The development of adsorbents capable of simultaneous adsorption of methyl iodide (CH3I) and iodine (I2) is meaningful but remains challenging. In this work, a novel Bi/Bi2O2SiO3 composite was prepared by one step method and employed for the simultaneous adsorption of gaseous CH3I and I2. In the single CH3I or I2 system, the Bi/Bi2O2SiO3 composite exhibited excellent adsorption capacities, reaching capacities of 1293 mg/g (CH3I) and 452 mg/g (I2). In the CH3I + I2 coexistent system, the total adsorption capacity was up to 1336 mg/g, which can be attributed to a synergistic effect between Bi and Bi2O2SiO3. The results indicated that the adsorption of both CH3I and I2 was chemical, and the adsorption product was BiI3. Furthermore, the adsorption mechanism of CH3I by Bi2O2SiO3 was catalytic cleavage reaction. Owing to its outstanding performance for simultaneous adsorption of CH3I and I2, the Bi/Bi2O2SiO3 composite could be considered as a promising candidate for the practical decontamination of radioactive iodine species in off-gas streams.

Tin-based materials are expected to be excellent iodine adsorbent, but the stability of the adsorption product (SnI4) poses challenge. Herein, a novel strategy based on the in-situ reconstruction of hydrophobic environment was presented for efficient iodine adsorption and storage. Stannous sulfide@mesoporous silica (SnS@SBA-15) was developed and employed for the adsorption of I2 gas. The optimal material, SnS@SBA-15-50wt%, exhibited an excellent iodine uptake of 2062 mg/g. The adsorption was attributed to a chemical reaction (SnS + 2I2 = SnI4 + S). Notably, the retention rate of SnI4 was as high as 76.5% after storage in air for 90 days due to the in-situ reconstructed hydrophobic environment. The obtained SnS@SBA-15 exhibited efficient iodine adsorption and excellent storage ability. This work presents a novel strategy to design iodine adsorbents, aimed at addressing the storage challenges of iodine adsorption products susceptible to hydrolysis.

The development of cost-effective and reusable adsorbents for radioactive iodine capture remains an interesting challenge. Herein, a cuprous oxide-silica composite (Cu2O@SiO2) was obtained by a simple reduction method, and the influence of temperature, contact time and iodine concentration on the adsorption performance of Cu2O@SiO2 material were systematically evaluated. The results demonstrated that the Cu2O@SiO2 material exhibited excellent adsorption capacity (897 mg/g) within a short period of time (60 min), and the final product of the adsorption process eventually existed in the stable form of CuI (Cu2O+I2-*2CuI+1/2O2). Moreover, the adsorbed material (I2-Cu2O@SiO2) could be effectively regenerated through a simple reduction process. The regenerated material exhibited outstanding reusability, maintaining over 91% of its initial capacity across ten consecutive cycles. These findings demonstrated that the Cu2O@SiO2 material exhibited significant potential for the safe management of radioactive iodine, offering a promising solution for environmental protection.

The adsorption of iodine and methyl iodide is a challenging topic that has attracted the attention of many researchers. In this article, a N-rich amino functionalized mesoporous SBA-15 (NH2@FS) was prepared by a simple impregnation method and applied for the adsorption of I2 and CH3I gas. The adsorption of I2 and CH3I gas was conducted under conditions close to real spent fuel reprocessing (150 degrees C), and the adsorption capacity of the obtained NH2@FS sample for I2 and CH3I can reach 1778 and 656 mg/g, respectively. It can be found that the N atom of amino group provided a lone pair of electrons, which combined with I to form protonated nitrogen species (N+). Meanwhile, the adsorbed I was presented as polyiodide in the I2-NH2@FS (I3- and I5- ) and CH3INH2@FS (I3- ) samples. These findings suggested that the obtained NH2@FS sample could be considerable potential adsorbent for the adsorption of I2 and CH3I gas.

