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1.
Mikrochim Acta ; 191(8): 498, 2024 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-39088087

RESUMO

A novel 3D magnetic nanocomposite material based on covalent organic polymers was successfully synthesized and utilized as an efficient sorbent for magnetic solid-phase extraction. It exhibited a regular core-shell structure, large specific surface area, superior stability, and paramagnetism. To evaluate its extraction efficiency, six flavonoids were tested, demonstrating maximum adsorption capacities ranging from 90 to 218 mg/g. Additionally, the material exhibited remarkable reusability and mechanical stability, maintaining its original state over eight cycles with consistent recovery. An analytical strategy combining magnetic solid-phase extraction with high performance liquid chromatography and tandem mass spectrometry was developed for the determination of flavonoids in orange, honey, soybean, and Dioscorea bulbifera L. samples. The low limits of detection (0.01-0.1 ng/mL) and limits of quantification (0.05-0.5 ng/mL), as well as satisfactory recovery (80.4-114.8%), were obtained. The linear range started from the limits of quantification to 500 ng/mL with R2 ≥ 0.9929. These results suggest that the prepared adsorbent possesses excellent adsorption capabilities for flavonoids, highlighting its significant potential for detecting these compounds in complex sample matrices.


Assuntos
Flavonoides , Limite de Detecção , Nanocompostos , Polímeros , Extração em Fase Sólida , Flavonoides/química , Flavonoides/isolamento & purificação , Adsorção , Nanocompostos/química , Extração em Fase Sólida/métodos , Polímeros/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem , Glycine max/química , Mel/análise , Citrus sinensis/química , Nanopartículas de Magnetita/química
2.
Mikrochim Acta ; 191(9): 512, 2024 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-39105857

RESUMO

Diphenylalanine(FF)-Zn self-assembly (FS) confined in covalent organic polymers (FS@COPs) with efficient fluorescence was synthesized for fluorescence sensing of biogenic amines, which was one of the most important indicators for monitoring food freshness. FS@COPs combined excellent biodegradability of self-assembled dipeptide with chemical stability, porosity and targeted site recognition of COPs. With an optimal excitation wavelength of 360 nm and an optimal emission wavelength of 450 nm, FS@COPs could be used as fluorescence probes to rapidly visualize and highly sensitive determination of tryptamine (Try) within 15 min, and the linear range was from 40 to 900 µg L-1 with a detection limit of 63.08 µg kg-1. Importantly, the FS@COPs showed a high fluorescence quantum yield of 11.28%, and good stability, solubility, and selectivity, which could successfully achieve the rapid, accurate and highly sensitive identification of Try. Furthermore, we revealed the mechanism of FS@COPs for fluorescence sensing of targets. The FS@COPs system was applied to the fluorescence sensing of Try in real samples and showed satisfactory accuracy of 93.02%-105.25%.


Assuntos
Dipeptídeos , Corantes Fluorescentes , Limite de Detecção , Espectrometria de Fluorescência , Triptaminas , Triptaminas/análise , Triptaminas/química , Dipeptídeos/química , Dipeptídeos/análise , Corantes Fluorescentes/química , Espectrometria de Fluorescência/métodos , Produtos da Carne/análise , Polímeros/química
3.
Chemphyschem ; : e202400283, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38634178

RESUMO

Halocarbons have important industrial applications, however they contribute to global warming and the fact that they can cause ozone depletion. Hence, the techniques that can capture and recover the used halocarbons with energy efficiency methods have recently received greater attention. In this contribution, we report the capture of dichlorodifluoromethane (R12), which has high global warming and ozone depletion potential, using covalent organic polymers (COPs). The defect-engineered COPs were synthesized and demonstrated outstanding sorption capacities, ~226 wt% of R12 combined with linear-shaped adsorption isotherms. We further identified the plausible microscopic adsorption mechanism of the investigated COPs via grand canonical Monte Carlo simulations applied to non-defective and a collection of atomistic models of the defective COPs. The modeling work suggests that significant R12 adsorption is attributed to a gradual increment of porosities due to isolated/interconnected micro-/meso-pore channels and the change of the long-range ordering of both COPs. The successive hierarchical-pore-filling mechanism promotes R12 molecular adsorption via moderate van der Waals adsorbate-adsorbent interactions in the micropores of both COPs at low pressure followed by adsorbate-adsorbate interactions in the extra-voids created at moderate to high pressure ranges. This continuous pore-filling mechanism makes defective COPs as promising sorbents for halocarbon adsorption.

