Capture Of Radioactive Iodine Research Articles

Design and Synthesis of Stable Sp2-Carbon-Linked Two-Dimensional Conjugated Covalent Organic Framework for Efficient Capture of Radioactive Iodine

Design and Synthesis of Stable Sp2-Carbon-Linked Two-Dimensional Conjugated Covalent Organic Framework for Efficient Capture of Radioactive Iodine

Vinyl-Functionalized Covalent Organic Frameworks for Effective Radioactive Iodine Capture in Aqueous Solution

Vinyl-Functionalized Covalent Organic Frameworks for Effective Radioactive Iodine Capture in Aqueous Solution

Interface assembly of specific recognition gripper wrapping on activated collagen fiber for synergistic capture effect of iodine

Efficient capture of radioactive iodine (129I, 131I) is of great significance in spent fuel treatment. In this paper, a new adsorbent named Catechin@ACF was successfully prepared through interface assembly of specific recognition gripper with plant polyphenols (catechin) on activated collagen fiber (ACF), and the catechin membrane with specific grip on iodine was successfully constructed on the surface of ACF. The results showed that the adsorbent assembled catechin membrane was rich in aromatic rings, hydroxyl groups and imine adsorption sites, and possessed specific recognition and capture characteristics of iodine. Moreover, the as-prepared Catechin@ACF showed excellent capture capacity for iodine vapor and iodine in organic solution with the maximum capture capacity of 2122.68 mg/g and 258.29 mg/g, respectively. In iodine-cyclohexane solution, the adsorption process was in according with the Pseudo first order kinetic and Langmuir isothermal model. In addition, the specific recognition and capture mechanism analysis indicated that the aromatic rings, phenolic hydroxyl groups and imine groups in the catechin membrane were the specific and effective grippers for iodine, and finally iodine formed a stable conjugated system with the adsorbent in the form of I- and I3-. Therefore, the as-prepared specific iodine capturer Catechin@ACF was expected to play a vital role in the capture of radioactive iodine in spent fuel off-gas because of its specific recognition, high capture capacity, large-scale preparation, and environment-friendly.

Radioactive iodine capture by metal organic frameworks in liquid and vapour phases: An experimental, kinetic and mechanistic study

For environmental protection, the effectual capture of radioiodine produced or released as nuclear fission products, is of utmost importance. In this aspect, metal-organic frameworks (MOFs) may be a kind of promising material to address this hazardous environmental issue. Herein, four different MOFs, [Co1.5(PhCOO)3(bpy)0.5]n (KQ-1), [Co(HCOO)2(bpy)]n (KQ-2), [Co(HCOO)2]n (KQ-3) and [Mn(HCOO)2]n (KQ-4) have been synthesized via solvothermal method by using benzoic acid (PhCOOH) or formic acid (HCOOH) as organic linker, 4,4′-bipyridine (bpy) as spacer and salts of Co(II) and Mn(II). The as-prepared MOFs were characterized in detail and their iodine (I2) adsorption/release performance was also investigated in vapor and solution phase by UV-Vis spectroscopy with the adsorption capacity being KQ-1 >KQ-2 >KQ-3 ≈ KQ-4. The highest sorption capacity of about 551 and 131.05 mg/g was observed for KQ-1 in vapor and solution phase, respectively, and with recyclability upto five cycles. Raman and XPS spectra indicate that iodine binds to MOF as I2 and I3- species. The plenty of aromatic rings form iodine-π charge transfer complex thus stabilizing the interaction to effect the iodine sorption (as evidenced in KQ-1). Henceforth, the iodine sorption is observed to depend on the presence of aromatic rings in the structure of MOFs.

