Organic Framework Nanocomposites Research Articles

Gamma-irradiated copper-based metal organic framework nanocomposites for photocatalytic degradation of water pollutants and disinfection of some pathogenic bacteria and fungi

BackgroundAlthough there are many uses for metal–organic framework (MOF) based nanocomposites, research shows that these materials have received a lot of interest in the field of water treatment, namely in the photodegradation of water contaminants, and disinfection of some pathogenic bacteria and fungi. This is brought on by excessive water pollution, a lack of available water, low-quality drinking water, and the emergence of persistent micro-pollutants in water bodies. Photocatalytic methods may be used to remove most water contaminants, and pathogenic microbes, and MOF is an excellent modifying and supporting material for photocatalytic degradation.MethodsThis work involved the fabrication of a unique Cu-MOF based nanocomposite that was exposed to gamma radiation. The nanocomposite was subsequently employed for photocatalytic degradation and as an antimicrobial agent against certain harmful bacteria and fungi. The produced Cu-MOf nanocomposite was identified by XRD, SEM, and EDX. Growth curve analysis, UV lighting impact, and antibiofilm potential have been carried out to check antimicrobial potential. Additionally, the membrane leakage test was used to determine the mechanism of the antimicrobial action. In an experimental investigation of photocatalytic activity, a 50 mL aqueous solution including 10.0 ppm of Rhodamine B (RB) was used to solubilize 10 mg of Cu-MOF. It has been investigated how pH and starting concentration affect RB elimination by Cu-MOF. Ultimately, RB elimination mechanism and kinetic investigations have been carried out.ResultsSEM images from the characterization techniques demonstrated the fact that the Cu-MOF was synthesized effectively and exhibited the Cu-MOF layers' flake-like form. Uneven clusters of rods make up each stratum. The primary peaks in the Cu-MOF's diffraction pattern were found at 2θ values of 8.75◦, 14.83◦, 17.75◦, 21.04◦, 22.17◦, 23.31◦, 25.41◦, and 26.38◦, according to the XRD data. After 135 min of UV irradiation, only 8% of RB had undergone photolytic destruction. On the other hand, the elimination resulting from adsorption during a 30-min period without light was around 16%. Conversely, after 135 min, Cu-MOF's photocatalytic breakdown of RB with UV light reached 81.3%. At pH 9.0, the greatest removal of RB at equilibrium was found, and when the amount of photocatalyst rose from 5 to 20 mg, the removal efficiency improved as well. The most sensitive organism to the synthesized Cu-MOF, according to antimicrobial data, was Candida albicans, with a documented MIC value of 62.5 µg mL−1 and antibacterial ZOI as 32.5 mm after 1000 ppm treatment. Cu-MOF also showed the same MIC (62.5 µg mL−1) values against Staphylococcus aureus and Escherichia coli, and 35.0 and 32.0 mm ZOI after 1000 ppm treatment, respectively. Ultimately, it was found that Cu-MOF (1000 µg/mL) after having undergone gamma irradiation (100.0 kGy) was more effective against S. aureus (42.5 mm ZOI) and E. coli (38.0 mm ZOI).ConclusionFrom the obtained results, the synthesized MOF nanocomposites had promising catalytic degradation of RB dye and high antimicrobial potential which encouraging their use in wastewater treatment against some pathogenic microbes and polluted dyes. Due to the exceptional physicochemical characteristics of MOF nanocomposites, it is possible to create and modify photocatalytic nanocomposites in a way that improves their recovery, efficiency, and recyclability.

Magnetic Graphene Oxide Modified with MOF-199 for Efficient Extraction of Aromatic Amines from Water Samples for Their Determination with Gas Chromatography

A metal–organic framework (MOF-199) nanocomposite was coated on magnetic graphene oxide (MGO) as a sorbent (MGO/MOF-199) and used for the isolation of aromatic amines by magnetic solid-phase extraction (MSPE). The analytes subsequently determined using gas chromatography with a flame ionization detector (GC-FID). The sorbent mass, desorption solvent, extraction time, desorption time, and pH were optimized. The calibration plots demonstrate linear ranges from 0.1 to 500 ng mL−1 with correlation coefficients from 0.9908 to 0.9939. The limits of detection (LOD) were between 0.03 and 0.1 ng mL−1. To evaluate the repeatability, relative standard deviations (RSD) were evaluated for 0.1, 10, and 100 ng mL−1 of the aromatic amines, yielding values from 3.2% to 4.5%. The developed method was employed to extract aromatic amines from tap water, seawater, and spring water. The relative recoveries were from 97.2% to 99.9%.

