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Photocatalytic and antioxidant potential of silver nanoparticles biosynthesized using Artemisia stelleriana leaf extracts
The antioxidant and photocatalytic activity of Artemisia stelleriana-based silver nanoparticles (AS-AgNPs) was investigated in this study. Microscopic, X-ray diffraction and spectroscopic studies were used to characterize the synthesized AS-AgNPs. UVvisible spectrophotometric examination revealed a peak at 425 nm. The phytocompounds involved in the transformation of silver ions into AS-AgNPs were confirmed using Fourier-transform infrared spectroscopy analysis. The crystalline nature of the AS-AgNPs was verified using the X-ray powder diffraction technique. Spherical-shaped AS-AgNPs with a size of 22.7 nm were proved using field emission scanning electron microscopy. The AS-AgNPs were top-notch photocatalysts for the degradation of Reactive Blue-222A (RB-222A) and Reactive Blue-220 (RB-220) dyes. After 80 min of UV light exposure, AS-AgNPs degraded RB-222A and RB-220 dyes by 94.6 and 90.8%, respectively. The phytotoxicity investigation in Vigna radiata and Arte-mia salina indicated that the hazardous dye can be degraded into innocuous chemicals by AS-AgNPs. The results suggest that AS-AgNPs are an excellent antioxidant and photocatalyst for the degradation of synthetic dyes. 2023 The Authors. -
Photocatalytic and eco-emission applications of green synthesized ZnO-CB nanoparticles
Herein, we report the synthesis of ZnO nanoparticles (ZnO-CB NPs) by employing the solution combustion method using an aqueous extract of brinjal calyxes as fuel. Characterization techniques, such as X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR), UVvisible spectroscopy, and Scanning electron microscopy (SEM), were used to investigate the structural, optical, and morphological properties of synthesized nanoparticles, respectively. Highly porous hexagonal crystalline ZnO-CB NPs with less than 7 nm particle size were obtained. The photocatalytic performance of synthesized material is measured with Malachite green (MG), Basic brown 1 (BB1), and Acid orange 36 (AO36) as benchmark dyes. It showed that the synthesized material worked effectively under pH 10 with UV light irradiation. The synthesized ZnO-CB NP shows good removal effectiveness of the MG, BB1, and AO36 dyes with 99.3 %, 99.6 %, and 99.5 %, respectively, which can be promising photocatalysts for ecological applications such as wastewater remediation. Further, the synthesized ZnO-CB NP was used as blends in the methyl ester of Millettia pinnata oil (MPME), which is blended 20 % with commercial diesel (MPME20). The synthesized ZnO-CB NP was added to the MPME20 in varying amounts to ascertain its effects on the quality of emissions of various greenhouse gases such as hydrocarbons, COx, and NOx. Moreover, brake thermal efficiency (BTHE) and brake-specific fuel consumption (BSFC) were studied for the blends. The blend MPME20 with 25 mg of ZnO-CB NP, i.e., MPME20-25 mg, ZnO-CB, displays the best performance and reduced emissions. 2024 The Author(s) -
Photocatalytic degradation of methylene blue and metanil yellow dyes using green synthesized zinc oxide (Zno) nanocrystals
In this work, ZnO nanocrystals (NCs) have been effectively synthesized by a simple, efficient and cost-effective method using coconut husk extract as a novel fuel. The synthesized NCs are characterized by UV-Vis, XRD, FT-IR, SEM, EDX, Raman and PL studies. The obtained ZnO were found to be UV-active with a bandgap of 2.93 eV. The X-ray diffraction pattern confirms the crystallinity of the ZnO with hexagonally structured ZnO with a crystallite size of 48 nm, while the SEM analysis reveals the hexagonal bipyramid morphology. Photocatalytic activities of the synthesized ZnO NCs are used to degrade methylene blue and metanil yellow dyes. 2021 by the authors. Licensee MDPI, Basel, Switzerland. -
Photocatalytic Degradation of Toxic Textile Dyes by Biosynthesized Silver Nanoparticles Synthesized from Strobilanthes hamiltoniana Leaf Extract
