Synthesis Characterisation of Nano-ZnO Particles by Chemical Reduction and their Application of Anti-Microbial Activity against some pathogens

Room temperature benzaldehyde oxidation using air over gold–silver nanoalloy catalysts

In this study silver nanoparticles were prepared by chemical reduction method using silver nitrate as metal precursor, starch as protecting agent, and sodium borohydride (NaBH4) as a reducing agent. Formation of silver nanoparticles was monitored using UV–vis absorption spectroscopy and dynamic light scattering (DLS). They were supported on silica by dispersing silica powder in the suspension of destabilized silver nanoparticles. Samples containing different proportions of silver were thus prepared. This method is at variance from the conventionally employed method, i.e., impregnation of silver salt from its solution on support. Ag/SiO2 samples were characterized by UV–vis absorption spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive coupled plasma optical emission spectroscopy (ICP-OES), and N2 adsorption–desorption. Superior catalytic performance of the catalyst prepared by the present method could be observed in a test reaction of ethylbenzene oxidation affording high selectivity to acetophenone as compared to the catalyst prepared by the conventional reported methods. The 5 wt % Ag/SiO2 catalyst was found not much susceptible to sintering as could be inferred from the comparable performance of the regenerated and fresh catalysts.

Research in the area of nanoparticles has grown considerably in recent years. Plant leaf extracts provide a platform for nanoparticle synthesis from metal and metal oxides, which is more economical and environmentally friendly than other methods, such as chemical reduction and physical methods. The present study conducted the biosynthesis of iron nanoparticles (FeNPs) using Thymus vulgaris L. (Thyme) leaf aqueous extract. The characterization of FeNPs was carried out by transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-Ray diffraction (XRD) techniques. UV-vis spectroscopy analysis demonstrated a visible peak around 440 nm. FTIR demonstrated the presence of iron metallic ions. Structural analysis of the nanoparticles by TEM showed agglomerations of spherical shapes. The average size of the synthesized FeNPs was around 40 nm. Regarding application, the ability of the FeNPs to degrade methyl orange was recorded as 95%. They were also examined for potential antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria and fungi. FeNPs demonstrated high antifungal activity against Candida albicans, C. parapsilosis and Aspergillus flavus, while their antibacterial activity was much weaker compared to commercial antibacterial agent. Thus, FeNPs synthesized using T. vulgaris could play an important role in controlling C. albicans, C. parasilosis and A. flavus and bioremediation of dyes.

In this study, we report a mild and controllable preparation method for graphene oxide (GO) and ZnO ultrafine powder, respectively. On this basis, reduced graphene oxide (rGO)/ZnO composite powder for the photoanodes of dye-sensitized solar cells (DSSCs) was synthesized by chemical reduction method. Phase composition, microstructure, chemical structure, conductivity, and specific surface area were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), Raman, and Brunauer-Emmett-Teller (BET) method, respectively. Photoelectric performance of DSSCs was studied by the current density-voltage (J-V), electrochemical impedance spectra (EIS) photoelectric test system. As rGO possesses higher adsorption capacity and excellent conductivity, hence it may effectively promote separation of electrons and holes, transmission ability of electrons and holes, and utilization of the light. By contrast, the as-synthesized zinc oxide (ZnO) may increase adsorption capacity of dye molecules, so photoelectric conversion efficiency (PCE) of the solar cells is increased by means of synergistic effects. When adding rGO in the rGO/ZnO composite powder at 1.25 wt%, PCE reaches to 6.27%, an increase of 20.6% more than that of pure ZnO as the photoanode.

Terfezia claveryi is a species that belongs to the genera of Terfeziaceae or desert truffles, which is a family of truffles. In the present study, silver nanoparticles were synthesized from aqueous extract of T. claveryi which are in the range of 25 to 60 nm. The synthesized nanoparticles were characterized by ultraviolet-visible (UV-Vis) spectroscopy, fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The effect of the silver nanoparticles on human breast cancer cell line has been tested. Peak absorption was recorded at 440 nm in UV-Vis spectra of silver nanoparticles. The XRD data reports that the silver nanoparticles are crystalline in nature and have face centered cubic geometry. FESEM showed the size range of synthesized silver nanoparticles as 25 to 50 nm. The TEM image represents that the majority of silver nanoparticles are in spherical shape with sizes ranging between 40 and 60 nm. The aim of the present study was to report for the first time fruit mediated synthesis of silver nanoparticles using the extract of T. claveryi and showed remarkable cytotoxicity activity against human breast MCF-7 cancer cell line. Key words: Silver nanoparticles, Terfezia claveryi, fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (FESEM), transmission electron microscopy (TEM), MCF-7 cancer cell line.

