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A HKUST-1 derivative composite based on LDH was synthesized to efficiently adsorb iodide anions in aqueous solutions. Specifically, Cu/Al-LDH, HKUST-1, HKUST-1@Cu/Al-LDH, Cu/Al-CLDH, Cu-C and Cu2O@Cu/Al-CLDH were synthesized and characterized. HKUST-1@Cu/Al-LDH kept the desirable characteristics of both Cu/Al-LDH and HKUST-1. Cu2O@Cu/Al-CLDH maintained the morphology of HKUST-1@Cu/Al-LDH, with its iodine anions absorption mechanism being chemical adsorption. Cu2O@Cu/Al-CLDH exhibited a significantly higher adsorption capacity than previously reported Cu-based adsorbents, with an adsorption capacity of 240.7 mg g−1 at pH 3, taking about 240 min to reach adsorption equilibrium. Thus, Cu2O@Cu/Al-CLDH is a promising adsorbent for removing iodide anions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Radioactive iodine is one of the inevitable by-products of nuclear energy application. However, it is a great threat to public health and the adsorbent needs to be adopted for removing the radioactive iodine. The iodine adsorbent needs to have some advantages, such as simple preparation method, low cost, high absorption capacity, and recyclable utilization. In order to meet the above requirements, the etched material of institute Lavoisier 101 (MIL-101) was prepared to absorb the gaseous iodine. After the MIL-101 is etched, the iodine adsorption performance has been greatly improved. The iodine adsorption experiment of etched MIL-101 with different etching time (1 h, 3 h, 4 h, and 6 h) was completed, the results show that the optimal etching time is 4 hours and the capture capacity of the etched MIL-101 is 371 wt%, which is about 22% higher than that of original MIL-101. The experiment results of XRD, FT-IR, and XPS prove that the components and structure of etched MIL-101 are accordable with those of MIL-101. The surface roughness is introduced in this work. The pore roughness is also an important factor to the adsorption capacity, and the related research also supports this conclusion. Furthermore, after iodine is absorbed, etched MIL-101 can be treated by ethanol for iodine release, and the etched MIL-101 has satisfied recyclability within three cycles. Compared with MIL-101, etched MIL-101 not only had good reversible adsorption of iodine but also can adsorb low-concentration iodine. The etched MIL-101 has a broad application prospect in nuclear emergency response and radiation detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Core-shell structured Bi 2 S 3 -ZnS@C nanocomposites were successfully fabricated using ZIF-8 as template. • Bi 2 S 3 -ZnS@C showed high adsorption capacity (1118.5 mg g−1) and high chemisorption percentage (87.3 %). • The excellent iodine capture performance derived from the chemical reaction between Bi 2 S 3 and I 2 to form BiI 3. • Bi 2 S 3 -ZnS@C exhibited excellent thermal and irradiation stability. • I-Bi 2 S 3 -ZnS@C could be immobilized in a commercial glass composition via a low-temperature sintering method. Effective capture of radioiodine is crucial for the sustainable development of nuclear power, given its environmental mobility, high toxicity, and long half-life. Herein, a new core–shell structured Bi 2 S 3 -ZnS@C derived from ZIF-8 was synthesized by cation exchange, sulfation and carbonization. The advantage of this structure is that Bi 2 S 3 uniformly loads on the surface of nanoparticles, effectively avoiding its aggregation and improving the utilization of active sites. The iodine capture experiments indicated that Bi 2 S 3 -ZnS@C had excellent adsorption capacity (up to 1118.5 mg g−1 within 120 min) and high chemisorption percentage (87.3 %) at 200 °C, as well as superior thermal and irradiation stability. The mechanism investigations revealed that the exceptional iodine uptake performance was predominantly attributed to the strong chemical reaction between Bi 2 S 3 and I 2 to generate BiI 3. Additionally, the iodine-captured Bi 2 S 3 -ZnS@C could be immobilized in a commercial glass composition via low-temperature sintering. The findings indicated that the captured BiI 3 and I 2 were efficiently converted to the chemically stable Bi x O y I during the sintering process. The initial leaching rate of iodine was 3.94 × 10−5 g m−2 d−1, which signified the excellent chemical durability of the resultant glass composites. Therefore, the obtained Bi 2 S 3 -ZnS@C could be a promising candidate for efficient capture and stable storage of radioiodine. [ABSTRACT FROM AUTHOR]

