Abstract
Nowadays, the demand for nuclear power is continue increasing due to its safety, cleanliness, and high economic benefits. Radioactive iodine from nuclear accidents and nuclear waste treatment processes poses a threat to humans and the environment. Therefore, the capture and storage of radioactive iodine are vital. Bismuth-based (Bi-based) materials have drawn much attention as low-toxicity and economical materials for removing and immobilizing iodine. Recent advances in adsorption and immobilization of vapor iodine by the Bi-based materials are discussed in this review, in addition with the removal of iodine from solution. It points out the neglected areas in this research topic and provides suggestions for further development and application of Bi-based materials in the removal of radioactive iodine.
1 Introduction
Nuclear energy is one of the main sources of electrical energy in the world today. It is advantageous in safety, cleanliness, and lower total operating costs than almost all fossil fuels. The main issues that nuclear energy faced are operational safety and the disposal of radioactive waste (; Woo, 2013). The released off-gas stream from the reprocessing of spent nuclear fuels and serious nuclear power plant accidents contains a variety of radioactive elements (99Tc, 137Cs, 90Sr, 129I, 131I, 3H14C, 85Kr, actinides, lanthanides, etc.) (Soelberg et al., 2013; Subrahmanyam et al., 2015; ; Riley et al., 2016). Radioactivity is a huge threat to humans and the environment due to its easy diffusion (; ; Yang et al., 2018; ). Among these radioactive elements, iodine compounds attract special attention because the iodine is concentrated in the thyroid, and its higher radioactivity can cause damage to the human body in a short time (; ; ; ; ; Thomas et al., 2009; Sava et al., 2013). The radioactivity is produced by 129I, a long-period isotope with a half-life of 1.57 × 107 years (Taylor, 1981; ; Zhang et al., 2011; ), and 131I, a short-lived isotope with a half-life of approximately 8.02 days (Thomas et al., 2009; ). In active waste gas, iodine mainly exists in the form of elemental substances, hydroiodic acid, and organic iodine (CH3I) (; ; ). The initial form of iodine in spent nuclear fuel is cesium iodide. During the dissolution of spent nuclear fuel, iodine ions will react with free radicals produced by radiation to generate volatile elemental iodine. Part of elemental iodine will also react with organic impurities to generate organic iodine (Wren et al., 1999; Taghipour and Evans, 2000; ). These volatile iodine species make the separation and safe storage of radioactive iodine a great challenge.
There are two methods to collect gaseous radioisotopes: the wet scrubbing and the solid phase adsorption. The wet scrubbing includes Mercurex, Iodox, electrolytic and caustic scrubbing (; ; Riley et al., 2016). In these processes, the radioactive iodine species are chemically reacted with the liquid, whereas a large amount of secondary waste is produced (Riley et al., 2016). Compared with wet scrubbing, solid phase adsorption has attracted more attention because of its low cost, simple operation, and high adsorption efficiency (). Many kinds of materials have been applied in the adsorption of vapor radioactive iodine, including activated carbon (; ), graphene-based materials (Scott et al., 2015), zeolites (; ; ; ; ), metal-organic frameworks (MOFs) (Sava et al., 2012; Zhang et al., 2019; ), covalent-organic frameworks (COFs) (Wang et al., 2018; Wang and Zhuang, 2019; Yang et al., 2019), layered double hydroxide-based materials (; ), and aerogels (Subrahmanyam et al., 2015). In the adsorption of radioactive iodine, loading capacity and adsorption efficiency (separation capacity) are the main criteria for evaluating solid adsorbents, along with the stability under the harsh conditions of radioactive gas. For example, the activated carbon, especially loaded with KI/TEDA, has a strong iodine adsorption capacity due to its high porosity and large specific surface area (; ; Pires et al., 2001; ; ; ; Zhou et al., 2014; ). However, the thermal stability of activated carbon is poor, and its adsorption capacity is diminished at the operating temperature of spent fuel processing. Silver-based materials have been widely studied in iodine capture because silver can react with iodine to generate insoluble AgI (; ; Sakurai and Takahashi, 1994; ; ; ; ; Takeshita and Azegami, 2004; Tanabe et al., 2010; ). Although silver-based materials have excellent performance in capturing ability and stability, the high cost and toxic of silver make it necessary to explore alternatives.
In recent years, Bi-based materials have received attentions from researchers due to their environmental and economic advantages including, 1) the toxicity of bismuth is relatively low, no occupational poisoning caused by bismuth or its compounds has been reported; 2) Bismuth is extremely weak in radioactivity with a half-life of about 1.9 × 1019 years; 3) bismuth is much cheaper than silver. In mechanism, bismuth can react with iodine to form BiI3. In addition, Bi2O3 and Bi2S3 can also react with iodine (; ). In an aqueous solution, the formation of products (BixOyIz) depends on the combined effects of the molar ratio of bismuth and iodine, temperature, pH, etc., (; ).
Up to now, various types of Bi-based materials have been developed. Tesfay Reda et al. (2021a) divided the Bi-base materials in iodine capture into two categories: the materials applied in the capture of aqueous iodine and in the capture of vapor iodine. The Bi-based materials for capturing aqueous iodine were emphatically summarized. Ranjan et al. (2020) summarized the capture of pollutants in water by Bi-based materials. The study by mentioned four Bi-based compounds for iodine capture. The Bi-based materials were also summarized in an overview of metal Oxide-based materials (). Recently, the works about capturing vapor iodine by Bi-based materials is growing rapidly. Still, there is a lack of systematic study of these works. The main purpose of this review is to summarize recent advances in Bi-based materials for capturing radioactive iodine, especially the vapor iodine. Besides, the immobilization of radioactive iodine by Bi-based materials is also discussed. It aims to provide methods and suggestions for developing novel Bi-based iodine adsorption materials.
2 Vapor iodine capture
Gaseous iodine capture materials are mainly composed of active sites and carriers. The active sites capture iodine by chemical adsorption (like bismuth), and the carriers provide physical adsorption and load the active sites. Various materials have been developed to capture vapor radioactive iodine, and many of them were commercialized. Some of them, such as zeolites, carbon materials, MOFs, and some other materials, were used as carrier for bismuth and its compounds (shown in Figure 1).
FIGURE 1
2.1 Capture mechanism
2.1.1 Carriers
The mechanism of most Bi-based materials capturing iodine composed by the primary chemical adsorption and the secondary physical adsorption. In the solid adsorbent, the main function of carriers is dispersing active sites. Some carriers (molecular sieves, carbon materials, organic polymers, etc.) also exhibit a certain degree of physical adsorption capacity due to their rich microporous structures. However, in the process of loading bismuth by impregnation, the microporous structure restricts bismuth from entering the materials, and the smaller pores are blocked which will decrease the specific surface area and increase the average pore diameter. On the contrary, mesoporous and macroporous structures have almost no physical adsorption capacity. The loading compounds are easier to enter the material, making the specific surface area and pore diameter smaller (). The observation of Bi0 nanoparticles by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) (Tian et al., 2021a; Xian et al., 2022a; Tian et al., 2022) verified the above phenomena.
2.1.2 Active sites
Iodine reacts chemically with bismuth to mainly generate BiI3, although other BixOyIz compounds can be formed (Yang et al., 2015; Yang et al., 2016; Zou et al., 2019; ). Bi2O3 and Bi2S3 also can react with iodine to form stable compounds. These materials’ adsorption mechanisms for iodide can be represented by the following equations (; Zou et al., 2021; ). In addition, bismuth exists in other forms of Bi(Ⅲ) in some materials (; Tesfay Reda et al., 2021b; ; Qin et al., 2022).
The change of the bismuth state in these materials can be detected by powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS). PXRD pattern can simply indicate the existence of Bi0 (2θ = 22.5, 27.2, 38.0, 39.7, 46.1, 46.7, 48.1, 55.8, 55.5, 55.8, 62.7, 64.6, 71.0, and 72.1°; PDF No. 85-1329), Bi2O3 (2θ = 27.9, 31.8, 32.8, 46.2, 46.9, 54.3, 55.5, 57.8, and 74.5°; PDF No. 78-1793), Bi2S3 (2θ = 22.4, 24.9, 28.6, 31.8, 32.9, 33.9, 45.5, and 46.4°; PDF No. 17-0320) particles loaded on the material before adsorption and the generation of BiI3 (2θ = 12.8, 14.3, 25.7, 27.0, 35.3, 39.2, 41.5, 43.6, 46.1, 50.4, 53.0, 55.6, 58.4, 67.2, 69.5, 71.8, and 72.9°; PDF No. 74-0457) and BiOI (2θ = 29.7, 31.7, 37.0, 39.4, 43.8, 45.4, 51.6, and 55.2°; PDF No. 73-2062) after adsorption. XPS spectra analysis is used to investigate the change in the valence states of bismuth. Due to measurement errors and manual calibration, the peak positions in different reports may be slightly different. The binding energy of Bi0 4f was about 157.2 and 162.6 eV (Xian et al., 2022b). The binding energy of Bi(Ⅲ) 4f is affected by its chemical environment. The duals peaks of Bi@Si-BEA and I-Bi@Si-BEA (Tian et al., 2022) at 159.0, 164.6 eV and 158.9, 164.3 eV were attributed to Bi2O3 and BiI3, while another work deconvolved the characteristic peaks into four peaks (Tesfay Reda et al., 2022). The duals peaks of Bi2S3@ZIF-8 () at 158.5 and 163.8 eV were attributed to Bi2S3. Compared to BiI3, the electronegativity of oxygen in BiOI was slightly higher than iodine, resulting in a slight increase in the binding energy of Bi 4f (Tian et al., 2021a). The analysis of I 3d peaks also varied in different works. For example, Qin et al. (2022) assigned the peaks at 618.8, 630.3, 619.6, and 631.1 eV to I−, I3−, I2, and I5−, respectively. The dual peaks in Bi2O3@g-CNN-PILC were deconvoluted into four peaks at 618.87, 620.57, 630.37, and 631.8 eV which were attributed to I3− and I5−. Tian et al. (2022) assumed that the two peaks at 619.3 eV and 630.8 eV could be attributed to I−. The variation in I 3d peaks may be caused by the adsorption form of iodine in different carriers.
