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Low-cost effective photocatalytic activity under visible light of pitch-based porous carbon nanofiber composites aided by zinc oxide
摘要： To explore and develop an economical, novel, and effective photocatalyst for the degradation of methylene blue (MB) under visible-light irradiation, polyacrylonitrile (PAN)/pitch-based carbon nanofibers (CNFs) with ZnO (PPZn) are successfully produced by one-step electrospinning of PAN, pitch, and zinc acetate in dimethylformamide (DMF) solution. The charge separation rate, adsorption capacity, and visible-light harvesting effects are all enhanced by the synergistic effect of PAN/pitch-based CNFs and ZnO coupling. The resulting PPZn photocatalysts exhibit excellent removal capacity of 100% of MB within 30 min and a kinetic rate constant of 0.018 min?1 under visible light. PPZn also exhibits a consistent and stable photocatalytic performance by maintaining nearly 100% removal of 15 ppm MB over 8 regeneration cycles. The PP-based CNFs in PPZn act as a charge reservoir to afford fast transport for suppressing the e?–h? recombination and high electrical conductivity induced by the pitch, thereby expanding the visible-light response. The PP(3)Zn composites demonstrate a promising potential as a low-cost photocatalyst material offering excellent photocatalytic efficiency in the visible-light spectrum.
关键词： Carbon nanofiber,ZnO,Methylene blue,Pitch,Visible light,Photocatalytic activity
更新于2025-09-23 15:23:52
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Photostable coumarin containing azo dyes with multifunctional property
摘要： A series five coumarin azo disperse dyes with thiophene bridge are synthesized using diazotized aniline derivatives which are confirmed by FT-IR, 1H NMR, 13C NMR, and CHN analysis. The dyes are applied on polyester and nylon material. The multifunctional properties (lightfastness, washing fastness, sublimation fastness, K/S, UPF, and antimicrobial activity) of the dyed fabric are determined. The dye 3a (-NO2) show red shifted absorption (649 nm) and blocking 95.5-97.4% of UV radiations with 96% antimicrobial property. The geometries of all the azo dyes are optimized using Density Functional Theory (DFT). The Global Reactivity Descriptors (GRD) are evaluated at the same method of theory. The GRD obtained shows a linear relation with lightfastness and UPF ratings. The antimicrobial activity of all synthesized dyes are determined by AATCC 100 test method and it is correlated with the HOMO-LUMO energy band gap.
关键词： UPF,fastness property,Coumarin-azo dyes,global reactivity descriptors,HOMO-LUMO gap,antimicrobial activity
更新于2025-09-23 15:23:52
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Facile green synthesis of Degraded-PVA coated TiO2 nanoparticles with enhanced photocatalytic activity under visible light
摘要： Grafting with conjugated structures has been proven to be an effective strategy to enhance the visible-light photocatalytic activity of TiO2, however, the preparation of conjugated structures modified TiO2 nanoparticles usually involves several tedious treatment steps and large amounts of organic solvents. In this research, a facile and green method to synthesize Degraded-PVA coated TiO2 (TiO2@D-PVA) nanoparticles containing conjugated structures was prepared. This method avoided using organic solvents and successfully coated D-PVA onto the surface of TiO2 just via physical mixing, centrifugation, and calcination. In addition, the content of D-PVA in TiO2@D-PVA could be controlled by the concentration of the PVA solution. Under visible light irradiation, the TiO2@D-PVA containing approximately 5 wt% D-PVA demonstrated an optimal photocatalytic activity which is 5.5 times higher than that of commercial P25 TiO2 nanoparticles. The Ti-O-C bonds and the conjugated structures in D-PVA could facilitate the electron transfer between D-PVA and TiO2, thus contributing to the enhanced visible light photocatalytic activity.
