Porphyrin COF and its mechanical pressing-prepared carbon fiber hybrid membrane for ratiometric detection, removal and enrichment of Cd2

An electrochemical immunosensor for carbohydrate antigen CA125 based on electroactive COFs as a signal probe

Levels of CA125 are strongly associated with cervical, pancreatic, bowel and breast cancer. However, the common CA125 detection method has the disadvantages of poor repeatability, high cost, easy to be disturbed and poor stability. In this work, a COF based electrochemical immunosensor was developed for the rapid, sensitive and stable detection of CA125. The COFDha-Tab synthesized by 2,5-dihydroxyp-phenyldiformaldehyde (Dha) and 1,3,5-tris(4-aminophenyl)benzene (Tab) can better absorb primary antibody (Ab1) of CA125 after epoxidation, and the COFDAAQ-TFP synthesized by 2,6-diaminoanthraquinone (DAAQ) and 2,4,6-triformylphloroglucinol (TFP) was modified with AuNPs, which can not only improve the electrochemical performance but also provide a platform for loading secondary antibody (Ab2). CA125 can be specifically recognized and captured by EP-COFDha-Tab adsorbed to Ab1, which can further bind the signal probe AuNPs@COFDAAQ-TFP/Ab2. The signal response of the electroactive molecule COFDAAQ-TFP is positively correlated with the concentration of CA125 to achieve the quantitative detection of CA125.The sensor exhibited a low detection limit of 0.0067 U/mL and a linear range from 0.01 to 100 U/mL. This work presents a novel approach utilizing electroactive COFs as signal probes for the sensitive and quantitative detection of carbohydrate antigens.

Determination of perfluoroalkyl carboxylic acids in mice serum and tissue by dispersive solid-phase extraction based on fluorine-functionalized covalent organic frameworks coupled with UPLC-MS/MS

Perfluoroalkyl carboxylic acids (PFCAs) are a class of persistent organic pollutants (POPs), which posed various hazards to organisms, including reproductive, developmental, neurological, and immunological toxicity. Consequently, developing an analytical method aimed at achieving highly sensitive detection of trace amounts of PFCAs in complex samples is clearly of great significance. Herein, the Fluorine-functionalized covalent organic framework (F-COF) was synthesized at ambient temperature, which has the advantages of high specific surface area (1297.7 m2 g-1), suitable selective adsorption pore size and good stability. Based on the multiple effects of suitable pore size, fluorine-fluorine interactions and hydrophobic interactions, F-COF exhibited high adsorption performance towards PFCAs. Accordingly, the method of F-COF-based dispersive solid-phase extraction (dSPE) coupled with UPLC-MS/MS was developed for the quantitative analysis of 5 PFCAs in complex biological samples. The results showed that the good linearity for the 5 PFCAs within the concentration ranges of 0.4 to 104 ng L-1, with correlation coefficients (r) all greater than 0.9993. The enrichment factors (EFs) ranged from 11.4 to 22.3 folds, and the limits of detection (LODs) were 0.11 to 0.17 ng L-1. The established method provided a powerful tool for the enrichment and detection of PFCAs in mice serum and tissue. F-COF holds promising application prospects as a solid-phase extraction material for efficient enrichment separation and detection of PFCAs.

Engineered covalent organic frameworks (COFs) for adsorption-based metal separation technologies: A critical review

Porous covalent organic frameworks (COFs) are promising materials used for separation and purification during environmental remediation. This critical review focuses on two key aspects. First, it critically examines strategies to improve COF design and structure and evaluates their impact on separation performance. Second, engineering approaches for enhancing the interactions between COF-based adsorbents and metals for enhanced separation and capture are elucidated. The latest body of research on separating metals (e.g., Li, K, Sr, Hg, Cd, Pb, Cr, Au, Ag, Pd, and U) using COF-based adsorbents is discussed to understand the factors that influence their performance. However, it is to be noted that COF-based adsorbents are still in their infancy and remain largley unexplored, mainly hindered by synthetic complexities and suboptimal crystalline structures. This highlights the need for further research and development to fully unlock the excellent potential of COFs for metal separation applications, particularly in environmental and energy applications.