Biocompatible nanoparticle synthesis from Strobilanthes hamiltoniana leaf extracts is an ecologically friendly, cost-effective and long-lasting technique for wastewater treatment, particularly for textile dye degradation. S. hamiltoniana mediated silver nanoparticles (SH-Ag NPs) showed a maximum absorbance of 432 nm. Based on the FESEM analysis, the SH-Ag NPs were usually spherical with an average diameter of nm. The FTIR analyses revealed the significance of functional groups in the formation of SH-Ag NPs. Degradation and rate of degradation for textile dyes after 320 min, SH-Ag NPs displayed 88.4%, 79.49%, 0.0059 min-1 and 0.00495 min-1 for reactive blue 220 (RB-220) and reactive blue 222A (RB-222A) dyes. The phytotoxicity study of SH-Ag NPs treated dye solutions demonstrated a significant decrease in inhibitory efficiency when compared to dye effluents. The biosynthesized SH-Ag NPs could represent a viable catalyst alternative for treating textile dye degradation both before and after it enters aquatic environments. 2024 Asian Publication Corporation. All rights reserved. -
Photocatalytic driven self-cleaning IPN membranes infused with a host-guest pair consisting of metal-organic framework encapsulated anionic nano-clusters for water remediation
Traditional water treatment membranes frequently encounter challenges in attaining an ideal equilibrium between permeability and selectivity. The performance of membranes is further hampered by hydrophobicity, scalability, and fouling problems, as well as excessive energy consumption. Hence, the current research is dedicated to the development of highly effective antifouling membranes, aiming for a significant balance between water permeance and separation efficiency, and featuring exceptional photocatalytic self-cleaning properties to ensure the sustainable reuse of membranes. In this study, a unique nanocomposite-based membrane is designed containing metal-organic frameworks (MOFs) MIL-101 (Fe) encapsulated copper-containing polyoxometalate (Cu-POM) incorporated into an interpenetrating polymer networks (IPNs) membrane. POMs are highly electronegative, oxo-enriched nanosized metal-oxygen cluster species and when composited with MOF yields POMOF which can help in the removal of pollutants from water through electrostatic site-specific binding. The IPN membrane designed by polymerizing aniline in the presence of polyvinylidene fluoride (PVDF) offers tunable pores of the membrane. The infusion of POMOF imparts a strong negative charge to the membrane surface, improving membrane hydrophilicity. This enhances pollutant removal through the Donnan exclusion principle and adds anti-fouling properties. Furthermore, the reduced pore size achieved by the IPN architecture in the POMOF@IPNs membrane effectively sieves out both cationic and anionic dyes, as well as pharmaceutical pollutants. Additionally, POMOF enhances the photocatalytic degradation of CR and MB dyes, coupled with essential self-cleaning attributes vital for separation processes. The IPNs structure, apart from housing POMOF, fortifies the membrane's mechanical strength with its distinctive network-like configuration. Furthermore, these advanced membranes showcase robust antibacterial and antiviral characteristics, while remaining non-cytotoxic to mammalian cells. Our findings indicate that the state-of-the-art POMOF@IPNs membrane is scalable and holds substantial promise for industrial wastewater treatment. 2024 Elsevier B.V. -
Photocatalytic nanomaterials: Applications for remediation of toxic polycyclic aromatic hydrocarbons and green management
Nanomaterials (NMs) have piqued the attention of scientists and researchers across many biomedical sciences due to their superior physical, chemical, and magnetic properties. The efficacy and efficiency of NMs depend on adapting to specific site conditions and soil composition. NMs have lately received much attention in the context of polycyclic aromatic hydrocarbons (PAHs) polluted soil remediation and water mitigation because of their unique properties resulting from their nanoscale sizes. The remediation of hazardous PAHs in water and soil is a hot research subject. Because the exposure of PAHs in water and soil results in pollution, which raises major human health concerns. The current review reports novel advancements in NMs that subsidize enhancement for degradation of PAHs. Challenges to the fabrication of high activity-based photocatalytic materials are also discussed. Furthermore, this review delivers exclusive and wide-ranging perspectives on the fabrication of nanomaterial-based photocatalytic systems. The knowledge of both soil remediation and water mitigation is also updated. 2022 -
Photocatalytic seawater splitting for hydrogen fuel production: impact of seawater components and accelerating reagents on the overall performance
