Fabrication of Protonated Two-Dimensional Metal–Organic Framework Nanosheets for Highly Efficient Iodine Capture from Water

Abstract

Radioactive iodine ( 129 I and 131 I), produced or released from nuclear-related activities, posed severe effects on both human health and environment. The efficient removal of radioiodine from aqueous medium and vapor phase is of paramount importance for the sustainable development of nuclear energy. Herein, a metal−organic framework (MOF) nanosheet with a positive charge was constructed for the capture of iodine for the first time. The as-synthesized ultrathin nanosheets, with a thickness of 4.4 ± 0.1 nm, showed a record-high iodine adsorption capacity (3704.08 mg g −1 ) from aqueous solution, which is even higher than that from the vapor phase (3510.05 mg g −1 ). It can be ascribed to the fully interactions between the extensive accessible active sites on the largely exposed surface of 2D MOF nanosheets and the target pollutants, which also gave rise to fast adsorption kinetics with relative high removal efficiencies in the low concentrations, even in seawater. Moreover, a facile recyclability with fast desorption kinetics can also be achieved for the MOF nanosheets. The excellent iodine removal performance in aqueous solution demonstrated that the electrostatic attraction between MOF nanosheets with a positive charge and the negatively charged triiodide (I 3 − , the dominant form of iodine in aqueous solution) is the driving force in adsorption, which endows the adsorbents with the characteristics of fast adsorption and desorption kinetics. The adsorption mechanism was systematically verified by the studies of ζ potential, Fourier transform infrared, X-ray photoelectron spectroscopy, and Raman spectra.

Exploiting a Multi-Responsive Oxadiazole Moiety in One Three-Dimensional Metal–Organic Framework for Remedies to Three Environmental Issues

“…This result for multimedia capture of iodine molecules is found to be among the highest reported ones and is comparable with those in the literature (Table S1). − …”

Rational Design and Assembly of Two-Dimensional Layered Metal–Organic Frameworks: Structure, Morphology, Fluorescence Regulation, and High Iodine Adsorption

“…Various materials have been prepared for the uptake of iodine. MOFs have been considered as promising candidates due to their tunable and modifiable structures, ultrahigh porosities, and surface areas. − 2D MOFs, integrating the features of MOFs and 2D materials, have shown great potential in this field recently. ,, HSB-W11–W14 are four 2D LMOFs, which have abundant uncoordinated carboxyl oxygen and secondary amines, and can retain their structures after activation (Figures S28–S31); therefore, they may be used as potential iodine adsorbents.…”

“…50−56 2D MOFs, integrating the features of MOFs and 2D materials, have shown great potential in this field recently. 35,57,58 HSB-W11−W14 are four 2D LMOFs, which have abundant uncoordinated carboxyl oxygen and secondary amines, and can retain their structures after activation (Figures S28−S31); therefore, they may be used as potential iodine adsorbents.…”

A Porous π-Stacked Self-Assembly of Cup-Shaped Palladium Complex for Iodine Capture

“…To date, a broad range of solid adsorbents has been found to be very promising for removing molecular iodine [ 15 , 16 , 17 , 18 , 19 ]. These adsorbents include zeolites [ 20 , 21 ], functionalized clays [ 22 ], activated carbon [ 23 ], metal/covalent–organic frameworks (MOFs and COFs) [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ], supramolecular cages [ 34 , 35 ], supramolecular assemblies [ 36 , 37 , 38 ], etc.…”