Covalent organic frameworks as superior adsorbents for the removal of toxic substances

Developing new materials capable of the safe and efficient removal of toxic substances has become a research hotspot in the field of materials science, as these toxic substances pose a serious threat to human health, both directly and indirectly. Covalent organic frameworks (COFs), as an emerging class of crystalline porous materials, have advantages such as large specific surface area, tunable pore size, designable structure, and good biocompatibility, which have been proven to be a superior adsorbent design platform for toxic substances capture. This review will summarize the synthesis methods of COFs and the properties and characteristics of typical toxicants, discuss the design strategies of COF-based adsorbents for the removal of toxic substances, and highlight the recent advancements in COF-based adsorbents as robust candidates for the efficient removal of various types of toxicants, such as animal toxins, microbial toxins, phytotoxins, environmental toxins, etc. The adsorption performance and related mechanisms of COF-based adsorbents for different types of toxic substances will be discussed. The complex host-guest interactions mainly include electrostatic, π-π interactions, hydrogen bonding, hydrophobic interactions, and molecular sieving effects. In addition, the adsorption performance of various COF-based adsorbents will be compared, and strategies such as reasonable adjustment of pore size, introduction of functionalities, and preparation of composite materials can effectively improve the adsorption efficiency of toxins. Finally, we also point out the challenges and future development directions that COFs may face in the field of toxicant removal. It is expected that this review will provide valuable insights into the application of COF-based adsorbents in the removal of toxicants and the development of new materials.

Accessing renewable magnetic cellulose nanofiber adsorbent to enhance separation efficiency for adsorption and recovery of Cd2

To address the issue of toxic cadmium pollution and meet the need for rapid separation from water body, a magnetic bio-composite material, marked as CFeMg, was prepared via a facile method. It explicitly includes components of cellulose nanofiber (CNF), Fe3O4 and Mg (OH)2. The microstructures and morphology were characterized and analyzed using XRD, FT-IR, SEM, and TEM. CNF was chemically coupled by Fe3O4, which together constructed the overall layered structure. Between layers were Mg(OH)2 flakes attached. While dealing with Cd2+, qmax of the best sample reached 361.5 mg g-1 with high adsorption efficiency. The roles of three components were explored and the adsorption mechanism was proposed. Assisted by magnetic CNF, it only took 3 min to efficiently and completely salvage the spent CFeMg sample from water after adsorption. Due to its high adsorption capacity and facile recovery performance, the prepared composite has promising application as water treatment.

Examining Terpyridine Ligand Binding Interactions with Cobalt and Aluminium: Synthesis, ADME Assessment, Reversibility, and DFT Analysis

This article emphasizes the influence of pyridine ring substitutions in 2,2':6',2″-terpyridine unit, allowing for precise adjustment of ligand properties. This study explores terpyridine-based molecular systems, with its unique coordination properties assessed against a range of competing metal ions, highlighting the specific affinity of the terpyridine ligand towards aluminium (Al) and cobalt (Co) detection in Acetonitrile-water (ACN-H2O) mixed solvent (80:20). The terpyridine-based probe's structural component is meticulously designed and detailed investigated to understand their influence on sensing performance. Synthesised probes are characterised using NMR, IR, UV-Vis spectroscopy, and mass spectrometry. Such modifications present ample opportunities to customise the attributes and applications of resultant metal complexes. The interaction between the terpyridine-based probes and target metal ions is investigated through various experimental methods, including fluorescence spectroscopy and UV studies along with unassisted discernment of Cobalt through Naked-Eye. Observation turns out that the limit of detection is 4.4 × 10-8 mol/L for cobalt and 4 × 10-7 mol/L for aluminium and coordination features Showing the binding stoichiometry to be 1:1 for R1. ADME Studies have been performed to analyse pharmacokinetic and biological actions. DFT calculations were performed to investigate the molecular probe's coordination features and its corresponding metal complex.