The future fuel, hydrogen, is a clean, sustainable energy source with a substantial density of energy per unit volume/weight. Breakthroughs in hydrogen production, storage, and transportation are essential to meet the sustainable global energy demands. Solar-to-hydrogen conversion through water-splitting reactions (via photo/electro/photoelectro-processes) is a promising strategy for producing green hydrogen fuel. Specifically, the photocatalytic hydrogen generation reaction, mimicking artificial photosynthesis, is a simple and cost-effective method adopted for solar-hydrogen production. Various semiconductor photocatalysts and hybrid photocatalytic systems have been developed to address the sluggish kinetics and selectivity of pristine water/seawater splitting reactions. Recently, seawater has been used as feedstock for large-scale hydrogen production to advance the field and alleviate the scarcity of freshwater sources. This review article, therefore, aims to highlight the importance of seawater splitting reactions using different photocatalytic systems. A brief introduction to the fundamentals, historical progress, and mechanism of the seawater splitting reaction is presented. The impact of seawater components and accelerating reagents on the intrinsic performance of water splitting catalysts is discussed in detail, followed by an elaborate discussion of natural water and artificial seawater splitting with emphasis on onerous photocatalyst designs. Finally, the current challenges and opportunities of saltwater electrolysis for sustainable hydrogen fuel generation and applications are discussed. 2023 The Royal Society of Chemistry. -
Photoisomerization Dynamics of 2-[(E)-(4-fluorophenyl)diazenyl]- 1H-imidazole: A Theoretical and Experimental Insight
This study investigates the photoresponsive behavior of substituted azobenzenes with a specific focus on their nonlinear optical response. This study suggests that azoimidazole substitution is a better alternative to azobenzene derivatives for nonlinear optical responses. The synthesis, characterization, photophysical property and isomerization pathway of 2-[(E)-(4-fluorophenyl)diazenyl]-1H-imidazole (E-2g) are presented as an optical limiter through a comprehensive blend of experimental and theoretical approaches. Notably, E-2g exhibited a lower energy barrier than reported azobenzenes. The trans-to-cis photostationary state was reached in 75 min, while the cis-to-trans state was achieved in 60 min at 354 nm. The study further explores the photoisomerization pathway of E-2g, highlighting its nonlinear absorption, which has a nonlinear absorption coefficient (?eff) of 8.8 10?11 m/W at 20 ?J, as determined by Z-scan measurements. The results suggest that E-2g exhibits significant nonlinear absorption characteristics, which helps in applications requiring protection from intense light sources. This study explores the photoresponsive behavior of substituted azobenzenes derivative, azoimidazole, over unsubstituted azobenzene derivatives for nonlinear optical properties. Through experimental and theoretical analyses, the title compound was synthesized, characterized, and shown to have a lower energy barrier and efficient photoisomerization in solution. Its strong nonlinear absorption properties make it a promising candidate for optical limiting applications, such as eye protection and safeguarding sensitive optical sensors. 2025 World Scientific Publishing Company. -
Photoisomerization Dynamics of 2-[(E)-(4-fluorophenyl)diazenyl]-1 H -imidazole: A Theoretical and Experimental Insight
This study investigates the photoresponsive behavior of substituted azobenzenes with a specific focus on their nonlinear optical response. This study suggests that azoimidazole substitution is a better alternative to azobenzene derivatives for nonlinear optical responses. The synthesis, characterization, photophysical property and isomerization pathway of 2-[(E)-(4-fluorophenyl)diazenyl]-1H-imidazole (E-2g) are presented as an optical limiter through a comprehensive blend of experimental and theoretical approaches. Notably, E-2g exhibited a lower energy barrier than reported azobenzenes. The trans-to-cis photostationary state was reached in 75 min, while the cis-to-trans state was achieved in 60 min at 354 nm. The study further explores the photoisomerization pathway of E-2g, highlighting its nonlinear absorption, which has a nonlinear absorption coefficient (?eff) of 8.8 10-11 m/W at 20 ?J, as determined by Z-scan measurements. The results suggest that E-2g exhibits significant nonlinear absorption characteristics, which helps in applications requiring protection from intense light sources. 2024 World Scientific Publishing Company. -