Designable Assembly of Aluminum Molecular Rings for Sequential Confinement of Iodine Molecules

AbstractAlthough numerous adsorbent materials have been reported for the capture of radioactive iodine, there is still demand for new absorbents that are economically viable and can be prepared by reliable synthetic protocols. Herein, we report a coordination‐driven self‐assembly strategy towards adsorbents for the sequential confinement of iodine molecules. These adsorbents are versatile heterometallic frameworks constructed from aluminum molecular rings of varying size, flexible copper ions, and conjugated carboxylate ligands. Additionally, these materials can quickly remove iodine from cyclohexane solutions with a high removal rate (98.8 %) and considerable loading capacity (555.06 mg g−1). These heterometallic frameworks provided distinct pore sizes and binding sites for iodine molecules, and the sequential confinement of iodine molecules was supported by crystallographic data. This work not only sets up a bridge between molecular rings and infinite porous networks but also reveals molecular details for the underlying host–guest binding interactions at crystallographic resolution.

Sponge-inspired reassembly of 3D hydrolyzed collagen aerogel with polyphenol-functionalization for ultra-capturing iodine from airborne effluents

The efficient capture of radioactive iodine (I-129, I-131) and radon (Rn-222) is crucial to the development of nuclear energy in spent fuel treatment. Herein, we successfully synthesized a new type of three-dimensional hydrolyzed collagen aerogel immobilized with catechin (Catechin@3DCF aerogel) as an effective adsorbent to remove iodine and radon through enzymatic hydrolysis, dialysis, freeze-drying, immobilization, and cross-linking. The as-prepared adsorbent was systematically characterized by FE-SEM, EDX, FT–IR, and XPS, showing that the adsorbent possesses ultra-high porosity, high content flake structure, and abundant adsorption sites on the surface of adsorbent. The results show that Catechin@3DCF aerogel exhibited excellent capture capacity for iodine and radon, with the maximum capture capacity of 222.67 wt% (88.5 wt% for 3DCF aerogel) and 44,877.9 Bq/Kg, respectively. Through the active group-shielding experiment analysis, the phenolic hydroxyl groups on the surface of adsorbent played a major role in iodine capture, followed by the -NHR group. In addition, mechanism studies have shown that the capture of iodine is mainly by chemical adsorption, while the capture of radon is mainly through physical adsorption, which is related to the numerous mesopores and flake structure of the adsorbent. Furthermore, Catechin@3DCF aerogel still maintains excellent adsorption capacity for iodine and radon under 60Co γ-ray irradiation at a total dose ranging from 10 to 350 kGy, indicating that it has excellent radiation resistance stability. Advantages such as novelty, ultra-high porosity, high-radiation stability, ultra-high capture capacity, environment-friendly, and low-cost indicate that biomass-derived Catechin@3DCF aerogel plays a role in the capture of radioactive iodine and radon from airborne effluents.

Bisindole [3]arenes—Indolyl Macrocyclic Arenes Having Significant Iodine Capture Capacity

Bisindole [3]arenes—Indolyl Macrocyclic Arenes Having Significant Iodine Capture Capacity

Boosting radioactive iodine capture of microporous polymers through strengthened host–guest interaction

Abstract Conjugated Microporous Polymers (CMPs) with strong host−guest interactions are promising adsorbents for decontamination of radioactive iodine pollutants, but the relationship between molecular structure and iodine capture performance is not well understood till now. Herein, we report a strategy to promote affinity of cost-effective and stable CMPs towards iodine contaminants through achieving a synergistic effect between the surface polarity and electron density, targeting a strong but reversible capture toward iodine species. The polymeric networks obtained through the coupling chemistry of cyanuric chloride and carbazole (denoted as CCBCB-CMP), presented an attractive adsorption capacity per unit BET specific surface area (11.56 wt/(m2/g)), which is 15 times that of a reference nitrogen-free one (Py-CMP) and surpasses most known counterparts. Furthermore, our CMPs can remove iodine efficiently from the solutions and are easily recovered in at least three consecutive runs through simple extraction. Our work verifies the viability of enhancing host−guest interaction through optimizing the dipole moment and electron density of the building blocks, which would facilitate the design of high-performance scavengers for removing radioactive pollutants.

Construction of Microporous Lignin-Based Hypercross-Linked Polymers with High Surface Areas for Enhanced Iodine Capture

The development of highly efficient, green, and economical materials for radioactive iodine capture has great significance in the safe development of nuclear energy. Here, organosolv lignin (OL) ex...

