Capture of organic iodides from nuclear waste by metal-organic framework-based molecular traps

Abstract

Effective capture of radioactive organic iodides from nuclear waste remains a significant challenge due to the drawbacks of current adsorbents such as low uptake capacity, high cost, and non-recyclability. We report here a general approach to overcome this challenge by creating radioactive organic iodide molecular traps through functionalization of metal-organic framework materials with tertiary amine-binding sites. The molecular trap exhibits a high CH3I saturation uptake capacity of 71 wt% at 150 °C, which is more than 340% higher than the industrial adsorbent Ag0@MOR under identical conditions. These functionalized metal-organic frameworks also serve as good adsorbents at low temperatures. Furthermore, the resulting adsorbent can be recycled multiple times without loss of capacity, making recyclability a reality. In combination with its chemical and thermal stability, high capture efficiency and low cost, the adsorbent demonstrates promise for industrial radioactive organic iodides capture from nuclear waste. The capture mechanism was investigated by experimental and theoretical methods.

Mechanochemical synthesis of pillar[5]quinone derived multi-microporous organic polymers for radioactive organic iodide capture and storage

“…One challenge to be faced with is the capture and reliable storage of nuclear waste including radioactive molecular iodine (I 2 ) and organic iodides (e.g., iodomethane and iodoethane) in the production to ensure safe nuclear energy usage 46,47 . The capture of radioactive organic iodides is particularly challenging due to their high volatility [46][47][48][49][50] . We envisioned that MHP-P5Q with abundant nitric groups and multi-micropore structures might be an ideal adsorbent to capture and store radioactive organic iodides.…”

Porous sorbents for the capture of radioactive iodine compounds: a review

“…Since then, MOFs have been particularly popular for the retention of iodine. 6,14,109,110,115,116,[118][119][120][121][122][123][124][125][126][127][129][130][131][132] Most of the studies were carried out on materials based on divalent metals such as Zn 2+ and Cu 2+ , as well as aluminium-based structures. In fact, the most commonly studied MOFs for the capture of iodine were the zeolitic imidazolate framework Zn(2methylimidazolate) 2 (ZIF-8) and HKUST-1 (Cu 3 (benzene-1,3,5tricarboxylate) 2 (H 2 O) 3 , Cu-BTC).…”

“…3,4 Gaseous radioactive wastes are a direct threat to the population and the environment owing to their easy dispersion through the atmosphere. The main components of such gaseous waste streams include the ssion products technetium ( 99 Tc), cesium ( 137 Cs) and strontium ( 90 Sr), as well as actinides, lanthanides and various volatile radionuclides ( 129 I, 131 I, 3 H, 14 C, 85 Kr, etc.). [5][6][7][8] Particular attention should be paid to iodine compounds, which are particularly abundant.…”

“…129 I is a highly volatile long-lived isotope with a half-life (t 1/2 ) of $1.57 Â 10 7 years, which needs to be captured and reliably stored during its long decay. In contrast, 131 I is a volatile short-lived isotope with a t 1/2 of $8.02 days, which needs to be captured immediately aer being released, as it tends to accumulate and become concentrated in the thyroid gland, which seriously affects human metabolic processes. [9][10][11][12][13][14][15] In addition, radioactive iodine is likely to form organic compounds such as methyl iodide (CH 3 I) with hydrocarbons and other volatile organic compounds present in the gas stream.…”

0D to 3D PrIII metal–organic networks crystal engineered for optimal iodine adsorption

“…Porous CPs, due to their high surface area, porosity, pore functionality, tunable structures and architectures, and hostguest interactions, are considered as next-generation candidates for I 2 capture (Yin et al, 2012;Falaise et al, 2013;Pei et al, 2014;Yan et al, 2015;Chae et al, 2015;Li et al, 2017;Zhang et al, 2017). Various radionuclides of I 2 are released during the fission of nuclear fuels and these volatile radionuclides should be immediately trapped in the vapour phase due to their hazardous effects and their impact on human metabolic processes (Banerjee et al, 2018).…”