Smartphone-based portable sensor with Bi-MOF nanocomposite for Cd (II) in vegetable samples

The accumulation of heavy metal cadmium (Cd) in the food chain poses a serious threat to human health, necessitating the development of rapid, on-site, and portable detection methods for Cd (II). Herein, we developed a smartphone-based electrochemical sensor for portable determination of Cd (II) in vegetables using a bismuth metal–organic framework (Bi-MOF) nanocomposite. Prismatic rod-like Bi-MOF was hydrothermally synthesized using trimesic acid as organic ligands, and subsequently, carboxyl-functionalized multi-walled carbon nanotubes (COOH-MWCNTs) were incorporated to form Bi-MOF nanocomposite network. The smartphone-based electrochemical sensor enables rapid, sensitive, and portable detection of Cd (II) in vegetable samples using Bi-MOF/COOH-MWCNTs-modified screen-printed carbon electrodes (SPCE). A comparative analysis of traditional electrochemical sensors coupled with desktop computer for linear voltametric responses for Cd (II) in the range of 0.2–500 ng/mL with a limit of detection (LOD) of 0.07 ng/mL using Bi-MOF/COOH-MWCNTs-modified glassy carbon electrodes (GCE), the portable sensor demonstrated good linear range in 0.7–350 ng/mL with a LOD of 0.22 ng/mL. This work introduces a novel approach for on-site and portable detection of Cd (II) in agricultural products.

Targeted biocompatible Zn-metal–organic framework nanocomposites for intelligent chemotherapy of breast cancer cells

Finding a novel drug delivery system (DDS) represents one of the most challenging endeavors in cancer therapy. Hence, in this study, we developed a new biocompatible and biodegradable zinc-based nanoscale metal–organic framework (Zn-NMOF) coated with folic acid (FA) functionalized chitosan (CS) to facilitate targeted delivery of doxorubicin (D), a standard chemotherapeutic agent, into breast cancer cells. The synthesis of the NMOF-CS-FA-D nanocomposite preceded its comprehensive characterization via FT-IR, DLS, XRD, SEM, and TEM analyses. Subsequent in vitro studies were conducted on MCF-7 breast cancer cells and HFF-1 normal cells, encompassing assessments of cell viability, expression levels of apoptotic and autophagy genes, cell cycle arrest, and apoptotic analyses. The size of the NMOF-CS-FA-D particles was determined to be less than 80 nm, with a drug loading efficiency of 72 ± 5%. The release kinetics of DOX from the nanocomposite were investigated, revealing controlled release behavior at pH 7.4 and accelerated release at pH 5.0, which is conducive to drug delivery into cancer cells. In vitro results indicated a 17.39% ± 6.34 cell viability after 24 h of treatment with a 40 nM concentration of the NMOF-CS-FA-D nanocomposite. Furthermore, the expression levels of Caspase-9 and BAX, key apoptotic genes, along with BECLIN1, an autophagy gene, were found to increase by two-fold, four-fold, and two-fold, respectively, following 5 h of treatment with the nanocomposite. Additionally, analysis of cell cycle distribution revealed 15.4 ± 2% of cells in the sub-G1 phase, indicative of apoptotic cells, and 31.9% of cells undergoing early and late apoptosis in MCF-7 cells. Collectively, these findings underscore the potential of the NMOF-CS-FA-D nanocomposite in inhibiting cancer cell proliferation with low side effects.

Preparation of deep eutectic solvent modified magnetic graphene oxide/metal organic framework nanocomposites for the extraction of three estrogens in cosmetics.

