RESUMEN
The prevalence of Alzheimer's disease (AD) is increasing globally due to population aging. However, effective clinical treatment strategies for AD still remain elusive. The mechanisms underlying AD onset and the interplay between its pathological factors have so far been unclear. Evidence indicates that AD progression is ultimately driven by neuronal loss, which in turn is caused by neuroapoptosis and neuroinflammation. Therefore, the inhibition of neuroapoptosis and neuroinflammation could be a useful anti-AD strategy. Nonetheless, the delivery of active drug agents into the brain parenchyma is hindered by the blood-brain barrier (BBB). To address this challenge, we fabricated a black phosphorus nanosheet (BP)-based methylene blue (MB) delivery system (BP-MB) for AD therapy. After confirming the successful preparation of BP-MB, we proved that its BBB-crossing ability was enhanced under near-infrared light irradiation. In vitro pharmacodynamics analysis revealed that BP and MB could synergistically scavenge excessive reactive oxygen species (ROS) in okadaic acid (OA)-treated PC12 cells and lipopolysaccharide (LPS)-treated BV2 cells, thus efficiently reversing neuroapoptosis and neuroinflammation. To study in vivo pharmacodynamics, we established a mouse model of AD mice, and behavioral tests confirmed that BP-MB treatment could successfully improve cognitive function in these animals. Notably, the results of pathological evaluation were consistent with those of the in vitro assays. The findings demonstrated that BP-MB could scavenge excessive ROS and inhibit Tau hyperphosphorylation, thereby alleviating downstream neuroapoptosis and regulating the polarization of microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. Overall, this study highlights the therapeutic potential of a smart nanomedicine with the capability of reversing neuroapoptosis and neuroinflammation for AD treatment.
Asunto(s)
Enfermedad de Alzheimer , Apoptosis , Barrera Hematoencefálica , Azul de Metileno , Nanomedicina , Enfermedades Neuroinflamatorias , Animales , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/patología , Barrera Hematoencefálica/efectos de los fármacos , Barrera Hematoencefálica/metabolismo , Apoptosis/efectos de los fármacos , Células PC12 , Enfermedades Neuroinflamatorias/tratamiento farmacológico , Ratas , Ratones , Nanomedicina/métodos , Azul de Metileno/farmacología , Azul de Metileno/uso terapéutico , Masculino , Especies Reactivas de Oxígeno/metabolismo , Ratones Endogámicos C57BLRESUMEN
A highly water-soluble and fluorescent N,S-doped carbon dots/europium (N,S-CDs/Eu) was successfully synthesized via a secondary hydrothermal method. This involved surface modification of N,S-CDs derived from sunflower stem pith (SSP) with europium ions (Eu3+) doping. When excited within the range of 400-470 nm, N,S-CDs/Eu exhibited a stable and broad optimal emission wavelength ranging from 505 to 540 nm. Notably, the photoluminescence quantum yield (PLQY) of N,S-CDs/Eu is 31.4%, significantly higher than the 19.5% observed for N,S-CDs. Additionally, by dissolving N,S-CDs/Eu into polyvinyl alcohol (PVA), a uniform fluorescent anti-counterfeiting ink can be prepared. The N,S-CDs/Eu/TiO2 composite demonstrates excellent photocatalytic degradation ability towards the organic dye methylene blue (MB). N,S-CDs/Eu has potential in the field of fluorescent inks and photocatalysis due to its simple and efficient preparation and excellent properties.