4.
Talanta ; 274: 126033, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38581855

RESUMO

Covalent organic polymers (COPs) have garnered considerable attention as promising adsorbents of online solid phase extraction (online SPE). Morphology modulation provides an appealing solution to enhance adsorption efficiency and reduce back-pressure in the absorbent. However, the synthesis of COPs with regular geometric shapes and specific adsorption selectivity remains challenging. In this study, a uniform spherical fluorinated COP (F-sCOP, average diameter: 2.14 µm) was successfully synthesized by Schiff base reaction of 1,3,5-triformylphoroglucinol (TP) and 2,2'-bis(trifluoromethyl)benzidine (TFMB). The F-sCOP had a large surface area (BET: 346.2 m2 g-1), remarkable enrichment capacity (enrichment factors: 186-782), high selectivity toward fipronil and its metabolites (adsorption efficiency >93.1%), and admirable service life (>60 times). Based on the adsorbent, a novel µ-matrix cartridge extraction-online-µ-solid phase extraction-high performance liquid chromatography-mass spectrometry (µ-MCE-online-µ-SPE-HPLC-MS) method was constructed and used to track trace fipronil and its metabolites in soil. The proposed method exhibited a wide linear range (0.05-1000 ng g-1), low quantitation limits (LOQs: 0.0027-0.011 ng g-1), high recoveries (90.1-119.6%) and good repeatability (RSD ≤10.5%, n = 3) for fipronil analysis. This study paves the way for pesticide analysis in soil risk assessment.

5.
J Colloid Interface Sci ; 661: 923-929, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38330664

RESUMO

Iron phthalocyanine (FePc) is an attractive nonprecious metal candidate for electrocatalytic oxygen reduction reaction (ORR). However, its low catalytic performance under acidic and neutral conditions limits its practical application. Herein, the FePc-based covalent organic polymers (COPFePc) polymerized in situ on the functionalized multiwalled carbon nanotubes (R-MWCNT) containing different electron-withdrawing or electron-donating groups (COPFePc/R-MWCNT, R = COOH, OH or NH2) were synthesized for ORR. Among them, COPFePc/COOH-MWCNT exhibited the best ORR performance under pH-universal conditions (acidic, neutral, and alkaline). Density-functional theory (DFT) calculations demonstrate that the electron-withdrawing or electron-donating effect of the functional groups in COPFePc/R-MWCNT causes charge redistribution of the active center Fe. The COOH functional group with an electron-withdrawing ability shifts the d-band center of Fe away from the Fermi energy level and reduces the binding strength of oxygen-containing intermediates, accelerating the ORR kinetics and optimizing the catalytic activity.

6.
Molecules ; 28(19)2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37836784

RESUMO

Owing to the poor treatment efficiency of wastewater containing fluoroquinolones (FQs), effective removal of such pollutants has become a significant issue in waste management. In this study, a ternary covalent organic polymer anchored with SO3H (COP-SO3H) was designed using the Schiff reaction and a multicomponent solvent thermal method. The synthesized COP-SO3H polymer possesses multiple functional binding sites, including amide groups, sulfonic groups, and aromatic frameworks, enabling it to effectively adsorb ciprofloxacin (which belongs to FQs) through mechanisms such as pore-filling effects, electrostatic interactions, hydrogen bonding, π-π electron donor-acceptor (EDA) interactions, and hydrophilic-lipophilic balance. COP-SO3H demonstrated outstanding adsorption performance for ciprofloxacin, exhibiting a high adsorption capacity, broad pH stability, strong resistance to ionic interference, and good regenerability. Moreover, it displayed preferential selectivity toward fluoroquinolone antibiotics. The present study not only investigates the intricate structural and functional design of COP-SO3H materials but also presents potential applications for the efficient adsorption of specific antibiotics.


Assuntos
Ciprofloxacina , Poluentes Químicos da Água , Polímeros/química , Adsorção , Antibacterianos , Fluoroquinolonas/química , Poluentes Químicos da Água/química
7.
Adv Sci (Weinh) ; 10(32): e2304497, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37749871

RESUMO

Sodium ion-batteries (SIBs) are considered as a class of promising alternatives to lithium-ion batteries (LIBs) to overcome their drawbacks of limited sources and safety problems. However, the lack of high-performance electrode materials hinders the wide-range commercialization of SIBs. Comparing to inorganic counterparts, organic electrode materials, which are benefitted from flexibly designable structures, low cost, environmental friendliness, and high theoretical gravimetric capacities, should be a prior choice. Here, a covalent organic polymer (COP) based material (denoted as CityU-9) is designed and synthesized by integrating multiple redox motifs (benzoquinone and thioether), improved conductivity (sulfur induction), and intrinsic insolubility (rigid skeleton). The half-cell SIBs exhibit ultrahigh specific capacity of 1009 mAh g-1 and nearly no capacity drop after 650 cycles. The first all-COP symmetric full-cell shows high specific capacity of 90 mAh g-1 and excellent rate capability. This work can extend the selection of redox-active moieties and provide a rational design strategy of high-performance novel organic electrode materials.