Photoluminescence studies of non-toxic monoclinic yttrium oxide quantum dots synthesized at low temperature for live cell imaging applications
Synthesis of monoclinic Y2O3 remains a challenging task due to complex formation conditions such as high pressure or high temperature environments. Monoclinic yttria exhibits better photoluminescence characteristics compared to the cubic phase and hence can be a better host for nanophosphors. Reports are available predicting the stability of monoclinic phase at low temperature in extremely fine particles. But experimental preparation of this phase at low temperature is not yet reported. Here we report the first-time preparation of monoclinic Y2O3 at 90 C using simple laboratory hot air oven. The synthesized nanoparticles exhibit intense PL emission in the blue region and hence can find applications in display industry. The band structure calculations were carried out using density functional theory and the excitonic Bohr radius was estimated using the electron as well as hole effective masses determined from band structure. The cytotoxicity studies reveal non-toxic nature the particles. The fluorescence imaging experiments show that the material is capable of emitting blue fluorescence in L6 skeletal cell lines and it ensures the applicability of this material in the biomedical field. 2022 Elsevier Ltd and Techna Group S.r.l. -
Photoluminescence, Judd-Ofelt and Thermoluminescence studies on bright red emitting CaY2O4:Eu3+ phosphor for display applications
The Eu3+-doped CaY2O4 phosphors were synthesised via high-temperature solid-state method. The XRD analysis suggests an Orthorhombic-like phase of the phosphor, with Eu3+ ions effectively substituting Y3+ sites, while the crystallite size analysis (Scherrer and W-H) reveals dopant-induced grain growth accompanied by strain relaxation. The photoluminescence spectra show an intense red-emission at 610 nm under a broad UV-to-blue excitation, with 466 nm emerging as the most efficient excitation wavelength, highlighting compatibility with blue LED sources. Concentration quenching behaviour suggests excitation-wavelength dependence, with optimum Eu3+ concentration at 1.5 mol% under deep UV-excitation (257 nm), and 2 mol% under near-UV/visible (393532 nm) excitations. Dexter analysis indicates the dipole-dipole interactions dominated quenching in the visible region, while the unusually low Q value under deep UV-excitation suggests the host-activator transfer. The Judd-Ofelt analysis indicates a non-centrosymmetric Eu3+ environment, and CIE coordinates (x = 0.643, y = 0.356) with ?94 % high colour purity demonstrates the saturated red emission. Thermoluminescence study exhibits multiple traps with near-linear UV dose response, supporting dosimetric potential. The combined broad excitation, high emission intensity, and colour purity make the CaY2O4: Eu3+ a promising red phosphor for display and LED applications. 2025 Elsevier B.V. -
Photometric and spectroscopic study of candidate be stars in the magellanic clouds
[No abstract available] -
Photometric identification of objects from galaxy evolution explorer survey and sloan digital sky survey
We have used Galaxy Evolution Explorer (GALEX) and Sloan Digital Sky Survey (SDSS) observations to extract seven band photometric magnitudes for over 80 000 objects in the vicinity of the North Galactic Pole. Although these had been identified as stars by the SDSS pipeline, we found through fitting with model spectral energy distributions that most were, in fact, of extragalactic origin. Only about 9 per cent of these objects turned out to be mainsequence stars and about 11 per cent were white dwarfs and red giants collectively, while galaxies and quasars contributed to the remaining 80 per cent of the data. We have classified these objects into different spectral types (for the stars) and into different galactic types (for the galaxies). As part of our fitting procedure, we derive the distance and extinction to each object and the photometric redshift towards galaxies and quasars. This method easily allows for the addition of any number of observations to cover a more diverse range of wavelengths, as well as the addition of any number of model templates. The primary objective of this work is to eventually derive a three-dimensional extinction map of the Milky Way Galaxy. 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. -
Photon, Electron, Proton and Alpha Particle Interaction Parameters of Different Clays
