SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Wen He,Zhenglemei Qiu,Qunying Sun,Zhouzhou Li,Zhuting Chen,Lijun Hu,Hongqing Wang
Constructing desirable morphology has been demonstrated to be an effective strategy for enhancing the capabilities of the covalent organic frameworks (COFs) for the processing of uranium. Traditional 3D-COFs only possess a limited number of structural nodes, not being the ideal structure for uranium adsorption, but 2D-COFs with rich structural nodes also suffer from reduced exposure of adsorption sites due to stacking during uranium treatment, which is not beneficial for achieving sustained and efficient adsorption. To this end, by polymerizing COFs on the silica carrier, followed by etching the silica carrier, and utilizing the conversion of nitrile to amidoxime groups as chelation sites, we designed and synthesized a hollow 3D-like structure of 2D-COFs (COF-TD-H-AO, similar to three-dimensional COFs) as adsorbents to capture the radionuclide uranium. Systematic studies were carried out for the adsorption characteristics of this material at different pH values and in the presence of interfering ions, as well as its adsorption thermodynamics and kinetics. Compared with COF-TD-AO (pure 2D-COFs) and SiO 2 @COF-TD-AO (unetched), COF-TD-H-AO exhibited a higher adsorption capacity as well as selective adsorption of uranium. This work provides an innovative perspective on material design and preparation by providing more adsorption sites in an effort to improve the capacity of adsorption and the selectivity of adsorption.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2022
·
IF 4.778
Meng Xia,Tieyin Shen,Chaokun Li,Ruimei Fan,Lijuan Feng,Qi Chen
In this contribution, we demonstrate the synthesis of hydrazone-linked COF-Paper composites (namely COF-Paper1 and COF-Paper2) constructed from two monomers of benzene-1,3,5-tricarbohydrazide (Bth) and dimethoxyterephthal-aldehyde (Dma) or 2,5-dihydroxyterephthalaldehyde (Dha) via in-situ growth method using filter paper as a matrix. Interestingly, 2D COFs paper composites display excellent luminescence in the solid-state, and the as-synthesized COF-Paper1 and COF-Paper2 can be used as turn-off fluorescence sensors to visually detect Fe 3+ ions and UO 2 2+ ions by the naked eye, respectively. Moreover, the visible limit of detection for Fe 3+ and UO 2 2+ was 5.6 ng cm −2 and 27 ng cm −2 , respectively. XPS and FT-IR results reveal that resulting COF-Papers have significant coordination ability toward target metal ions . This effective coordination induces electron transfer from the electron-rich building module to the electron-deficient metal ion, resulting in the fluorescence quenching process. This work not only provides a methodology to grow and assemble 2D COFs into large size ensembles but also paves a new pathway for visual detection of target metal ions.
研究领域:
材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
TRIBOLOGY INTERNATIONAL
·
2026
·
IF 7.6
Zhuangzhuang Bi,Le Gu,Yuanyuan Guo,Huanhuan Wei,Qing Qu,Bo Wu
Water intrusion into organic base fluids frequently induces boundary lubrication failure. To address this challenge, two-dimensional covalent organic frameworks (2D COFs) were investigated as water-tolerant nano-additives. Two COFs with distinct linkages were compared: the rigid imine-linked TFB-DB and the flexible β -ketoenamine-linked TFP-ODA. A combined experimental and multiscale simulation strategy was employed to correlate nanoscale interfacial dynamics with mesoscale tribofilm morphology. Although both COFs exhibited similar macroscopic wettability, their lubrication behaviors differed significantly. Multiscale simulations revealed a confinement-limited geometric saturation effect under extreme local contact pressures. Because the confined-water hydrogen-bond network reached geometric saturation, functional-group abundance alone could not proportionally enhance lubrication. Instead, structural adaptability was identified as the critical factor. Computations demonstrated that the flexible TFP-ODA framework provided favorable local water affinity and dynamically stabilized the confined water layer under severe shear, preventing hydration network collapse. Morphological analyses confirmed that this microscale flexibility directly facilitated mesoscale tribofilm continuity. While the rigid TFB-DB produced discontinuous deposits, TFP-ODA formed a continuous, strongly adhered tribofilm that effectively shielded the high-shear metallic substrate. Consequently, TFP-ODA demonstrated exceptional water-contamination tolerance, achieving an optimal friction coefficient of ∼0.15 in a 50% ethylene glycol/water mixture. These results indicate that the boundary lubrication performance of COF additives is governed synergistically by dynamic hydration-layer stabilization and continuous tribofilm formation, rather than by macroscopic wettability or functional-group density alone.
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·Vol. 12
·期 32
·21398-21405
·
IF 10.7
Yi Yu,Meng Wang,Ying Wu,Hongxia Xi
Covalent organic frameworks (COFs) with permanent porosity, high structural stability and framework modifiability offer unique superiority for heterogeneous catalysis. Herein, we propose an in situ metallization strategy to construct a series of metal-functionalized 2D COFs (M/COFs, M = Co, Ni and Zn). The 2D matrix provides inherent accessible Lewis base sites, along with the introduced metal species acting as Lewis acid sites. These active sites with synergistic effects boost the catalytic CO2 conversion performance of these materials. Our results show that these M/COFs efficiently convert CO2 and olefins into cyclic carbonates through one-pot tandem catalysis. Specifically, Co/COFs achieve nearly complete styrene conversion and 85% yield of styrene carbonate without a co-catalyst at 80 °C and 1 bar. Simulation results further reveal the higher interaction energy of Co/COFs and guests and elucidate the underlying catalytic mechanisms of COF catalysts before and after modification. This work provides both scientific and applicational insights into designing high-performance metal-functionalized materials for optimal tandem catalytic performance.
研究领域:
材料科学
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催化
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化学工程
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环境化学
✓ 已验证
产品关联
DOI
高影响因子
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