Radioactive iodine generated from nuclear waste and nuclear accidents can cause serious hazards to the environment and human body. In this study, bismuth-doped ZIF-8 composites (Bi 2 O 3 @ZIF-8) were synthesized by in situ synthesis at room temperature to study their adsorption of iodine in gaseous state and in solution. The Bi 2 O 3 @ZIF-8 composites were characterized and analyzed by means of tests. Bi 2 O 3 @ZIF-8 exhibited high specific surface area and contained abundant microporous structures. However, when the bismuth doping amount reached 10%, 10%-Bi 2 O 3 @ZIF-8 appeared mesoporous. The specific surface area of 1%-Bi 2 O 3 @ZIF-8, 5%-Bi 2 O 3 @ZIF-8 and 10%-Bi 2 O 3 @ZIF-8 could reach 1110.6 m2/g, 973.21 m2/g and 927.82 m2/g, respectively. The adsorption of gaseous iodine by 5%-Bi 2 O 3 @ZIF-8 reached equilibrium after 3.5 h with the maximum adsorption capacity of 298 wt%. And the maximum adsorption capacity of iodine in solution was 751.4 mg/g. The effects of the initial concentration of the solution, reaction temperature and contact time on the adsorption process were investigated. The adsorption of Bi 2 O 3 @ZIF-8 on iodine was consistent with the pseudo-second-order kinetics and the Langmuir model. The results of thermodynamic studies indicated that the adsorption of iodine by Bi 2 O 3 @ZIF-8 was spontaneous and exothermic. This study provides a reference for the synthesis of metal organic framework-based materials and provides theoretical guidance for the removal of practical radioactive iodine. We synthesized composites of Bi 2 O 3 -ZIF-8 with different bismuth doping amounts for the adsorption of gaseous iodine as well as iodine in cyclohexane solution. [Display omitted] • Bismuth-doped ZIF-8 composites (Bi 2 O 3 @ZIF-8) were synthesized by in situ synthesis method. • Bi 2 O 3 @ZIF-8 had high specific surface area and contained abundant micropores. • The material with 10%-Bi 2 O 3 @ZIF-8 appeared mesopores. • Theses adsorbents adsorbed iodine in both gaseous and solution form. • The adsorption mechanism of radioactive iodine by Bi 2 O 3 @ZIF-8 was discussed. [ABSTRACT FROM AUTHOR]

Due to the critical importance of capturing radioiodine from aquatic environments for human health and ecosystems, developing highly efficient adsorbent materials with rapid kinetics for capturing iodide ions in aqueous solutions is urgently needed. Although extensive research has been conducted on iodine adsorption in gas and organic phases, limited research has been dedicated to adsorption in aqueous solutions. An effective technique for removing iodide was proposed using Ag@Cu-based MOFs synthesized by incorporating Ag into calcined HKUST-1 with varying mass ratios of Ag/Cu–C. Extensive characterization using SEM, XRD, XPS, and nitrogen adsorption-desorption analysis confirmed successful incorporation of Ag in Cu–C. Batch adsorption experiments were conducted, demonstrating that the 5% Ag@Cu–C material exhibited a high adsorption capacity of 247.1 mg g−1 at pH 3. Mechanism investigations revealed that Cu0 and dissolved oxygen in water generate Cu 2 O and H 2 O 2 , while Ag and a small amount of CuO generate Ag 2 O and Cu 2 O. Furthermore, iodide ions in the solution are captured by Cu+ and Ag+ adsorption sites. These findings highlighted the potential of Ag@Cu-based MOFs as highly effective adsorbents for iodine anions removal in radioactive wastewater. • Ag@Cu-based MOFs with varying mass ratios of Ag/Cu–C were successfully synthesized by modifying calcined HKUST-1 with Ag. • 5%Ag@Cu–C showed a high adsorption capacity of 247.1 mg g−1 at pH 3. • The superior iodine anion removal performance was attributed to the strong chemical affinity of Cu+ and Ag+ to iodide. • Ag@Cu–C had great potential as a selective iodide removal material for radioactive wastewater. [ABSTRACT FROM AUTHOR]