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The copper benzene tricarboxylic acid (Cu-BTC) cannot be used as an adsorbent in water due to hydrophilicity. However, the calcination process can destroy the benzene ring structure to lose hydrophilicity and retains carbon structure skeleton. The CuO composite and CuO/Cu2O composite based on cubical Cu-BTC (C-Cu-BTC) and dodecahedral Cu-BTC (D-Cu-BTC) are successfully manufactured to absorb radioactive iodine ion from water. Before and after calcination, the SEM and XRD were used to characterize the changes of morphology and material structure. The adsorption experiment for iodine ion showed that their saturated adsorption capacities can reach 28.64 mg/g (for C-CuO), 49.63 mg/g (for D-CuO), 49.84 mg/g (for C-CuO/Cu2O) and 91.91 mg/g (for D-CuO/Cu2O), respectively. The iodine ion adsorption of adsorbent is an exothermic reaction as shown thermodynamic curves. Through results of adsorption kinetics it is proved that the iodide ion adsorption of CuO composite is physical adsorption and the iodide ion adsorption of CuO/Cu2O composite is chemical adsorption. Compared with CuO composite, CuO/Cu2O composite had better absorption capacity for iodide ions. Furthermore, the interference of common ion on iodide absorption has also been studied. The different types of ion, such as Cl−, SO42− and CO32−, have effects on the iodine ions absorption capacity for two types of adsorbent. These ions have a slightly effect on iodine ions adsorption of CuO composite. However, these ions have greater influences on iodine ions absorption capacity of the CuO/Cu2O composite. The biggest influence is CO32−, and the CO32− reduces the adsorption capacity by 44% iodine ion absorption capacity for the CuO/Cu2O composite.

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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.