C[double bond, length as m-dash]N linked covalent organic framework for the efficient adsorption of iodine in vapor and solution.

Volatile nuclear wastes, such as iodine, have received worldwide attention because it poses risks to public safety and pollutes the environment. The efficient capture of radioactive iodine is of vital importance for the safe utilization of nuclear power. Herein, we report a series of stable covalent organic framework (COF) materials with high efficiency to capture radioactive iodine species. Results indicated that all COFs showed high iodine adsorption, which reached up to 5.82 g g−1 in vapor and 99.9 mg g−1 in solution, suggesting that all COFs can be an effective potential adsorbent for the removal of iodine. Furthermore, all COFs are renewable due to the excellent recycling performance. Moreover, all COFs are suitable for large-scale synthesis at room temperature, which have potential for practical applications. Theoretical calculations were also performed to analyze the relationship between iodine molecules and COFs, offering mechanisms underlying the potent adsorption abilities of COFs.

Boosting the Iodine Adsorption and Radioresistance of Th-UiO-66 MOFs via Aromatic Substitution.

Effective capture of radioactive iodine is of paramount importance for the safe and long-term storage of fission products in the nuclear fuel cycle. Herein, a series of functionalized Th-UiO-66 MOFs was employed as a model to investigate the effects of substituents on iodine adsorption in both solution and vapor states. Sorption studies revealed that the electro-donating amino group exhibits the most positive role on increasing the removal rate of iodine from cyclohexane and the uptake capacity of iodine vapor. Particularly, the disubstituted Th-UiO-66-(NH2 )2 can effectively remove 91.9 % of iodine (300 mg L-1 ) from cyclohexane and capture 969 mg g-1 iodine vapor, significantly higher than 59.6 % and 334 mg g-1 of untagged Th-UiO-66, respectively. In addition, the substituent effect on the radiolytic stability of MOFs was for the first time investigated, leading to the unearthing of one of the most radioresistant MOFs Th-UiO-66-NH2 reported to date.

Capture of Iodine from Nuclear-Fuel-Reprocessing Off-Gas: Influence of Aging on a Reduced Silver Mordenite Adsorbent after Exposure to NO/NO2.

Iodine radioisotopes released during nuclear fuel reprocessing must be removed from the off-gas stream before discharge. One promising material for iodine capture is reduced silver mordenite (Ag0Z). Nevertheless, the adsorbent's capacity will degrade, or age, over time when the material is exposed to other off-gas constituents. Though the overall impact of aging is known, the underlying physical and chemical processes are not. To examine these processes, Ag0Z samples were prepared and aged in 2% NO2 in dry air and in 1% NO in N2 gas streams at 150 °C for up to six months. Aged samples were then characterized using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray absorption spectroscopy. These techniques show that aging involves two overarching processes: (i) oxidation of the silver nanoparticles present in Ag0Z and (ii) migration of oxidized silver into the mordenite's inner network. Silver on the nanoparticle's surface is oxidized through adsorption of O2, NO, and NO2. Raman spectroscopy and X-ray absorption spectroscopy indicate that nitrates are the primary products of this adsorption. Most of these nitrates migrate into the interior of the mordenite and exchange at framework binding sites, returning silver to its unreduced state (AgZ). The remaining nitrates exist at a persistent concentration without aggregating into bulk-phase AgNO3. X-ray absorption spectroscopy results further indicate that iodine adsorption occurs on not just Ag0Z but also on AgZ and a portion of the nitrates in the system. AgZ adsorbs a sizable quantity of iodine early in the aging process, but its capacity drops rapidly over time. For well-aged samples, nitrates are responsible for up to 95% of mordenite's iodine capacity. These results have enhanced our understanding of the aging process in silver mordenite and are expected to guide the development of superior adsorbents for the capture of radioactive iodine from reprocessing off-gas.