8.
ACS Nano ; 17(18): 18190-18199, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37706655

RESUMO

Herein, we introduce a p-type redox conjugated covalent organic polymer (p-PNZ) as a universal and high-rate cathode for diverse dual-ion batteries. By constructing an n-type redox counterpart (n-PNZ) with an analogous reticular structure and redox-site composition, we also attain a comparative platform to probe how the redox-site nature and counterion chemistry affect the rate performance of polymer cathodes. It is disclosed that the charge dilution in p-type redox sites and bulky anions engenders their weak interaction and rapid anion diffusion in electrodes, while the trivial interaction of the solvent with anions facilitates anion desolvation and interfacial charge transfer. Thus, p-PNZ possesses rapid surface-controlled redox kinetics with a high anion diffusion coefficient regardless of its inferior porosity and conductivity relative to n-PNZ. Along with a long cycle life of over 50000 cycles, the p-PNZ-engaged Zn-based dual-ion battery with a dilute electrolyte delivers nearly constant capacities of ∼149 mAh g-1 at various rates of ≤10 A g-1─such an unusual rate capability has rarely been observed previously─and retains ∼99 mAh g-1 at 40 A g-1, surpassing the n-PNZ counterpart and most existing p-type organic cathodes. The p-PNZ cathode can also be applied to build high-rate Li-based batteries, signifying its universality, while the "ready-to-charge" character of p-PNZ enables anode-free dual-ion batteries with a high-rate capability and long lifespan.

9.
Mikrochim Acta ; 190(10): 402, 2023 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-37726434

RESUMO

A new nano-scale spherical vinyl-functionalized covalent organic polymer (TAPT-DVA-COP) with uniform sizes around 300 nm was initially constructed using 2,5-divinyl-1,4-benzaldehyde (DVA) and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) as monomers. Then, a sulfonic acid (-SO3H) modified COP termed COP-SO3H was developed based on post-sythesis method employing TAPT-DVA-COP as precursor. Capillary electrochromatography (CEC) monolithic columns were fabricated using the physical doping technique to exhibit the application potential of TAPT-DVA-COP and COP-SO3H. Compared to the TAPT-DVA-COP monolithic column, the COP-SO3H monolithic column achieved a highly selective separation between analytes with different properties, including monosubstituted benzenes, alkylbenzenes, hydroxybenzoates, nucleoside bases, and biogenic amines. Non-covalent interaction (NCI) analysis and experimental data show that the synergism of the sulfonic acid group and aromatic moieties on COP-SO3H endows the new stationary phase with diverse interactions, including ion exchange, hydrophobic, π-π and hydrogen bonding. In addition, the COP-SO3H monolithic column exhibited good reproducibility and excellent potential for the determination of hydroxybenzoates in compact powders and alkylbenzenes in effluent samples.

10.
Angew Chem Int Ed Engl ; 62(44): e202311002, 2023 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-37714815

RESUMO

Artificially performing chemical reactions in living biosystems to attain various physiological aims remains an intriguing but very challenging task. In this study, the Schiff base reaction was conducted in cells using Sc(OTf)3 as a catalyst, enabling the in situ synthesis of a hollow covalent organic polymer (HCOP) without external stimuli. The reversible Schiff base reaction mediated intracellular Oswald ripening endows the HCOP with a spherical, hollow porous structure and a large specific surface area. The intracellularly generated HCOP reduced cellular motility by restraining actin polymerization, which consequently induced mitochondrial deactivation, apoptosis, and necroptosis. The presented intracellular synthesis system inspired by the Schiff base reaction has strong potential to regulate cell fate and biological functions, opening up a new strategic possibility for intervening in cellular behavior.


