Radioactive iodine(such as 129I and 131I)is one of the major gaseous contaminants resulting from the utilization of nuclear energy and/or nuclear accidents.During the initial dissolution process in the spent fuel repr...Radioactive iodine(such as 129I and 131I)is one of the major gaseous contaminants resulting from the utilization of nuclear energy and/or nuclear accidents.During the initial dissolution process in the spent fuel reprocessing,for example,most of the iodine is released into the off-gas system in the form of highly volatile I2 and small amounts of organic iodine compounds(such as methyl iodide,ethyl iodide,butyl iodide).The remaining iodine in the dissolution solution exists in the forms of I2,IO3−,I−,IO−,and iodine colloids(AgI,PdI2).When the iodine in the dissolution solution enters the subsequent solvent extraction process,it can lead to solvent degradation,organic iodine formation,and reduction in the quality of uranium and plutonium products.Therefore,during the dissolution stage of spent fuel elements,it is generally preferred to convert as much iodine in the dissolution solution as possible into I2 and drive it into the off-gas.Overall,in the current nuclear fuel cycle system,radioactive iodine produced by nuclear fission mainly exists in the gaseous form.In the event of an accident,this radioactive iodine can easily leak,which presents a potential threat to the environment and public health due to its long half-life(e.g.,129I has a half-life of 1.57×10^(7)years),high mobility,ease of dispersion through air and water,and tendency to accumulate in living organisms[1].Consequently,the development of efficient and recyclable adsorbent materials for the capture and fixation of radioactive iodine has become a research priority in the fields of nuclear environmental remediation,nuclear emergency response,and nuclear fuel cycle management.Covalent organic frameworks(COFs),as a novel class of crystalline porous materials,have demonstrated promising potential for the capture of gaseous radioactive iodine due to their distinctive physicochemical properties[2,3].Specifically,COFs are composed of organic monomers connected by covalent bonds,providing high chemical and thermal stability.And the highly conjugated structure of COFs can significantly improve their resistance to irradiation[4].These enable them to maintain structural integrity and functionality under various extreme environments,making them suitable for handling complex radioactive contamination scenarios.This enables them to maintain structural integrity and functionality under various extreme environments,making them suitable for handling complex radioactive contamination scenarios.展开更多
基金supported by the New Iodine Adsorbent Material Project(JCKY2022130C022)the National Science Fund for Distinguished Young Scholars(21925603).
文摘Radioactive iodine(such as 129I and 131I)is one of the major gaseous contaminants resulting from the utilization of nuclear energy and/or nuclear accidents.During the initial dissolution process in the spent fuel reprocessing,for example,most of the iodine is released into the off-gas system in the form of highly volatile I2 and small amounts of organic iodine compounds(such as methyl iodide,ethyl iodide,butyl iodide).The remaining iodine in the dissolution solution exists in the forms of I2,IO3−,I−,IO−,and iodine colloids(AgI,PdI2).When the iodine in the dissolution solution enters the subsequent solvent extraction process,it can lead to solvent degradation,organic iodine formation,and reduction in the quality of uranium and plutonium products.Therefore,during the dissolution stage of spent fuel elements,it is generally preferred to convert as much iodine in the dissolution solution as possible into I2 and drive it into the off-gas.Overall,in the current nuclear fuel cycle system,radioactive iodine produced by nuclear fission mainly exists in the gaseous form.In the event of an accident,this radioactive iodine can easily leak,which presents a potential threat to the environment and public health due to its long half-life(e.g.,129I has a half-life of 1.57×10^(7)years),high mobility,ease of dispersion through air and water,and tendency to accumulate in living organisms[1].Consequently,the development of efficient and recyclable adsorbent materials for the capture and fixation of radioactive iodine has become a research priority in the fields of nuclear environmental remediation,nuclear emergency response,and nuclear fuel cycle management.Covalent organic frameworks(COFs),as a novel class of crystalline porous materials,have demonstrated promising potential for the capture of gaseous radioactive iodine due to their distinctive physicochemical properties[2,3].Specifically,COFs are composed of organic monomers connected by covalent bonds,providing high chemical and thermal stability.And the highly conjugated structure of COFs can significantly improve their resistance to irradiation[4].These enable them to maintain structural integrity and functionality under various extreme environments,making them suitable for handling complex radioactive contamination scenarios.This enables them to maintain structural integrity and functionality under various extreme environments,making them suitable for handling complex radioactive contamination scenarios.