Efficient capture of radioactive iodine by a new bismuth-decorated electrospinning carbon nanofiber

Radioactive iodine isotopes that are discharged into environment have been of significant concern due to its long-term impact on public health. In this work, a new bismuth-based composite named Bi@ESCNF (bismuth-decorated electrospinning carbon nanofibers) was prepared and investigated for capturing iodine-129 (129I). This material used an electrospinning carbon nanofiber membrane as the substrate and metallic Bi nanoparticles were uniformly inlaid on the fibers, providing a rich active site to capture iodine gas. Due to the strong affinity of bismuth and iodine, Bi@ESCNF exhibited a very high iodine uptake capacity up to 559 mg/g after exposure to iodine for 4 h at 200 °C which could reach approximately two-fold higher than that of the commercial silver exchanged zeolite and even larger than other reported bismuth-based adsorbents. The uptake mechanism was also unraveled by the combined BET, PXRD, SEM, TEM, XPS, and Raman spectra characterizations. It is found that such excellent iodine capture property by this material was attributed to the chemical reaction between bismuth and iodine, which will generate a stable phase of BiI3, and possess a huge specific surface area of 537 m2/g. Thus, our results showed that the new and highly efficient Bi@ESCNF would be a promising adsorbent for radioactive iodine removal.

One-pot synthesis of nitrogen-rich aminal- and triazine-based hierarchical porous organic polymers with highly efficient iodine adsorption

Design and preparation of porous adsorption materials for dealing with environmental issues is attractive and promising, but it remains some challenges such as effective capture of radioactive iodine. Here, two nitrogen-rich porous organic polymers named PAN-B and PAN-T containing triazine and aminal linkages were synthesized through the polycondensation of the triazine-based hexamine (TDATPA) and two aldehyde monomers (benzaldehyde and 2-thenaldehyde) by polycondensation reaction. Fourier transform infrared (FT-IR) and 13C cross polarization/magic angle spinning nuclear magnetic resonance (13C CP/MAS NMR) measurements were performed to characterize their structures. The nitrogen-rich polymers (PAN-B and PAB-T) have hierarchical porous structures, with high Brunauer−Emmett−Teller specific surfaces (SBET) of 1254 m2/g and 1273 m2/g, respectively. And their micropore volume were satisfactory (0.275 cm3/g and 0.279 cm3/g). Moreover, PAN-B and PAN-T behaved very high iodine adsorption efficiency of 237 wt% and 243 wt% in 20 min, respectively, and had high iodine adsorption capacity of above 311 wt%.

Functional porous organic polymer with high S and N for reversible iodine capture

Abstract Nuclear waste such as radioactive iodine has been received worldwide attention because of the effects of radiation on biological health. The efficient capture of radioactive iodine is of great importance for the safe utilization of nuclear energy. In this study, a functional porous organic polymer (P-TzTz) with high sulfur and nitrogen contents was synthesized by the catalyst-free hydrothermal process of dithiocarbanate (DTO) and benzo[1,2-b:3,4-b′:5,6-b″]trithiophene-2,5,8-tricarbaldehyde (BTT-THO) in N,N-dimethylformamide under N2 atmosphere. This tailor-made amorphous polymer exhibits high affinity and adsorption capacity for iodine owing to its effective electron-rich sorption sites, π-conjugated structure and hierarchically porous structure. P-TzTz displays an excellent reversible iodine uptake with capacity of 326 wt% for volatile iodine. After five cycles of volatile iodine adsorption, P-TzTz almost retains the same adsorption capacity with the original adsorbent. In addition, P-TzTz also exhibits excellent adsorptive performance for the removal of iodine from iodine/cyclohexane solution with an adsorption capacity of 494.09 mg g−1, suggesting that P-TzTz may be also an effective adsorbent for the removal of iodine from solution.

