In order to achieve the long-term safe disposal of gaseous radioactive iodine,silver-modified silica gel composites were prepared by hydrothermal impregnation method using silica gel as a carrier,and the iodine-enriched composites were treated with low temperature glass solidification.The morphology and structure of the composites were characterized by scanning electron microscopy and X-ray diffraction.The effects of impregnation reaction temperature on silver loading,adsorption time,and iodine mass concentration on iodine adsorption were investigated.The adsorption kinetic curves and adsorption isotherms were fitted.The results showed that silver nitrate was loaded on the silica gel surface,and the silver loading reached 17.8%.The adsorption of gaseous iodine by the composites within 30min could reach equilibrium,and the adsorption behavior conformed to the quasi-second-order kinetic model,which was chemisorption.The Langmuir isothermal adsorption model was more suitable to describe the isothermal adsorption process of gaseous iodine by composites,suggesting a monolayer adsorption behavior.The theoretical maximum adsorption capacity of iodine by composites was 169.5mg/g.The solidification results indicated that the glass-cured body sequestered iodine mainly in the forms of silver iodide (AgI) and iodine pentabismuth heptoxide (Bi5O7I),and the leaching rate of iodine was 1.436×10-6g/(m2·day).
Huang Shuangshuang, Lei Hao, Tang Jiao, Zou Hao, Pan Ning, Wang Xiaoqiang
. Capture and solidification of gaseous iodine by silver-modified silica gel composites[J]. New Chemical Materials, 2024
, 52(4)
: 172
-177
.
DOI: 10.19817/j.cnki.issn1006-3536.2024.04.002
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