Asunto(s)
Carbono , Europio , Helianthus , Tinta , Puntos Cuánticos , Europio/química , Carbono/química , Catálisis , Puntos Cuánticos/química , Helianthus/química , Procesos Fotoquímicos , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Azul de Metileno/química , FluorescenciaRESUMEN
The rapid detection of contaminants in water resources is vital for safeguarding the environment, where the use of eco-friendly materials for water monitoring technologies has become increasingly prioritized. In this context, the role of biocomposites in the development of a SERS sensor is reported in this study. Grafted chitosan was employed as a matrix support for Ag nanoparticles (NPs) for the surface-enhanced Raman spectroscopy (SERS). Chitosan (CS) was decorated with thiol and carboxylic acid groups by incorporating S-acetyl mercaptosuccinic anhydride (SAMSA) to yield CS-SAMSA. Then, Ag NPs were immobilized onto the CS-SAMSA (Ag@CS-SAMSA) and characterized by spectral methods (IR, Raman, NIR, solid state 13C NMR with CP-MAS, XPS, and TEM). Ag@CS-SAMSA was evaluated as a substrate for SERS, where methylene blue (MB) was used as a model dye adsorbate. The Ag@CS-SAMSA sensor demonstrated a high sensitivity (with an enhancement factor ca. 108) and reusability over three cycles, with acceptable reproducibility and storage stability. The Raman imaging revealed a large SERS effect, whereas the MB detection varied from 1-100 µM. The limits of detection (LOD) and quantitation (LOQ) of the biocomposite sensor were characterized, revealing properties that rival current state-of-the-art systems. The dye adsorption profiles were studied via SERS by fitting the isotherm results with the Hill model to yield the ΔG°ads for the adsorption process. This research demonstrates a sustainable dual-function biocomposite with tailored adsorption and sensing properties suitable for potential utility in advanced water treatment technology and environmental monitoring applications.
Asunto(s)
Quitosano , Nanopartículas del Metal , Plata , Espectrometría Raman , Quitosano/química , Espectrometría Raman/métodos , Plata/química , Nanopartículas del Metal/química , Límite de Detección , Colorantes/química , Colorantes/análisis , Cationes/análisis , Contaminantes Químicos del Agua/análisis , Azul de Metileno/químicaRESUMEN
Laser texturing seems to be a promising technique for reducing bacterial adhesion on titanium implant surfaces. This work aims to demonstrate the possibility of obtaining a functionally orientated surface of titanium implant elements with a specific architecture with specific bacteriological and photocatalytic properties. Femtosecond laser-generated surface structures, such as laser-induced periodic surface structures (LIPSS, wrinkles), grooves, and spikes on titanium, have been characterised by XRD, Raman spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of the titanium surfaces produced was tested based on the degradation effect of methylene blue (MB). The correlation between the photocatalytic activity of TiO2 coatings and their morphology and structure has been analysed. Features related to the size, shape, and distribution of the roughness patterns were found to influence the adhesion of the bacterial strain on different surfaces. On the laser-structurised surface, the adhesion of Escherichia coli bacteria were reduced by 80% compared to an untreated reference surface.
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Antibacterianos , Adhesión Bacteriana , Escherichia coli , Rayos Láser , Propiedades de Superficie , Titanio , Titanio/química , Titanio/farmacología , Escherichia coli/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/química , Adhesión Bacteriana/efectos de los fármacos , Catálisis , Microscopía Electrónica de Rastreo , Humanos , Azul de Metileno/química , Azul de Metileno/farmacología , Periimplantitis/microbiologíaRESUMEN
An in-situ nanozyme signal tag combined with a DNA-mediated universal antibody-oriented strategy was proposed to establish a high-performance immunosensing platform for Alzheimer's disease (AD)-related biomarker detection. Briefly, a Zr-based metal-organic framework (MOF) with peroxidase (POD)-like activity was synthesized to encapsulating the electroactive molecule methylene blue (MB), and subsequently modified with a layer of gold nanoparticles on its surface. This led to the creation of double POD-like activity nanozymes surrounding the MB molecule to form a nanozyme signal tag. A large number of hydroxyl radicals were generated by the nanozyme signal tag with the help of H2O2, which catalyzed MB molecules in situ to achieve efficient signal amplification. Subsequently, a DNA-aptamer-mediated universal antibody-oriented strategy was proposed to enhance the binding efficiency for the antigen (target). Meanwhile, a poly adenine was incorporated at the end of the aptamer, facilitating binding to the gold electrode and providing anti-fouling properties due to the hydrophilicity of the phosphate group. Under optimal conditions, this platform was successfully employed for highly sensitive detection of AD-associated tau protein and BACE1, achieving limits of detection with concentrations of 3.34 fg/mL and 1.67 fg/mL, respectively. It is worth mentioning that in the tau immunosensing mode, 20 clinical samples from volunteers of varying ages were analyzed, revealing significantly higher tau expression levels in the blood samples of elderly volunteers compared to young volunteers. This suggests that the developed strategy holds great promise for early AD diagnosis.