Synthesis of metal–organic framework nanocrystals immobilized with 3D flowerlike Cu–Bi-layered double hydroxides for iodine efficient removal

Abstract

Cheap and biodegradable amino acid-based deep eutectic solvents for radioactive iodine capture via halogen bonds

Entrapment of hazardous radioactive iodine has attracted much attention due to the release of radioactive iodine during the application of nuclear energy, such as nuclear waste disposal and nuclear disaster. Deep eutectic solvents (DESs) are deemed as green solvents, designable solvents and solvents of the 21st century. Amino acids are cheap, highly biocompatible and highly biodegradable. Here, we for the first time develop amino acid-based DESs for iodine capture with high efficiency. Effect of structural factors (e.g., mole ratio, composition and composition) and external factors (e.g., mass, concentration and volume of iodine solution) on iodine capture is comprehensively studied. Cysteine:lactic acid (1:8) owns the highest rate and capacity for iodine capture, which shows similar efficiency with previous reports but owns lower cost and higher biodegradability. The high iodine-capturing efficiency of cysteine:lactic acid (1:8) is ascribed to the dominating halogen-bonding interaction (ca. 90%). This work opens a new route for the sustainable capture of radioactive iodine with high efficiency.

Sustainable wastewater treatment by deep eutectic solvents and natural silk for radioactive iodine capture.

The pollution from nuclear leaks and nuclear disasters (e.g. radioactive iodine) would cause serious harm to human beings and ecosystems for many years. Cocoon silk and deep eutectic solvents (DESs) are both green substances. DESs are easily synthesized, cheap, highly biocompatible and highly biodegradable. Here, we combine the removal of organic dyes and the capture of radioactive iodine by using green DES-pretreated cocoon silk. It is the first time organic dyes have been removed from wastewater by DES-disrupted silk for the purpose of favourably removing iodine. Organic dyes-captured DES-pretreated cocoon silk could be used to capture iodine efficiently. It opens a new route to dispose of one waste from nuclear energy with organic dyes from wastewater captured by green solvents-pretreated natural silk.

Controllable Synthesis of Porous Cu-BTC@polymer Composite Beads for Iodine Capture.

The efficient and safe capture of radioactive iodine (129I or 131I) is of great significance in nuclear waste disposal. Here, we report millimeter-scale poly(ether sulfone) composite beads loaded with porous Cu-BTC [Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate] (Cu-BTC@PES), prepared by a phase inversion method for the removal of volatile iodine. Three kinds of Cu-BTC@PES composite beads were obtained with different Cu-BTC contents of 48.6, 60.2, and 71.9%, respectively. While maintaining crystallinity, the composite beads exhibited higher I2 vapor adsorption capacity (639 mg/g) in the form of iodine molecules. The iodine absorption up to 260 mg/g and the adsorption was followed Langmuir isotherm and pseudo-second-order kinetic model. Furthermore, the composite beads can still absorb more than 85% of iodine after 3 cycles of regeneration with excellent recyclability. The resulting Cu-BTC@PES composite beads show great potential for the sustainable removal of radioactive iodine.

Efficient capture of iodine by a polysulfide-inserted inorganic NiTi-layered double hydroxides

Effective capture of radioactive iodine is highly desirable but still remains a significant challenge. We reported here a polysulfide (Sx2−) intercalated inorganic cationic Ni-Ti layered double hydroxide, NiTi-Sx-LDH, which was prepared by coprecipitation method and ion exchange method for efficient capture of iodine. Due to the strong chemical attraction between the soft Lewis base Sx2− and the soft Lewis acid I2, and the reducing property of Sx2−, NiTi-Sx-LDH exhibits highly efficient iodine capture. During the adsorption process, I2 is reduced to I3− by the intercalated Sx2−. In combination with chemical adsorption and physical adsorption, the adsorption capacity of NiTi-Sx-LDH to iodine vapor reaches 52% (wt%). In addition, the adsorption properties of NiTi-Sx-LDH on elemental iodine in organic solvent cyclohexane were also studied, and the maximum adsorption capacity of NiTi-Sx-LDH for iodine reaches up to 527.4 mg/g. Compared with various sorbents for iodine, it is cost-effective, capable of achieving scale-up preparation, and the good performance for the iodine adsorption suggests that NiTi-Sx-LDH may be considered as a promising sorbent for efficient removal of radioactive iodine from reprocessing plant off-gas streams.