No abstract

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.

The exploration of transforming various metals as metal sources into metal organic frameworks (MOFs) has attracted considerable attention in recent years. This study used triethylamine and 5,6-dimethylbenzimidazole (DMBIM) to modify the iron-doped cobalt zeolite imidazole framework on carbon fiber structure. The results showed that the ZIF(Fe/Co)1.25@CNF exhibited high CEF removal efficiency that over 97% of ceftiofur sodium (CEF) was removed within 10 min, which was significantly higher than that of the common ZIF-67 materials. Compared with other ZIF-67 composites, ZIF(Fe/Co)x@CNF has a larger specific surface area, resulting in a larger contact area and more active sites during the reaction. After the introduction of DMBIM, the ZIF(Fe/Co)1.25@CNF not only easily separated from the solution but also enhanced the hydrophobicity, which provided higher catalytic stability and catalytic performance. In addition, the effects of different catalyst ratios, pollutant concentrations, solution pH, and different radicals (•OH, SO4•−, 1O2) on the activation of peroxymonosulfate (PMS) were investigated. The mechanism of degradation was elucidated by electron paramagnetic resonance experiments. This study provides a new perspective for the preparation of high-performance MOF catalysts with excellent catalytic performance and may facilitate the application of MOF materials in more practical situations.