Tin-based materials are promising for iodine capture. However, they suffer from the instability of adsorption product SnI4 that is easily hydrolyzed even in atmospheric environment due to the presence of moisture. Herein, we report a strategy of constructing the hydrophobic microenvironment on Sn0@SBA-15 materials, which isolates moisture and subsequently stabilizes SnI4. Hydrophobic Sn0@SBA-15 materials (P-Sn0@SBA-15) were fabricated by polymethylhydrosiloxane (PHMS) modification and applied for iodine capture. The obtained P-Sn0@SBA-15 exhibited a record high iodine adsorption capacity (2599mg/g) among inorganic adsorbents. The dominant adsorption mechanism was found that Sn0 reacted with I2 to form SnI4. Remarkably, SnI4 in P-Sn0@SBA-15 was stable up to 3 months exposure to humid atmosphere, while almost all SnI4 in Sn0@SBA-15 was hydrolyzed. The obtained P-Sn0@SBA-15 could be added to the list of iodine adsorbents due to its excellent adsorption capacity and stability. Moreover, the facile strategy could provide reference for the development of other functional materials.

Developing new matrix for efficient actinides immobilization is of great significance for the sustainable development of nuclear energy. Herein, novel ZrSiO4-borosilicate glass-ceramics (Z-B) were prepared for immobilization of cerium (Ce) as the simulated tetravalent actinides. The effect of Ce content on the phase transformation and microstructure of the obtained Z-B was investigated, and the loading capacity limit of Ce was evaluated. The results demonstrated that Z-B glass-ceramics with high ZrSiO4 phase (91 wt%) was obtained. Owing to the synergistic effect of ZrSiO4 and borosilicate glass phases, the loading capacity limit of Ce in the obtained Z-B reached up to 12 at%. Furthermore, the obtained Z-B waste forms exhibited excellent aqueous durability. The results of this work demonstrated that the Z-B is potential matrix for immobilization of tetravalent actinides due to their good loading capacity and aqueous durability.

Developing new matrices capable of simultaneous immobilization of lanthanides and actinides are challenging. Herein, this paper reported the ZrSiO4-based borosilicate glass-ceramics with excellent immobilization capabilities of lanthanides and actinides. The phase evolution and microstructure transformation affected by the (Nd, Ce)-co-doping content were investigated systematically. The results indicated that the solubility limits of Nd and Ce in the obtained glass-ceramics decreased with increasing temperature, which were up to 18, 16 and 10 at% at 1400 degrees C, 1450 degrees C and 1500 degrees C, respectively. The formation rate of ZrSiO4 increased with the increase of the (Nd, Ce)-co-doping content and temperature, which reached the highest value of 96.43 wt% with Nd and Ce content of 10 at% at 1500 degrees C. The densification of the obtained glass-ceramics also increased with the increase of the content of Nd and Ce. In addition, it was found that the immobilization mechanism of the resulting glass-ceramics was the synergistic immobilization effect of the ceramic crystal and glass network. This work indicated that the ZrSiO4-based borosilicate glass-ceramics might be promising matrices for immobilizing high-level radioactive wastes containing lanthanides and actinides.

The development of matrix with high capacity and stability immobilization of nuclear waste is highly desirable. Herein, new type of zircon-based borosilicate glass-ceramics (ZBGC) with high immobilization capacity and excellent aqueous stability was prepared and applied to immobilize simulated trivalent actinide (Nd). The effects of Nd doping and sintering temperature on the microstructure and phase composition of the obtained ZBGC were researched. The experimental suggested that high ZrSiO4 formation rate (97.49 wt%) was obtained by tuning the Nd content and sintering temperature. The record high immobilization capacity of Nd in ZGBC (18 at%) was achieved owing to the synergistic effect between the crystal lattice and glass network immobilization. Additionally, the obtained Nd-doped ZBGC exhibited excellent aqueous stability (similar to 10(-6) g m(-2) d(-1)) due to the high compactness. The results demonstrated that ZBGC with high immobilization capacity and aqueous stability could be potential matrix for actinides immobilization.