Noble metal-free porphyrin covalent organic framework layer for CO2 photoreduction to CO

The presence of greenhouse CO2 gas in the atmosphere causes serious environmental issues. Consequently, the development of photocatalysts for reducing CO2 is essential for mimicking artificial photosynthesis. In this study, we prepared a 5,15-di(4-aminophenty)-10,20-diphentyporphyrin copper (CuDAPP)-1,3,5-triformylphloroglucinol (TP)-covalent organic framework (COF) layer on a glass sheet via a layer-by-layer (LBL) method. The 2D CuDAPP-TP-COF layer was used as a photocatalyst for CO2 reduction, and it demonstrated excellent photocatalytic activity under gas-solid conditions without sacrificial reagents, noble metals, or photosensitisers. The CO production yield was 282.6 μmol g-1 under visible-light irradiation for 6 h, outperforming the raw material CuDAPP and a mixture of CuDAPP and TP, indicating a high application potential of the 2D porphyrin COF layer material in photocatalytic CO2 reduction.

Covalent Organic Framework-Involved Sensors for Efficient Enrichment and Monitoring of Food Hazards: A Systematic Review

The food safety issues caused by environmental pollution have posed great risks to human health that cannot be ignored. Hence, the precise monitoring of hazard factors in food has emerged as a critical concern for the food safety sector. As a novel porous material, covalent organic frameworks (COFs) have garnered significant attention due to their large specific surface area, excellent thermal and chemical stability, modifiability, and abundant recognition sites. This makes it a potential solution for food safety issues. In this research, the synthesis and regulation strategies of COFs were reviewed. The roles of COFs in enriching and detecting food hazards were discussed comprehensively and extensively. Taking representative hazard factors in food as the research object, the expression forms and participation approaches of COFs were explored, along with the effectiveness of corresponding detection methods. Finally, the development directions of COFs in the future as well as the problems existing in practical applications were discussed, which was beneficial to promote the application of COFs in food safety and beyond.

Label-free and ultrasensitive detection of environmental lead ions based on spatially localized DNA nanomachines driven by hyperbranched hybridization chain reaction

A label-free fluorescent sensing strategy for the rapid and highly sensitive detection of Pb2+ was developed by integrating Pb2+ DNAzyme-specific cleavage activity and a tetrahedral DNA nanostructure (TDN)-enhanced hyperbranched hybridization chain reaction (hHCR). This strategy provides accelerated reaction rates because of the highly effective collision probability and enriched local concentrations from the spatial confinement of the TDN, thus showing a higher detection sensitivity and a more rapid detection process. Moreover, a hairpin probe based on a G-triplex instead of a G-quadruplex or chemical modification makes hybridization chain reaction more controlled and flexible, greatly improving signal amplification capacities and eliminating labeled DNA probes. The enhanced reaction rates and improved signal amplification efficiency endowed the biosensors with high sensitivity and a rapid response. The label-free detection of Pb2+ based on G-triplex combined with thioflavin T can be achieved with a detection limit as low as 1.8 pM in 25 min. The proposed Pb2+-sensing platform was also demonstrated to be applicable for Pb2+ detection in tap water, river water, shrimp, rice, and soil samples, thus showing great potential for food safety and environmental monitoring.

Rapid aggregation of amyloid-like protein enhanced by mTGase to prepare functional wool fabrics for efficient and sustainable remove heavy metals from wastewater

To counteract the increasing severity of water pollution and purify water sources, wastewater treatment materials are essential. In particular, it is necessary to improve the bonding strength between the adsorption material and the substrate in a long-term humid environment, and resist the invasion of microorganisms to prolong the service life. In this study, an amyloid-like aggregation method of lysozyme catalyzed by microbial transglutaminase (mTGase). Lysozyme self-assembles into an amyloid-like phase-transited lysozyme (PTL) in the presence of a reducing agent. Simultaneously, mTGase catalyzes acyl transfer reactions within lysozyme molecules or between lysozyme and keratin molecules, and driving PTL assembly on the wool fiber (TG-PTL@wool). This process enhances the grafting amount and fastness of PTL on the wool. Moreover, the tensile strength of wool fabric increased to 523 N. TG-PTL@wool achieves a 97.32 % removal rate of heavy metals, maintaining a removal rate of over 95 % after 5 cycles. TG-PTL@wool has excellent antibacterial property (99 %), and it remains above 90 % after 50 times of circulating washing. This study proved that mTGase can enhance the amyloid aggregation of lysozyme and enhance the bonding strength between PTL coating and substrate. Moreover, TG-PTL@wool provides a sustainable, efficient and cleaner solution for removing heavy metals from water.