In several reports, the distinct lattice stripes could be observed in the high-resolution transmission electron microscopy (HRTEM) images. The lattice spacing of 0.328, 0.320, 0.31, 0.330, 0.30, and 0.256Â nm corresponded to the planes of Bi0(Xian et al., 2022a; Xian et al., 2022b; Tian et al., 2022), Bi2O3(Tesfay Reda et al., 2022), Bi2S3(), BiI3(Xian et al., 2022a; Tian et al., 2022), BiOI (Qin et al., 2022), and I2(Xian et al., 2022a), respectively. Besides, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and nuclear magnetic resonance (NMR) were also applied in the analysis of iodine adsorption by bismuth-based materials.
2.2 Bismuth-based Materials
2.2.1 Zeolites or molecular sieves
Zeolites are the microporous aluminosilicate solids, which are the most typical molecular sieves. Their covalent network structures are formed by linking the corner oxygen atoms of AlO4 and SiO4 tetrahedra. Due to their regular pore structures, acid resistance, high hydrothermal stability, and cation exchange capacities, zeolites are effective materials for adsorbing elemental iodine and its compounds. Several Ag-exchanged zeolites with different structures have been studied for this application, including mordenite (MOR) (; Verger et al., 2001; ; ; ; Zhao et al., 2011; ; Soelberg et al., 2013; ; ; ; Riley et al., 2016; Zakirova et al., 2017), NaX zeolite (), NaY zeolite, ZSM-5, ZSM-11 (; ), ferrierite and β zeolite.
Compared with silver-exchanged zeolite, bismuth-exchanged zeolite has rarely been applied in the adsorption of vapor iodine. developed bismuth-doped mordenite (Bi5@Mordenite). After being exposed to iodine at 200°C for 6 h, its iodine adsorption capacity could reach a maximum of 538 mg I2 per gram adsorbent (hereinafter referred to as mg/g), which doubled the iodine adsorption capacity of the raw zeolite (214 mg/g) and Ag@Mordenite (275 mg/g). The SEM and XPS results showed that the surface area and pore volume of zeolite increased due to the dealumination of zeolite in the process of loading bismuth in nitric acid. It is indicated that Bi-exchanged mordenite could be an alternative to Ag-exchanged mordenite for the capture of iodine.
In industrial processes, the humidity of radioactive iodine off-gas is relatively high which could diminish the iodine capture ability of most zeolites. Tian et al. (2022) introduced the all-silica beta zeolite to improve the hydrophobic properties. A bismuth-modified all-silica beta zeolite (Bi@Si-BEA) (Figures 2A, B) was synthesized through a wetness impregnation process followed by ultrasonication and H2 reduction. The total iodine adsorption capacity can reach 650 mg/g at approximately 120°C. The synthesis process was scaled up for possible industrial applications. However, the mechanisms of effects from water vapor or other substances in off-gas require more investigation. Hydrophobic modification of the zeolite is another way to reduce the negative effect of water vapor. Recently, developed a hydrophobic zeolite (NaY-NH4F-Bi2S3) containing Bi2S3 by NH4F solution etching and a hydrothermal method (Figures 2C, D). The maximum adsorption capacity of NaY-NH4F-Bi2S3 (30 wt%) at equilibrium is 491 mg/g. The adsorption capacity and equilibration time of the zeolite (50 wt%) both decreased after granulation.
FIGURE 2
Bismuth-modified SBA-15 is one of the relatively well-studied molecular sieves. Yang et al. (2015) first applied bismuth-doped mesoporous silica (SBA-15) in the field of iodine adsorption and long-term storage. Bismuth was incorporated into the SBA-15 material by previously modifying the silica surface with thiol groups and subsequent thermal treatment that led to the formation of a Bi2S3 phase. The as-synthesized sorbents could effectively capture iodine gas with the maximal loading capacity of 540Â mg/g, which was attributed to the strong reaction tendency of bismuth sulfide with iodine gas, as well as elevated specific surface area and porosity of SBA-15. Furthermore, a chemically durable iodine-loaded material was made with a facile post-sorption process, during which the iodine-incorporated phase was effectively changed from BiI3 to chemically durable Bi5O7I.
Furthermore, the bismuth-embedded SBA-15 is examined as a vapor iodine filtration material at a higher temperature up to 250°C (
Recently, Xian et al. (2022a) improved the impregnation reduction method to facilely fabricate Bi0-SBA-15, with Bi (NO3)3∙5H2O as bismuth source and SnCl2∙2H2O as reductant (Figure 3). The reaction is represented by the following equation. The bismuth was loaded on the surface of SBA-15 in the form of flocculent and spherical nanoparticles, which provides abundant active sites. The capture capacity was up to 925 mg/g at 200°C within 60 min (Figure 3B). They also scaled up the synthesis with the same route to get a Bi0-SiO2 which had a capture capacity of 1019 mg/g at 200°C (Xian et al., 2022b). Compared with SBA-15, commercial SiO2 is affordable, easy to be scaled up, and time-saving but has a smaller specific surface area. The adsorption capacity after granulation needs to be further investigated.
FIGURE 3

(A) Preparation and Iodine Adsorption of Bi0-SBA-15; (B) Capture Capacity of Iodine at 200°C; (C) SEM image of 0.5Bi0-SBA-15 (Xian et al., 2022a).
2.2.2 Carbon materials
In 2020,
In another research, Zou et al. (2021) reported a composite with high iodine capture capacity. The Bi2S3 reduced graphene oxide (RGO) was produced via a solvothermal method which was shown in Figure 4. The adsorption capacities of iodine could reach 1042.8 mg/g at 200 °C for 2 h under a static air atmosphere. Graphitic carbon nitride (g-C3N4) or graphitic carbon nitride nanosheets (g-CNN) can be easily obtained by modifying melamine, which is eco-friendly and cheap. Tesfay Reda et al. (2022) synthesized Bi2O3@g–CNN and added pillared interlayered clays (PILC) to increase stability, as shown in Figure 5. The product, Bi2O3@g–CNN-PILC, had an iodine capture capacity of 830 ± 44 mg/g at 100°C within 8 h.
FIGURE 4

(A) and (B) Preparation, Iodine Adsorption and Immobilization of Bi2S3-RGO; (C) FESEM image Bi2S3-RGO-I (Zou et al., 2021).
FIGURE 5

(A) SEM image Bi2O3@g-CNN-PILC; (B) Preparation of Bi2O3@g-CNN-PILC (Tesfay Reda et al., 2022).
2.2.3 MOFs
In the past 20 years, various studies have been carried out on metal-organic frameworks (MOFs) owing to their extremely high specific surface areas (up to 104 m2 g−1), high compositional flexibility, and selective gas absorption (
FIGURE 6

Fabrication of BZ core-shell nanocomposites (
Besides, some MOFs with bismuth ions directly act as connectors in the framework have been reported. They are mostly used for photocatalysis and gas adsorption.
2.2.4 Other materials
Yu Q et al. (2020) synthesized millimeter-sized spherical bismuth sulfide@polyacrylonitrile (Bi2S3@PAN) hybrid beads. Under 75°C, the iodine capture capacity of Bi2S3@PAN hybrid beads could reach 986 mg/g. Compared with most powder materials, the beads exhibit not only high iodine adsorption properties but also easy storage and manipulation.
Another report conducted by Tian et al. (2021b) developed bismuth and silver functionalized Ni foam composites (Bi-Ni foam and Ag-Ni foam). As illustrated in Figure 7A, Bi-Ni foam shows a higher iodine capture capacity (658Â mg/g) but slower adsorption kinetics than Ag-Ni foam (456Â mg/g). Due to the more active sites (Bi0 or Ag0 particles) and the external structure of the Ni foam skeleton, the physically adsorbed iodine is much less than the chemically adsorbed iodine (96% iodine captured in the term of stable form in the I-Bi-Ni foam). Besides, thanks to the nickel skeleton, the material has the advantages of convenient shaping and manipulation.
FIGURE 7

(A) Preparation and Iodine Adsorption of Bi-Ni and Ag-Ni foams; (B) SEM image of I-Bi-Ni foam (Tian et al., 2021b); (C) Preparation and Iodine Adsorption of Bi@AlCu-PILC; (D) SEM image of Bi@AlCu-PILC-I (Tesfay Reda et al., 2021b).