Exploring the influence of sintering atmosphere on the formation of ZrSiO4 is of great significance. Herein, ZrSiO4 ceramics were prepared by the solid-state reactive sintering method under different atmospheres (air, N-2, vacuum, and Ar + 5%H-2). The influence of sintering atmosphere on the phase and microstructure evolutions of the obtained ceramics was investigated. It was found that ZrSiO4 ceramics could be prepared under air atmosphere, whereas ZrO2-SiO2 glass ceramics were obtained under N-2, vacuum, and Ar + 5%H-2 atmosphere, which may be due to the fact that the oxygen-deficient environment inhibits the transformation of ZrO2 to tetragonal phase (t-ZrO2) and the crystallization of amorphous SiO2. The results demonstrated that t-ZrO2 and c-SiO2 were beneficial for the formation of ZrSiO4. The ZrSiO4 conversion fraction was up to 96.16% under air atmosphere at 1450 degrees C for 6 h. Furthermore, the predominant formation mechanism of ZrSiO4 was the reaction between t-ZrO2 and c-SiO2.

Using conventional solid state sintering method to synthesize ZrSiO4 ceramics may result in high temperature and time consumption. Herein, a novel preparation route combining the advantages of molten -salt method and hot -pressing sintering (MH) was developed and used to efficiently prepare 0.2ZrO2/ZrSiO4 ceramics (Z/Z). The phase structure, micromorphology, compactness and hardness of the obtained ceramics affected by the salt to oxide ratio, sintering temperature and holding time were investigated and discussed. It was found that the obtained Z/Z ceramics with high density (95.44 % of theoretical density) and high hardness (12.77 GPa) were prepared by the MH at low temperature and short holding time. The discussion of the results revealed that the optimum ratio of salt to oxide was 10: 1, molten -salt sintering conditions were 1300 degrees C and 6 h, hot -pressing sintering conditions were 64 MPa, 1200 degrees C and 0.5 h. The results demonstrated that the novel preparation route could be extended to prepare other high -performance ceramics.

Developing recyclable adsorbents for co-capture of I2 and CH3I gas is a meaningful and challenging topic. Herein, Cu0-based mesoporous silica (C-S) materials were synthesized and applied for CH3I capture for the first time. Factors (Cu0 content, temperature, contact time and CH3I concentration) affecting the adsorption behavior were investigated. The results demonstrated that the CH3I adsorption capacity of the obtained C-S materials reached up to 1060 mg/g at 200 ℃. Furthermore, the C-S material exhibited excellent reusability (91.3 %, 5 cycles). It was found that Cu0 could cleave the carbon iodine bonds, causing CH3I to dissociate into •CH3 and I-. Then the Cu+ converted from Cu0 reacted with I- to achieve the purpose of CH3I capture. The adsorption mechanism of CH3I on the C-S materials could be concluded that Cu0 reacted with CH3I form CuI (Cu + CH3I → CuI + •CH3). This work suggested that the obtained C-S materials could be promising adsorbents for CH3I capture.

A series of Ag0@C/SiO2 adsorbents were prepared using rice husk-based C/SiO2 as supports and applied to capture iodine gas. The results demonstrated that 50

It is of great significance to develop a kind of adsorbent which can adsorb and in-situ immobilize radionuclides from aqueous solution. Herein, new amino-functionalized mesoporous zirconia-silica (ZNSi) composites were prepared and applied to adsorb and in-situ immobilize the simulated trivalent actinides (Nd) from aqueous solution. The obtained ZNSi composites exhibited high Nd adsorption capacity (31.14 mg/g) owing to the formation of Nd(OH)3 via the reaction between Nd3+ and OH- derived from the protonation of amino groups. The spent adsorbents with adsorbed Nd3+ were successfully changed to stable ZrSiO4-based glass ceramics by simple sintering treatment. The ZrO2 and Nd contents had great effect on the phase composition, microstructure evolution and aqueous stability of the obtained ZrSiO4-based glass ceramics waste forms. The immobilized Nd showed excellent aqueous stability (10-7 g m- 2 d-1) due to the crystal lattice immobilization of ZrSiO4. Owing to the efficient adsorption and in-situ immobilization ability, the obtained ZNSi could be potential materials for radioactive wastewater treatment.

