Guang-Li Zhou,Bo-Wen Liu,Guang-Yu Cui,Wei Zhang,Ji-Min Yang
Radioactive iodine waste from the nuclear industry poses a critical threat to human health, and its effective capture has become an important research topic. In this study, modified UiO-66-X adsorbents (where X is ATA, BTA, or STA) were used to investigate the effects of the free functional groups in the UiO-66 skeleton on iodine capture in the vapor and solution states. The adsorption behavior revealed that the capture efficiency of UiO-66-ATA was substantially higher than that of UiO-66-BTA and UiO-66-STA because the electron-donating amino groups could enhance the I − I···π halogen bond interactions compared with the electron-withdrawing carboxyl and sulfonic acid groups. In addition, the pore volume of UiO-66-ATA was significantly higher than those of UiO-66-BTA and UiO-66-STA. In particular, the removal uptakes of UiO-66-ATA were 1108.1 mg/g (vapor phase) and 3601.9 mg/g (aqueous solution). This study is the first to investigate the effects of functional groups on the adsorption uptake of UiO-66 toward iodine. This efficient functional group modification strategy holds significant promise for the development of novel metal–organic framework adsorbents.
Ammonia borane (AB) has attracted much attention in the field of solid-state hydrogen storage due to its high hydrogen storage capacity. Nanoconfinement in UiO-66 can reduce the hydrogen release temperature. In particular, terephthalic acid was used as a linker to further improve the dehydrogenation properties through the modification of -NH2, -OH, -NO2, -Br, and -F groups. The hydrogen release content of 0.5AB/UiO-66 was 1.98 wt.%, whereas the hydrogen release content of UiO-66-2OH modified by -OH groups increased to 3.85 wt.%. The non-covalent interaction results show that -NH2and -OH preferred adsorption with -BH3, and the H in -NH2and -OH were able to interact directly with the H in AB to modify the dehydrogenation process of AB, whereas -NO2, -Br, and -F indirectly affected the charge density of hydrogen atoms in AB to alter the dehydrogenation property of AB. The modification of functional groups provides a theoretical basis for the design of high-performance MOF nanoconfinement AB composite hydrogen storage materials.
Deshuai Zhen,Chunlin Liu,Qiuhui Deng,Le Li,Craig A. Grimes,Shengyuan Yang,Qingyun Cai,Yu Liu
Monitoring and purification of uranium contamination are of great importance for the rational utilization of uranium resources and maintaining the environment. In this work, an olefin-linked covalent organic framework (GC-TFPB) and its amidoxime-modified product (GC-TFPB-AO) are synthesized with 3-cyano-4,6-dimethyl-2-hydroxypyridine (GC) and 1,3,5-tris(4-formylphenyl) benzene (TFPB) by Knoevenagel condensation. GC-TFPB-AO results in specificity for rapid fluorescent/smartphone uranyl ion (UO22+) detection based on the synergistic effect of multifunctional groups (amidoxime, pyridine, and hydroxyl groups). GC-TFPB-AO features a rapid and highly sensitive detection and adsorption of UO22+ with a detection limit of 21.25 nM. In addition, it has a good recovery (100–111%) for fluorescence detection in real samples, demonstrating an excellent potential of predesigned olefin-linked fluorescent COFs in nuclear contaminated wastewater detection and removal.
Functional groups modified metal-organic frameworks (MOFs) was synthesized via a pre-tailor method and served as an adsorbent for perfluorooctanoic acid (PFOA) removal. The material was characterized using Fourier transform infrared spectroscopy , scanning electron microscopy, X-ray diffraction and N 2 sorption-desorption. Monte Carlo simulation and molecular dynamics are derived to predict the possible molecular packing and adsorption mechanism. The Hirshfeld surface with reduced density gradient analysis demonstrates that PFOA is adsorbed on MOF-X mainly affected by van der Waals interactions and steric effects. Adsorption kinetics and isotherms were investigated on the basis of a static experiment. The pseudo-second-order kinetic model and Langmuir isotherm were fitted well to characterize adsorption process. Hereinto, amino-modified MOFs reached the highest adsorption efficiency and the maximum capacity was 185.6 mg/g. Combing the experimental data with theoretical simulation, results indicated that functional group modification is an effective approach to alter the crystal structure and then affect the adsorptive properties of MOFs.
危险品化学品经营许可证（带存储）