Anovel magnetic dispersive solid phase extraction (MDSPE) procedure based on the deep eutectic solvent (DES) modified magnetic graphene oxide/metal organic frameworks nanocomposites (MGO@ZIF-8@DES) was established and used for the efficient enrichment of estradiol, estrone, and diethylstilbestrol in cosmetics (toner, lotion, and cream) for the first time. Then, thethree estrogens were separated and determined by UHPLC-UV analysis method. In order to study the features and morphology of the synthesized adsorbents, various techniques such as FT-IR, SEM, and VSM measurements were executed. The MGO@ZIF-8@DES nanocomposites combine the advantages of high adsorption capacity, adequate stability in aqueous solution, and convenient separation from the sample solution. To achieve high extraction recoveries, the Box-Behnken design and single factor experiment were applied in the experimental design. Under the optimum conditions, the method detection limits for three estrogens were 20-30ngg-1. This approach showed a good correlation coefficient (r more than 0.9998) and reasonable linearity in the range 70-10000ngg-1. The relative standard deviations for intra-day and inter-day were beneath 7.5% and 8.9%, respectively. The developed MDSPE-UHPLC-UV method was successfully used to determine three estrogens in cosmetics, and acceptable recoveries in the intervals of 83.5-95.9% were obtained. Finally, three estrogens were not detected in some cosmetic samples. In addition, the Complex GAPI tool was used to evaluate the greenness of the developed pretreatment method. The developed MDSPE-UHPLC-UV method is sensitive, accurate, rapid, and eco-friendly, which provides a promising strategy for determining hormones in different complex samples.

A critical review of recent advancements in zinc based metal organic framework nanocomposites and their derivatives for supercapacitor applications with future perspectives and challenges

Among various energy storage materials, Zinc-based metal-organic frameworks (Zn-MOFs used as precursors, templates, and shape controllers) act as potential candidates for supercapacitor (SC) applications due to their remarkable properties, such as facile preparation methods, high specific surface area (SSA), large porosity, outstanding power (Pden) & energy density (Eden), astonishing crystallinity, adjustable sizes, exceptional chemical & thermal stability, elongated life-cycle, framework diversity, and tunable structures. The present review focuses on the most recent progress on pristine Zn-MOFs, nanocomposites (with graphene (Gr), carbon nanotubes (CNTs), and polyaniline (PANI)), and their derivatives (metal oxides (MOs) & hydroxides (MHOs), porous carbon (PC) & activated carbon (AC), and metal sulfides (MSs)) as electrode materials to present the most up-to-date overview in this specific field. We first discuss the fundamental charging mechanisms (electric double-layer capacitance and pseudocapacitance) and the electrochemical techniques (cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy) of SCs. We then analyzed different methods with advantages and disadvantages of Zn-based MOF synthesis, such as solvothermal, hydrothermal, sonochemical, microwave heat-assisted, simple stirring, slow evaporation, mechanochemical, and electrochemical. Furthermore, structural, morphological, and electrochemical assessment techniques of reported Zn-based MOFs were examined in detail in three- and two- electrode configurations (asymmetric/symmetric devices with power and energy density). Finally, the ongoing issues and future developments in this field for architecturing supercapacitive devices are also discussed.

The trace detection of Hg2+ by flexible electrochemical biosensor based on covalent organic framework synergistic amplified strategy

Mercury (II) ion (Hg2+) is highly toxic, which is harmful to the environment and human health. Hg2+ electrochemical detection method lacks high sensitivity and convenience. Thus, we fabricated a new-style flexible sandwich biosensor for ultra-sensitive identification of trace mercury ions in water. A large number of gold nanoparticles (AuNPs) were electrodeposited on the flexible electrode as the sensing interface, and the Au-functionalized covalent organic framework (COF) nanocomposites adsorbed a large amount of methylene blue (MB) were used as the signal amplifier. COF/Au provided a large specific surface area, which was easier to assemble with mercaptan functionalized capture DNAs (cDNA) aptamers via S-Au bonds for selective recognition of mercury, to improve the conductivity and electrochemical performance. Meanwhile, gold nanoparticles (AuNPs), MB and reporter DNA (rDNA) were anchored to COF to fabricate the COF/Au/MB/rDNA probe. The prepared COF based probe exhibited a large surface area, excellent electrical signal response, and good environmental compatibility. After incubation with Hg2+, rDNA was tightly bound to cDNA via thymidine-Hg2+-thymine pairing (T-Hg2+-T). Thus, the COF based probe was specifically connected to the flexible interface to generate electrical signals. Experimental results indicated that the biosensor exhibited wider linear response range of 0.1 pM to 100 nM Hg2+, and lower detection limit of 45.2 fM (3σ/k). In addition, the prepared ligand sensor also showed reliable detection performance in real water samples.