Asunto(s)
Enfermedad de Alzheimer , Aptámeros de Nucleótidos , Biomarcadores , Técnicas Biosensibles , Técnicas Electroquímicas , Oro , Nanopartículas del Metal , Proteínas tau , Técnicas Biosensibles/métodos , Humanos , Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/sangre , Técnicas Electroquímicas/métodos , Oro/química , Aptámeros de Nucleótidos/química , Biomarcadores/sangre , Nanopartículas del Metal/química , Proteínas tau/sangre , Estructuras Metalorgánicas/química , Inmunoensayo/métodos , Límite de Detección , Secretasas de la Proteína Precursora del Amiloide , Azul de Metileno/química , Ácido Aspártico Endopeptidasas/sangre , Peróxido de Hidrógeno/química , CatálisisRESUMEN
BACKGROUND: Potassium nitrate poisoning is a rare but potentially serious condition that can result in methemoglobinemia and subsequent cyanosis. This case report presents a unique instance of rapid-onset methemoglobinemia resulting from the ingestion of a traditional medicine preparation containing potassium nitrate, known as "kalmi shora." CASE PRESENTATION: A 14-year-old Pakistani boy reported to the emergency department with a history of sudden-onset headache, drowsiness agitation, irritability, and generalized cyanosis. Pulse oximetry showed a concerning oxygen saturation level of 58%, whereas arterial blood gas analysis revealed a normal partial pressure of oxygen (90 mmHg). The profile of abrupt onset of symptoms, generalized cyanosis, and the discrepancy between the partial pressure of oxygen and oxygen saturation readings necessitated a comprehensive assessment including inquiries into potential toxins. The peculiar appearance of the blood, resembling chocolate in color, further indicated the possibility of methemoglobinemia. The patient was successfully treated with methylene blue, leading to a prompt resolution of symptoms. CONCLUSION: This case highlights the significance of considering toxin exposures, such as traditional-medicine-induced poisoning, in emergency settings. The report contributes to the medical literature by highlighting the potential risks associated with traditional remedies and emphasizes the critical role of prompt diagnosis and intervention in optimizing patient outcomes. Recognition of the specific etiology of methemoglobinemia, in this case, traditional medicine ingestion, is essential for effective management in emergency medicine.
Asunto(s)
Metahemoglobinemia , Azul de Metileno , Humanos , Azul de Metileno/uso terapéutico , Metahemoglobinemia/inducido químicamente , Metahemoglobinemia/tratamiento farmacológico , Masculino , Adolescente , Nitratos/envenenamiento , Resultado del Tratamiento , Cianosis/inducido químicamenteRESUMEN
Two polyurethane polyaniline nanocomposites have been synthesized using two in situ polymerization routes of dried and wet bases to valorize the polyurethane waste. The physical and chemical properties of polyurethane-based nanocomposites were compared using SEM, XRD, FTIR, and Zeta potential. SEM images showed that the average particle size of the dried-based composite was 56 nm, while the wet-based composite had an average size of 75 nm. The separation efficiency for methylene blue (MB) and Congo red (CR) dyes was evaluated against free polyurethane foam waste. It was evident that pure polyurethane (PPU) achieved only 4.79% and 16.71% removal for MB and CR, respectively. These dye decontamination efficiencies were enhanced after nano polyaniline decoration of polyurethane foam either through dried base polymerization (DPUP) or wet base polymerization (WPUP). WPUP composite records 11.23% and 85.99% for MB and CR removal, respectively, improved to 26.69% and 90.07% removal using DPUP composite for the respective dyes. The adsorption kinetics, isotherms, and thermodynamics were investigated. The experimental results revealed the pseudo-second-order kinetic model as the most accurately described kinetics model for both CR and MB adsorption. The Langmuir model provided the best fit for the data, with maximum adsorption capacities of 110.98 mg/g for CR and 26.86 mg/g for MB, with corresponding R-squared values of 0.9974 and 0.9608, respectively. Regeneration and reusability studies of PPU, WPUP, and DPUP showed effective reusability, with DPUP displaying the highest adsorption capacity. These results aid in creating eco-friendly and cost-efficient adsorbents for dye removal in environmental sanitation.
