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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 has highly radioactive and biological toxicity, and its effective recovery is of primary importance. However, few materials can show good iodine adsorption in different media. Herein, Cu/Al 2 O 3 -Pal aerogels with improved mechanical properties and hierarchical pore structures were prepared by constructing the three-dimensional support skeleton of the aerogel with palygorskite fibers. The Cu/Al 2 O 3 -Pal aerogel exhibited excellent adsorption properties for I− (aqueous phase, 264–411 mg/g) and I 2 (organic phase, 503–744 mg/g), I 2 vapor (459–1122 mg/g), and CH 3 I vapor (559–1032 mg/g). Notably, the aerogel also exhibited ultra-high removal rates for trace iodide in solution (>90 %) and was able to efficiently convert to stable CuI. Importantly, the Cu/Al 2 O 3 -Pal aerogel can be prepared directly for use as a monolithic material, allowing for an easy recovery process. Overall, our work demonstrates the great potential of Cu/Al 2 O 3 -Pal x wt% aerogels for radioactive iodine elimination. Cu/Al 2 O 3 -Pal aerogels with good mechanical properties and hierarchical pore structures were prepared by constructing the three-dimensional support skeleton of the aerogel with palygorskite fibers. The Cu/Al 2 O 3 -Pal aerogel exhibited excellent adsorption properties for I− (aqueous phase, 264–411 mg/g) and I 2 (organic phase, 503–744 mg/g), I 2 vapor (459–1122 mg/g), and CH 3 I vapor (559–1032 mg/g). Notably, the aerogel also exhibited ultra-high removal rates for trace iodide in solution (>90 %) and was able to efficiently convert to stable CuI. Importantly, the Cu/Al 2 O 3 -Pal aerogel can be prepared directly for use as a block, allowing for an easy recovery process. [Display omitted] • Cu/Al 2 O 3 -Pal aerogel can be used to eliminate iodine in various phases. • The removal rate of trace iodine by Cu/Al 2 O 3 -Pal aerogel exceeded 90 %. • The adsorption product was stable and not easy to desorption. • Monolithic Cu/Al 2 O 3 -Pal aerogel was easy to recover. [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]