AgNPs-Containing Metal–Organic Frameworks for the Effective Adsorption and Immobilization of Radioactive Iodine

Abstract

Among the numerous nuclear wastes, radioactive iodine (I2) has become one of the main pollutants due to its serious adverse effects on the human thyroid gland. Therefore, the design and synthesis of adsorbents for efficient elimination of radioactive I2 from nuclear waste is an attractive target. Herein, we developed a novel silver nanoparticle (AgNP)-loaded metal–organic framework (MOF) of UiO-66, which exhibits excellent I2 adsorption performance due to the synergistic effect between UiO-66 MOFs and AgNPs. The designed AgNPs@UiO-66 adsorbent possesses good porosity and high Ag-loading ability, which assists the adsorbent to achieve a high adsorption I2 capacity of 1260 mg/g. The pseudo-second-order model and Langmuir model are considered to be suitable for describing the I2 adsorption behavior over AgNPs@UiO-66. Additionally, some important experimental parameters, such as adsorption time, adsorbent concentration, secondary pollution, and adsorption mechanism, have also been studied in detail. These satisfactory results manifest that AgNPs@UiO-66 is a latent adsorbent for I2 removal in nuclear waste management.

CN linked covalent organic framework for the efficient adsorption of iodine in vapor and solution

“…Among them, inorganic adsorbents, 7,8 such as ion-exchange zeolites 9,12,13 and silver-functionalized silica aerogels, 10,11 usually exhibit high cost, low uptake capacities and instability toward water and moisture. In recent years, metal-organic frameworks (MOFs) [14][15][16][17][18][19][20] and porous organic polymers (POPs), [21][22][23][24][25] which include conjugated microporous polymers (CMPs), 25,26 covalent triazine frameworks (CTFs), 27 charged porous aromatic frameworks (PAFs) 21,28,29 and covalent organic frameworks (COFs), 24,[30][31][32][33][34][35][36][37][38][39][40][41] have attracted a lot of attention for worthwhile iodine capture. POPs have been found to exhibit high potential for iodine capture and storage due to their high surface area, and the high interaction between adsorbents and iodine.…”

Silver Ion-Exchanged Anionic Metal–Organic Frameworks for Iodine Adsorption: Silver Species Evolution from Ions to Nanoparticles

“…That is, anionic MOFs provide enormous opportunities to rationally design the scaffold with a precise and tunable microenvironment to disperse and stabilize metal species. Recently, Ag nanoparticles were generated in the pores of anionic MOFs using ethanol as the reducing agent after the Ag + -exchanged treatment. , Besides, Ag nanoparticles can also be produced by the reduction of dimethyl formamide (DMF) in the pores of neutral UiO-66 after Ag + impregnation . The Ag species loaded in zeolites have been extensively investigated in recent decades .…”

A Ni(ii) metal–organic framework with helical channels for the capture of iodine via guest exchange induced amorphization

“…The risk of thyroxine disease and even cancer is increased when the human body is exposed to a high dose of radioactive iodine. 5 Therefore, the removal of radioactive iodine from a contaminated environment is highly desirable. 6,7 The capture of iodine by porous materials is one of the most intriguing technologies for iodine removal.…”

“…25 Therefore, a small number of studies have focused on achieving more effective iodine capture in the absence of MOFs. 5,[25][26][27] For example, silver nanoparticles (AgNPs) were loaded on UiO-66 to form AgNPs@UiO-66 complexes to enhance the immobilization of iodine (Scheme 1, I). 5 The other strategy of interest is the amorphization of iodine-loaded ZIF crystals to achieve irreversible trapping of iodine.…”

“…5,[25][26][27] For example, silver nanoparticles (AgNPs) were loaded on UiO-66 to form AgNPs@UiO-66 complexes to enhance the immobilization of iodine (Scheme 1, I). 5 The other strategy of interest is the amorphization of iodine-loaded ZIF crystals to achieve irreversible trapping of iodine. 27 The collapse of the framework leads to the decrease or disappearance of pores, which prevents the release of the guest iodine molecule.…”