Dialdehyde cellulose films covalently crosslinked with porphyrin-based covalent organic polymers for photodynamic sterilization

Foodborne pathogens result in a great harm to human, which is an urgent problem to be addressed. Herein, a novel cellulose-based packaging films with excellent anti-bacterial properties under visible light were prepared. A porphyrin-based covalent organic polymer (Por-COPs) was constructed, then covalently grafted onto dialdehyde cellulose (DAC). The addition of Por-COPs enhanced the mechanical, hydrophobicity, and water resistance of the DAC-based composite films. DAC/Por-COP-2.5 film exhibited outstanding properties for the photodynamic inactivation of bacteria under visible light irradiation, delivering inactivation efficiencies of 99.90 % and 99.45 % towards Staphylococcus aureus and Escherichia coli within 20 min. The DAC/Por-COPs films efficiently generated •O2- and 1O2 under visible light, thereby causing oxidative stress to cell membranes for bacterial inactivation. The prepared composite film forms a protective barrier against bacterial contamination. Results guide the development of high performance and more sustainable packaging films for the food sector.

Construction of a Biomimetic Receptor Based on Hydrophilic Multifunctional Monomer Covalent Organic Framework Molecularly Imprinted Polymers for Molecular Recognition of Cyanidin-3-O-Glucoside

Anthocyanins (AOCs) are phenols that are readily soluble in water and are commonly present in plants. The chemical instability of AOC, however, causes it to be severely limited in terms of extraction and purification. Hence, in order to obtain efficient and stable extraction of AOC, we designed hydrophilic multifunctional monomer covalent organic framework molecularly imprinted polymers (HMCMIPs) as adsorbents. The functional reagent, p-aminobenzenesulfonic acid (ASA), was added to this material during synthesis to facilitate the sulfonation modification of covalent organic frameworks (COFs), which enhanced its affinity for hydrophilic guests (cyanidin-3-O-glucoside, the representative nutritional and functional ingredient in AOC). With ASA serving as a terminator, overextension of the material to form micron-level cross-linked structures is prevented, thereby increasing its surface area and mass transfer efficiency. The biomimetic receptors were then created by integrating MIPs into sulfonated COFs in order to create multiple binding sites specific for C3G recognition. HMCMIPs exhibited excellent adsorption capacity (1566 mg/g) and superior selectivity (selectivity coefficient >12) for C3G. It has been demonstrated that high purity (93.72%) C3G can be obtained rapidly and efficiently by utilizing HMCMIPs. There may be a potential benefit to the synthesis strategy of HMCMIPs for the extraction of specific active ingredients in the future.

Immunosensing of neuron-specific enolase based on signal amplification strategies via catalysis of ascorbic acid by heteropolysate COF

In view of the importance of quantification of neuron-specific enolase (NSE), an electrochemical NSE immunosensor was developed. The sandwich voltammetric immunosensor utilized vinyl-functionalized crystalline covalent organic framework (COFTAPT-Dva) modified electrode to load lots of Ab1 via thiol-ene "click" reaction as matrix. A crystalline cationic EB-COF:Br was used to load Au nanoparticles (AuNPs) and H3[PMo12O40] (PMo12) as immunoprobe. The AuNPs with the size of about 30 nm were firstly grown on EB-COF:Br and then a large number of electroactive PMo12 were uniformly assembled on AuNPs/EB-COF:Br via ion exchanging reaction. The AuNPs not only facilitated the bonding of Ab2 based on Au-S bond, but also improved performance of Ab2/AuNPs/EB-COF:PMo12 immunoprobe. The sensitivity of sandwich electrochemical immunosensor could be primarily amplified based on loaded abundant PMo12. Secondary sensitivity amplification of immunosensor could be achieved by using PMo12 to catalyze ascorbic acid. The linear range of sandwich voltammetric immunosensor based on current change of differential pulse voltammetry is 500 ± 36 fg mL-1 - 100 ± 8 ng mL-1. Thanks to the dual sensitivity amplification strategy, the sensitivity is as high as 54.06 ± 3.2 μA cm-2/lg(cNSE/ng mL-1), and the detection limit is as low as 166 ± 10.8 fg mL-1. It proves that it is completely feasible to amplify sensitivity of sandwich voltammetric immunosensors using polyoxometalate-COF and its catalytic substrate.