Modern life has made human beings and nature vulnerable to harmful radiations at different levels. This can be a great health hazard of our times. Since there is no probability of dodging the harmful influence, the practical way out is having protective shielding. Lead, the most efficient attenuator in current use has the drawbacks of being heavy, toxic and capable of producing secondary radiations. Other attenuators concrete, glass etc. have similar deficits in use. This is the context of the scientific world's quest for a perfect shielding material which can provide protection from harmful radiations effectively, economically and environment friendly. This work attempts a computational study on the radiation shielding efficiency of different types of clays, understanding of which would enable its applications for radiation shielding. The presence of high Z elements and the layered structure of clay along with its good thermal stability make it ideal filler for an effective radiation shield. In this work, we have performed a systematic study of the mass attenuation coefficients, effective atomic number and electron density of various clay samples. 2022 American Institute of Physics Inc.. All rights reserved. -
Photophysical and antitubercular studies on newly synthesised structurally architectured sulphonamide
This study presents the synthesis and characterisation of four mono-azo sulphonamide derivatives through diazo-coupling electrophilic substitution reactions. The structural analysis of the synthesised molecules was conducted utilising FT-IR, 1H-NMR and HR-MS techniques. Absorption and fluorescence maxima of the synthesised molecules were determined across solvents of varying polarity to explore Solvatochromic behaviour. Density functional theory was employed to elucidate electronic and optical properties, including the computation of HOMOLUMO energies using Gaussian 09W software, with comparisons to experimental data. Molecular electrostatic potential 3D plots identified electrophilic and nucleophilic sites. Solvent interactions were evaluated using KamletAbboud Taft and Catalan parameters. Further, global chemical reactivity descriptors were estimated to ascertain chemical reactivity of the molecules. Additionally, the effectiveness of the colourant anti-tubercular activity was evaluated using in vitro and molecular docking techniques. The biological activity results reveal that methyl-pyridone and barbituric acid coupled with sulphamethizole (SMP and SMB) displayed excellent anti-tubercular activity compared with the standard Gentamycin. 2024 Informa UK Limited, trading as Taylor & Francis Group. -
Photophysical and antitubercular studies on newly synthesised structurally architectured sulphonamide
This study presents the synthesis and characterisation of four mono-azo sulphonamide derivatives through diazo-coupling electrophilic substitution reactions. The structural analysis of the synthesised molecules was conducted utilising FT-IR, 1H-NMR and HR-MS techniques. Absorption and fluorescence maxima of the synthesised molecules were determined across solvents of varying polarity to explore Solvatochromic behaviour. Density functional theory was employed to elucidate electronic and optical properties, including the computation of HOMOLUMO energies using Gaussian 09W software, with comparisons to experimental data. Molecular electrostatic potential 3D plots identified electrophilic and nucleophilic sites. Solvent interactions were evaluated using KamletAbboud Taft and Catalan parameters. Further, global chemical reactivity descriptors were estimated to ascertain chemical reactivity of the molecules. Additionally, the effectiveness of the colourant anti-tubercular activity was evaluated using in vitro and molecular docking techniques. The biological activity results reveal that methyl-pyridone and barbituric acid coupled with sulphamethizole (SMP and SMB) displayed excellent anti-tubercular activity compared with the standard Gentamycin. 2024 Informa UK Limited, trading as Taylor & Francis Group. -
Photophysical and Electrochemical Studies of Anchored Chromium (III) Complex on Reduced Graphene Oxide via Diazonium Chemistry
Covalently anchored chromium complex on reduced graphene oxide (rGO-Cr) is successfully synthesised through trimethoxy silyl propanamine (TMSPA) and phenyl azo salicylaldehyde (PAS) coupling. The rGO-Cr is characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron dispersive analysis of X-rays (EDAX), Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Absorption and emission properties of rGO-TMSPA-PAS are studied by excitation dependent photoluminescence emissions at room temperature. Electrochemical sensing activity of rGO-Cr is monitored for paracetamol using modified glassy carbon electrode. Cyclic voltammetry measurements indicated that rGO-Cr substantially enhance the eletrochemical response of paracetamol. The experimental factors are investigated and optimized. 2019 John Wiley & Sons, Ltd. -
