A novel strategy for iodine removal from nuclear reactor accidental gases: efficient adsorption of CH₃I on the moderately hydrophobic modified silver-loaded zeolite under high temperature and humidity conditions

ABSTRACT

Ensuring nuclear energy safety through effective gas emission filtration from nuclear reactor containment in accident scenarios is paramount. The efficacy of hydrophobic modified Ag-loaded zeolites for methyl iodide (CH₃I) removal under challenging conditions of high temperature, humidity, and irradiation is studied in this work. Through hydrophobic modification of AgX zeolite with three different silane coupling agents, a series of modified zeolites with varied hydrophobicity levels is produced. The adsorption capabilities of these modified materials are assessed using a self-designed gas adsorption setup, focusing on CH₃I removal from a gas mixture emblematic of nuclear accident environments. Results indicate that all hydrophobically modified zeolites exhibited superior CH₃I removal rates compared to their unmodified counterparts, with the variant modified with 10% phenyltriethoxysilane achieving the highest removal rate of 99%. Additionally, zeolites modified with octyltrimethoxysilane demonstrate commendable irradiation resistance at a radiation dose of 4.2 × 10⁵ Gy. The results suggest that optimally hydrophobically modified AgX zeolites hold significant promise for filtering gases containing radioactive iodine, offering novel insights for the advancement of adsorbent materials in nuclear reactor containment discharge systems.

GRAPHICAL ABSTRACT

KEYWORDS:

• Methyl iodide
• Zeolite
• Adsorption

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Acknowledgments

We acknowledge financial support from the National Natural Science Foundation of China (22206039), the CNPE-HEU Joint Laboratory on Containment Thermal-Hydraulics (Project Number: KY22082).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [22206039]; the CNPE-HEU Joint Laboratory on Containment Thermal-Hydraulics [KY22082].