Regenerable and stable sp2 carbon-conjugated covalent organic frameworks for selective detection and extraction of uranium

Abstract

Uranium is a key element in the nuclear industry, but its unintended leakage has caused health and environmental concerns. Here we report a sp 2 carbon-conjugated fluorescent covalent organic framework (COF) named TFPT-BTAN-AO with excellent chemical, thermal and radiation stability is synthesized by integrating triazine-based building blocks with amidoxime-substituted linkers. TFPT-BTAN-AO shows an exceptional UO 2 2+ adsorption capacity of 427 mg g −1 attributable to the abundant selective uranium-binding groups on the highly accessible pore walls of open 1D channels. In addition, it has an ultra-fast response time (2 s) and an ultra-low detection limit of 6.7 nM UO 2 2+ suitable for on-site and real-time monitoring of UO 2 2+ , allowing not only extraction but also monitoring the quality of the extracted water. This study demonstrates great potential of fluorescent COFs for radionuclide detection and extraction. By rational designing target ligands, this strategy can be extended to the detection and extraction of other contaminants.

Redox-triggered switching in three-dimensional covalent organic frameworks

“…Covalent organic frameworks (COFs) 15 , 16 , an emerging class of porous crystalline polymers with two- or three-dimensional (2D or 3D) structures, have gained increasing attention and found potentials in gas storage and separation 17 – 21 , optoelectronics 22 – 26 , heterogeneous catalysis 27 – 30 , sensor 31 – 34 , energy storage 35 – 38 , etc. In principle, COFs can also be used as the platform for efficient tuning of molecular switches in solid state, but more importantly, they can show enhanced stability in contrast to most MOFs, due to their robust covalent linkages in the framework.…”

A New Squaraine‐Linked Triazinyl‐Based Covalent Organic Frameworks: Preparation, Characterization and Application for Sensitive and Selective Determination of Fe3+ Cations

“…COFs are linked by strong covalent bonds, such as B−O, C=N, C−N, B−N, and N=N bond linkages, which make them more stable and lower in density. Due to their remarkable properties, COFs present the potential in many specific functional applications, including gas storage and separation,[4] heterogeneous catalyst, photocatalysis, dye adsorption, optoelectricity, fluorescence detection, drug delivery, separation analysis, electric analysis, power storage, detection and adsorption of radioactive substances, and so on. At present, there are more and more functional COFs about fluorescence detection were reported.…”

Covalent Organic Frameworks: Synthesis, Properties and Applications—An Overview

“…Adsorption capacities of other heavy metals have also been reported, namely ions frequently found in industrial wastewater such as Cd(II) [ 84 , 85 , 86 ], Cr(VI) [ 87 , 88 , 89 ], Cu(II) [ 90 , 91 ] or Pb(II) [ 92 , 93 ], as well as Au(III) [ 94 ], lanthanides [ 95 ] and others [ 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 ].…”