77 research outputs found
A Study on Atomic Spectroscopic Term Symbols for Nonequivalent Electrons of (n-1) d 1 s 1 p 1 Configuration Using RussellSaunders Coupling Scheme
No full textCorrosion Inhibitive and Adsorption Behaviour of Methanolic Extracts of Adansonia digitata (Baobab) Fruit Pulp and Seeds for Mild Steel in 1.0 M H2SO4
No full textA Review on Synthesis and Characterization of Ag2O Nanoparticles for Photocatalytic Applications
No full textEven though the photocatalytic processes are a good technology for treatment of toxic organic pollutants, the majority of current photocatalysts cannot utilize sunlight sufficiently to realize the decomposition of these organic pollutants. As stated by various researchers, metal oxide nanoparticles have a significant photocatalytic performance under visible light source. Among various chemical and physical methods used to synthesize nanostructured silver oxide, green synthetic route is a cheaper and environmental friendly method. To confirm the optimum production of Ag2O NPs, effect of pH, extract concentration, metal ion concentration, and contact time were optimized. The structure, morphology, crystallinity, size, purity, elemental composition, and optical properties of obtained Ag2O NPs were characterized by different techniques, such as scanning electron microscopy (SEM), transmission electron microscope (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and UV-visible spectrophotometer accordingly as revealed by our literature review. The photocatalytic performance of the synthesized nanocrystalline Ag2O by photocatalytic degradation of organic dyes under visible light irradiation has been discussed thoroughly in this review. Many past studies revealed that organic dyes and pollutants are decomposed completely by green synthesized Ag2O NPs under irradiation of visible light
Porous PVA/Zn–Fe–Mn oxide nanocomposites: methylene blue dye adsorption studies
No full textAdsorption is one of the noble techniques for remediation of organic and inorganic pollutants. The poly (vinyl alcohol) supported sol-gel and self-propagation routes have been used for the synthesis of porous ternary metal oxides nanocomposites. The optical, chemical bonding, crystallinity, morphological, textural, and electrochemical properties of the synthesized materials were characterized by DRS-UV–vis, FT-IR, XRD, SEM/EDX and TEM/HRTEM/SAED, BET, and CV/EIS techniques, respectively. The characterization of the nanocomposites confirmed their porous nature, high surface area, and better electrochemical properties. The synthesized nanomaterials were tested for the adsorption property of methylene blue dye. Important parameters such as the amount of PVA supported ternary metal oxide nanocomposite, pH of the solution, contact time, and concentration of methylene blue dye were optimized. For further understanding of the adsorption process, the adsorption isotherms and adsorption kinetics models were used. The adsorption tests revealed the presence of the chemisorption type of the adsorption process
Supercapacitor Performance of NiO, NiO-MWCNT, and NiO–Fe-MWCNT Composites
No full textThe NiO-CNT and NiO–Fe-CNT composites that have
been prepared
from waste high density polyethylene plastic and their carbon nanotube
(CNT) quality-dependent supercapacitance tuning have been reported
here. Multiwalled CNT (MWCNT) formation has been confirmed from TEM
and Raman spectra with an ID/IG ratio of 0.77, which stands for high graphitization.