The development of Bi-based composites with low cost, high adsorption capacity and retention is highly desired for iodine gas capture. Herein, three novel Bi-based composites (Bi0-SiO2, Bi0-C/SiO2 and Bi0-C) were prepared by simple sintering process using rice husk as C and SiO2 sources and applied for iodine gas capture. The results demonstrated that the type of support strongly affected the iodine adsorption and retention. The Bi0-SiO2, Bi0-C/ SiO2 and Bi0-C composites exhibited the iodine adsorption capacity of 812, 911 and 1334 mg/g, and the iodine retention ratio of 90.9, 86.9 and 65.4%. The Bi0-SiO2 showed the highest iodine retention because the SiO2 supports have no affinity for iodine and the adsorption mainly came from the chemical adsorption of Bi0 (2Bi + 3I2 = 2BiI3). While the Bi0-C exhibited the highest adsorption capacity due to the synergistic adsorption effect between C supports and Bi0 sites. Except for the chemical reaction, charge transfer between C and I (C-I) also contributed to the iodine adsorption. The results demonstrated that the new Bi-based composites would be promising iodine gas adsorbent and the new strategy could be extended to the development of other adsorbents.

Zircon (ZrSiO4) ceramics are candidate waste form for immobilizing actinides. However, ZrSiO4 with single phase suffers from the low actinides solubility. Herein, 0.2Zr1-aNdaO2-a/2/Zr1-bNdbSiO4-b/2 (0 <= a+b <= 0.3) multiphase ceramics were fabricated and their actinides immobilization ability and aqueous stability were evaluated. The evolutions of phase and microstructure affected by Nd doping were investigated. 0.2Zr1-aNdaO2-a/ 2/Zr1-bNdbSiO4-b/2 ceramics with 0 <= a+b<0.1 exhibited monoclinic ZrO2, tetragonal ZrO2 and ZrSiO4 mixed phases, while monoclinic ZrO2, tetragonal ZrO2, ZrSiO4 and Nd2Si2O7 phases with 0.1 <= a+b <= 0.3. The increase of lattice volume revealed the successful lattice immobilization of Nd by ZrO2/ZrSiO4. Due to synergistic immobilization effect, the Nd immobilization capacity of ZrO2/ZrSiO4 is up to 10 at%, which is higher than that of single-phase ZrSiO4 (4 at%). Furthermore, the obtained ceramics waste form exhibited good compactness and excellent aqueous stability. The results indicated that zirconia/zircon multiphase ceramics can be a potential candidate waste form for actinides.

MnO2@SBA-15 adsorbents were prepared and applied for the adsorption and in situ solidification of Cs+. The adsorption and in situ solidification performance of the obtained MnO2@SBA-15 were systematically investi-gated. The results demonstrated that the Cs+ adsorption capacity of MnO2@SBA-15 reached 76.63 mg/g. The adsorption data can be well fitted by the Langmuir model and Pseudo-second-order model. Moreover, Cs+ was in situ solidified in glass ceramic matrix through simple sintering the MnO2@SBA-15 adsorbed Cs+ mixtures at low temperature (800-1000 degrees C). The glass ceramic sintered at 800 degrees C exhibited quartz and braunite two phases. With increasing temperature to 900 and 1000 degrees C, quartz transformed to cristobalite. At 900 and 1000 degrees C, glass ce-ramics with cristobalite and braunite mixed phases were obtained. The obtained glass ceramics showed good compactness and excellent aqueous durability. Owing to its efficient adsorption and in situ solidification ca-pacity, MnO2@SBA-15 is a promising material for cesium removal and solidification.