Assuntos
Polímeros , Bases de Schiff , Bases de Schiff/química
11.
ACS Appl Mater Interfaces ; 15(34): 40519-40528, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37607045

RESUMO

CO2 photoconversion to syngas with superb selectivity is a splendid and bright option to achieve environmental improvement, energy substitution, and industrial needs. Herein, a series of Ni-porphyrin covalent organic polymers (COPs) interspersed with furan and thiophene using a mixed-blocks-engineering strategy, named as OXSY-Ni COPs (X and Y refer to the relative amounts of furan and thiophene blocks, respectively), are synthesized for photocatalytic CO2-to-syngas. Ni-coordinated porphyrin cores prefer to act as mediators of CO2-to-CO photoconversion because of the higher adsorption capacity of CO2. Ni-free porphyrins work mainly as active sites of H2 photoevolution. Furthermore, introducing different amounts of furan and thiophene modulates jointly the electronic structure of Ni-porphyrin COPs and optimizes the conduction band alignment. The above controllable variables achieve a wonderful syngas (CO/H2) ratio range from 2:1.06 to 1:1.04 for the Fischer-Tropsch process within common industrial reactions. Notably, the COP of the O1S3-Ni COPs exhibits excellent photocatalytic CO2-to-syngas activity under visible light, with a syngas yield of 8442.5 µmol g-1 h-1 (CO/H2 = 1:1.02) and an apparent quantum efficiency (AQE) of 1.92% at 450 nm. This strategy would provide a significance path to design functional and efficient organic semiconductors.

12.
Anal Sci ; 39(12): 1939-1946, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37584814

RESUMO

Azo-linked covalent organic polymers (ACOPs) were synthesized by a simple azo reaction, with 2,2'-bis(trifluoromethyl)benzidine and 1,3,5-trihydroxybenzene as the monomers. The preparation process was mild, green, and environmental-friendly, avoiding the use of high temperature, metal catalysis, and harmful organic reagent. The obtained ACOPs were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and Brunauer-Emmett-Teller. With the prepared ACOPs as adsorbent, a method of pipette tip solid-phase extraction-liquid chromatography-tandem mass spectrometry detection (PTSPE-LC-MS/MS) was proposed for the analysis of target sedatives in animal tissues. Furthermore, the parameters for the extraction of five sedatives, including the amount of adsorbent, pH value, ion strength, elution solvent and volume, were investigated. Under the optimized conditions, the linear dynamic range was found from 0.1 to 10.0 µg kg-1, and the limits of detection were ranged from 0.02 to 0.1 µg kg-1. The method was assessed by the analysis of target sedatives in animal tissues, and the recoveries for the spiked pork muscle and pork liver samples were 84-102% and 83-101%, respectively. The results show that the developed method of PTSPE-LC-MS/MS with ACOPs as adsorbent is efficient for the analysis of trace sedatives in animal tissues.


Assuntos
Polímeros , Espectrometria de Massas em Tandem , Animais , Polímeros/química , Cromatografia Líquida , Adsorção , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão
13.
Environ Sci Technol ; 57(26): 9615-9626, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-37350071

RESUMO

Uranium detection and extraction are necessary for the ecological environment as the growing demand for nuclear energy. Hence, exploring stable materials with excellent performance in uranium extraction and detection is highly desired. Herein, by amidoxime-functionalizing tetrafluoroterephthalonitrile (TFTPN) crosslinked hydroquinone (bP), phloroglucinol (tP), and 4,4',4″-trihydroxytriphenylmethane (tBP), three covalent organic polymers (COPs) bPF-AO, tPF-AO, and tBPF-AO with different crosslinked architectures are fabricated. Uranium extraction and detection related to the difference in molecule construction were systemically investigated, giving some reference for the rational design and fabrication of advanced materials for the removal and monitoring of uranium in the environment. The tPF-AO with a compact steric structure achieves the highest theoretical maximum adsorption capacity of 578.9 ± 15.2 mg g-1 and the best recyclability. The scattering electron center and U(VI) selective binding sites endow tBPF-AO with excellent capability in selective detection for U(VI), with a limit of detection of 24.2 nmol L-1, which is well below the standard for U(VI) in drinking water of the World Health Organization (WHO). Moreover, the COPs possess prominent physicochemical stability and recyclability, and more importantly, the PAE-based COPs are derived from inexpensive industry materials with easy processing methods, providing an efficient and economical way for the detection and adsorption of uranium.


