Functional covalent organic framework illuminate rapid and efficient capture of Cu (II) and reutilization to reduce fire hazards of epoxy resin

Salted Dried Bamboo Shoots-Derived Mesoporous Carbon Inherently Doped with SiC and Nitrogen for Capacitive Deionization

Dried bamboo shoots (DBS) are a natural resource with inherent silica content, which can serve as sacrificial templates for the formation of mesoporous carbon but also promote the generation of silicon carbide (SiC). Building on this, we introduced mesoporous and graphitic carbon/SiC (SiC/BSC) as the CDI electrode for copper ion (Cu2+) removal. Mesoporous carbon electrodes facilitate faster ion transport, diffusion, and electron-transfer pathways. Furthermore, SiC accelerates electron transfer and promotes faradic redox reactions during the charge and discharge processes. Consequently, the synergistic effect of SiC/BSC mesoporous carbon material leads to a promising electrode for Cu2+ capacitive deionization. Leveraging these unique properties, the SiC/BSC electrode material exhibits an outstanding CDI performance of 381.5 mg/g at 1.8 V. This study offers a strategy for the preparation of efficient mesoporous carbon materials as CDI electrodes, specifically tailored for the deionization of Cu2+ ions.

Applications of covalent organic frameworks for the elimination of dyes from wastewater: A state-of-the-arts review

Covalent organic frameworks (COFs) are class of porous coordination polymers made up of organic building blocks joined together by covalent bonding through thermodynamic and controlled reversible polymerization reactions. This review discussed versatile applications of COFs for remediation of wastewater containing dyes, emphasizing the advantages of both pristine and modified materials in adsorption, membrane separation, and advanced oxidations processes. The excellent performance of COFs towards adsorption and membrane filtration has been centered to their higher crystallinity and porosity, exhibiting exceptionally high surface area, pore size and pore volumes. Thus, they provide more active sites for trapping the dye molecules. On one hand, the photocatalytic performance of the COFs was attributed to their semiconducting properties, and when coupled with other functional semiconducting materials, they achieve good mechanical and thermal stabilities, positive light response, and narrow band gap, a typical characteristic of excellent photocatalysts. As such, COFs and their composites have demonstrated excellent potentialities for the elimination of the dyes.

Advanced Covalent Organic Framework-Based Membranes for Recovery of Ionic Resources

Membrane technology has shown a viable potential in conversion of liquid-waste or high-salt streams to fresh waters and resources. However, the non-adjustability pore size of traditional membranes limits the application of ion capture due to their low selectivity for target ions. Recently, covalent organic frameworks (COFs) have become a promising candidate for construction of advanced ion separation membranes for ion resource recovery due to their low density, large surface area, tunable channel structure, and tailored functionality. This tutorial review aims to analyze and summarize the progress in understanding ion capture mechanisms, preparation processes, and applications of COF-based membranes. First, the design principles for target ion selectivity are illustrated in terms of theoretical simulation of ions transport in COFs, and key properties for ion selectivity of COFs and COF-based membranes. Next, the fabrication methods of diverse COF-based membranes are classified into pure COF membranes, COF continuous membranes, and COF mixed matrix membranes. Finally, current applications of COF-based membranes are highlighted: desalination, extraction, removal of toxic metal ions, radionuclides and lithium, and acid recovery. This review presents promising approaches for design, preparation, and application of COF-based membranes in ion selectivity for recovery of ionic resources.

Hierarchical core-shell SiO2@COFs@metallic oxide architecture: An efficient flame retardant and toxic smoke suppression for polystyrene

SiO₂@3COFs@CuO and SiO₂@3COFs@Fe₂O₃ are prepared in this study. Then SiO₂ and its hybrids are incorporated into PS through solution blending method. The thermal stability, mechanical performance, combustion performance and smoke density of PS and its nanocomposite are investigated. The temperature at 5 wt% weight loss and the maximum weight loss rate of PS/SiO₂@3COFs@ Fe₂O₃ (PS 4) under air are 15 and 14 °C higher than that of neat one, respectively. The glass-transition temperature of PS/SiO₂@3COFs (PS 2) is 1.5 °C lower than that of PS, which can conclude that SiO₂@3COFs contributes to impact strength of PS 0. The peak heat release rate (20.8%) and total heat release (14.0%) of PS 2 decreases further compared with that of PS 0. The smoke density of PS 4 is 23.1% lower than that of neat PS. The influence of SiO₂ and its nano-hybrids on the pyrolysis and combustion of PS is investigated. Incorporation of SiO₂ and its nano-hybrids shows little effect on pyrolysis process of PS. However, heat resistance of PS is enhanced obviously and thermal degradation rate of PS is also decreased through incorporation of SiO₂ and its nano-hybrids. The gaseous pyrolysis products (aromatic compounds and alkenyl compounds) of PS and its nanocomposite also decrease.

Structural Characteristics and Environmental Applications of Covalent Organic Frameworks

Covalent organic frameworks (COFs) are emerging crystalline polymeric materials with highly ordered intrinsic and uniform pores. Their synthesis involves reticular chemistry, which offers the freedom of choosing building precursors from a large bank with distinct geometries and functionalities. The pore sizes of COFs, as well as their geometry and functionalities, can be pre-designed, giving them an immense opportunity in various fields. In this mini-review, we will focus on the use of COFs in the removal of environmentally hazardous metal ions and chemicals through adsorption and separation. The review will introduce basic aspects of COFs and their advantages over other purification materials. Various fabrication strategies of COFs will be introduced in relation to the separation field. Finally, the challenges of COFs and their future perspectives in this field will be briefly outlined.