Asunto(s)
Compuestos de Anilina , Colorantes , Nanocompuestos , Poliuretanos , Contaminantes Químicos del Agua , Poliuretanos/química , Compuestos de Anilina/química , Colorantes/química , Contaminantes Químicos del Agua/química , Nanocompuestos/química , Adsorción , Azul de Metileno/química , Eliminación de Residuos Líquidos/métodos , Descontaminación/métodos , Cinética , Rojo Congo/químicaRESUMEN
Lanthanum nickelate (LaNiO3), known for its high visible-light absorption, is a promising photocatalyst for water purification. However, the low conduction band position and high photogenerated carrier complexation rate of pure LaNiO3 limit its photocatalytic activity. To address this issue, we investigated the synergistic effects of doping and constructing heterojunctions. A La0.9Sr0.1NiO3 (20%)/g-C3N4 (L2CN8) heterojunction was successfully created. In addition, various characterisation techniques were then employed to analyse the structure-performance relationships of these heterojunction photocatalysts in degrading organic dyes. Results revealed that at a 10% Sr doping level, the oxygen vacancy content was 0.68, which is significantly higher than that of LaNiO3 (0.05). The increased number of oxygen vacancies enhanced the electron capture ability and improved the separation efficiency of photogenerated carriers. Furthermore, the optimised L2CN8 (20 mg) achieved 81.2% and 73.8% removal of methylene blue (50.0 mL, 10 mg L-1) and tetracycline (50.0 mL, 10 mg L-1) under simulated visible-light irradiation (λ > 420 nm). Furthermore, an active species capture experiment confirmed the significant role of superoxide radicals (·O2-) in the degradation process. Based on these experimental findings, we proposed a rational Z-type charge transfer mechanism. This study holds great importance for water pollution control and environmental protection.
Asunto(s)
Lantano , Luz , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/análisis , Catálisis , Lantano/química , Níquel/química , Azul de Metileno/química , Fotólisis , Procesos Fotoquímicos , Compuestos de Nitrógeno/química , Tetraciclina/química , Nitrilos/química , GrafitoRESUMEN
In this study, four adsorbents were developed: layered silicate magadiite material (mag), Hexadecyltrimethylammonium intercalated magadiite (HDTMA@mag), a cross-linked composite of sodium alginate and magadiite (ALG@mag) and a cross-linked composite of sodium alginate and HDTMA@magadiite (ALG@HDTMA@mag). The adsorbents were evaluated for their effectiveness in removing of Methylene Blue (MB) and Eriochrome Black T (EBT) dyes. The prepared adsorbents were characterized using SEM, XRD, FTIR, and zeta potential measurements. Kinetic modeling results indicated that both film diffusion and intraparticle diffusion are useful as rate-determining processes in adsorption for all adsorbents. For both dyes, the Langmuir isotherm model provided a good correlation with the adsorption equilibrium data. ANOVA analysis for the best adsorbent (ALG@HDTMA@mag beads) revealed that MB removal was significantly influenced by the positive individual effects of contact time and ALG@HDTMA@mag dose. However, the individual effect of MB concentration exhibited an antagonistic effect throughout the adsorption process. The optimal parameters for achieving an adsorption capacity of 118.54 mg/g were a dye concentration of 60 ppm, a contact period of 1800 min, and an ALG@HDTMA@mag dose of 50 mg.
Asunto(s)
Alginatos , Colorantes , Aguas Residuales , Contaminantes Químicos del Agua , Purificación del Agua , Alginatos/química , Colorantes/química , Colorantes/aislamiento & purificación , Adsorción , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Aguas Residuales/química , Cinética , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Azul de Metileno/química , Azul de Metileno/aislamiento & purificación , Compuestos Azo/química , Compuestos Azo/aislamiento & purificaciónRESUMEN
Hydrogels based on biopolymers have attracted considerable interest in the last decades. Herein, an interpenetrating network hydrogel (IPN-Gel) adsorbent from starch-chitosan was fabricated facilely in one-pot through tandem Schiff base reaction and photopolymerization. First, aldehyde starch (DAS) was synthesized by the reaction of soluble starch with sodium periodate. Afterward, acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), polyethylene glycol dimethacrylate (PEGDMA), photoinitiator, chitosan and DAS were dissolved in water to obtain a clear solution. Schiff base reaction between chitosan and DAS took place quickly to form the first network, and then photopolymerization of AM, AMPS, and PEGDMA occurred under ultraviolet radiation to form the second network. The preparation conditions of the as-prepared IPN-Gel were optimized with two indexes of gel mass fraction and swelling ratio. Its swelling behavior with pH and temperature change was explored. Finally, its adsorption performance was characterized with methylene blue (MB) as a model contaminant. The maximum adsorption capacity of IPN-Gel can reach 2039 mg·g-1 at pH =10. Its adsorption performance accords with Langmuir isothermal model and pseudo-second-order kinetic model and it was mainly controlled by chemisorption. This strategy is expected to found broad application prospects in the preparation of hydrogel adsorbents.