Recent progress of covalent organic frameworks membranes: Design, synthesis, and application in water treatment

To date, significant efforts have been devoted to eliminating hazardous components to purify wastewater through the development of various nanomaterials. Covalent organic frameworks (COFs), an important branch of the porous crystalline family, possess the peculiarity of ultrahigh surface area, adjustable pore size, and facile functionality. Exciting studies from design fabrication to potential applications in water treatment by COF-based membranes (COMs) have emerged. This review summarizes various preparation strategies and synthesis mechanisms for COMs, including layer-by-layer stacking, in situ growth, interfacial polymerization, and electrochemical synthesis, and briefly describes the advanced characterization techniques for COMs. Moreover, the application of COMs in heavy metal removal, dye separation, purification of radionuclides, pollutant detection, sea water desalination, and so on, is described and discussed. Finally, the perspectives on future opportunities for designing COMs in water purification have been proposed.

Gold nanoparticle-decorated covalent organic frameworks as amplified light-scattering probes for highly sensitive immunodetection of Salmonella in milk

Traditional immunoassays exhibit insufficient screening sensitivity for foodborne pathogens due to their low colorimetric signal intensities. Herein, we propose an ultrasensitive dynamic light scattering (DLS) immunosensor for Salmonella based on a "cargo release-seed growth" strategy enabled by a probe, namely gold nanoparticle-decorated covalent organic frameworks (COF@AuNP). Large amounts of AuNPs in COF@AuNP can be released by acid treatment-induced decomposition of the imine-linked COF, and then they are enlarged via gold growth to generate a dramatically enhanced light-scattering signal, leading to a vast improvement in detection sensitivity. Based on an immunomagnetic microbead carrier, the proposed DLS immunosensor is capable of detecting trace Salmonella in milk in the range of 2.0 × 102-2.0 × 105 CFU mL-1, with a limit of detection of 60 CFU mL-1. The immunosensor also demonstrated excellent selectivity, good accuracy and precision, and high reliability for detecting Salmonella in milk.

Microwave absorbing characteristics of porphyrin derivates: a loop of conjugated structure

Microwave absorbing architectures have gained a great deal of attention due to their widespread application in diverse fields, especially in refining electromagnetic pollution. The aim of this study is to investigate the metamaterial characteristics of porphyrin derivatives as conjugated rings in the microwave region and evaluate the influence of electron-withdrawing and donating groups on microwave attenuating performance. Initially, an innovative microwave curing procedure was applied to synthesize the derivates; following that, the phenyl, aniline, and nitrophenyl-coupled structures were identified by XRD, FTIR, FESEM, and DRS analyses. The optical features illustrated that the characteristic band gap of the conjugated loops is obtained and that the optical performance can be manipulated by coupling the functional groups. Eventually, the achieved results demonstrated that the best microwave absorbing performance is related to aniline-coupled porphyrin with a maximum reflection loss (RL) value of -104.93 dB at 10.09 GHz with 2.80 mm in thickness attaining an efficient bandwidth (EB) (RL ≤ 10 dB) higher than the X-band. Noticeably, polyethylene (PE) was applied as an absorbing matrix presenting a meaningful idea for the development of practical microwave absorbers as a new generation of electromagnetic refining and stealth materials. The presented research provides precious inspiration to tailor novel microwave absorbing materials with metamaterial capability to promote their microwave absorbing performance.

