Covalent Organic Frameworks as a Decorating Platform for Utilization and Affinity Enhancement of Chelating Sites for Radionuclide Sequestration

Abstract

The potential consequences of nuclear events and the complexity of nuclear waste management motivate the development of selective solid-phase sorbents to provide enhanced protection. Herein, it is shown that 2D covalent organic frameworks (COFs) with unique structures possess all the traits to be well suited as a platform for the deployment of highly efficient sorbents such that they exhibit remarkable performance, as demonstrated by uranium capture. The chelating groups laced on the open 1D channels exhibit exceptional accessibility, allowing significantly higher utilization efficiency. In addition, the 2D extended polygons packed closely in an eclipsed fashion bring chelating groups in adjacent layers parallel to each other, which may facilitate their cooperation, thereby leading to high affinity toward specific ions. As a result, the amidoxime-functionalized COFs far outperform their corresponding amorphous analogs in terms of adsorption capacities, kinetics, and affinities. Specifically, COF-TpAb-AO is able to reduce various uranium contaminated water samples from 1 ppm to less than 0.1 ppb within several minutes, well below the drinking water limit (30 ppb), as well as mine uranium from spiked seawater with an exceptionally high uptake capacity of 127 mg g . These results delineate important synthetic advances toward the implementation of COFs in environmental remediation.

An Ion‐Crosslinked Supramolecular Hydrogel for Ultrahigh and Fast Uranium Recovery from Seawater

“…However, the proven uranium ore reserves on land are limited, and can only provide for about 70 years of consumption of global nuclear energy . To efficiently recover uranium from seawater, for the long‐term sustainable development of nuclear power, many types of uranium adsorbents have been developed, such as inorganic materials, synthetic organic and polymeric materials, various nanostructured adsorbents including grafted polymeric porous supports, metal–organic frameworks, covalent organic frameworks, porous carbons, porous aromatic frameworks, porous‐organic polymers, and recent protein/biomass‐based materials . For all this, a great number of technical difficulties are associated with massive uranium extraction from seawater, because of the ultralow concentrations of uranium and the severe interference of massive coexisting ions, as well as the complicated biological environment which can corrode/destroy the adsorbents and devices .…”

Opportunities of Covalent Organic Frameworks for Advanced Applications

“…[59] Wang and co-workers reported the first application of fluorescent COFs for selectively detecting and removing Hg ions, as demonstrated by a thioether-functionalized hydrazine linked COF, COF-LZU8, which was constructed by the condensation of 1 and 2 (Figure 14). [58] Copyright 2018, John Wiley and Sons. Given the high affinity of thioether toward mercury, the COF can selectively capture Hg 2+ from a variety of interference ions and thereby the realization of efficient detection with a Adv.…”

Covalent Organic Frameworks with Chirality Enriched by Biomolecules for Efficient Chiral Separation

“…Emerging as an ew class of crystalline solid-state materials,COFs feature high surface area, low mass density,tunable pore size,high stability,and easily tailored functionality, [12][13][14] which means they hold promise for applications in many fields such as gas storage, [15] photoelectricity, [16] catalysis, [17][18][19] environmental remediation, [20] drug delivery, [21] and functional devices. [22] Thedevelopment of COFs for chiral separation is still in the infancy stage, [23][24][25] primarily relying on the construction of chiral COFs based on chiral monomers.O n the basis of our recent success in immobilizing enzymes into COFs, [26] in this work we present an alternative strategy to introduce chirality into COFs by covalently anchoring aseries of biomolecules,such as amino acids,peptides,and enzymes, onto the channel walls of achiral COFs to form biomolecu-les&COFs (Scheme 1).…”