Asunto(s)
Quitosano , Hidrogeles , Azul de Metileno , Almidón , Contaminantes Químicos del Agua , Purificación del Agua , Quitosano/química , Azul de Metileno/química , Almidón/química , Adsorción , Hidrogeles/química , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Agua/química , Cinética , TemperaturaRESUMEN
Mucin 1 (MUC1) is frequently overexpressed in various cancers and is essential for early cancer detection. Current methods to detect MUC1 are expensive, time-consuming, and require skilled personnel. Therefore, developing a simple, sensitive, highly selective MUC1 detection sensor is necessary. In this study, we proposed a novel "signal-on-off" strategy that, in the presence of MUC1, synergistically integrates catalytic hairpin assembly (CHA) with DNA tetrahedron (Td)-based nonlinear hybridization chain reaction (HCR) to enhance the immobilization of electrochemically active methylene blue (MB) on magnetic nanoparticles (MNP), marking the MB signal "on". Concurrently, the activation of CRISPR-Cas12a by isothermal amplification products triggers the cleavage of single-stranded DNA (ssDNA) at the electrode surface, resulting in a reduction of MgAl-LDH@Fc-AuFe-MIL-101 (containing ferrocene, Fc) on the electrode, presenting the "signal-off" state. Both MB and MgAl-LDH@Fc-AuFe-MIL-101 electrochemical signals were measured and analyzed. Assay parameters were optimized, and sensitivity, stability, and linear range were assessed. Across a concentration spectrum of MUC1 spanning from 10 fg/mL to 100 ng/mL, the MB and MgAl-LDH@Fc-AuFe-MIL-101 signals were calibrated with each other, demonstrating a "signal-on-off" dual electrochemical signaling pattern. This allows for the precise and quantitative detection of MUC1 in clinical samples, offering significant potential for medical diagnosis.
Asunto(s)
Técnicas Biosensibles , Sistemas CRISPR-Cas , Técnicas Electroquímicas , Mucina-1 , Hibridación de Ácido Nucleico , Mucina-1/análisis , Mucina-1/genética , Técnicas Electroquímicas/métodos , Humanos , Técnicas Biosensibles/métodos , Sistemas CRISPR-Cas/genética , Azul de Metileno/química , Nanopartículas de Magnetita/química , ADN de Cadena Simple/química , ADN de Cadena Simple/genética , Electrodos , Límite de Detección , Oro/químicaRESUMEN
Simultaneous detection of multiple targets is of great significance for accurate disease diagnosis. Herein, based on duplex-specific nuclease (DSN) assisted signal amplification and the toehold-mediated strand displacement reaction (TSDR), we constructed an electrochemical biosensor with high sensitivity and high specificity for dual-target detection. MiRNA-141 and miRNA-133a were used as the targets, and ferrocene (Fc) and methylene blue (MB) with significant peak potential differentiation were used as the electrochemical signal probes. The elaborately designed hairpin probe H1, which was fixed on the electrode surface, could be hybridized with the target miRNA-141 to perform signal amplification by the DSN-assisted enzyme cleavage cycle; thus, miRNA-141 could be detected by Fc signal changes at 0.41 V. The hairpin H1 can also combine with the MB-labeled signal probe (SP) output from miRNA-133a-induced TSDR, and the detection of miRNA-133a can be realized according to the response signal generated by MB at -0.26 V. The two sensing lines are independent of each other, and there is no mutual interference in the detection process. Therefore, two independent detection lines could be connected in series, and the simultaneous detection of two targets can be achieved on a single electrode. This novel detection strategy provides a new way to simultaneously detect different biomarkers.
Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , MicroARNs , MicroARNs/análisis , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Humanos , Metalocenos/química , Compuestos Ferrosos/química , Azul de Metileno/química , Técnicas de Amplificación de Ácido Nucleico/métodos , Hibridación de Ácido Nucleico , Límite de Detección , ElectrodosRESUMEN
To develop an amperometric flow-biosensor for glucose, the stabilizing effect of methylene blue (MB) toward adsorbed glucose oxidase (GOx) on carbon felt (CF) was successfully applied to prepare the GOx-modified CF-based enzyme reactor combined with a horseradish peroxidase (HRP)-modified CF-based H2O2 detector. Upon mixing MB in the GOx-adsorption solution, the O2-dependent GOx-activity was significantly increased with increasing concentration of MB in the GOx-adsorption solution. The GOx-immobilization protocol on CF is very straightforward [i.e., adsorption of the GOx/MB mixed aqueous solution for 5 min under ultrasound (US)-irradiation]. Under the optimized operational conditions (i.e., applied potential, 0 vs. Ag/AgCl; carrier pH, 5.0; carrier flow rate, 4.0 mL min-1), the resulting GOx/MB-CF-reactor and HRP/TN-CF-detector combined amperometric flow-biosensor exhibited sensitive, selective, reproducible and stable cathodic peak current responses to glucose with the following analytical performances: sensitivity, 6.22 µA mM-1; linear range, 0.01 to 1 mM; limit of detection, 9.6 µM (S/N = 3, noise level, 20 nA); sample throughput, 46-96 samples per h for 10-0.1 mM glucose. The developed amperometric flow-biosensor allowed the determination of glucose in beverages and liquors, and the analytical results by the sensor were in fairly good agreement with those by conventional spectrophotometry.
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Técnicas Biosensibles , Carbono , Glucosa Oxidasa , Glucosa , Peroxidasa de Rábano Silvestre , Glucosa Oxidasa/química , Glucosa Oxidasa/metabolismo , Peroxidasa de Rábano Silvestre/química , Técnicas Biosensibles/métodos , Glucosa/química , Glucosa/análisis , Carbono/química , Fenotiazinas/química , Enzimas Inmovilizadas/química , Adsorción , Técnicas Electroquímicas/métodos , Colorantes/química , Límite de Detección , Azul de Metileno/química , Peróxido de Hidrógeno/químicaRESUMEN
The work was aimed at evaluating the adsorptive properties of waste newspaper (WN) activated carbons chemically produced using sodium salts for methylene blue (MB) and congo red (CR) removal. The activated carbons, designated as AC1, AC2, AC3 and AC4 were prepared through impregnation with NaH2PO4, Na2CO3, NaCl and NaOH, respectively and activation at 500 °C for 1 h. The activated carbons were characterized for surface chemistry, thermal stability, specific area, morphology and composition. The AC1 with a surface area of 917 m2/g exhibits a greater MB capacity of 651 mg/g. Meanwhile, a greater CR capacity was recorded by AC2 at 299 mg/g. The pseudo-second order model fitted well with the kinetic data, while the equilibrium data could be described by Langmuir model. The thermodynamic parameters, i.e.., positive ΔH°, negative ΔG° and positive ΔS° suggest that the adsorption of dyes is endothermic, spontaneous and feasible at high solution temperature. To conclude, WN is a potential cellulose source for producing activated carbon, while NaH2PO4 activation could be employed to convert WN into activated carbon for effective dye wastewater treatment.
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Celulosa , Carbón Orgánico , Rojo Congo , Azul de Metileno , Azul de Metileno/química , Celulosa/química , Rojo Congo/química , Adsorción , Carbón Orgánico/química , Cinética , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Papel , Purificación del Agua/métodos , Termodinámica , Sales (Química)/química , TemperaturaRESUMEN
This study focuses on developing copper oxide-based nanocomposites using plant extracts for photocatalytic applications. Curcuma amada leaf and Alysicarpus vaginalis leaf extracts were utilized alongside recycled copper precursors to synthesize photocatalysts via a green synthesis approach. Structural characterization through X-ray diffraction confirmed the formation of monoclinic CuO with reduced crystallite sizes due to plant extract incorporation. Fourier-transform infrared spectroscopy identified additional functional groups from the plant extracts, enhancing the material's properties. UV-Vis spectroscopy demonstrated increased light absorption and narrowed bandgaps in the nanocomposites, crucial for efficient photocatalysis under visible light. Morphological studies using FESEM revealed unique leaf-like structures in nanocomposites, indicative of the plant extract's influence on morphology. Photocatalytic degradation of methylene blue, rhodamine B, Congo red, and reactive blue 171 dyes showed enhanced performance of plant extract-modified CuO compared to without plant extract mediated CuO, attributed to improved charge carrier separation and extended lifetime. The effects of pH, catalyst dosage, and dye concentration on degradation efficiency were systematically investigated, highlighting optimal conditions for each dye type. Radical scavenger studies confirmed the roles of holes and hydroxyl radicals in the degradation process. Kinetic analysis revealed pseudo-second-order kinetics for dye degradation, underscoring the effectiveness of the nanocomposites. Overall, this research provides insights into sustainable photocatalytic materials using plant extracts and recycled copper, showcasing their potential for environmental remediation applications.