关键词： TiO2,photocatalytic activity,PVA,visible light
更新于2025-09-23 15:23:52
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Photobiological properties of phthalocyanine photosensitizers Photosens, Holosens and Phthalosens: A comparative in vitro analysis
摘要： Photobiological properties of phthalocyanine photosensitizers, namely, clinically approved Photosens and new compounds Holosens and Phthalosens were analyzed on transitional cell carcinoma of the urinary bladder (T24) and human hepatic adenocarcinoma (SK-HEP-1). Photosens is a sulfated aluminum phthalocyanine with the number of sulfo groups 3.4, which is characterized by a high degree of hydrophilicity, slow cellular uptake, localization in lysosomes and the lowest photodynamic activity. Holosens is an octacholine zinc phthalocyanine, a cationic compound with significant charge. Holosens more efficiently enters the cells; it is localized in Golgi apparatus in addition to lysosomes and exhibits a significant inhibitory effect on cell viability upon irradiation. The highest photodynamic activity was demostrated by Phthalosens. Phthalosens is a metal-free analog of Photosens with a number of sulfo groups 2.5, which determines its amphiphilicity. Phthalosens is characterized by the highest rate of cellular uptake through the outer cell membrane, localization in cell membrane as well as in lysosomes and Golgi apparatus, and the highest activity upon irradiation among the photosensitizers studied. In general, changes in the physicochemical properties of Holosens and Phthalosens ensured an increase in their efficiency in vitro compared to Photosens. The features of accumulation, intracellular distribution and their interrelation with photodynamic activity, revealed in this work, indicate the prospects of Phthalosens and Holosens for clinical practice.
关键词： Photodynamic treatment,photodynamic activity,Holosens,dark toxicity,Phthalosens,Photosens,intracellular distribution,phthalocyanines
更新于2025-09-23 15:23:52
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Facile green synthesis and antimicrobial performance of Cu2O nanospheres decorated g-C3N4 nanocomposite
摘要： In recent years, biosynthesis and green chemistry are the novel approach for the fabrication of nanoparticles. Cu2O nanospheres decorated graphitic carbonitride (g-C3N4) nanocomposite have been synthesized by hydrothermal method using extracts of Citrus limon leaves which acts as reducing and stabilizing elements for the biosynthesis of nanoparticles. The comparative antimicrobial assay of different mass percentage(1%,5%,10%) of Cu content in the nanocomposites revealed that the CuCN10 has the more effective zone of inhibition due to their average particle size range 2–10nm. The addition of g-C3N4 as a support for the Cu2O photocatalyst helps in enhancing the charge transfer and improving photocatalytic degradation of contaminants and microorganisms. Moreover, the synthesized composite showed good antibacterial properties against both Gram-negative and Gram-positive bacterial strains.
关键词： biosynthesis,zone of inhibition.,green chemistry,Citrus limon,photocatalyst,antimicrobial activity
更新于2025-09-23 15:23:52
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Promising red emission from functionalized Polypyrrole/CaTiO3:Eu3+ nano-composites for photonic applications
摘要： CaTiO3:Eu3+ luminescent nanoparticles (NPs) and Ppy/CaTiO3:Eu3+ nanocomposites (NCs) are synthesized via combustion and solution casting techniques respectively and their structural and optical properties are investigated. The powder X-ray diffraction patterns of the as-formed products show single orthorhombic phase. The crystallite size measurement is assessed utilizing Scherrer's technique and observed to be in the range of 40–45 nm. The impact of Eu3+ ions on luminescence properties of the produced nanophosphors is examined the outcomes are given in detail. The phosphors displayed splendid red emission at 398 nm excitation. The emission peaks observed at 540, 593, 615, 653, 696 and 706 nm (5D0→7Fj = 0, 1, 2, 3, 4, 5) are assigned to Eu3+ ions transitions. The electronic transition equivalent to 5D0→7F2 (615 nm) is robust than the magnetic dipole transition 5D0→7F1 of Eu3+ ions (596 nm). The CIE chromaticity co-ordinates are ascertained from emanation spectra, the obtained values are very close to NTSC standard value of red emission. Hence, the present phosphors are exceedingly valuable for display applications. The obtained results demonstrate that Ppy-assisted solution casting is an effective methodology for the synthesis of rare-earth doped CaTiO3:Eu3+ nanocomposites (NCs).
关键词： Diffuse reflectance,Microbial activity,Nanocomposites,Color diagrams,Polypyrrole
更新于2025-09-23 15:23:52
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Effect of operational parameters on the photocatalytic degradation of Methylene blue dye solution using manganese doped ZnO nanoparticles
摘要： Photocatalytic degradation of aqueous solution of methylene blue dye under UV light illumination was studied by using manganese doped ZnO (Zn1-xMnxO, where x = 0.00, x = 0.02 and x = 0.05) nanoparticles as a photocatalyst. The nanophotocatalysts were synthesized by wet chemical co-precipitation method. The structural, morphological, and optical properties of the photocatalysts were done by X-ray diffraction (XRD), Scanning Electron microscope (SEM), Energy Dispersive X-Ray (EDX), photoluminescence (PL), Fourier Transform Infrared Ray (FTIR) and UV- visible spectroscopic techniques. An improved photocatalytic efficiency of ZnO was observed upon doping with Mn and 2% Mn-doped ZnO exhibited the highest photocatalytic activity among the doped samples. The effect of operating parameters such as amount of catalyst, the initial dye concentration, and initial pH on the rate of dye degradation using 2% Mn-doped ZnO was studied. Under the optimum operation conditions, approximately 99% of dye removal was achieved after 120 min of irradiation.