Photophysical and In Vitro-In Silico Studies on Newly Synthesized Ethyl 3-((3-Methyl-1-phenyl-1H-pyrazol-5-yl)oxy)-2-methyleneheptanoate
Abstract: In the present work, the aryl-substituted pyrazolone derivative ethyl 3-((3-methyl-1-phenyl-1H-pyrazol-5-yl)oxy)-2-methyleneheptanoate (ETT) has been synthesized by the reaction of Baylis-Hillman acetate with pyrazolones and screened for their in vitro antifungal, antibacterial, and antioxidant properties. The molecule shows good in vitro antifungal and antibacterial activities due to the presence of pentane, which enhances the absorption rate by its increased lipid solubility and improves the pharmacological activity. It is also evident from the results obtained from structure-activity relationship (SAR) studies. In silico studies were conducted on the synthesized molecule, examining its interactions with DNA Gyrase, Lanosterol14 alpha demethylase, and KEAP1-NRF2 proteins. The results revealed strong binding interactions at specific sites. Further, the photophysical properties of synthesized compounds were theoretically estimated using the ab-intio technique. The ground state optimization, dipole moment, and HOMOLUMO energy levels are calculated using the DFT-B3LYP-6-31G(d) basis set. Using the theoretically estimated HOMOLUMO value, global chemical reactivity descriptor parameters are estimated, and the result shows the synthesised molecule has a highly electronegative and electrophilic index. NBO analysis proved the presence of intermolecular ON.H hydrogen bonds caused by the interaction of the lone pair of oxygen with the anti-bonding orbital. The results suggest that pentane-substituted pyrazolone derivatives show good photophysical and biological applications. Pleiades Publishing, Ltd. 2024. -
Photophysical study of 6-amino-3-methyl-4-(4-nitrophenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile and estimation of ground-state and singlet excited-state dipole moments by solvatochromic approaches
An investigation of absorption and fluorescence behaviour of 6-amino-3-methyl-4-(4-nitrophenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (NDPPC) at room temperature was carried out using a series of twelve organic solvents with different polarities. Ground and excited state dipole moments were determined experimentally by using LippertMataga polarity function, Bakhshiev solvent polarity parameter, Kawski-Chamma-Viallet solvent polarity parameter, Reichardt's microscopic solvent polarity parameter, Kamlet-Abboud-Taft multiple linear regression and Catalan dipolar polarizibility approach. Due to considerable ?- electron density redistribution, the value of excited state dipole moment was found to be greater than that of the ground state. The ground state dipole moment value was determined by quantum chemical method which was used to estimate excited state dipole moment using solvatochromic correlations. Both non-specific solute-solvent interactions and hydrogen bonding interactions were investigated by using Kamlet-Abboud-Taft and Catalan method. TD-DFT (B3LYP/6-311G (d,p)) was used for the determination of HOMO-LUMO energies. 2016 Elsevier B.V. -
Photoresponse and electrochemical behaviour of azobenzene anchored graphene oxide for energy storage application
Solar energy is considered to be a renewable source of energy that is intrinsically more sustainable than fossil fuels. Developing photoactive hybrid materials to store solar energy has recently received much attention. Herein, a photoactive molecule-graphene oxide hybrid was synthesized and characterized systematically. The solar energy storage performances of the hybrids were studied using various photophysical studies. The energy density and power density of the hybrid materials were 47 WhKg?1 and 156.6 WKg-1 respectively which showed 3 fold higher than the pristine compound. The photoelectrochemical behaviour of the hybrid were also studied using Cyclic voltammetry and Electrochemical impedance spectroscopy (EIS). Results showed the electrochemical performances can be varied due to their changing conformations from trans-to-cis isomerization. This work enables the research community in developing a promising material for solar thermal fuels as well as in energy storage devices. 2023 Elsevier B.V.