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Cobre , Nanocompuestos , Extractos Vegetales , Nanocompuestos/química , Cobre/química , Extractos Vegetales/química , Catálisis , Azul de Metileno/químicaRESUMEN
Carbon quantum dots (CQDs) were successfully synthesized from carbohydrate-rich residue of birch obtained following the lignin-first strategy. The optical and physicochemical properties of the CQDs were studied, along with their potential for photocatalytic pollutant degradation. By combining solvothermal and chemical oxidation methods, the product yield of CQDs from carbohydrate-rich residue reached 8.1 wt%. Doping nitrogen enhances the graphitization of CQDs and introduces abundant amino groups to the surface, thereby boosted the quantum yield significantly from 8.9 % to 18.7 %-19.3 %. Nitrogen-doped CQDs exhibited efficient photocatalytic degradation of methylene blue, reaching 37 % within 60 min, with a kinetic degradation rate of 0.00725 min-1. This study demonstrates that carbohydrate-rich residue obtained from lignin-first strategy are ideal precursors for synthesizing CQD with high mass yield and quantum yield by combining solvothermal treatment and chemical oxidation methods, offering a novel approach for the utilization of whole biomass components following the lignin-first strategy.
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Betula , Carbono , Lignina , Puntos Cuánticos , Puntos Cuánticos/química , Lignina/química , Carbono/química , Betula/química , Carbohidratos/química , Azul de Metileno/química , Nitrógeno/química , Catálisis , CinéticaRESUMEN
Chitosan, as a biomaterial, has increasingly garnered attention. However, its limited solubility in water-only dissolving in certain dilute acidic solutions-substantially restricts its broader application. In this investigation, chitosan underwent a solubilization modification to acquire water solubility, facilitating its dissolution in neutral aqueous mediums. Subsequently, this water-soluble chitosan (WSC) was interlinked with oxidized carboxymethyl cellulose (OCMC), characterized by varied oxidation extents, to synthesize hydrogels. Structural characterization verified the formation of imine bonds resulting from crosslinking interactions between the amino groups of water-soluble chitosan and the aldehyde groups of oxidized carboxymethyl cellulose. Employing performance characterization analysis, it was discerned that an increase in the oxidation level of the oxidized carboxymethyl cellulose corresponded to a denser hydrogel network architecture and the hardness increased from 3.01 N to 6.16 N. Moreover, the capacity of these hydrogels to adsorb methylene blue was meticulously examined. Notably, the hydrogel denoted as WSC/66%OCMC manifested an adsorption capability of 28.08 mg/g for methylene blue. Analytical findings from adsorption kinetics and isotherm studies indicate that the adsorption mechanism of the WSC/66%OCMC hydrogel follows the pseudo-second-order kinetic model and corresponds to the Freundlich isotherm model.
Asunto(s)
Carboximetilcelulosa de Sodio , Quitosano , Hidrogeles , Azul de Metileno , Oxidación-Reducción , Solubilidad , Agua , Azul de Metileno/química , Hidrogeles/química , Hidrogeles/síntesis química , Quitosano/química , Carboximetilcelulosa de Sodio/química , Agua/química , Adsorción , CinéticaRESUMEN
N-doped TiO2/carbon composites (N-TiPC) have shown excellent photodegradation performances to the organic contaminants but are limited by the multistage preparation (i.e., preparation of porous carbon, preparation of N-doped TiO2, and loading of N-doped TiO2 on porous carbon). Here, we develop a handy way by combining the Pickering emulsion-gel template route and chelation reaction of polysaccharides. The N-TiPC is obtained by calcinating pectin/Dl-serine hydrazide hydrochloride (SHH)-Ti4+ chelate and is further described by modern characterization techniques. The results show that the N atom is successfully doped into the TiO2 lattice, and the bandgap value of N-TiPC is reduced to 2.3 eV. Moreover, the particle size of N-TiPC remains about 10 nm. The configurations of the composites are simulated using DFT calculation. The photocatalytic experiments show that N-TiPC has a high removal efficiency for methylene blue (MB) and oxytetracycline hydrochloride (OTC-HCL). The removal ratios of MB (20 mg/L, 50 mL) and OTC-HCL (30 mg/L, 50 mL) are 99.41 % and 78.29 %, respectively. The cyclic experiments show that the photocatalyst has good stability. Overall, this study provides a handy way to form N-TiPC with enhanced photodegradation performances. It can also be promoted to other macromolecules such as cellulose and its derivatives, sodium alginate, chitosan, lignin, etc.
