Supercritical CO 2 (SC-CO 2 ) technology promises to overcome the trade-off between secondary waste volume and decontamination efficiency in traditional radioactivity decontamination methods. However, attempts to use this technology for decontaminating uranium-contaminated fabrics have remained unexplored. Hence, we investigated the role of additives in decontaminating uranium-contaminated fabrics using SC-CO 2 technology, with particular emphasis on off-line versus in-situ preparation methods. Additives prepared via the off-line method, comprising H(NO 3 ) · TBP complexes, demonstrated superior efficiency owing to immediate solubility and reactivity in SC-CO 2 . Molecular dynamics (MD) simulations also supported these experimental observations by visualizing the microstructural evolution of the additive molecules. The factors, including pressure (20 MPa) and temperature (343 K), were optimized, achieving up to 97.4 % decontamination efficiency in 40 min. The radioactivity of the fabric surface was reduced to the level that allowed for reuse in the nuclear field. Notably, the mechanism analysis revealed the transformation of uranium contaminants from UO 2 (OH) 2 to UO 2 (NO 3 ) 2 · 2TBP complexes, which were efficiently dissolved in SC-CO 2 . Furthermore, the technology demonstrated high versatility, successfully decontaminating various fabric types and real radioactive samples, achieving results suitable for reuse in the nuclear field. These findings suggest that SC-CO 2 , when combined with optimized additives, offers an environmentally sustainable and highly effective method for uranium decontamination in the nuclear industry.
Ming-Bang Wu,Shi-Cheng Liu,Jin-Yan Fei,Hao Ye,Lu-Lin Ma
The effective treatment of uranium (U)-containing radioactive wastewater that from the mining process and nuclear leakage accidents is considered as the promise for the sustainable development of nuclear energy. Herein, amidoxime-functionalized microspheres with high grafting densities were prepared by the non-solvent induced phase separation and followed by surface chemical modifications while choosing celluloses as the raw materials in terms of broad resource, good hydrophilicity, and antimicrobial property. The excellent hydrophilicity of cellulose could reduce the rates of phase separation, leading to porous surface structures and spongy internal structures. In addition, the following swelling treatments would further modulate for higher pore sizes and porosities which could not only create more reaction sites during the modification but also promote the mass transfer as well as increase contact areas and retention times during the adsorption process. The obtained microspheres could selectively decontaminate more than 390 mg/g of uranium due to their abundant adsorption sites. In addition, their outstanding hydrophilicity endows them with good reusability and anti-fouling properties. The microspheres could also be put into filtration columns for long-term and dynamic adsorption which could be regarded as a decided advantage compared with common fiber-based adsorbents. The filtration columns could capture more than 17 mg/g after 20 days of uranium even with ultralow initial uranium concentrations and ultrahigh concentrations of other coexisting ions, demonstrating their desirable potentials in remediating radioactive wastewater.
危险品化学品经营许可证（带存储）