关键词： Manganese doped ZnO,Photocatalytic activity,Methylene blue dye
更新于2025-09-23 15:23:52
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Antimicrobial photodynamic inactivation of fungal biofilm using amino functionalized mesoporus silica-rose bengal nanoconjugate against Candida albicans
摘要： Candida albicans is an opportunistic fungal pathogen that causes both superficial and systemic infection and an important candidate that contribute to high morbidity and mortality rates in immunocompromised patients. The ability of C. albicans to switch from yeast to filamentous form and thereby forming biofilms make them resistant to most of the antifungal drugs available today. Thus the development of more effective antifungal drugs are essential and crucial at this point of time. Antimicrobial photodynamic therapy is an alternative modality to treat such biofilm forming resistant strains. This study aims to investigate the enhanced efficiency of newly synthesized MSN-RB conjugate as an antimicrobial photosensitizer for antimicrobial photodynamic therapy against C. albicans. Functionalization of MSN with amino groups was performed to increase the dye loading capacity. Conjugation process of MSN-RB was confirmed using different techniques including UV–Vis spectroscopy, Fluorescent spectroscopy and FTIR analysis. A low power green laser 50 mW irradiation was applied (5 min) for activation of MSN-RB conjugate and RB against C. albicans biofilm and planktonic cell. The comparative study of MSN-RB conjugate and free RB on aPDT was evaluated using standard experimental procedures. Antibiofilm efficacy was determined using biofilm inhibition assay, cell viability, EPS quantification and CLSM studies. The results revealed that MSN-RB conjugate has a significant antimicrobial activity (88.62 ± 3.4%) and antibiofilm effect on C. albicans when compared to free dye after light irradiation. The MSN-RB conjugate based aPDT can be employed effectively in treatment of C. albicans infections.
关键词： Antimicrobial photodynamic therapy,Conjugation,Amino functionalization,Mesoporus silica nanoparticles,Lipid peroxidation,Anti-biofilm activity
更新于2025-09-23 15:23:52
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Direct detection of cysteine peptidases for MALDI-TOF MS analysis using fluorogenic substrates
摘要： A method is described for the direct detection of unstable cysteine peptidase activity in polyacrylamide gels after native electrophoresis using new selective fluorogenic peptide substrates, pyroglutamyl-phenylalanyl-alanyl-4-amino-7-methylcoumaride and pyroglutamyl-phenylalanyl-alanyl-4-amino-7-trifluoromethyl-coumaride (Glp-Phe-Ala-AFC). The detection limit of the model enzyme papain was 17 pmol (0.29 μg) for Glp-Phe-Ala-AMC and 43 pmol (0.74 μg) for Glp-Phe-Ala-AFC, with increased sensitivity and selectivity compared to the traditional method of protein determination with Coomassie G-250 staining or detection of activity using chromogenic substrates. Using this method, we easily identified the target digestive peptidases of Tenebrio molitor larvae by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analysis. The method offers simplicity, high sensitivity, and selectivity compared to traditional methods for improved identification of unstable cysteine peptidases in multi-component biological samples.
关键词： Postelectrophoretic activity,Cysteine peptidases,Fluorogenic substrates,Tenebrio molitor,Native electrophoresis
更新于2025-09-23 15:23:52
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Preparation of 3D flower-like Fe-Bi2O3 nanocomposite and its photocatalytic performance under visible light irradiation
摘要： The objective followed by this research is the synthesis of 3D ?ower-like Fe-Bi2O3 and the study of its capability for the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 400 nm). Samples were obtained by a simple sol–gel method at room temperature. The as-prepared Fe-Bi2O3 exhibited excellent photocatalytic performance under the visible light due to its relatively narrow band gap energy (2.83 eV). The photocatalytic activity was carefully evaluated with respect to RhB photodegradation in di?erent conditions such as light source and reaction time. The experimental results showed that the degradation rate of 3D ?ower-like Fe-Bi2O3 is up to 82% under visible light irradiation, when EtOH/H2O volume ratio and Bi/Fe molar ratio are 7:3 and 20:1, respectively.
关键词： Nanocomposites,Fe-Bi2O3,Sol-gel,Photocatalytic activity
更新于2025-09-23 15:23:52