Asunto(s)
Carbono , Pectinas , Serina , Titanio , Pectinas/química , Titanio/química , Carbono/química , Serina/química , Nitrógeno/química , Catálisis , Fotólisis , Porosidad , Azul de Metileno/químicaRESUMEN
Peroxymonosulfate (PMS), which is dominated by free radical (SO4â¢-) pathway, has a good removal effect on organic pollutants in complex water matrices. In this article, a new catalyst (CFM@NC) was synthesized by hydrothermal carbonization method with chitosan (CS) as N and C precursors, and used to activate PMS to degrade dye wastewater. CFM@NC/PMS system can degrade 50 mg·L-1 rhodamine B by 99.59 % within 30 min, and the degradation rate remains as high as 97.32 % after 5 cycles. It has good complex background matrices, acid-base anti-interference ability (pH 2.6-10.1), universality and reusability. It can degrade methyl orange and methylene blue by >98 % within 30 min. The high efficiency of the composite is due to the fact that CS-modified MoS2 as a carrier exposes a large number of active sites, which not only disperses CuFe2O4 nanoparticles and improves the stability of the catalyst, but also provides abundant electron rich groups, which promotes the activation of PMS and the production of reactive oxygen species (ROS). PMS is effectively activated by catalytic sites (Cu+/Cu2+, Fe2+/Fe3+, Mo4+/Mo6+, pyridine N, pyrrole N, edge sulfur and hydroxyl group) to produce a large number of radicals to attack RhB molecules, causing chromophore cleavage, ring opening, and mineralization. Among them, free radical SO4â¢- is the main ROS for RhB degradation. This work is expected to provide a new idea for the design and synthesis of environmentally friendly and efficient heterogeneous catalysts.
Asunto(s)
Carbono , Quitosano , Colorantes , Cobre , Peróxidos , Contaminantes Químicos del Agua , Quitosano/química , Cobre/química , Peróxidos/química , Carbono/química , Colorantes/química , Catálisis , Contaminantes Químicos del Agua/química , Hierro/química , Nanopartículas/química , Purificación del Agua/métodos , Molibdeno/química , Nitrógeno/química , Compuestos Azo/química , Azul de Metileno/químicaRESUMEN
The optimization of hydrogel structure is crucial for adsorption capacity, mechanical stability, and reusability. Herein, a chitosan and laponite-XLS co-doped poly(acrylic acid-co-acrylamide) hydrogel (CXAA) with honeycomb-like porous structures is synthesized by cooperative cross-linking of 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) and laponite-XLS in reticular frameworks of acrylic acid (AAc) and acrylamide (AM). The CXAA exhibits extraordinary mechanical performances including tough tensile strength (3.36 MPa) and elasticity (2756 %), which facilitates recycling in practical adsorption treatment and broadens potential applications. Since the regular porous structures can fully expose numerous adsorption sites and electronegative natures within polymer materials, CXAA displays efficient and selective adsorption properties for cationic dyes like methylene blue (MB) and malachite green (MG) from mixed pollutants and can reach record-high values (MB = 6886 mg g-1, MG = 11,381 mg g-1) compared with previously reported adsorbents. Therefore, CXAA exhibits promising potential for separating cationic and anionic dyes by their charge disparities. Mechanism studies show that the synergistic effects of HACC, laponite-XLS, and functional groups in monomers promote highly efficient adsorption. Besides, the adsorption capacity of CXAA remains stable even after undergoing five cycles of regeneration. The results confirm that CXAA is a promising adsorbent for effectively removing organic dyes in wastewater.