Zou et al. (2019) developed Bi-Bi2O3-TiO2-C, which was prepared by a sol-gel method for capturing vapor iodine. Bi-Bi2O3-TiO2-C exhibited an iodine adsorption capacity of up to 504Â mg/g, which was almost two-fold higher than that of AgX. The authors proposed that majority of iodine was chemically captured in the form of BiI3 while a small amount was also physically captured as I2. In addition, TiO2 contributes to an important portion of the captured iodine.
A bismuth-modified zinc aluminum layered double hydroxide (BiZnAl-LDH) was synthesized via co-precipitation by
By impregnating AlCu-oxides pillared Montmorillonite (MMN) with bismuth, Tesfay Reda et al. (2021b) produced Bi-based mesoporous material (Bi@AlCu-PILC), as shown in Figure 7B. AlCu-oxides formed pillars in the gallery of montmorillonite by ion exchange. After calcination, the bismuth was loaded onto these pillars. This single-phase material had high capture capacity (485 ± 54 mg/g under 75°C) and thermal stability.
Several authors have studied chalcogen aerogel containing bismuth as potential adsorbents for iodine, technetium, and uranium trapping. Riley et al. (2013) developed structured aerogels, Co0.7Bi0.3MoS4 (CoBiMoS), which could remove more than 99.0% vapor iodine over the test duration. The adsorption mechanism has also been reported. Chalcogens enclosed in chalcogels are classified as weak Lewis bases according to the hard and soft acids and bases (HSAB) concept (Riley et al., 2011). Consequently, the chalcogens have a high affinity for iodine (I2), which is known as a weak Lewis acid. The removal efficiency was governed by the affinity of I2(g) and S other than the surface area of chalcogels. This aerogel has the potential for radionuclides removal from solution and gas. However, sulfur compounds could be formed considering the sulfur is part of the material, which will produce secondary pollution. The thermal stability of stored iodine over 150°C has not been examined in this study. However, chalcogels with other adsorbents (Zn2Sn2S6 and Sb4Sn3S12) (Subrahmanyam et al., 2015) have a quite low thermal stability of iodine capture (or the formed iodides). TGA results showed that beyond that temperature, iodine was released progressively.
2.3 Summary
The capture capacity of the materials mentioned above is summarized in Table 1. The performance of most materials are better than that of bare adsorbents or Ag-modified adsorbents, which is partly due to the reaction mechanism between bismuth and iodine. However, due to the different thermal stability of raw materials and other reasons, the optimal capture temperature varied widely. At the same time, the volume of the containers used in the static adsorption experiments and the mass of solid iodine added were also different. There are still few studies in this topic, making it difficult to compare the actual properties of different materials objectively. The density of different materials is also dissimilar, resulting in large differences in volume which is important in practical adsorption devices.
TABLE 1
| Material | Forms of bismuth | Load content (wt%) | Adsorption temperature (°C) | Capture capacity (mg/g) | Approximate equilibrium time (h) | Modification method | Ref. |
|---|---|---|---|---|---|---|---|
| Bi5@Mordenite | Bi2O3 | 5 | 200 | 538 | 6 | Impregnation, Calcination | |
| Bi@Si-BEA | Bi0 | 25 | 160 | 650 | 2 | Impregnation, H2 Reduction | Tian et al. (2022) |
| NaY-NH4F-Bi2S3 | Bi2S3 | 30 | 75 | 491 | 6 | Etching, Hydrothermal | |
| Bir-SBA-15-SH2A | Bi2S3 | / | 200 | 540 | / | Hydrothermal, Impregnation, H2 Reduction | Yang et al. (2015) |
| Bi-SBA-15 | Bi2S3 | / | 150 | −750 | / | ||
| Bi0-SBA-15 | Bi0 | 25 | 200 | 925 | 1 | Impregnation, H2 Reduction | Xian et al. (2022a) |
| 150 | 1027 | ||||||
| Bi0-SiO2 | Bi0 | / | 200 | 1019 | 1 | Impregnation, H2 Reduction | Xian et al. (2022b) |
| Bi@ESCNF | Bi0 | / | 200 | 559 | 1.5 | Electrospinning, Pre-oxidation, Carbonization | |
| HT-Bi-ESCNF | Bi0 | / | 200 | 732 | 1.5 | Electrospinning, Pre-oxidation, Carbonization, Hydrothermal | Tian et al. (2021a) |
| HT-Bi-Bi2O3-ESCNF | Bi0 Bi2O3 | 461 | 0.75 | ||||
| HT-Bi2O3-ESCNF | Bi2O3 | 364 | 0.5 | ||||
| Bi2S3-RGO | Bi2S3 | / | 200 | 1042.8 | / | Solvothermal | Zou et al. (2021) |
| Bi2O3@g–CNN-PILC | Bi2O3 | 15 | 100 | 830 | 8 | Impregnation, Solvothermal | Tesfay Reda et al. (2022) |
| Bi-mna | Bi3+ | / | 77–227 | −700 | / | Solvothermal | |
| Bi2S3@ZIF-8 (BZ) | Bi2S3 | 5 | 77 | 2637 | 6 | Solvothermal, Mix | |
| BiZnAl-LDH | Bi3+ | / | 75 | 433 | / | Mix, Crystallization | |
| Bi2S3@PAN | Bi2S3 | 70 | 75 | 986 | / | Hydrothermal, Polyacrylonitrile Hybrid | Yu Q et al. (2020) |
| Bi@AlCu-PILC | Bi3+ | 20 | 75 | 485 | 72 | Impregnation | Tesfay Reda et al. (2021b) |
| Bi-Bi2O3-TiO2-C | Bi0 Bi2O3 | / | 200 | 504 | <2 | Sol-gel, Calcination | Zou et al. (2019) |
| Bi-Ni foam | Bi0 | / | 200 | 618 | 2.5 | Solvothermal | Tian et al. (2021b) |
| 3DOM-SB20 | Bi0 | 20 | 200 | 696 | / | Sol–gel, Calcination | |
| NOTT-220 | Bi3+ | / | 75 | 955 | 27 | Heating | Qin et al. (2022) |
| Bi@MVF | Bi0 | 20 | 120 | 1560 | 6 | Carbonization, Impregnation, H2 Reduction | |
| Bi0@SiO2-P | Bi0 | / | 960 | 75 | 2 | Templet Synthesis, Impregnation, H2 Reduction | |
| 890 | 130 | ||||||
| 830 | 200 |
Bi-based materials for vapor iodine capture.
In practical industrial processes, the inevitably generated CH3I must be removed because of its high toxicity and radioactivity. Compared to silver-based materials, the ability of Bi-based materials to adsorb CH3I needs to be further investigated. Besides, many materials’ considerable capture capacities are owing to the large number of active sites on the materials’ surface. It is necessary to study how to test the performance in dynamic adsorption experiments while keeping the performance after granulation.
3 Materials stability and immobilization
3.1 Materials stability after adsorption
The stability of the materials after adsorption is mainly divided into chemical durability and thermal stability.
Physically adsorbed iodine will desorb over time, especially if the iodine-containing waste is exposed to hot air or solution. A higher ratio of physical adsorption capacity corresponds to the poor chemical durability of waste.
In the TGA of Bi-based materials and immobilization tests, BiOI and Bi7O5I showed better thermal stability. In most experiments, the BiI3 decomposed in the range of 200°C–500°C with the reducing of iodine to bismuth ratio, which led to the escape of iodine. The mechanisms can be demonstrated by the following equations (Yang et al., 2016; Zou et al., 2019; Zou et al., 2021). To safely immobilize iodine, additional bismuth must be mixed with the waste of adsorption materials.
The thermal stability of the waste includes that of bismuth-iodine compounds (BixOyI) and supports. Comparing TGA and adsorption results of different materials, under approximately 200°C, BiI3 and BiOI are not easily oxidized. The slight weight loss is attributed to the loss of free water and physically adsorbed iodine. Such as Bi2S3-RGO-I, only 1.5% of weight was lost (the physically adsorbed water and iodine) till 200°C, and the left 83.5% weight was lost from 200°C to 450°C (the chemically adsorbed iodine). The TG-DSC results of Bi-Bi2O3-TiO2-C showed a vast weight loss of 47.97% when heated from 200°C to 300°C, which suggested that the stability of the material was relatively low. The TGA curves showed that after iodine capture, Bi2O3@g–CNN-PILC (Tesfay Reda et al., 2022) only lost 18.7% of the total weight when heated up to 800°C, which exhibited excellent thermal stability.
3.2 Immobilization
For the above reasons, additional bismuth materials are necessary to prevent iodine overflow during immobilization. A study led by Yang et al. (2016) aimed to stabilize iodine confined in Bi-embedded SBA-15. The iodine-containing waste was mixed with low-temperature sintering glasses and Bi2O3, which were used as binders and stabilizing additives, respectively. A quite satisfactory leaching rate of iodine was measured by a PCT test ranging from 10−3 to 10−2 g/m2 day, which suggested that the glass composite waste form of bismuth embedded SBA-15 could be a potential candidate material for the stable storage of 129I. However, the leaching experiment was not performed over an extended duration, and further investigation of stability over a longer period is necessary for better insight. Bi@AlCu-PILC (Tesfay Reda et al., 2021b) was transformed into a more stable form (Bi5O7I) by post-sorption treatment with Bi2O3 at 500°C, which had the potential to serve as a long-term disposable iodine waste form.
Some other studies have explored the use of bismuth-containing glass powder for solidification and sintering after adsorption. In these studies, bismuth was added in the immobilization and sintering process to prevent iodine’s escape, while majority of the adsorbents were silver-based materials.
