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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]

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]