Porous Silsesquioxane–Imine Frameworks as Highly Efficient Adsorbents for Cooperative Iodine Capture

Abstract

The efficient capture and storage of radioactive iodine (I or I), which can be formed during nuclear energy generation or nuclear waste storage, is of paramount importance. Herein, we present highly efficient aerogels for reversible iodine capture, namely, porous silsesquioxane-imine frameworks (PSIFs), constructed by condensation of octa(3-aminopropyl)silsesquioxane cage compound and selected multitopic aldehydes. The resulting PSIFs are permanently porous (Brunauer-Emmet-Teller surface areas up to 574 m/g), thermally stable, and present a combination of micro-, meso-, and macropores in their structures. The presence of a large number of imine functional groups in combination with silsesquioxane cores results in extremely high I affinity with uptake capacities up to 485 wt %, which is the highest reported to date. Porous properties can be controlled by the strut length and rigidity of linkers. In addition, PSIF-1a could be recycled at least four times while maintaining 94% I uptake capacity. Kinetic studies of I desorption show two strong binding sites with apparent activation energies of 77.0 and 89.0 kJ/mol. These energies are considerably higher than the enthalpy of sublimation of bulk I.

Emerging Functional Porous Polymeric and Carbonaceous Materials for Environmental Treatment and Energy Storage

“…Iodine uptake [88] PAN3 Phenyl and pyrrolyl rings Iodine uptake [89] MelPOP-2 and TatPOP-2 50.5 and 36.5 Phosphorus and nitrogen heteroatoms, and p-π conjugated units Iodine uptake [90] COF-DL229 1762 π-conjugated pore walls Iodine uptake [91] CalPOF Azo groups, macrocyclic π-rich cavities and phenolic units Iodine uptake [92] PHF-1-Ct Positive charge and nitrogen Iodine uptake [93] PSIFs Imine groups and silsesquioxane Iodine uptake [94] HCMP-1, 2, 3, 4 Amine groups Iodine uptake [95] Azo-Trip 510. different mechanisms of separation, we will summarize the novel porous polymers in both adsorption and membrane separation area. As a kind of traditional ion-exchange resins, crosslinked polystyrene-based resins and their carbonized derivatives have found wide applications in material adsorption, extraction, and analysis.…”

“…The enhanced adsorption performance can be realized by presetting N heteroatomic units, such as amine, imine, pyrrole, and other N containing rings. [88][89][90][92][93][94][95][96][97][98]100] The π-conjugated structure in aromatic frameworks also increased the adsorption affinity to iodine species. [88,[90][91][92]97,99] Moreover, other heteroatoms (P, S, and B), [87,90,100] phenolic groups, [92] and charged groups [86,93] are also beneficial to elevate the uptake performance.…”

A crosslinking alkylation strategy to construct nitrogen-enriched tetraphenylmethane-based porous organic polymers as efficient carbon dioxide and iodine adsorbents

“…38 However, to achieve these values, these adsorbents took significantly longer time (12-30 h), leaving our mPTPM-3 as a fast and efficient adsorbent for I2. Previous studies showed that I2 desorption can be readily induced by heating the I2loaded samples at 393-473 K, [39][40][41] providing a facile route to recover the adsorbents.…”

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

“…synthesized an azo‐linked porous organic network that exhibits an excellent guest uptake of 238 wt% in iodine vapor and reversible adsorption of iodine in solution. Janeta et al . present a porous aerogel for reversible idone capture with extremely high affinity with uptake capacity up to 485 wt %.…”

“…Dang et al [19] synthesized an azolinked porous organic network that exhibits an excellent guest uptake of 238 wt% in iodine vapor and reversible adsorption of iodine in solution. Janeta et al [20] present a porous aerogel for reversible idone capture with extremely high affinity with uptake capacity up to 485 wt %. In our previous work, we synthesized N-rich porous organic polymers as sorbents for remediation of iodine vapor with a high capacity up to 382 wt %.…”