4 Aqueous iodine capture
4.1 Capture mechanism and solubility
The adsorption mechanisms for aqueous iodide and iodate can be represented by the following equations (
Different from the capture of vapor iodine, the formation of BixOyIz depends on the bismuth to iodine ratio in the solution. By leaching experiments,
4.2 Removal of radioactive iodine in synthetic groundwater
Synthetic groundwater (SGW) refers to the groundwater at the Hanford Site (WA, United States), where multiple radionuclides and other hazardous contaminants are detected.
TABLE 2
| Material | Form | Initial concentration (mg/L) | Final concentration (mg/L) | Sampling time (d) | Iodine loading (mg/g) | Kd (mL/g) | Ref. |
|---|---|---|---|---|---|---|---|
| BINa | powder | 1.0100 | 0.001 | 1 | / | 2.02 × 105 | |
| Bi-Co-Al | powder | 0.9900 | 0.02 | 1 | / | 1.28 × 104 | |
| BIN | powder | 0.2080 | <0.126c | 30 | / | / | |
| BIN | powder | 1.0700 | 0.00001 | 1 | 0.214 | 2.14 × 107 | |
| BSNb | powder | 1.0700 | 0.00001 | 0.214 | 2.14 × 107 | ||
| BIN-S | silica substrate (unwashed) | 1.0750 | 0.0332 | 0.209 | 6.50 × 103 | ||
| BIN | PAN beads | 1.0800 | 0.0005 | 0.216 | 4.75 × 105 | ||
| BSN | PAN beads | 1.0050 | 0.001 | 0.199 | 1.99 × 105 |
Batch experiments of some Bi-based materials in synthetic groundwater.
BIN, is the abbreviation of Bismuth(oxy)hydroxide.
BSN, is the abbreviation of Bismuth subnitrate.
The iodine concentration is below the detection limit of the instrument.
4.3 Materials
A nitrate-containing bismuth compound, Bi5(NO3)O7, was discussed for removing and solidifying aqueous iodine among other halogenide ions from solution. The NO3− ion was significant for the removal for its effective exchange with iodide ion. When 244 mg of Bi5(NO3)O7 reacted with 0.1 mol/dm3 of iodide at 50°C and 75°C, over 99.99% of iodine ion was removed (
Another nitrate incorporated bismuth oxide, BiPbO2NO3 (BPN), was developed to remove iodide ions in a solution and fix them in the solidified material BiPbO2I (BPI) by the ion exchange reaction (
Fiber materials are widely used in the field of adsorption thanks to their excellent surface area, porous nature, and the presence of the functional group. By varieties of modifications, these materials have improved the selectivity to increase the capture capacity of iodine. Several polyacrylonitrile were modified with bismuth oxyhydroxide (PAN-BIN) (
With low solubility in water, Bi2O3 could capture iodine by reacting with I− to form insoluble compounds, such as BiOI, Bi5O7I, and Bi7I3O9 (
Most Bi-based materials for capturing aqueous iodine in batch experiments had been listed by Tesfay Reda and Muhire (Tesfay Reda et al., 2021a;
TABLE 3
| Material | Form of iodine | Solvent | Temperature (°C) | Capture capacity (mg/g) | Ref. |
|---|---|---|---|---|---|
| Bi15/Al-DMAPS | I2 | toluene | 50 | 251.3 | |
| Bi2S3@ZIF-8 | I2 | cyclohexane | R. T. | 532.9 | |
| NaY-NH4F-Bi2S3 (30%) | I2 | cyclohexane | / | 285 | |
| δ-Bi2O3@PES | I− | water | R. T. | 95.4 | Zhao et al. (2021) |
| IO3− | R. T. | 170.6 | |||
| ZIF-67/CuBi–CO3-LDH | I2 | n-hexane | / | 180.23 | Yu F et al. (2020) |
Recent Bi-based materials for iodine capture in solution.
5 Conclusion
With advantages of safety, green emission, and high economic efficiency, nuclear energy is one of the main energy sources in the world. The radioactive iodine and its compounds from serious nuclear accidents and the reprocessing of spent nuclear fuels demand efficient capture and safe storage. Compared with other mature adsorbents (such as activated carbon and Ag-based materials), Bi-based materials with lower toxicity, lower cost, and almost no radioactivity have attracted the researchers’ attention recently. These materials were applied in the capture of both aqueous iodine and vapor iodine.
The capture capacities of many Bi-based materials were higher than commercial adsorbents. Most Bi-based modified absorbents combined the advantages of high specific surface area and abundant active sites. It demonstrates that developing Bi-based modified materials based on existing supports is feasible. By characterization, leaching experiments, and immobilization experiments, it is indicated that Bi, Bi2O3, and Bi2S3 can react with iodine to generate BixOyIz. At higher temperature, the stability of Bi5O7I is superior to BiOI and BiI3, which means that chemisorbed iodine can be released and additional bismuth is needed for immobilization. Although the types of Bi-based materials are rich, there is a lack of systematic research and comparison. Besides, the research about the capture of Bi-based materials for CH3I, one of the radioactive iodine components, needs to be further investigated. For already developed adsorbents, granulation and dynamic adsorption experiments are also of consequence.
Statements
Author contributions
CL and CX conceived the idea of the study, outlined the structure of this paper, and revised the manuscript draft. YH and ZT reviewed the literature and drafted the original manuscript. All authors approved the final version of the manuscript to be published.
Funding
This research is financially supported by the National Natural Science Foundation of China (Nos. 22176017 and U2067213).
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Publisher’s note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
References
1
AbneyC. W.NanY.TavlaridesL. L. (2017). X-ray absorption spectroscopy investigation of iodine capture by silver-exchanged mordenite. Ind. Eng. Chem. Res.56 (16), 4837–4846. 10.1021/acs.iecr.7b00233
2
Al-MamooriA.AlsalbokhM.LawsonS.RownaghiA. A.RezaeiF. (2020). Development of bismuth-mordenite adsorbents for iodine capture from off-gas streams. Chem. Eng. J.391, 123583. 10.1016/j.cej.2019.123583
3
AlsalbokhM.FakeriN.RownaghiA. A.LudlowD.RezaeiF. (2021). Aminosilane-grafted bismuth-alumina adsorbents: Role of amine loading and bismuth content in iodine immobilization from aqueous solutions. Chem. Eng. J.409, 128277. 10.1016/j.cej.2020.128277
4
AmayaT.MukunokiA.ShibuyaM.KodamaH. (2000). Study of BiPbO2NO3 for I-129 fixation under reducing conditions. MRS Online Proc. Libr.663, 43. 10.1557/PROC-663-43
5
AmpelogovaN. I.KritskiiV. G.KrupennikovaN. I.SkvortsovA. I. (2002). Carbon-fiber adsorbent materials for removing radioactive iodine from gases. At. Energy92 (4), 336–340. 10.1023/a:1016558127710
6
AspromonteS. G.MizrahiM. D.SchneebergerF. A.LópezJ. M. R.BoixA. V. (2013). Study of the nature and location of silver in Ag-exchanged mordenite catalysts. Characterization by spectroscopic techniques. J. Phys. Chem. C117 (48), 25433–25442. 10.1021/jp4046269
7
BennettT. D.SainesP. J.KeenD. A.TanJ.-C.CheethamA. K. (2013). Ball-milling-induced amorphization of zeolitic imidazolate frameworks (ZIFs) for the irreversible trapping of iodine. Chem.-Eur. J.19 (22), 7049–7055. 10.1002/chem.201300216
8
BruffeyS. H.JubinR. T.JordanJ. A. (2016). Capture of elemental and organic iodine from dilute gas streams by silver-exchanged mordenite. Procedia Chem.21, 293–299. 10.1016/j.proche.2016.10.041
9
ChabautyA. L.CampayoL.MéarF. O.MontagneL. (2019). Niobium- and bismuth-silver phosphate glasses for the conditioning of radioactive iodine. J. Non-Cryst. Solids510, 51–61. 10.1016/j.jnoncrysol.2019.01.015
10
ChangS.WangK.GaoL.LiuJ.WangL.LiY.et al (2022a). Highly efficient adsorption of radioiodine by a three-dimensional ordered macroporous bismuth-silica composite aerogel. Chem. Eng. Sci.260, 117856. 10.1016/j.ces.2022.117856
11
ChangS.WangK.WangL.SongX.LiuJ.ChenJ.et al (2022b). Effects of calcination rate and temperature on microstructure and gaseous iodine capture capacity of 3DOM-SiO2 aerogels. Prog. Nucl. Energy151, 104328. 10.1016/j.pnucene.2022.104328
12
ChapmanK. W.ChupasP. J.NenoffT. M. (2010). Radioactive iodine capture in silver-containing mordenites through nanoscale silver iodide formation. J. Am. Chem. Soc.132 (26), 8897–8899. 10.1021/ja103110y