The specific surface area (SSA) of MWCNTs in the NiO–Fe-CNT
composite was 87.8 m2/g, while in the NiO-CNT composite,
it was 25 m2/g. NiO–Fe-CNT displayed higher specific
capacitance and energy density (1360 Fg–1 and 1180
W h kg–1) than NiO-CNT (1250 Fg–1 and 1000 W h kg–1), which may be due to the presence
of higher-quality MWCNTs in the NiO–Fe-CNT composite. NiO–Fe-CNT
displayed higher contributions of electric double-layer capacitor
(59%) behavior compared to NiO-CNT (38%) and represented a hybrid
supercapacitor. NiO–Fe-CNT also displayed a capacitive retention
of 96% after 1000 charge–discharge cycles. Furthermore, studies
in acidic electrolytes revealed higher performance of NiO–Fe-CNT
than NiO-CNT, displaying specific capacitances of NiO–Fe-CNT
to be 1147 Fg–1 in 2 M H2SO4 and 943 Fg–1 in 2 M HCl. It has been qualitatively
explored that the quality of CNTs, SSA, and quantum confinement effects
in the composites may be the factors responsible for the performance
difference in NiO–Fe-CNT and NiO-CNT. The present work is geared
toward the low-cost fabrication of high-quality CNT composites for
supercapacitors and energy storage applications. The present work
also contributes quantitatively to the understanding of CNT quality
as an important parameter for the performance of CNT-composite-based
supercapacitors
Green synthesized CaO decorated ternary CaO/g-C3N4/PVA nanocomposite modified glassy carbon electrode for enhanced electrochemical detection of caffeic acid
No full textA highly selective, sensitive caffeic acid (CA) detection based on calcium oxide nanoparticles (CaO NPs) derived from extract of Moringa oleifera leaves decorated graphitic carbon nitride covalently grafted poly vinyl alcohol (CaO/g-C3N4/PVA) nanocomposite modified glassy carbon electrode (GCE) was studied. A facile sonochemical method was adapted to synthesis nanomaterials and characterized by HR-TEM (High resolution transmission electron microscopy), FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), FE-SEM (Field emission scanning electron microscopy), EDX (Energy dispersive X-ray analysis), Mapping and BET (Brunauer-Emmett-Teller) analysis, and electrochemical techniques. The nanocomposite modified GCE exhibited an excellent catalytic performance to the oxidation of CA under optimized conditions owing to better electron transfer efficiency, conductivity and high surface area of the electrode material. The present electrochemical sensor showed high selectivity towards the determination of 10 µM CA in the presence of 100-fold higher concentrations of interferents. The modified CA sensor exhibited a wide sensing linear range from 0.01 µM to 70 µM and the detection limit (LOD) was found to be 0.0024 µM (S/N = 3) in 0.1 M phosphate buffer saline (PBS) as a supporting electrolyte at pH 7.0. The fabricated CA sensor provides an excellent stability, reproducibility and selectivity for the determination of CA. The modified CA sensor was applied to real blood plasma samples and obtained good recovery (97.6-100.1%) results. © The Author(s) 2024
Synthesis of ZnO and ZnO/PVA nanocomposite using aqueous Moringa Oleifeira leaf extract template: antibacterial and electrochemical activities
No full textThe application of flexible polymer nanocomposites for food packaging to inactivate microorganisms associated with foods is the demand of the present-day food industry to assure quality throughout the packaging operation. The utilization of polyvinyl alcohol (PVA) assisted zinc oxide nanocomposite for food stuff packaging has been very attractive in the recent past. Nanostructured ZnO was synthesized at optimized pH (10.5) from different ratios of zinc acetate and Moringa oleifeira leaf extract (1:7, 1:3, 1:1 and 3:1). ZnO coated polyvinyl alcohol (ZnO/PVA) nanocomposites were prepared from 5, 9, 13 and 16% by wt of ZnO and PVA using solution casting method. The thermal stability of ZnO synthesized with 1:1 ratio at pH 10.5 was investigated with TGA/DTA. The analytical techniques such as X-ray diffraction (XRD), ultra-violate visible analysis (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) were used for the characterization of the synthesized ZnO and ZnO/PVA nanocomposites (NCs). The antibacterial activity of the synthesized ZnO and ZnO/PVA NCs were evaluated against gram negative E. coli and gram positive S. aureus bacteria. The electrochemical stability of ZnO/PVA NCs was also investigated by cyclic voltammetric (CV) method. The thermogram of ZnO indicated that the oxide was found to be stable even beyond 500°C. The SEM analysis revealed rod shaped morphology for synthesized ZnO from 1:1 ratio at pH 10.5. But the nanocomposite prepared with 5% of ZnO of (1:1) at the same pH exhibited uniformly dispersed rod-shaped particle on the surface as well as in matrix of polyvinyl alcohol film. According to XRD result, ZnO synthesized with more percentage of plant extract resulted in the small size crystallites while that with low percentage of plant extract resulted in the larger crystallite size. The antibacterial inhibition efficiency of ZnO/PVA NCs was better and found to increase with increase in the amount of ZnO
