An Ultrastable Crystalline Acylhydrazone‐Linked Covalent Organic Framework for Efficient Removal of Organic Micropollutants from Water

Abstract

As an important member of crystalline porous polymers, acylhydrazone-linked covalent organic frameworks (COFs) have gained much attention in recent years. However, the low structural stability imparts a limit on their practical applications. To tackle this problem, we report a simple strategy to increase the chemical stability of acylhydrazonelinked COFs by incorporating azobenzene groups in the conjugated framework. Through reinforcing the π-π stacking interactions between the adjacent layers with increased πsurface, it is surprising to find that the resulting materials exhibit extreme stability in harsh environments, such as in strong acid, strong base, aqueous educing agent and boiling water, even exposed to air for one year. As a proof-ofconcept, such frameworks have been used to remove various organic micropollutants such as antibiotics, plastic components, endocrine disruptors, and carcinogens from water with high capacity, fast speed and excellent reusability over a wide pH range at environmentally relevant concentrations. The results provide a new avenue to significantly enhance the stability of COFs for practical applications.

The Ionic Liquid–H2O Interface: A New Platform for the Synthesis of Highly Crystalline and Molecular Sieving Covalent Organic Framework Membranes

“…These merits make COF materials attractive for membrane applications. However, conventional synthesis methods such as solvothermal − and microwave − often produce insoluble microcrystalline COF powders. Transforming these powders into membranes, though imperative for the practical application, , confronts a significant challenge owing to the poor processability.…”

Missing-linker defects in a covalent organic framework photocatalyst for highly efficient synthesis of tetrahydroquinoline

“…The high chemical stability of COF-HNU30-10 can be attributed to the intramolecular hydrogen bond between O–H and CN. 38…”

“…The high chemical stability of COF-HNU30-10 can be attributed to the intramolecular hydrogen bond between O-H and CvN. 38 Next, the catalytic activity of COF-HNU30-x was evaluated for the OCCR of N,N-dimethylanilines with maleimides to prepare tetrahydroquinolines under visible-light irradiation. N,N-Dimethylaniline (1a) and maleimide (2a) were initially selected as model substrates to explore the optimal reaction conditions in ambient air.…”

Design of a novel green bio-based organic–inorganic hybrid material for cost-effective and sustainable monitoring of antibiotic residues

“…SPE column packing is essential for effective enrichment and purification. 26 To date, many traditional and novel SPE packing methods have been widely used to enrich target analytes, including C18, 27 hydrophilic-lipophilic balance (HLB), 28,29 carbon nanotubes (CNTs), 30 mesoporous silica nanoparticles, 31 molecularly imprinted polymers (MIPs), 32 covalent organic frameworks (COFs), 33,34 metalorganic frameworks (MOFs), 35 etc. Although these adsorbents have largely solved the problem of MAC enrichment and separation in complex matrices, most of them are consumable adsorbents, the raw materials involved are difficult to regenerate and degrade and there are still some problems including the complicated preparation process, which involves consumption of many organic reagents, harsh reaction conditions, single interaction, susceptibility to interference by co-existing components, and limited recovery.…”