon dots/carbon nitride (CDs/CN) composites were synthesized and SerCDs/CN with the best photo-assisted uranium removal performance was screened out. It was found that the introduction of CDs could bring in higher photocurrent density, lower interfacial charge transfer impedance and narrower band gap, resulting in a much-improved removal performance. SerCDs/CN had shown a removal capacity as high as 1690 mg/g and the reaction could be operated under air atmosphere which is promising in real application.
In this work, we proposed a new U(Ⅵ) removal strategy combining adsorption and photocatalytic reduction by the PMo12/UiO-66 heterojunctions. The PMo12 has been encapsulated in the cavities of UiO-66 by a one-step hydrothermal method, and the PMo12/UiO-66 exhibited high adsorption capacity and photocatalytic activity. The maximal theoretical sorption capacity of U(Ⅵ) on 15% PMo12/UiO-66 reached 225.36 mg/g and the photoreduction rate of 15% PMo12/UiO-66 is about thirty times as much as UiO-66. Under the light irradiation, the photogenerated electrons rapidly transport from UiO-66 to PMo12, and the photo-generated electrons could efficiently reduce the pre-enriched U(Ⅵ) to U(Ⅳ). This work provides new insights into remediation of the radioactive environment.
Uranium removal from aqueous solutions using environmentally friendly photocatalytic technology is a novel approach for resource recovery. Herein, carbon nitride/activated carbon composite materials (CN/AC) were investigated for U(Ⅵ) reduction under visible light. An exceptional boost in photocatalytic activity was observed for CN/AC composites (up to 70 times over the conventional bulk g-C3N4). The strong interactive conjugated π-bond structure between g-C3N4 and AC accelerated the migration of carriers and then prolonged the electron lifetime. CN/AC composites exhibited excellent compatibility with different water substrates and were resilience to a wide range of pH changes and abundant competitive anions/cations. Quenching experiments and electron microscopy characterization indicated that U(Ⅵ) was reduced by photogenerated electrons and deposited on the edge of CN/AC composites. The low-cost, high-performance carbon-based composite material proposed in this work is a potential candidate for the efficient treatment of radioactive wastewater.
The works on the procedure of fluorescent sensors for the detection of biological analytes are extremely momentous. Among diverse analytical approaches, fluorescence is the most eye-catching due to its high sensitivity, selectivity, rapidity, robustness, ease of measurement and non-destructive approaches. Herein, we show different fluorescent probes synthesized for estimation and detection of biological analytes (H2S, SO32−/HSO3−, H2O2, HOCl, HNO, ONOO−). These probes were constructed by masking the functional groups (hydroxyl and amino) of fluorophore and formation of active C=C, C=N, C=O and N=N for specific analytes. In this review we concentrate on synthesis of the probe, their photophysical properties and applications to biological studies.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