Efficient food safety analysis for vegetables by a heteropore covalent organic framework derived silicone tube with flow-through purification

A heteropore covalent organic framework incorporated silicone tube (S-tube@PDA@COF) was used as adsorbent to purify the matrices in vegetable extracts. The S-tube@PDA@COF was fabricated by a facile in-situ growth method and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and N₂ adsorption-desorption. The as-prepared composite exhibited high removal efficiency of phytochromes and recovery (81.13-116.62%) of 15 chemical hazards from 5 representative vegetable samples. This study opens a promising avenue toward the facile synthesis of covalent organic frameworks (COFs)-derived silicone tubes for streamline operation in food sample pretreatment.

Photo-Fenton self-cleaning carbon fibers membrane supported with Zr-MOF@Fe2O3 for effective phosphate removal from algae-rich water

Adsorbents featuring abundant binding sites and high affinity to phosphate have been used to resolve water eutrophication. However, most of the developed adsorbents were focused on improving the adsorption ability of phosphate but ignored the effect of biofouling on the adsorption process especially used in the eutrophic water body. Herein, a novel MOF-supported carbon fibers (CFs) membrane with high regeneration and antifouling capability, was prepared by in-situ synthesis of well-dispersed MOF on CFs membrane, to remove phosphate from algae-rich water. The hybrid UiO-66-(OH)₂@Fe₂O₃@CFs membrane exhibits a maximum adsorption capacity of 333.3 mg g^-1 (pH 7.0) and excellent selectivity for phosphate sorption over coexisting ions. Moreover, the Fe₂O₃ nanoparticles anchored on the surface of UiO-66-(OH)₂ through 'phenol-Fe(III)' reaction can endow the membrane with the robust photo-Fenton catalytic activity, which improves long-term reusability even under algae-rich condition. After 4 times photo-Fenton regenerations, the regeneration efficiency of the membrane could remain 92.2%, higher than that of hydraulic cleaning (52.6%). Moreover, the growth of C. pyrenoidosa was significantly reduced by 45.8% within 20 days via metabolism inhibition due to membrane-induced P-deficient conditions. Hence, the developed UiO-66-(OH)₂@Fe₂O₃@CFs membrane holds significant prospects for large-scale application in phosphate sequestration of eutrophic water bodies.

Visual and Real-Time Monitoring of Cd2+ in Water, Rice, and Rice Soil with Test Paper Based on [2 + 2] Lanthanide Clusters

Cadmium ions (Cd²⁺) are highly toxic to animal and human health, especially through the drinking of Cd²⁺-contaminated water and eating Cd²⁺-contaminated rice. Therefore, accurate detection of Cd²⁺ in water, rice, and rice soil is urgent. In this work, two [2 + 2] lanthanide clusters of Tb₂Tb₂ and Eu₂Eu₂ were synthesized and characterized in detail. Interestingly, Tb2Tb2 is a rapid sensor for Cd²⁺ through luminescence "turn-off". Further studies show that Tb2Tb2 is a highly sensitive and selective sensor toward Cd²⁺ in water, rice supernatants, and rice soil supernatants, with a very short response time of 20 s. The limit of detection (LOD) in the above three real samples is as low as 0.0112, 1.1240, and 0.1124 ppb, respectively, which is lower than the national standards for food safety in China (GB 2762-2022). More interestingly, a portable sensing device of test paper based on Tb2Tb2 is developed with a facile method, which shows visible, highly sensitive, and selective sensing toward Cd²⁺ in real samples of water, rice supernatants, and rice soil supernatants. Tb2Tb2 and its sensing device of test paper are an on-site analysis sensor for potentially non-expert users, especially for people in remote rural areas.

