Graphene-based sorbents for iodine-129 capture and sequestration

Abstract

The capture and sequestration of Iodine-129 (129 I), a long-lived byproduct of nuclear fission, is essential to the implementation of advanced nuclear fuel cycles and effective nuclear waste management. Current state-of-the-art technologies inherently require silver to bind iodine, e.g., silver-loaded silica aerogels or silver-loaded zeolite (AgZ), which are very expensive and an environmental concern. It is highly desirable to develop alternative cost-effective adsorbents for iodine capture and sequestration. Herein, we report graphene-based nanomaterials including graphene powder and graphene aerogel as novel iodine sorbents showing exceptional adsorption capability and kinetics. By measuring iodine sorption capacities and uptake rates in an I 2(g) saturated environment, graphene sorbents display impressive iodine sorption capacities with powdered samples achieving mass gains in excess of 85 mass%, and aerogels exceeding 100% mass gains. A direct correlation among specific surface area, defect concentration, and maximum sorption capacity has been established, and the sorption kinetics of the graphene for iodine capture was determined.

Efficient Capture and Reversible Storage of Radioactive Iodine by Porous Graphene with High Uptake

“…The weight gain of iodine was 4110 mg g −1 for PG‐800, 3460 mg g −1 for PG‐700, and 2460 mg g −1 for PG‐600, much higher than that of graphene (1700 mg g −1 ) and other solid adsorbents,,,,, (Table ). To our best knowledge, the iodine uptake for PG‐800 is the highest value for the carbon‐based solid adsorbents reported to date ,. Besides, the iodine uptake capacity correlate to the BET surface areas and pore volumes of the porous graphene as determined by nitrogen gas adsorption/desorption.…”

“…Graphene‐based materials for radioactive iodine species take many advantages of high available surface areas, chemical and hydrothermal stability. However, studies focused on the enrichment and capture of radioactive iodine species by graphene‐based materials are rare . Considering those unique properties of graphene, we aimed at exploring novel and efficient graphene‐based materials towards iodine capture and enrichment.…”

Adsorption of radioactive iodine and krypton from off-gas stream using continuous flow adsorption column

“…During the aqueous reprocessing of used nuclear fuel (UNF) several radioactive volatile compounds, such as 129 I, 85 Kr, 3 H, 14 C, and Xe are released into the atmosphere via the process off-gas stream [1]. 129 I is a primary concern for removal due to its high mobility, and when released into the environment it can collect in 'hot spots' in the earth's atmosphere [2].…”

“…However, nitrogen oxides generated during aqueous reprocessing undergo explosive reactions with the carbon and it cannot be used as a sorbent for off-gas streams [8,9]. To circumvent this issue, thermally stable sorbents, such as zeolites, metalorganic frameworks (MOFs), and graphene materials have been tested [10][11][12][13][14]. Zeolites are porous alumina-silicate materials, of which over 40 have been discovered, making a wide range of materials available.…”

Applications of Graphene-Modified Electrodes in Microbial Fuel Cells

“…With the rapid developments in materials research, graphene, a new and renowned member of the carbon family, has been adopted in MFC electrodes because of its excellent physical and chemical properties, for instance, its high specific surface area (2630 m 2 ·g −1 ) [29,30,31], outstanding electrical conductivity [32], and extraordinary biocompatibility [33]. Additionally, it has been widely used in Li-ion batteries [34], supercapacitors [35,36], sensors [37], electrochemical catalysts [38], and oil sorbents [39].…”