A nitrogen-rich covalent organic framework for simultaneous dynamic capture of iodine and methyl iodide

Ionic Functionalization of Multivariate Covalent Organic Frameworks to Achieve an Exceptionally High Iodine‐Capture Capacity

“…Reprocessing of spent nuclear fuel produces volatile radioactive compounds containing iodine isotopes ( 129 I and 131 I), [1] which must be removed before the off‐gas is discharged. Compared with traditional liquid scrubbing processes used to capture radioactive I 2 and other I‐containing compounds from the off‐gas, adsorption processes applying porous solid adsorbents have numerous advantages, including simple operation and low maintenance costs, and do not require the use of highly corrosive solutions [1b, 2] . Various adsorbents for I 2 capture applications have been reported, including ceramics, [3] zeolites, [4] aerogels, [5] metal‐organic frameworks, [6] and other materials.…”

“…As an emerging class of adsorbents, porous organic polymers (POPs) generally exhibit outstanding I 2 adsorption capacities per unit mass due to their low density and high porosity [1c, 7] . Extensive research into POP‐based I 2 capture has found that electron‐rich adsorbents can effectively adsorb electron‐deficient I 2 via the formation of charge‐transfer complexes [2, 7d, 8] . To prepare electron‐rich adsorbents, various synthetic strategies have been developed, including the construction of π‐conjugated networks, [8b] doping with heteroatoms, [9] incorporating heterocyclic moieties, [2, 7d] and combinations thereof [7c, 10] .…”

“…Extensive research into POP‐based I 2 capture has found that electron‐rich adsorbents can effectively adsorb electron‐deficient I 2 via the formation of charge‐transfer complexes [2, 7d, 8] . To prepare electron‐rich adsorbents, various synthetic strategies have been developed, including the construction of π‐conjugated networks, [8b] doping with heteroatoms, [9] incorporating heterocyclic moieties, [2, 7d] and combinations thereof [7c, 10] . For example, N‐containing structural moieties (e.g., amine, imine, imidazole, triazine, and pyridine) have been introduced into aromatic networks to facilitate a high I 2 adsorption capacity [2, 7d, 8] .…”

“…To prepare electron‐rich adsorbents, various synthetic strategies have been developed, including the construction of π‐conjugated networks, [8b] doping with heteroatoms, [9] incorporating heterocyclic moieties, [2, 7d] and combinations thereof [7c, 10] . For example, N‐containing structural moieties (e.g., amine, imine, imidazole, triazine, and pyridine) have been introduced into aromatic networks to facilitate a high I 2 adsorption capacity [2, 7d, 8] . Another strategy effectively promoting I 2 adsorption is the generation of cationic sites in the adsorbent, which can bind dynamically formed polyiodide anions via Coulomb interactions [7a, 11] …”

Methyl Iodide Adsorption on Reduced Silver-Functionalized Silica Aerogel: How Temperature Impacts the Adsorption?

“…Multiple forms of organic iodides (from CH 3 I to C 12 H 25 I) were observed, and among these organic iodides, CH 3 I and C 12 H 25 I were reported to be the two most abundant ones. [5][6][7][8][9][10] To remove the radioactive iodine, multiple adsorbents were developed and studied including reduced silvercontaining materials such as silver functionalized silica aerogel (Ag 0 -Aerogel) 11 , hydrogen reduced silver exchanged mordenite (Ag 0 Z) 12,13 , silver nitrate impregnated alumina (AgA) 14 ; bismuth-containing materials such as Bi-Bi 2 O 3 -TiO 2 -C 15 , bismuth-decorated electrospinning carbon nanofiber 16 ; and other organic materials such as graphene aerogel 17 , nitrogen-rich covalent organic framework (SCU-COF) 18 and metal organic frameworks (MOF) 19 . Among these materials, the silver-containing ones are the most matured and commonly used.…”