13
ChebbiM.AzambreB.CantrelL.HuvéM.AlbiolT. (2017a). Influence of structural, textural and chemical parameters of silver zeolites on the retention of methyl iodide. Microporous Mesoporous Mat.244, 137–150. 10.1016/j.micromeso.2017.02.056
14
ChebbiM.AzambreB.VolkringerC.LoiseauT. (2018). Dynamic sorption properties of metal-organic frameworks for the capture of methyl iodide. Microporous Mesoporous Mat.259, 244–254. 10.1016/j.micromeso.2017.10.018
15
ChebbiM.ChibaniS.PaulJ.-F.CantrelL.BadawiM. (2017b). Evaluation of volatile iodine trapping in presence of contaminants: A periodic dft study on cation exchanged-faujasite. Microporous Mesoporous Mat.239, 111–122. 10.1016/j.micromeso.2016.09.047
16
CheeT.-S.TianZ.ZhangX.LeiL.XiaoC. (2020). Efficient capture of radioactive iodine by a new bismuth-decorated electrospinning carbon nanofiber. J. Nucl. Mater.542, 152526. 10.1016/j.jnucmat.2020.152526
17
ChenK.WangP.GuA.Djam MiensahE.GongC.MaoP.et al (2022). Core-shell Bi2S3 nanorods loaded ZIF-8 nanocomposites for efficient and reversible capture of radioactive iodine. Microporous Mesoporous Mat.339, 111983. 10.1016/j.micromeso.2022.111983
18
ChengQ.YangW.LiZ.ZhuQ.ChuT.HeD.et al (2015). Adsorption of gaseous radioactive iodine by Ag/13X zeolite at high temperatures. J. Radioanal. Nucl. Chem.303 (3), 1883–1889. 10.1007/s10967-014-3736-3
19
ChibaniS.ChebbiM.LebègueS.CantrelL.BadawiM. (2016). Impact of the Si/Al ratio on the selective capture of iodine compounds in silver-mordenite: A periodic DFT study. Phys. Chem. Chem. Phys.18 (36), 25574–25581. 10.1039/c6cp05015h
20
ChienC.-C.HuangY.-P.WangW.-C.ChaoJ.-H.WeiY.-Y. (2011). Efficiency of moso bamboo charcoal and activated carbon for adsorbing radioactive iodine. Clean-Soil Air Water39 (2), 103–108. 10.1002/clen.201000012
21
ChoiB.-S.ParkG.-I.LeeJ.-W.YangH.-Y.RyuS.-K. (2003). Preparation and structural studies of organotin(IV) complexes formed with organic carboxylic acids. J. Radioanal. Nucl. Chem.256 (1), 19–26. 10.1023/a:1023383505788
22
ChoiB. S.ParkG. I.KimJ. H.LeeJ. W.RyuS. K. (2001). Adsorption equilibrium and dynamics of methyl iodide in a silver ion-exchanged zeolite column at high temperatures. Adsorpt.-J. Int. Adsorpt. Soc.7 (2), 91–103. 10.1023/a:1011660121182
23
CordovaE. A.Garayburu-CarusoV.PearceC. I.CantrellK. J.MoradJ. W.GillispieE. C.et al (2020). Hybrid sorbents for 129I capture from contaminated groundwater. ACS Appl. Mater. Interfaces12 (23), 26113–26126. 10.1021/acsami.0c01527
24
DeitzV. R. (1987). Interaction of radioactive iodine gaseous species with nuclear-grade activated carbons. Carbon25 (1), 31–38. 10.1016/0008-6223(87)90037-6
25
DeuberH. (1986). Investigations on the retention of elemental radioiodine by activated carbons at high-temperatures. Nucl. Technol.72 (1), 44–48. 10.13182/nt86-a33751
26
DingY.-H.ZhangX.-L.ZhangN.ZhangJ.-Y.ZhangR.LiuY.-F.et al (2018). A visible-light driven Bi2S3@ZIF-8 core–shell heterostructure and synergistic photocatalysis mechanism. Dalton Trans.47 (3), 684–692. 10.1039/c7dt03256k
27
DingY.FanW.XianQ.DanH.ZhuL.DuanT. (2023). Capture of iodine gas by Bi0 modified silica with different morphologies: Influence of pore characteristic on the stable and unstable forms of adsorption. Chem. Eng. J.451, 138887. 10.1016/j.cej.2022.138887
28
DinhT. D.ZhangD.TuanV. N. (2020). High iodine adsorption performances under off-gas conditions by bismuth-modified ZnAl-LDH layered double hydroxide. RSC Adv.10 (24), 14360–14367. 10.1039/d0ra00501k
29
FunabashiK.FukasawaT.KikuchiM. (1995). Investigation of silver-impregnated alumina for removal of radioactive methyl iodide. Nucl. Technol.109 (3), 366–372. 10.13182/nt95-a35085
30
GarinoT. J.NenoffT. M.KrumhanslJ. L.RademacherD. X. (2011). Low-temperature sintering Bi–Si–Zn-Oxide glasses for use in either glass composite materials or core/shell 129I waste forms. J. Am. Ceram. Soc.94 (8), 2412–2419. 10.1111/j.1551-2916.2011.04542.x
31
GoldsmithJ. R.GrossmanC. M.MortonW. E.NussbaumR. H.KordyshE. A.OuastelM. R.et al (1999). Juvenile hypothyroidism among two populations exposed to radioiodine. Environ. Health Perspect.107 (4), 303–308. 10.1289/ehp.99107303
32
Gonzalez-GarciaC. M.RomanS.GonzalezJ. F.SabioE.LedesmaB. (2013). Surface free energy analysis of adsorbents used for radioiodine adsorption. Appl. Surf. Sci.282, 714–717. 10.1016/j.apsusc.2013.06.040
33
GrossmanC. M.MortonW. E.NussbaumR. H. (1996). Hypothyroidism and spontaneous abortions among Hanford, Washington, downwinders. Arch. Environ. Health51 (3), 175–176. 10.1080/00039896.1996.9936012
34
GrossmanC. M.NussbaumR. H.NussbaumF. D. (2003). Cancers among residents downwind of the Hanford, Washington, plutonium production site. Arch. Environ. Health58 (5), 267–274. 10.3200/aeoh.58.5.267-274
35
GrossmanC. M.NussbaumR. H.NussbaumF. D. (2002). Thyrotoxicosis among Hanford, Washington, downwinders: A community-based health survey. Arch. Environ. Health57 (1), 9–15. 10.1080/00039890209602911
36
HanS.UmW.KimW.-S. (2019). Development of bismuth-functionalized graphene oxide to remove radioactive iodine. Dalton Trans.48 (2), 478–485. 10.1039/c8dt03745k
37
HeX.ChengW.YanM.SongW.LiuY.ZhangZ.et al (2022). Performance research and engineering application of B2O3-Bi2O3-ZnO glass powder for solidifying iodine-containing silver silica gel. J. Non-Cryst. Solids576, 121305. 10.1016/j.jnoncrysol.2021.121305
38
HerdesC.ProsenjakC.RománS.MüllerE. A. (2013). Fundamental studies of methyl iodide adsorption in DABCO impregnated activated carbons. Langmuir29 (23), 6849–6855. 10.1021/la401334d
39
HornerD. E.MailenJ. C.PoseyF. A. (1977). Electrolytic trapping of iodine from process gas streams. Washington, DC: U.S. Patent and Trademark Office. U.S. Patent No 4,004,993.
40
HriziC.SametA.AbidY.ChaabouniS.FliyouM.KouminaA. (2011). Crystal structure, vibrational and optical properties of a new self-organized material containing iodide anions of bismuth(III), [C6H4(NH3)2]2Bi2I10·4H2O. J. Mol. Struct.992 (1), 96–101. 10.1016/j.molstruc.2011.02.051
41
HuangR. J.SeitzK.BuxmannJ.PöhlerD.HornsbyK. E.CarpenterL. J.et al (2010). In situ measurements of molecular iodine in the marine boundary layer: The link to macroalgae and the implications for O-3, IO, OIO and NOx. Atmos. Chem. Phys.10 (10), 4823–4833. 10.5194/acp-10-4823-2010
42
HughesJ. T.SavaD. F.NenoffT. M.NavrotskyA. (2013). Thermochemical evidence for strong iodine chemisorption by ZIF-8. J. Am. Chem. Soc.135 (44), 16256–16259. 10.1021/ja406081r
43
InagakiY.ImamuraT.IdemitsuK.ArimaT.KatoO.NishimuraT.et al (2008). Aqueous dissolution of silver iodide and associated iodine release under reducing conditions with FeCl2 solution. J. Nucl. Sci. Technol.45 (9), 859–866. 10.1080/18811248.2008.9711487
44
JiangM.ZhuL.ZhaoQ.ChenG.WangZ.ZhangJ.et al (2022). Novel synthesis of NaY-NH4F-Bi2S3 composite for enhancing iodine capture. Chem. Eng. J.443, 136477. 10.1016/j.cej.2022.136477
45
JungY.-E.KangS.-W.YimM.-S. (2021). Feasibility study of using Bi-mna metal–organic frameworks as adsorbents for radioiodine capture at high temperature. Ind. Eng. Chem. Res.60 (16), 5964–5975. 10.1021/acs.iecr.1c00450
46
KangS. W.YangJ.-H.YimM.-S. (2020). Examining practical application feasibility of bismuth-embedded SBA-15 for gaseous iodine adsorption. Nucl. Technol.206 (10), 1593–1606. 10.1080/00295450.2020.1713680
47
KikuchiM.KitamuraM.YusaH.HoriuchiS. (1978). Removal of radioactive methyl iodide by silver impregnated alumina and zeolite. Nucl. Eng. Des.47 (2), 283–287. 10.1016/0029-5493(78)90071-7
48
KindelO.HoeflichV.HerrmannF. J.PatzeltP. (1993). Removal of iodooraganic compounds from kerosene in nuclear fuel reprocessing. J. Radioanal. Nucl. Chem.176 (3), 251–259. 10.1007/bf02163676
49
KlimakovA. M.PopovkinB. A.NovoselovaA. V. (1974). T-X projection of structural diagrams of BiL3-Bi2O3 system. Russ. J. Inorg. Chem.19, 2553–2556.