Microstructural, morphological and dielectric properties of Mo, Se co-doped Ba0.6Sr0.4TiO3 perovskites
No full textPrevious studies have shown that co-doping of BST resulted in enhanced dielectric properties of BST. Meanwhile, no work was reported about effect of Mo, Se on the dielectric properties of Barium strontium titanate (BST). Hence, this report was expected to contribute on the ways of enhancing the dielectric activity of BST through doping. The purpose of the research was to investigate the microstructural, morphological as well as the dielectric properties of BST and Mo, Se co-doped BST following their slow injection sol–gel synthesis and calcined at 800 °C. The effective synthesis of cubic Ba0.6(Sr0.4-xSex)(MoyTi1-y)O3 nanopowder has been confirmed using FT-IR, Raman spectroscopy, EDS, and XRD techniques where the presence of every element and the empirical formula matched with the predicted ones. The average crystallite size of BST increased from 23.97 nm to 26.18 nm after doping. Likewise, the average grain size elevated from 40.13 nm to 53.27 nm accompanied by the elevation of the number of agglomerated crystallites in a grain per SEM particle (1.98 to 3.55). The average particle size of Mo and Se co-doped BST was found as 26.63 nm. The lowering of pore size as well as pore volume of BST was also observed after doping. All these properties led to the elevation of dielectric constant (from 248.8 to 953.00) and lowering of the dielectric loss (from 0.1620 to 0.0928). Therefore, the Mo, Se co-doped BST possessed such varied properties from BST which makes it to be effectively utilized in capacitive applications such as supercapacitors
In Situ Green Synthesis of Co3O4@ZnO Core-Shell Nanoparticles Using Datura stramonium Leaf Extract: Antibacterial and Antioxidant Studies
No full textInvestigating and synthesizing potent antibacterial NPs using biological methods is highly preferred, and it involves nontoxic, cost-effective, and environmentally friendly chemicals and methods. Antibiotic drug resistance and oxidative stress have become a serious public health issue worldwide. Hence, the key objective of this study was to biologically synthesize and characterize the potent antibacterial Co3O4@ZnO core-shell nanoparticles for the antibacterial application. The radical scavenging ability of green synthesized Co3O4@ZnO core-shell nanoparticles was also determined. In this study, Co3O4@ZnO core-shell nanoparticles (CZCS NPs) have been synthesized using three different core to shell materials ratios of Co3O4 to ZnO (0.5 : 0.25 CZCS (1), 0.5 : 0.5 CZCS (2), and 0.5 : 0.75 M CZCS (3)) by employing Datura stramonium leaf extract. The polycrystalline nature of Co3O4@ZnO core-shell nanoparticles was investigated using the XRD and SAED characterization techniques. The investigated nanostructure of Co3O4@ZnO core-shell nanoparticles appeared with Co3O4 as the core and ZnO as an outer shell. Additionally, a variety of physicochemical properties of the nanoparticles were determined using various characterization techniques. The average crystallite sizes of CZCS (1), CZCS (2), and CZCS (3) were found to be 24±1.4, 22±1.5, and 25±1.5 nm, respectively. The band gap energy values for CZCS (1), CZCS (2), and CZCS (3) determined from the UV-DRS data were found to be 2.75, 2.76, and 2.73 eV, respectively. The high inhibition activities against S. aureus, S. pyogenes, E. coli, and P. aeruginosa bacterial strains were obtained for the small size CZCS (2) nanoparticles at the concentration of 100 mg/mL with 22 ± 0.34, 19 ± 0.32, 18 ± 0.45, and 17 ± 0.32 mm values, respectively. The high inhibition performance of CZCS (2) nanoparticles against Gram-positive and Gram-negative bacteria which is even above the control drug ampicillin is because of its small size and synergistic effect. The percentage scavenging activity of Co3O4@ZnO core-shell nanoparticles was also studied and CZCS (2) nanoparticles showed a good scavenging capacity (86.87%) at 500 μg/mL with IC50 of 209.26 μg/mL
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