Assuntos
Urânio , Floroglucinol , Adsorção , Sítios de Ligação , Elétrons , Polímeros
14.
J Hazard Mater ; 452: 131247, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-36963199

RESUMO

Saxitoxin (STX), the most widely distributed neurotoxin in marine waters and emerging cyanotoxin of concern in freshwaters, causes paralytic shellfish poisoning in humans upon consumption of contaminated shellfish. To allow for the efficient monitoring of this biotoxin, it is of high importance to find high-affinity materials for its adsorption. Herein, we report the design and synthesis of a covalent organic polymer for the efficient adsorption of STX. Two ß-keto-enamine-based materials were prepared by self-assembly of 2,4,6-triformylphloroglucinol (Tp) with 2,5-diaminobenzoic acid (Pa-COOH) to give TpPa-COOH and with 2,5-diaminotoluene (Pa-CH3) to give TpPa-CH3. The carboxylic acid functionalized TpPa-COOH outperformed the methyl-bearing counterpart TpPa-CH3 by an order of magnitude despite the higher long-range order and surface area of the latter. The adsorption of STX by TpPa-COOH was fast with equilibrium reached within 1 h, and the Langmuir adsorption model gave a calculated maximum adsorption capacity, Qm, of 5.69 mg g-1, making this material the best reported adsorbent for this toxin. More importantly, the prepared TpPa-COOH also showed good reusability and high recovery rates for STX in natural freshwater, thereby highlighting the material as a good candidate for the extraction and pre-concentration of STX from aquatic environments.


Assuntos
Toxinas Marinhas , Saxitoxina , Humanos , Adsorção , Neurotoxinas/análise , Frutos do Mar/análise
15.
J Hazard Mater ; 448: 130821, 2023 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-36709736

RESUMO

Lignin, the most abundant source of renewable aromatic compounds derived from natural lignocellulosic biomass, has great potential for various applications as green materials due to its abundant active groups. However, it is still challenging to quickly construct green polymers with a certain crystallinity by utilizing lignin as a building block. Herein, new green lignin-based covalent organic polymers (LIGOPD-COPs) were one-pot fabricated with water as the reaction solvent and natural lignin as the raw material. Furthermore, by using paraformaldehyde as a protector and modulator, the LIGOPD-COPs prepared under optimized conditions displayed better crystallinity than reported lignin-based polymers, demonstrating the feasibility of preparing lignin-based polymers with improved crystallinity. The improved crystallinity confers LIGOPD-COPs with enhanced application performance, which was demonstrated by their excellent performances in sample treatment of non-targeted food safety analysis. Under optimized conditions, phytochromes, the main interfering matrices, were almost completely removed from different phytochromes-rich vegetables by LIGOPD-COPs, accompanied by "full recovery" of 90 chemical hazards. Green, low-cost, and reusable properties, together with improved crystallinity, will accelerate the industrialization and marketization of lignin-based COPs, and promote their applications in many fields.


Assuntos
Lignina , Polímeros , Lignina/química , Polímeros/química , Biomassa , Água , Solventes
16.
J Colloid Interface Sci ; 634: 431-439, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36542972

RESUMO

Using oxygen in the air as the sole oxidant to oxidize hydrocarbons into high value-added compounds is a highly promising synthesis strategy with economic advantages. However, the oxidation of hydrocarbons with molecular oxygen under mild conditions is challenging due to the large C-H bond energy in hydrocarbons. Herein, a metal-free two-dimensional covalent organic polymers (COP) functionalized by photoactive pyridinium units has been developed for heterogeneous photocatalytic oxidation of hydrocarbons. This is the first kind of COPs material that can achieve photocatalytic oxidation of hydrocarbons without any additives or stoichiometric oxidants except for the oxygen in the air.

17.
Sci Total Environ ; 862: 160773, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36509275

RESUMO

Levofloxacin (LEV) is prone to be retained in aquifers due to its strong adsorption affinity onto sand, thus posing a threat to groundwater quality. In-situ injection technology for remediating LEV-contaminated soil and groundwater is still challenging owing to the lack of appropriate remedial agents. Herein, two novel multi-component porous covalent-organic polymers (namely, SLEL-1 and SLEL-2) with alkyl chains were constructed through Schiff-base reactions to adsorb LEV from an aqueous solution, in which the kinetics, isotherms, influenced factors were investigated. Plausible adsorption mechanisms were proposed through characterization and experimental analysis, including pore filling effect, π-π electron-donor-acceptor (EDA) interaction, hydrogen bonding force, hydrophobic-hydrophobic interaction as well as electrostatic force. In addition, response surface methodology (RSM) revealed the treatment optimization and reciprocal relationship within multi-variables. Furthermore, taking advantage of favorable dispersion and outstanding competitive behavior, SLEL-1 was established as an in-situ adsorptive agent in dynamic saturated columns on a laboratory scale to investigate the removal of LEV from water-bearing stratum. Overall, the findings of this work provided an insight into the fabrication of SLELs as long-term mobile and reusable adsorptive agents for practical in-situ applications in the future.