50
KodamaH. (1992). Solidification of iodide ion by reaction with Bi2O3. Bull. Chem. Soc. Jpn.65 (11), 3011–3014. 10.1246/bcsj.65.3011
51
KodamaH. (1994). The removal and solidification of halogenide ions using a new inorganic compound. Bull. Chem. Soc. Jpn.67 (7), 1788–1791. 10.1246/bcsj.67.1788
52
KosakaK.AsamiM.KobashigawaN.OhkuboK.TeradaH.KishidaN.et al (2012). Removal of radioactive iodine and cesium in water purification processes after an explosion at a nuclear power plant due to the Great East Japan Earthquake. Water Res.46 (14), 4397–4404. 10.1016/j.watres.2012.05.055
53
KrämerV. (1979). Investigations of sulphide systems by thermal analysis and chemical vapour transport. J. Therm. Anal.16 (2), 295–306. 10.1007/bf01910692
54
KrumhanslJ. L.NenoffT. M. (2011). Hydrotalcite-like layered bismuth–iodine–oxides as waste forms. Appl. Geochem.26 (1), 57–64. 10.1016/j.apgeochem.2010.11.003
55
KulyukhinS. A.MizinaL. V.ZaninaE. V.RumerI. A.KonovalovaN. A.LevushkinD. S. (2012). Synthesis of sorbents based on coarsely dispersed silica gel, containing nanoparticles of Ag compounds, for localization of volatile radioactive iodine compounds from the water vapor-air medium. Radiochemistry54 (4), 368–378. 10.1134/s1066362212040108
56
LawterA. R.LevitskaiaT. G.QafokuO.BowdenM. E.ColonF. C.QafokuN. P. (2021). Simultaneous immobilization of aqueous co-contaminants using a bismuth layered material. J. Environ. Radioact.237, 106711. 10.1016/j.jenvrad.2021.106711
57
LeeS.-H.TakahashiY. (2020). Selective immobilization of iodide onto a novel bismuth-impregnated layered mixed metal oxide: Batch and EXAFS studies. J. Hazard. Mater.384, 121223. 10.1016/j.jhazmat.2019.121223
58
LeeU.KimM. J.KimH. R. (2018). Radioactive iodine analysis in environmental samples around nuclear facilities and sewage treatment plants. Nucl. Eng. Technol.50 (8), 1355–1363. 10.1016/j.net.2018.07.017
59
LeeW. E.OjovanM. I.StennettM. C.HyattN. C. (2006). Immobilisation of radioactive waste in glasses, glass composite materials and ceramics. Adv. Appl. Ceram.105 (1), 3–12. 10.1179/174367606x81669
60
LinC.-C. (1981). Volatility of iodine in dilute aqueous solutions. J. Inorg. Nucl. Chem.43 (12), 3229–3238. 10.1016/0022-1902(81)80094-2
61
LinG.ZhuL.DuanT.ZhangL.LiuB.LeiJ. (2019). Efficient capture of iodine by a polysulfide-inserted inorganic NiTi-layered double hydroxides. Chem. Eng. J.378, 122181. 10.1016/j.cej.2019.122181
62
LiuL.LiuW.ZhaoX.ChenD.CaiR.YangW.et al (2014). Selective capture of iodide from solutions by microrosette-like δ-Bi2O3. ACS Appl. Mater. Interfaces6 (18), 16082–16090. 10.1021/am504000n
63
LiuS.KangS.WangH.WangG.ZhaoH.CaiW. (2016). Nanosheets-built flowerlike micro/nanostructured Bi2O2.33 and its highly efficient iodine removal performances. Chem. Eng. J.289, 219–230. 10.1016/j.cej.2015.12.101
64
LiuS.ZengY.LiuJ.LiJ.PengH.XieH.et al (2022). Efficient capture and stable storage of radioactive iodine by bismuth-based ZIF-8 derived carbon materials as adsorbents. Sep. Purif. Technol.302, 122151. 10.1016/j.seppur.2022.122151
65
LiuY.LiB.ShuX.ZhangZ.WeiG.LiuY.et al (2021). Low-sintering-temperature borosilicate glass to immobilize silver-coated silica-gel with different iodine loadings. J. Hazard. Mater.403, 123588. 10.1016/j.jhazmat.2020.123588
66
MaS.IslamS. M.ShimY.GuQ.WangP.LiH.et al (2014). Highly efficient iodine capture by layered double hydroxides intercalated with polysulfides. Chem. Mater.26 (24), 7114–7123. 10.1021/cm5036997
67
MailenJ. C.HornerD. E. (1976). Removal of radioiodine from gas streams by electrolytic scrubbing. Nucl. Technol.30 (3), 317–324. 10.13182/nt76-a31646
68
MichelR.HandlJ.ErnstT.BotschW.SzidatS.SchmidtA.et al (2005). Iodine-129 in soils from Northern Ukraine and the retrospective dosimetry of the iodine-131 exposure after the Chernobyl accident. Sci. Total Environ.340 (1), 35–55. 10.1016/j.scitotenv.2004.08.006
69
MiensahE. D.GuA.KokulokuL. T.JrChenK.WangP.GongC.et al (2022). Strategies for radioiodine capture by metal organic frameworks and their derived materials. Microporous Mesoporous Mat.341, 112041. 10.1016/j.micromeso.2022.112041
70
MineoH.GotohM.IizukaM.FujisakiS.HagiyaH.UchiyamaG. (2003). Applicability of a model predicting iodine-129 profile in a silver nitrate silica-gel column for dissolver off-gas treatment of fuel reprocessing. Sep. Sci. Technol.38 (9), 1981–2001. 10.1081/ss-120020130
71
MineoH.GotohM.IizukaM.FujisakiS.UchiyamaG. (2002). A simple model predicting iodine profile in a packed bed of silica-gel impregnated with silver nitrate. J. Nucl. Sci. Technol.39 (3), 241–247. 10.1080/18811248.2002.9715181
72
ModoloG.OdojR. (1997). Investigations on the partitioning of 129I from silver-impregnated silica in preparation for future transmutation. Nucl. Technol.117 (1), 80–86. 10.13182/nt97-a35337
73
MooreR. C.PearceC. I.MoradJ. W.ChatterjeeS.LevitskaiaT. G.AsmussenR. M.et al (2020). Iodine immobilization by materials through sorption and redox-driven processes: A literature review. Sci. Total Environ.716, 132820. 10.1016/j.scitotenv.2019.06.166
74
MoriyamaK.TashiroS.ChibaN.HirayamaF.MaruyamaY.NakamuraH.et al (2010). Experiments on the release of gaseous iodine from gamma-irradiated aqueous CsI solution and influence of oxygen and methyl isobutyl ketone (MIBK). J. Nucl. Sci. Technol.47 (3), 229–237. 10.1080/18811248.2010.9711949
75
MowryC. D.BradyP. V.GarinoT. J.NenoffT. M. (2015). Development and durability testing of a low-temperature sintering Bi–Si–Zn oxide glass composite material (GCM) 129I Waste Form. J. Am. Ceram. Soc.98 (10), 3094–3104. 10.1111/jace.13751
76
MuhireC.Tesfay RedaA.ZhangD.XuX.CuiC. (2022). An overview on metal oxide-based materials for iodine capture and storage. Chem. Eng. J.431, 133816. 10.1016/j.cej.2021.133816
77
MunakataK.KanjoS.YamatsukiS.KogaA.IanovskiD. (2003). Adsorption of noble gases on silver-mordenite. J. Nucl. Sci. Technol.40 (9), 695–697. 10.1080/18811248.2003.9715408
78
NanY.LiuJ.TangS.LinR.TavlaridesL. L. (2018). Silver-exchanged mordenite for capture of water vapor in off-gas streams: A study of adsorption kinetics. Ind. Eng. Chem. Res.57 (3), 1048–1058. 10.1021/acs.iecr.7b04420
79
NandanwarS. U.ColdsnowK.UtgikarV.SabharwallP.Eric AstonD. (2016). Capture of harmful radioactive contaminants from off-gas stream using porous solid sorbents for clean environment – a review. Chem. Eng. J.306, 369–381. 10.1016/j.cej.2016.07.073
80
NenoffT. M.RodriguezM. A.SoelbergN. R.ChapmanK. W. (2014). Silver-mordenite for radiologic gas capture from complex streams: Dual catalytic CH3I decomposition and I confinement. Microporous Mesoporous Mat.200, 297–303. 10.1016/j.micromeso.2014.04.041
81
NgC. H. B.FanW. Y. (2016). Shape-controlled preparation of basic bismuth nitrate crystals with high iodide-removal capacities. ChemNanoMat2 (2), 133–139. 10.1002/cnma.201500179
82
OjovanM. I.LeeW. E. (2011). Glassy wasteforms for nuclear waste immobilization. Metall. Mater. Trans. A-Phys. Metall. Mater. Sci.42 (4), 837–851. 10.1007/s11661-010-0525-7
83
PearceC. I.CordovaE. A.GarciaW. L.SaslowS. A.CantrellK. J.MoradJ. W.et al (2020). Evaluation of materials for iodine and technetium immobilization through sorption and redox-driven processes. Sci. Total Environ.716, 136167. 10.1016/j.scitotenv.2019.136167