Olefin-linked cationic covalent organic frameworks for efficient extraction of ReO4-/99TcO4. JOURNAL OF HAZARDOUS MATERIALS 2023;446:130603. [PMID: 36580784 DOI: 10.1016/j.jhazmat.2022.130603]

Efficient extraction of radioactive ⁹⁹TcO₄^- from strong acid/base solutions by porous adsorbents is extremely desirable but remains a great challenge. To overcome the challenge, here we report the first example of an olefin-linked cationic covalent organic framework (COF) named BDBI-TMT with excellent acid, base and radiation stability is synthesized by integrating robust imidazolium salt-based linkers with triazine building blocks. BDBI-TMT shows an ultra-fast adsorption kinetics (equilibrium is reached within 1 min) and an excellent ReO₄^- (a non-radioactive surrogate of ⁹⁹TcO₄^-) capture capacity of 726 mg g^-1, which can be attributed to the abundance of precisely tailored imidazolium salt-based units on the highly accessible pore walls of the ordered pore channels. Furthermore, the formation of the highly conjugated bulky alkyl skeleton enhances the hydrophobicity of BDBI-TMT, which significantly improves not only the affinity toward ReO₄^-/⁹⁹TcO₄^- but also the chemical stability, allowing selective and reversible extraction of ReO₄^-/⁹⁹TcO₄^- even under extreme conditions. This work demonstrates the great potential of olefin-linked cationic COFs for ReO₄^-/⁹⁹TcO₄^- extraction, providing a new avenue to construct high-performance porous adsorbents for radionuclide remediation.

Application of covalent organic frameworks and metal–organic frameworks nanomaterials in organic/inorganic pollutants removal from solutions through sorption-catalysis strategies

With the fast development of agriculture, industrialization and urbanization, large amounts of different (in)organic pollutants are inevitably discharged into the ecosystems. The efficient decontamination of the (in)organic contaminants is crucial to human health and ecosystem pollution remediation. Covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) have attracted multidisciplinary research interests because of their outstanding physicochemical properties like high stability, large surface areas, high sorption capacity or catalytic activity. In this review, we summarized the recent works about the elimination/extraction of organic pollutants, heavy metal ions, and radionuclides by MOFs and COFs nanomaterials through the sorption-catalytic degradation for organic chemicals and sorption-catalytic reduction-precipitation-extraction for metals or radionuclides. The interactions between the (in)organic pollutants and COFs/MOFs nanomaterials at the molecular level were discussed from the density functional theory calculation and spectroscopy analysis. The sorption of organic chemicals was mainly dominated by electrostatic attraction, π-π interaction, surface complexation and H-bonding interaction, whereas the sorption of radionuclides and metal ions was mainly attributed to surface complexation, ion exchange, reduction and incorporation reactions. The porous structures, surface functional groups, and active sites were important for the sorption ability and selectivity. The doping or co-doping of metal/nonmetal, or the incorporation with other materials could change the visible light harvest and the generation/separation of electrons/holes (e−/h+) pairs, thereby enhanced the photocatalytic activity. The challenges for the possible application of COFs/MOFs nanomaterials in the elimination of pollutants from water were described in the end.

Rational design, structure properties, and synthesis strategies of dual-pore covalent organic frameworks (COFs) for potent applications: A review

Dual-pore covalent organic frameworks (COFs) offer a molecular scaffold for introducing building blocks into periodically organized polygonal skeletons to produce fascinating structural features. The rapid development of this material has attracted intensive interest from researchers with diverse expertise. This review selects the leading scientific findings about dual-pore COFs and highlights their functions and perspectives on design, structure properties, and synthesis strategies. Dual-pore COFs, as newly hetero-pore COFs by integrating particular pores into one polygonal skeleton, have been compared to conventional COFs. Dual-pore COFs display hierarchical/heterogeneous porosities and homogeneous porosity, which endow them with exceptional features involving mass diffusion, charge transfer, and large surface area with abundant active sites. Additionally, the strategic dual-pore design by opting for different approaches, such as integration of [D_2h + C₂] symmetries, kagome-type lattices, and other symmetric arrangements of monomers, are inclusively discussed. Identification and construction of dual-pores in COFs via optimal synthetic methods, such as desymmetrization, multiple linking sites, and orthogonal reactions, are highlighted as the primary pore engineering routes to simultaneously regulate the growth and alter the characteristics of COFs for promising applications. Lastly, a focused discussion on various challenges and critical fundamentals of dual-pore engineering is successfully outlined, with potential prospects of introducing dual-pore in COFs.