Green decoration of Pd nanoparticles on MXene/metal organic framework support for photocatalytic degradation of ofloxacin

The widespread use of fluoroquinolone antibiotics, such as ofloxacin (OFL), has led to their unintended presence in aquatic environments. The removal of OFL from water bodies is crucial to mitigate the spread of antibiotic resistance. In this work, palladium nanoparticles supported on MXene/metal organic framework (Pd/MXOF) nanocomposite was successfully prepared via a green approach and then employed as a novel catalyst material for the photocatalytic degradation of OFL. The Pd/MXOF sample demonstrates improved absorption in the visible region in contrast to MXOF samples, possibly attributed to better electronic transfer at catalyst surface. According to experimental results, a higher photocatalytic activity was obtained for Pd/MXOF catalyst in comparison with MXene, MIL-101(Fe), and MXOF substances. Excellent photodegradation efficiency (∼100 %) of OFL after 30 min irradiation of visible light was obtained using Pd/MXOF. The effectiveness degradation of OFL through the suggested photocatalysis process was dependent on the initial concentration of OFL, catalyst dosage, and solution pH value. Following four cycles, the photocatalyst exhibited acceptable stability and reusability. The key roles of hole (h+) and •O2− radical in the photocatalytic reaction were elucidated by the active species trapping studies. This work may provide a very potent strategy to photodegrade antibiotic pollutants in contaminated waters.

Enhanced Antimicrobial Activity of Laser‐induced Graphene Wrapped Tri‐Metal Organic Framework Nanocomposites

Crystalline and porous metal‐organic frameworks (MOFs) are potential candidates for different antibacterial, photocatalytic, and adsorption applications. Moreover, multi‐principal element nanoparticles are effective against multidrug‐resistant bacteria, and combining metals with carbon nanomaterials can enhance activity. In this study, a Tri‐MOF comprised of iron, zinc, and cobalt and 2‐methyl imidazole was grown together with laser‐induced graphene (LIG) powder. Electron microscopy imaging showed the successful preparation and the crystalline nature of the LIG/Tri‐MOF composite. Fourier‐transform infrared and X‐ray photoelectron spectroscopy confirmed a non‐covalent mixture of LIG and Tri‐MOF. Compared with the negligible activity of LIG alone, low doses (0.91‐4.54 mg/mL) of the prepared LIG/Tri‐MOF composite showed excellent antibacterial activity (≥ 95% bacterial removal) and a MIC of 0.6 mg/mL, for Gram‐negative bacteria via the gradual leaching of metal ions and organic linker from the material enhanced by bacterial aggregation near the LIG/Tri‐MOF. Compared to a mixture of separately synthesized Tri‐MOF and LIG, the LIG/Tri‐MOF composite showed improved antibacterial effects. All materials showed cytotoxicity for L929 mouse cell lines, the solids showing a disrupting effect on cells grown in vitro. Performance‐enhancing combinations of various materials leading to synergistic or additive antimicrobial effects is an essential strategy for minimizing the possible emergence of antibiotic‐resistant strains.This article is protected by copyright. All rights reserved.

Pompon mum-like ionic covalent organic framework nanocomposites for efficient solid-phase extraction of nonsteroidal anti-inflammatory drugs

Molecularly imprinted ionic covalent organic framework nanocomposites (MI-IC-COF@SnO2) were prepared as potential adsorbents for the enhanced adsorption of nonsteroidal anti-inflammatory drugs (NSAIDs) from aqueous solution. The resulting material exhibited a pompon mum-like structure, featuring a large surface area, and well-defined mesopores. The presence of uniform positive ions within the three-dimensional skeleton of MI-IC-COF@SnO2 facilitated a rapid adsorption rate and high adsorption capacity for target analytes. Thermodynamic fitting revealed the adsorption process of NSAIDs to be feasible, endothermic, and spontaneous. Additionally, the adsorbent material exhibited respectable selectivity, as evidenced by imprinting factor values ranging from 2.8 to 6.7. Utilizing MI-IC-COF@SnO2 as the sorbent, a solid-phase extraction method coupled with high-performance liquid chromatography-ultraviolet detection (SPE-HPLC-UV) was developed and optimized. The proposed method demonstrated good linear range with determination coefficients of 0.998–0.999, and low limit of detection (0.18–1.35 µg L−1). Recoveries of NSAIDs in urine and river water samples were 78.1 %–106.1 %, with relative standard deviations lower than 12.5 %. This rapid and sensitive method enables the determination of NSAIDs at trace levels in complex matrices, providing reliable and reproducible results.