Amino-functionalized SBA-15 (AS) with different pore lengths (short pore: 300 nm, SAS and long pore: several tens mu m, LAS) were synthesized and applied for CO2 adsorption. The adsorption capacity and amino efficiency affected by pore length, temperature and amino-functionalization were systematically investigated. It was found that CO2 adsorption behavior strongly depended on the pore length, amino-functionalization and adsorption temperature. With decreasing pore length, the adsorption capacity and amino efficiency increased. The amino efficiency increased and the adsorption capacity decreased with increasing temperature. The obtained SAS with short pore exhibited the highest adsorption capacity (1.58, 1.26 and 0.96 mmol CO2/g) and amino efficiency (0.07, 0.19 and 0.27 mol CO2/mol N) under 273, 298 and 323 K at 1 bar, respectively, owing to the high uti-lization of internal pores. Furthermore, the obtained adsorbents showed good temperature adaptability and reusability. The results demonstrated the potential of the obtained adsorbents for CO2 adsorption.

ZrSiO4-based ceramics have been considered as one of the candidate nuclear waste forms, while the immobili-zation behavior of mixed-valent uranium in the structure of the ceramics was unclear. Herein, ZrSiO4-U ceramics with a general formula of Zr1-4x(U-x(6+) U-2x(5+))SiO4 were designed and synthesized. The evolutions of phase and microstructure depending on the content of U were investigated. The ceramics with 0 <= x < 0.04 showed a single ZrSiO4 phase, while U3O8 phase was detected when x >= 0.04. The results demonstrated that the solubility limit of U in ZrSiO4 ceramic was up to 1.51 at.% or 11.06 wt%. The calculated lattice parameters increased with the increase of U content. The increased parameters provided the evidence of the immobilization of both U5+ and U6+ into ZrSiO4 crystal lattice by replacing Zr4+. Furthermore, the obtained ZrSiO4-U ceramics exhibited good aqueous durability (similar to 10(-5) g m(-2) d(-1)). The results indicated that ZrSiO4-based ceramics can be employed to effectively immobilize mixed-valent U.

Cu-based materials have been considered as good adsorbents for iodine adsorption. However, the development of Cu-based adsorbent with high Cu utilization remains a significant challenge. Herein, we report a new Cu0-SBA-15 adsorbent with high Cu utilization for high capacity adsorption of iodine in gas and solution. An improved solvothermal reduction strategy was proposed to fabricate Cu0-SBA-15 composite with high Cu utilization. The benefit of the strategy was that the Cu0 nanoparticles were confined on the surface or pore wall of mesoporous SBA-15, which improved the utilization of adsorption sites for iodine. The results demonstrated that the obtained Cu0-SBA-15 composite showed high adsorption capacities of 954 mg/g and 842 mg/g for iodine in gas and solution, respectively, and reached a record high Cu utilization of 96.93%. The obtained Cu0-SBA-15 composite showed high thermal stability. Furthermore, the iodine adsorption mechanism was that Cu0 reacted with I2 to form stable CuI. Owing to the excellent adsorption performance, the obtained Cu0-SBA-15 might be potential promising iodine adsorbent.

Exploring novel iodine sorbent with high efficiency and low cost is a meaningful and challenging topic. Herein, a series of iodine sorbents Cu0@SiO2 were firstly prepared by using SiO2 derived from rice husks as support materials. The obtained Cu0@SiO2 materials were employed to capture iodine gas. The effects of Cu content, contact time and adsorption temperature on the iodine adsorption behavior were investigated. The I2 adsorption capacity of Cu0@SiO2 reached up to 1105 mg/g with short time at 200 °C. The high chemical iodine adsorption ratio (95.11%) was achieved. Furthermore, the iodine capture mechanism for Cu0@SiO2 was mainly chemical, that is formation of stable CuI by chemical reaction between Cu0 and I2. The results demonstrated that Cu0@SiO2 derived from rice husk was a potential promising adsorbent owing to the low cost and high capture efficiency.