84
PeiC.BenT.XuS.QiuS. (2014). Ultrahigh iodine adsorption in porous organic frameworks. J. Mater. Chem. A2 (20), 7179–7187. 10.1039/c4ta00049h
85
PhamT. C. T.DocaoS.HwangI. C.SongM. K.ChoiD. Y.MoonD.et al (2016). Capture of iodine and organic iodides using silica zeolites and the semiconductor behaviour of iodine in a silica zeolite. Energy Environ. Sci.9 (3), 1050–1062. 10.1039/c5ee02843d
86
PillarE. A.GuzmanM. I.RodriguezJ. M. (2013). Conversion of iodide to hypoiodous acid and iodine in aqueous microdroplets exposed to ozone. Environ. Sci. Technol.47 (19), 10971–10979. 10.1021/es401700h
87
PiresJ.CarvalhoA.de CarvalhoM. B. (2001). Adsorption of volatile organic compounds in Y zeolites and pillared clays. Microporous Mesoporous Mat.43 (3), 277–287. 10.1016/s1387-1811(01)00207-4
88
QinH.LvY.KobayashiH.XiaoM.SongH.YangJ. (2022). Fabrication of NOTT-220 @I2 via iodine adsorption and immobilization in bismuth organic framework for efficient CO2 photo-reduction. J. Alloys Compd.920, 165900. 10.1016/j.jallcom.2022.165900
89
RanjanM.SinghP. K.SrivastavA. L. (2020). A review of bismuth-based sorptive materials for the removal of major contaminants from drinking water. Environ. Sci. Pollut. Res.27 (15), 17492–17504. 10.1007/s11356-019-05359-9
90
RileyB. J.ChunJ.RyanJ. V.MatyasJ.LiX. S.MatsonD. W.et al (2011). Chalcogen-based aerogels as a multifunctional platform for remediation of radioactive iodine. RSC Adv.1 (9), 1704–1715. 10.1039/c1ra00351h
91
RileyB. J.ChunJ.UmW.LepryW. C.MatyasJ.OlsztaM. J.et al (2013). Chalcogen-based aerogels as sorbents for radionuclide remediation. Environ. Sci. Technol.47 (13), 7540–7547. 10.1021/es400595z
92
RileyB. J.ViennaJ. D.StrachanD. M.McCloyJ. S.JerdenJ. L. (2016). Materials and processes for the effective capture and immobilization of radioiodine: A review. J. Nucl. Mater.470, 307–326. 10.1016/j.jnucmat.2015.11.038
93
SakuraiT.TakahashiA. (1994). Catalytic effect of silver-impregnated silica-gel (AgS) on reaction of methyl iodide with nitrogen dioxide. J. Nucl. Sci. Technol.31 (1), 86–87. 10.1080/18811248.1994.9735119
94
SavaD. F.ChapmanK. W.RodriguezM. A.GreathouseJ. A.CrozierP. S.ZhaoH.et al (2013). Competitive I2 sorption by Cu-BTC from humid gas streams. Chem. Mater.25 (13), 2591–2596. 10.1021/cm401762g
95
SavaD. F.GarinoT. J.NenoffT. M. (2012). Iodine confinement into Metal–Organic Frameworks (MOFs): Low-temperature sintering glasses to form novel glass composite material (GCM) alternative waste forms. Ind. Eng. Chem. Res.51 (2), 614–620. 10.1021/ie200248g
96
SavaD. F.RodriguezM. A.ChapmanK. W.ChupasP. J.GreathouseJ. A.CrozierP. S.et al (2011). Capture of volatile iodine, a gaseous fission product, by zeolitic imidazolate framework-8. J. Am. Chem. Soc.133 (32), 12398–12401. 10.1021/ja204757x
97
Sava GallisD. F.ErmanoskiI.GreathouseJ. A.ChapmanK. W.NenoffT. M. (2017). Iodine gas adsorption in nanoporous materials: A combined experiment modeling study. Ind. Eng. Chem. Res.56 (8), 2331–2338. 10.1021/acs.iecr.6b04189
98
ScottS. M.HuT.YaoT.XinG.LianJ. (2015). Graphene-based sorbents for iodine-129 capture and sequestration. Carbon90, 1–8. 10.1016/j.carbon.2015.03.070
99
SoelbergN. R.GarnT. G.GreenhalghM. R.LawJ. D.JubinR.StrachanD. M.et al (2013). Radioactive iodine and krypton control for nuclear fuel reprocessing facilities. Sci. Technol. Nucl. Install.2013, 1–12. 10.1155/2013/702496
100
SubrahmanyamK. S.SarmaD.MalliakasC. D.PolychronopoulouK.RileyB. J.PierceD. A.et al (2015). Chalcogenide aerogels as sorbents for radioactive iodine. Chem. Mater.27 (7), 2619–2626. 10.1021/acs.chemmater.5b00413
101
TaghipourF.EvansG. J. (2000). Radiolytic organic iodide formation under nuclear reactor accident conditions. Environ. Sci. Technol.34 (14), 3012–3017. 10.1021/es990507d
102
TakeshitaK.AzegamiY. (2004). Development of thermal swing adsorption (TSA) process for complete recovery of iodine in dissolver off-gas. J. Nucl. Sci. Technol.41 (1), 91–94. 10.1080/18811248.2004.9715463
103
TanabeH.SakuragiT.YamaguchiK.SatoT.OwadaH. (2010). Development of new waste forms to immobilize iodine-129 released from a spent fuel reprocessing plant. Adv. Sci. Technol.73, 158–170. 10.4028/www.scientific.net/ast.73.158
104
TaylorD. M. (1981). The radiotoxicology of iodine. J. Radioanal. Chem.65 (1), 195–208. 10.1007/bf02516104
105
Tesfay RedaA.PanM.ZhangD.XuX. (2021a). Bismuth-based materials for iodine capture and storage: A review. J. Environ. Chem. Eng.9 (4), 105279. 10.1016/j.jece.2021.105279
106
Tesfay RedaA.ZhangD.XuX.PanM.ChangC.MuhireC.et al (2021b). Bismuth-impregnated aluminum/copper oxide-pillared montmorillonite for efficient vapor iodine sorption. Sep. Purif. Technol.270, 118848. 10.1016/j.seppur.2021.118848
107
Tesfay RedaA.ZhangD.XuX.XuS. (2022). Highly stable iodine capture by pillared montmorillonite functionalized Bi2O3@g-C3N4 nanosheets. Sep. Purif. Technol.292, 120994. 10.1016/j.seppur.2022.120994
108
ThomasG. D.SmithS. M.TurcotteJ. A. (2009). Using public relations strategies to prompt populations at risk to seek health information: The Hanford Community Health Project. Health promot. Pract.10 (1), 92–101. 10.1177/1524839907307676
109
TianZ.CheeT.-S.MengR.HaoY.ZhouX.MaB.et al (2022). Incipient wetness impregnation to prepare bismuth-modified all-silica beta zeolite for efficient radioactive iodine capture. Environ. Funct. Mater.1 (1), 92–104. 10.1016/j.efmat.2022.05.006
110
TianZ.CheeT.-S.ZhangX.LeiL.XiaoC. (2021a). Novel bismuth-based electrospinning materials for highly efficient capture of radioiodine. Chem. Eng. J.412, 128687. 10.1016/j.cej.2021.128687
111
TianZ.CheeT.-S.ZhuL.DuanT.ZhangX.LeiL.et al (2021b). Comprehensive comparison of bismuth and silver functionalized nickel foam composites in capturing radioactive gaseous iodine. J. Hazard. Mater.417, 125978. 10.1016/j.jhazmat.2021.125978
112
VergerP.AurengoA.GeoffroyB.Le GuenB. (2001). Iodine kinetics and effectiveness of stable iodine prophylaxis after intake of radioactive iodine: A review. Thyroid11 (4), 353–360. 10.1089/10507250152039082
113
WangC.HuH.YanS.ZhangQ. (2020). Activating Bi2O3 by ball milling to induce efficiently oxygen vacancy for incorporating iodide anions to form BiOI. Chem. Phys.533, 110739. 10.1016/j.chemphys.2020.110739
114
WangJ.ZhuangS. (2019). Covalent organic frameworks (COFs) for environmental applications. Coord. Chem. Rev.400, 213046. 10.1016/j.ccr.2019.213046
115
WangP.XuQ.LiZ.JiangW.JiangQ.JiangD. (2018). Exceptional iodine capture in 2D covalent organic frameworks. Adv. Mater.30 (29), 1801991. 10.1002/adma.201801991
116
WeiG.LuoF.LiB.LiuY.YangJ.ZhangZ.et al (2021). Immobilization of iodine waste forms: A low-sintering temperature with Bi2O3-B2O3-ZnO glass. Ann. Nucl. Energy150, 107817. 10.1016/j.anucene.2020.107817
117
WeiG.ShuX.ZhangZ.LiQ.LiuY.WangX.et al (2020). B2O3–Bi2O3–ZnO based materials for low-sintering temperature immobilization of iodine adsorbed waste. J. Solid State Chem.289, 121518. 10.1016/j.jssc.2020.121518
118
WooT. H. (2013). Atmospheric modeling of radioactive material dispersion and health risk in Fukushima Daiichi nuclear power plants accident. Ann. Nucl. Energy53, 197–201. 10.1016/j.anucene.2012.09.003