Ultrasensitive detection of chlortetracycline in animal-origin food using molecularly imprinted electrochemical sensor based on SnS2/ZnCo-MOF and AuNPs

The chlortetracycline (CTC) residue in food poses a threat to human health. Therefore, developing sensitive, convenient and selective analytical methods for CTC detection is crucial. This study innovatively uses tin disulfide/bimetallic organic framework (SnS2/ZnCo-MOF) nanocomposites in conjunction with gold nanoparticles (AuNPs) to co-modify a glassy carbon electrode (GCE). Further, a molecularly imprinted polymer (MIP)-based electrochemical sensing platform Au-MIP/SnS2/ZnCo-MOF/Au/GCE (AZG) was fabricated for selective CTC detection. SnS2/ZnCo-MOF enhanced the stability and surface area of the AZG sensor. The presence of AuNPs facilitated electron transport between the probe and the electrode across the insulating MIP layer. The fixation of AuNPs and MIP via electropolymerization enhanced the selective recognition of this sensor and amplified its output signal. The AZG sensor demonstrated a wide linear detection range (0.1–100 μM), low detection limit (0.072 nM), and high sensitivity (0.830 μA μM−1). It has been used for detecting CTC in animal-origin food with good recovery (96.08%–104.60%).

Synthesis of new Ampicillin supported on Cr/Oxidized pectin supported on Ti bimetal–organic framework as an efficient antimicrobial and anticancer nanocomposite

To synthesize, develop and provide advanced materials with unique properties, in this study, new bimetal–organic framework nanocomposites using Titanium, chromium, oxidized petin and ampicillin were synthesized. With TGA/DTG, FT-IR, XRD, XPS, BET, and EDAX mapping, the structure of the newly synthesized compound was identified, and its structural features were reported. The thermal stability up to 200 °C, particle size of 82 nm and the specific surface area of 27.700 m2/g was from the specifications of the final product. Antimicrobial properties of different bacterial and fungal species and anticancer properties on breast cancer cells were evaluated. In biological evaluation, the synthesized nanocomposites have unique activity and was more effective than some commercial drugs. In antimicrobial activities, MIC was observed between 2–64 μg/mL and in anticancer properties IC50 of 183 μg/mL.

Facile synthesis of magnetic covalent organic framework nanocomposites for the enrichment and quantification of trace organophosphorus pesticides in fruit juice

Facile synthesis of magnetic covalent organic framework nanocomposites for the enrichment and quantification of trace organophosphorus pesticides in fruit juice

A Comprehensive Review of Bimetallic Nanoparticle–Graphene Oxide and Bimetallic Nanoparticle–Metal–Organic Framework Nanocomposites as Photo-, Electro-, and Photoelectrocatalysts for Hydrogen Evolution Reaction

This review extensively discusses current developments in bimetallic nanoparticle–GO and bimetallic nanoparticle–MOF nanocomposites as potential catalysts for HER, along with their different synthesis methodologies, structural characteristics, and catalytic mechanisms. The photoelectrocatalytic performance of these catalysts was also compared based on parameters such as Tafel slope, current density, onset potential, turnover frequency, hydrogen yield, activation energy, stability, and durability. The review shows that the commonly used metal alloys in the bimetallic nanoparticle–GO-based catalysts for HERs include Pt-based alloys (e.g., PtNi, PtCo, PtCu, PtAu, PtSn), Pd-based alloys (e.g., PdAu, PdAg, PdPt) or other combinations, such as AuNi, AuRu, etc., while the most used electrolyte sources are H2SO4 and KOH. For the bimetallic nanoparticle MOF-based catalysts, Pt-based alloys (e.g., PtNi, PtCu), Pd-based alloys (e.g., PdAg, PdCu, PdCr), and Ni-based alloys (e.g., NiMo, NiTi, NiAg, NiCo) took the lead, with KOH being the most frequently used electrolyte source. Lastly, the review addresses challenges and prospects, highlighting opportunities for further optimization and technological integration of the catalysts as promising alternative photo/electrocatalysts for future hydrogen production and storage.

