The increasing pressure for lithium resources from the
electric
vehicle and nuclear energy industries means that new technologies
to separate Mg2+ from Li+ from salt water are
in demand. To address this need, we fabricated lithium pyrene squarate
covalent organic frameworks (Li-SQCOFs) to separate Mg2+/Li+ mixtures from salt water. We optimized the effect
of the electrolyte and the amount of the adsorbent and then carried
out a kinetics study on the adsorbent recovery at various pH levels
using both batch and continuous flow adsorption methods. Li-SQCOF
was found to have excellent selectivity for solutions containing a
mixture of Mg2+/Li+ ions. This work represents
a unique path for the separation of Mg2+/Li+ through direct adsorption using a covalent organic framework (COF).
The COF-supported ultrafiltration bed made in this study gave a Mg2+ separation flux of 60.5 h–1 m–2.
The synthesis of a fluorescent covalent organic framework (COF) using perylene and pyrene building blocks (PEPy-COF), via a one-pot condensation reaction is reported. PEPy-COF is crystallized into 2D nanosheets with a cubic and prismatic crystalline morphology and demonstrates structural stability at temperatures up to 500 °C. The structural morphology is confirmed using X-ray diffraction and atomic-level simulations. These 2D porous polymer sheets form a tetragonal framework that is found to have a high specific surface area of 772 m 2 g −1 . Based on the definition of porous materials, the network is mesoporous with an observed pore size of 3.03 nm, which is in good agreement with the material's calculated pore size. The experimentally obtained HOMO-LUMO band gap is 2.62 eV, confirming the semiconducting nature of PEPy-COF. PEPy-COF emits a shiny blue luminescence under UV and visible light. This luminescence intensity is temperature-dependent in solvents with different polarities and dielectric constants demonstrating that the PEPy-COF has potential use in a wide range of temperature-sensing devices. The fluorescence intensity ratio is similar for different temperatures under ultra-sound conditions and varying solvents.
PEPy‐COF, a new covalent organic framework (COF), exhibits a shiny blue fluorescence under UV and visible light. In article number 2300412, Amin Zadehnazari, Alireza Abbaspourrad, and colleagues built PEPy‐COF via a one‐pot condensation reaction using perylene and pyrene building blocks. PEPy‐COF features temperature‐dependent and solvent‐independent fluorescence and a semiconductor band gap making it an excellent candidate for temperature sensing devices.
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