Effective capture of radioactive iodine is highly desirable for decontamination purposes in spent fuel reprocessing. Cu-based adsorbents with a low cost and high chemical affinity for I2 molecules act as a decent candidate for iodine elimination, but the low utilization and stability remain a significant challenge. Herein, a facile in situ confined synthesis strategy is developed to design and synthesize a copper-encapsulated flaky silicalite-1 (Cu@FSL-1) zeolite with a thickness of ≤300 nm. The maximum iodine uptake capacity of Cu@FSL-1 can reach 625 mg g–1 within 45 min, which is 2 times higher than that of a commercial silver-exchanged zeolite even after nitric acid and NOX treatment. The Cu nanoparticles (NPs) confined within the zeolite exert superior iodine adsorption and immobilization properties as well as high stability and fast adsorption kinetics endowed by the all-silica zeolite matrix. This study provides new insight into the design and controlled synthesis of zeolite-confined metal adsorbents for efficient iodine capture from gaseous radioactive streams.
Mingwei Weng,Zihao Zhang,Francis Okejiri,Yue Yan,Yubing Lu,Jinshu Tian,Xiuyang Lu,Siyu Yao,Jie Fu
Catalytic transfer hydrogenation (CTH) of biomass-derived furfural (FAL) to furfuryl alcohol is recognized as one of the most versatile techniques for biomass valorization. However, the irreversible sintering of metal sites under the high-temperature reaction or during the coke removal regeneration process poses a serious concern. Herein, we present a silicalite-1-confined ultrasmall CuO structure (CuO@silicalite-1) and then compared its catalytic efficiency against conventional surface-supported CuO structure (CuO/silicalite-1) toward CTF of FAL with alcohols. Characterization results revealed that CuO nanoparticles encapsulated within the silicalite-1 matrix are ∼1.3 nm in size in CuO@silicalite-1, exhibiting better dispersion as compared to that in the CuO/silicalite-1. The CuO@silicalite-1, as a result, exhibited nearly 100-fold higher Cu-mass-based activity than the CuO/silicalite-1 counterpart. More importantly, the activity of the CuO@silicalite-1 catalyst can be regenerated via facile calcination to remove the surface-bound carbon deposits, unlike the CuO/silicalite-1 that suffered severe deactivation after use and cannot be effectively regenerated.
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