Development of a continuous magnetic dispersive solid phase extraction method for the extraction of seven widely used pesticides from fruit juices

Generally, food safety monitoring is vital issue to preserve human health and guarantee a longer lifespan. In present study, a continuous mode of magnetic dispersive solid phase extraction method based on using magnetic covalent organic framework@metal organic framework nanocomposite as sorbent has been proposed. The developed method has been tested for the extraction of some pesticides (pirimicarb, terbutryn, fenthion, triticonazole, hexaconazole, diniconazole, and haloxyfop-R-methyl) from commercial fruit juices prior to their analysis by high performance liquid chromatography–tandem mass spectrometry. In the current research, the properties of nanocomposite were characterized by scanning electron microscopy, Fourier–transform infrared spectrophotometry and X–ray diffraction techniques. In the next step, the synthesized nanocomposite was employed as an efficient sorbent in the developed extraction procedure that was done in a narrow bore tube. Under optimum extraction conditions, extraction recoveries were in the ranges of 67–83 %. Moreover, the limits of detection and quantification of the selected analytes were in the ranges of 17–43 and 56–143 ng L−1, respectively. Finally, the proposed method was successfully applied in the analysis of the opted pesticides in sixty fruit juice samples.

Metal–Organic Framework Nanocomposites in Conquering Hypoxia for Tumor Therapy

AbstractHypoxia, as a distinctive feature of tumors, is closely related to tumor recurrence, metastasis, and treatment resistance. Metal–organic framework (MOF) exhibits an increasing number of advantages in cancer therapy owing to its porous structure, large specific surface area, and tunable function. The MOF nanocomposites constructed by adjusting components can effectively overcome tumor hypoxia and significantly enhance the anti‐tumor effect. In this review, the hypoxic characteristics of tumors and current strategies for constructing MOF nanocomposites that can overcome tumor hypoxia are summarized, including for delivering O2 or endogenously generating O2 to elevate intra‐tumor O2 content; inhibiting HIF‐1 and its induced products to alleviate tumor hypoxia; reducing cellular aerobic respiration to decrease cellular O2 consumption, and exacerbating hypoxia to improve the efficacy of hypoxia‐activated pre‐drugs. At the same time, the applications of MOF nanocomposites applied to overcome tumor hypoxia in different therapeutic methods at the present stage are described, and finally, the challenges and opportunities in further development of MOF nanocomposites are discussed.

Functionalized magnetic metal organic framework nanocomposites for high throughput automation extraction and sensitive detection of antipsychotic drugs in serum samples

Due to the complexity of biological sample matrix, the automated and high-throughput pretreatment technology is urgently needed for monitoring the antipsychotic drugs for mental patients. In this study, functionalized magnetic zirconium-based organic framework nanocomposites (Fe3O4@SiO2@Zr-MOFs) were successfully designed and synthesized by the layer-by-layer growth. Among them, Fe3O4@SiO2@UiO-67-COOH showed the best adsorption performance, and at the same time it exhibited excellent water dispersibility, high thermal stability, chemical stability and high hydrophobicity. Results of adsorption kinetics, isotherm and FT-IR showed that the adsorption process was dominated by chemical adsorption (hydrogen bond, electrostatic interaction, π-π interaction) and monolayer adsorption. Moreover, the smaller pore size improved the protein exclusion rate which reached 98.9–99.8%. Based on the above result, the synthesized magnetic nanoparticles were introduced to 96-well automatic extractor, antipsychotic drugs in 96 serum samples were automatically extracted within 9 min, which most greatly saved the time and labor costs and avoided artificial errors. By further integrating with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), antipsychotic drugs can be detected in the range of 0.2–3.0 ng mL−1 with a quantitative limit of 0.06–0.9 ng mL−1. The recoveries of antipsychotic drugs and their metabolites in serum ranged from 95.7% to 112.3% within 1.4–6.5% of RSD. These features indicate that the proposed method is promising for high throughput and sensitively monitoring of drugs and other hazardous substances.