119
WrenJ. C.BallJ. M.GlowaG. A. (1999). The interaction of iodine with organic material in containment. Nucl. Technol.125 (3), 337–362. 10.13182/NT99-A2952
120
WuB.YanM.LuoF.ShuX.LiuY.WeiG.et al (2021). Low-temperature fabrication of glass-based iodine waste forms via a novel preparation method. J. Solid State Chem.300, 122186. 10.1016/j.jssc.2021.122186
121
WuD.WeiG.ShuX.LiuY.HanW.ZhangZ.et al (2022). Immobilization of iodine waste at low sintering temperature: Phase evolution and microstructure transformation. Ann. Nucl. Energy173, 109145. 10.1016/j.anucene.2022.109145
122
XianQ.ChenL.FanW.LiuY.HeX.DanH.et al (2022a). Facile synthesis of novel Bi0-SBA-15 adsorbents by an improved impregnation reduction method for highly efficient capture of iodine gas. J. Hazard. Mater.424, 127678. 10.1016/j.jhazmat.2021.127678
123
XianQ.GanY.YuJ.XiaoX.ChenQ.DanH.et al (2022b). Scalable and economical Bi0-SiO2 for the high efficient capture of iodine gas. J. Nucl. Mater.567, 153849. 10.1016/j.jnucmat.2022.153849
124
XiongY.DangB.WangC.WanH.ZhangS.SunQ.et al (2017). Cellulose fibers constructed convenient recyclable 3D graphene-formicary-like delta-Bi2O3 aerogels for the selective capture of iodide. ACS Appl. Mater. Interfaces9 (24), 20554–20560. 10.1021/acsami.7b03516
125
XiongY.WangC.WangH.JinC.SunQ.XuX. (2018). Nano-cellulose hydrogel coated flexible titanate-bismuth oxide membrane for trinity synergistic treatment of super-intricate anion/cation/oily-water. Chem. Eng. J.337, 143–151. 10.1016/j.cej.2017.12.080
126
XuW.ZhangW.KangJ.LiB. (2019). Facile synthesis of mesoporous Fe-based MOFs loading bismuth with high speed adsorption of iodide from solution. J. Solid State Chem.269, 558–565. 10.1016/j.jssc.2018.10.028
127
YanM.WuB.LuoF.ShuX.LiuY.WeiG.et al (2021). Bi2O3 doped B2O3-ZnO glass powder for immobilization of radioactive iodine waste at low temperature. Ann. Nucl. Energy161, 108480. 10.1016/j.anucene.2021.108480
128
YangJ. H.ChoY.-J.ShinJ. M.YimM.-S. (2015). Bismuth-embedded SBA-15 mesoporous silica for radioactive iodine capture and stable storage. J. Nucl. Mater.465, 556–564. 10.1016/j.jnucmat.2015.06.043
129
YangJ. H.ParkH. S.AhnD.-H.YimM.-S. (2016). Glass composite waste forms for iodine confined in bismuth-embedded SBA-15. J. Nucl. Mater.480, 150–158. 10.1016/j.jnucmat.2016.08.001
130
YangK.WangY.ShenJ.ScottS. M.RileyB. J.ViennaJ. D.et al (2022). Cs3Bi2I9-hydroxyapatite composite waste forms for cesium and iodine immobilization. J. Adv. Ceram.11 (5), 712–728. 10.1007/s40145-021-0565-z
131
YangK.ZhuW.ScottS.WangY.WangJ.RileyB. J.et al (2021). Immobilization of cesium and iodine into Cs3Bi2I9 perovskite-silica composites and core-shell waste forms with high waste loadings and chemical durability. J. Hazard. Mater.401, 123279. 10.1016/j.jhazmat.2020.123279
132
YangY.XiongX.FanY.LaiZ.XuZ.LuoF. (2019). Insight into volatile iodine uptake properties of covalent organic frameworks with different conjugated structures. J. Solid State Chem.279, 120979. 10.1016/j.jssc.2019.120979
133
YangY.ZengZ.ZhangC.HuangD.ZengG.XiaoR.et al (2018). Construction of iodine vacancy-rich BiOI/Ag@AgI Z-scheme heterojunction photocatalysts for visible-light-driven tetracycline degradation: Transformation pathways and mechanism insight. Chem. Eng. J.349, 808–821. 10.1016/j.cej.2018.05.093
134
YuF.ChenY.WangY.LiuC.QinJ. (2020). Synthesis of metal–organic framework nanocrystals immobilized with 3D flowerlike Cu–Bi-layered double hydroxides for iodine efficient removal. J. Mater. Res.35 (3), 299–311. 10.1557/jmr.2020.1
135
YuQ.JiangX.ChengZ.LiaoY.PuQ.DuanM. (2020). Millimeter-sized Bi2S3@polyacrylonitrile hybrid beads for highly efficient iodine capture. New J. Chem.44 (39), 16759–16768. 10.1039/d0nj03229h
136
YuanY.DongX.ChenY.ZhangM. (2016). Computational screening of iodine uptake in zeolitic imidazolate frameworks in a water-containing system. Phys. Chem. Chem. Phys.18 (33), 23246–23256. 10.1039/c6cp02156e
137
ZakirovaG. G.MladentsevD. Y.BorisovaN. E. (2017). Synthesis of chelating tertiary phosphine oxides via palladium-catalysed C–P bond formation. Tetrahedron Lett.58 (35), 3415–3417. 10.1016/j.tetlet.2017.07.055
138
ZhangL.JaroniecM. (2017). SBA-15 templating synthesis of mesoporous bismuth oxide for selective removal of iodide. J. Colloid Interface Sci.501, 248–255. 10.1016/j.jcis.2017.04.063
139
ZhangL.WangW.YangJ.ChenZ.ZhangW.ZhouL.et al (2006). Sonochemical synthesis of nanocrystallite Bi2O3 as a visible-light-driven photocatalyst. Appl. Catal. A308, 105–110. 10.1016/j.apcata.2006.04.016
140
ZhangS.DuJ.XuC.SchwehrK. A.HoY. F.LiH. P.et al (2011). Concentration-dependent mobility, retardation, and speciation of iodine in surface sediment from the Savannah River Site. Environ. Sci. Technol.45 (13), 5543–5549. 10.1021/es1040442
141
ZhangS.XuC.CreeleyD.HoY.-F.LiH.-P.GrandboisR.et al (2013). Iodine-129 and iodine-127 speciation in groundwater at the Hanford site, U.S.: Iodate incorporation into calcite. Environ. Sci. Technol.47 (17), 9635–9642. 10.1021/es401816e
142
ZhangX.da SilvaI.FazziR.ShevelevaA. M.HanX.SpencerB. F.et al (2019). Iodine adsorption in a redox-active metal–organic framework: Electrical conductivity induced by Host−Guest charge-transfer. Inorg. Chem.58 (20), 14145–14150. 10.1021/acs.inorgchem.9b02176
143
ZhaoH.NenoffT. M.JenningsG.ChupasP. J.ChapmanK. W. (2011). Determining quantitative kinetics and the structural mechanism for particle growth in porous templates. J. Phys. Chem. Lett.2 (21), 2742–2746. 10.1021/jz201260n
144
ZhaoQ.ChenG.WangZ.JiangM.LinJ.ZhangL.et al (2021). Efficient removal and immobilization of radioactive iodide and iodate from aqueous solutions by bismuth-based composite beads. Chem. Eng. J.426, 131629. 10.1016/j.cej.2021.131629
145
ZhouJ.HaoS.GaoL.ZhangY. (2014). Study on adsorption performance of coal based activated carbon to radioactive iodine and stable iodine. Ann. Nucl. Energy72, 237–241. 10.1016/j.anucene.2014.05.028
146
ZouH.GuoJ.SongM.YiF.WangX.PanN.et al (2021). Bi2S3-reduced graphene oxide composite for gaseous radioiodine capture and its immobilization within glass composite material. Prog. Nucl. Energy135, 103705. 10.1016/j.pnucene.2021.103705
147
ZouH.YiF.SongM.WangX.BianL.LiW.et al (2019). Novel synthesis of Bi-Bi2O3-TiO2-C composite for capturing iodine-129 in off-gas. J. Hazard. Mater.365, 81–87. 10.1016/j.jhazmat.2018.11.001
Summary
Keywords
spent fuel reprocessing, radioactive iodine, bismuth-based materials, nuclear waste, capture
Citation
Hao Y, Tian Z, Liu C and Xiao C (2023) Recent advances in the removal of radioactive iodine by bismuth-based materials. Front. Chem. 11:1122484. doi: 10.3389/fchem.2023.1122484
Received
13 December 2022
Accepted
09 January 2023
Published
24 January 2023
Volume
11 - 2023
Edited by
Feng Luo, East China University of Technology, China
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© 2023 Hao, Tian, Liu and Xiao.
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*Correspondence: Chuanying Liu, cyliu@zju.edu.cn; Chengliang Xiao, xiaoc@zju.edu.cn
This article was submitted to Inorganic Chemistry, a section of the journal Frontiers in Chemistry
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