Assuntos
Levofloxacino , Poluentes Químicos da Água , Levofloxacino/análise , Areia , Porosidade , Polímeros , Adsorção , Poluentes Químicos da Água/química
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 289: 122182, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36512967

RESUMO

To ensure the long-term sustainable development of nuclear energy as well as the prevention and control of uranium pollution, new materials that can simultaneously detect and separate uranium are still urgently needed. Herein, a new fluorescent covalent organic polymer (COP), namely HT-COP-AO, was synthesized andemployed as both the fluorescent probe and absorbent for simultaneous uranium detection and separationconsidering its excellent fluorescence property and strong uranium coordination ability. The results showed that the fluorescence of HT-COP-AO was quickly quenched by uranium within 2 min, and the limit of detection was 0.23 µM (3σ/K). Further studies implied that uranium was coordinated with the amidoxime groups of HT-COP-AO through U-N and O = U = O bonds, which resulted in electron transfer from uranium to HT-COP-AO and quenching the fluorescence of HT-COP-AO consequently. Meanwhile, HT-COP-AO exhibited excellent absorption ability towards uranium, and the maximum absorption capacity (qmax = 401.3 mg/g) was higher than most reported amidoxime modified materials. The HT-COP-AO also showed high selectivity for both uranium detection and separation which makes it a great promising for uranium monitoring in real water samples.


Assuntos
Urânio , Corantes Fluorescentes , Transporte de Elétrons , Polímeros
19.
Adv Mater ; 35(1): e2208661, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36314400

RESUMO

Nitrogen-coordinated single-cobalt-atom electrocatalysts, particularly ones derived from high-temperature pyrolysis of cobalt-based zeolitic imidazolate frameworks (ZIFs), have emerged as a new frontier in the design of oxygen reduction cathodes in polymer electrolyte fuel cells (PEFCs) due to their enhanced durability and smaller Fenton effects related to the degradation of membranes and ionomers compared with emphasized iron-based electrocatalysts. However, pyrolysis techniques lead to obscure active-site configurations, undesirably defined porosity and morphology, and fewer exposed active sites. Herein, a highly stable cross-linked nanofiber electrode is directly prepared by electrospinning using a liquid processability cobalt-based covalent organic polymer (Co-COP) obtained via pyrolysis-free strategy. The resultant fibers can be facilely organized into a free-standing large-area film with a uniform hierarchical porous texture and a full dispersion of atomic Co active sites on the catalyst surface. Focused ion beam-field emission scanning electron microscopy and computational fluid dynamics experiments confirm that the relative diffusion coefficient is enhanced by 3.5 times, which can provide an efficient route both for reactants to enter the active sites, and drain away the produced water efficiently. Resultingly, the peak power density of the integrated Co-COP nanofiber electrode is remarkably enhanced by 1.72 times along with significantly higher durability compared with conventional spraying methods. Notably, this nanofabrication technique also maintains excellent scalability and uniformity.

20.
J Sep Sci ; 46(2): e2200637, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36377530

RESUMO

Covalent organic polymers are an emerging class of amorphous microporous materials that have raised increasing concerns in analytical chemistry due to their unique structural and surface chemical properties. However, the application of covalent organic polymers as mixed-mode stationary phases in chromatographic separations has rarely been reported. Herein, novel spherical silica hydroxyl-functionalized covalent organic polymer composites were successfully prepared via a layer-by-layer approach. The structure and morphology of the materials were carefully characterized by elemental analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, Brunauer-Emmett-Teller, and contact angle measurements. Baseline separations of various alkylbenzenes, polycyclic aromatic hydrocarbons, and nucleosides and bases were achieved on the prepared stationary phase under reversed-phase/hydrophilic interaction mode. The column efficiencies of 23 853 and 36 580 plates/m were obtained for butylbenzene and uracil, respectively, and the relative standard deviation of the retention time for continuous injections was less than 1.38% (n = 10), suggesting satisfactory column efficiency and repeatability. Additionally, this novel stationary phase realized the complete separation of the endocrine-disrupting chemicals in river water. This work affords a new route for synthesizing covalent organic polymers-based mixed-mode stationary phase and further reveals their great potential in chromatographic separation.

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