MoS2 Nanosheets@Metal organic framework nanocomposite for enhanced visible light degradation and reduction of hazardous organic contaminants

Present research focuses on the environmental cleanup of hazardous organic pollutants that are discharged into the natural aquatic bodies which upshots an undesirable shift in the ecological balance. Recently, aromatic nitro compounds and hazardous organic dyes have been recognized as a threat to fauna, flora and human life forms. Therefore, effective and selective eradication of these hazardous pollutants from wastewater systems is a pressing global issue for the academic community. This study aims to design a MoS2 Nanosheets (NS)@Cu-MOF (MS−HK) catalyst via a convenient hydrothermal approach for the elimination of organic and aromatic nitro contaminants from wastewater effluent. Under visible light irradiation, this photocatalyst presented 96.4% removal efficiency for Rose Bengal (RB) dye within a short duration of 30 min, with a first order degradation rate constant of 0.12223 min−1and a catalyst loading of 240 mg/L. Again, the rate constant of the room temperature reduction of 2,4,6−trinitrophenol (TNP) using NaBH4 as a reducing agent, in presence of the prepared nanocatalyst was calculated to be 2.7 × 10−3 s−1. This excellent degradation efficiency could be due to the loading of HKUST-1 with a narrow band gap semiconductor MoS2 leading to enhanced visible light absorption, effective separation and transport of photoinduced h+−e− pairs that limit their recombination. The plausible photodegradation mechanism was supported by photoluminescence and radical trapping experiments. In addition, the impact of various inorganic ions, water matrices, environmental conditions, different dye molecules and mixed dye system was explored on the RB degradation of the synthesized catalyst. Meanwhile, the as-prepared MS−HK nanocomposite displayed significant stability during the photocatalytic experiments, as evident from XRD results, until four successive cycles maintaining an outstanding degradation efficiency of >89%.

One stone two birds: electrochemical and colorimetric dual-mode biosensor based on copper peroxide/covalent organic framework nanocomposite for ultrasensentive norovirus detection

Norovirus (NoV) is regarded as one of the most common causes of foodborne diarrhea in the world. It is urgent to identify the pathogenic microorganism of the diarrhea in short time. In this work, we developed an electrochemical and colorimetric dual-mode detection for NoV based on the excellent dual catalytic properties of copper peroxide/COF-NH2 nanocomposite (CuO2@COF-NH2). For the colorimetric detection, NoV can be directly detected by the naked eye based on CuO2@COF-NH2 as a laccase-like nonazyme using “peptide-NoV-antibody” recognition mode. The colorimetric assay displayed a wide and quality linear detection range from 1 copy/mL to 5000 copies/mL of NoV with a low limit of detection (LOD) of 0.125 copy/mL. For the electrochemical detection of NoV, CuO2@COF-NH2 showed an oxidation peak of copper ion from Cu+ to Cu2+ using “peptide-NoV-antibody” recognition mode. The electrochemical assay showed a linear detection range was 15000 copies/mL with a LOD of 0.152 copy/mL. It’s worthy to note that this assay does not need other electrical signal molecule, which provide the stable and sensitive electrochemial detection for NoV. The electrochemical and colorimetric dual-mode detection was used to detect NoV in foods and faceal samples, which has the potential for improving food safety and diagnosing of NoV-infected diarrhea.

Bifunctional Fe-MOF@Fe3O4NPs for colorimetric and ratiometric fluorescence detection of uric acid in human urine

Nanozymes as a substitute for natural enzymes have attracted many attention owing to their high stability, low cost, and satisfactory catalytic activity. In this study, a new dual-readout detection strategy was proposed for colorimetric and ratiometric fluorescence detection of uric acid (UA) based on bifunctional metal–organic framework nanocomposite (Fe-MOF@Fe3O4NPs), which functions as fluorescent indicators as well as peroxidase mimics. In the presence of uricase, the decomposition of UA can produce H2O2, and Fe-MOF@Fe3O4NPs catalyzed H2O2 into the OH radicals, which could oxidize o-phenylene-diamine to 2,3-diaminophenazine, accompanied by a fluorescence emission at 600 nm and a UV–vis absorption peak at 450 nm. At the same time, the fluorescence of Fe-MOF@Fe3O4NPs at 460 nmcould be quenched by 2,3-diaminophenazine via Förster resonance energy transfer. Therefore, the fluorescence intensity ratio (I600/I460) and UV–vis absorption intensities are employed to construct the dual-readout biosensor for the determination of UA. The linear range was 0.2–200 μM and the limit of detection for the fluorometric and colorimetric detection were 0.03 μM and 0.18 μM, respectively. Finally, the biosensor was employed to determine UA in urine samples, and satisfactory results were obtained.