One plant seed extract (Psidium guajava) was screened for their bioreduction behavior for synthesis of silver nanoparticles. Psidium guajava (PG) was found to exhibit the good reducing and protecting action in terms of synthesis rate and monodispersity of the prepared silver nanoparticles. UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) was performed to ascertain the formation of Ag-NPs. Our measurements indicate that biosynthesis of Ag nanoparticles by Psidium guajava (PG) produces Ag nanoparticles with the diameters in the range of 30-36 nm. XRD studies reveal a high degree of crystallinity and monophasic Ag nanoparticles of facecentered cubic (FCC) structure. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of drugs used againstbacterial diseases.

Spectrum analysis of the reduction degree of two-step reduced graphene oxide (GO) and the polymer/r-GO composites

Characterization and Aggregation of Silver Nanoparticles Dispersed in an Aqueous Solution

In this study, magnetite nanoparticles were functionalized with metallic silver using a chemical reduction method, and their structural, morphological, thermal, electrokinetic and magnetic properties were characterised using thirteen complementary techniques. Combined analysis by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy (Raman) and X-ray Photoelectron Spectroscopy (XPS) revealed a promising surface configuration, where silver is deposited on the surface of magnetite as metallic Ag⁰, forming nanoclusters without penetrating the spinel crystal lattice or altering the iron's oxidation state. This configuration generates a biphasic system, where magnetite retains its magnetic properties while silver provides a modulated surface capable of interacting electrostatically with anionic species. The synthesis and characterization approach were comprehensive, following a multi-technique strategy where each technique reinforced or limited the interpretations of others: XRD confirmed the crystalline identity, XPS ruled out chemical bonding, and Raman–FTIR complemented vibrational analysis. TEM and SEM revealed surface organization, while Brunauer–Emmett–Teller Surface Area Analysis (BET) and laser diffraction characterized porosity and dispersion. Thermogravimetry (TG)– Differential Scanning Calorimetry (DSC) studies demonstrated enhanced thermal stability and Point of Zero Charge (PZC) analysis provided evidence of electrostatic modulation, with magnetometry confirming the magnetic retention after functionalization. This integrative strategy not only validated the physical nature of the silver–magnetite interaction but also demonstrated that silver acts as an electrostatic modulator without compromising internal magnetism. The combination of Van der Waals interactions, increased surface area, and localized positive charge regions favours the adsorption of anionic pollutants. This was corroborated in previous adsorption experiments (e.g., nitrate and amoxicillin removal), confirming the material’s potential in environmental decontamination applications. In conclusion, the rational design of Fe₃O₄@Ag systems through surface functionalization with silver enables the integration of physical, thermal and electrostatic enhancements, which, when analysed through a coherent multi-technique methodology, converge toward a single functional objective: the development of effective adsorbent nanomaterials for water treatment.

This study has encountered with the fabrication of ferrites (Mg and Mn) using citric acid as anionic surfactant in sol-gel method followed by calcinations at varied temperatures (300, 600, 800°C) for 2h, respectively. The fabricated ferrites have been characterized by FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-Ray Diffraction), SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope). The FTIR spectrum for MnFeO3 shows that some functional groups already removed under 300°C calcination due to several oxidation numbers possessed by Mn leading to more flexibility. The XRD diffractograms for both MgFe2O4 and MnFeO3 show that the transition phase from amorphous to crystalline structure occurred in the temperature range of 300-600°C. The SEM mappings based on the Fe distribution for both MgFe2O4 and MnFeO3 show that more Fe distributed over the ferrites surface at 600 and 800°C, while the SEM mappings for both ferrites (Mg and Mn) show less Fe distribution at 300°C calcination, thus, it indicates more repulsion force bearing by higher amounts of Fe atoms at higher thermal agitation due to volume expansion. The TEM spectra proved that both ferrites existed as crystals after calcined at 600°C. The fabricated ferrites have remarkable electrical properties useful for the manufacture of semiconducting materials.

Wastewater adversely affects humans and another animal including metal like Pb, As, Zn, Hg, and Cd in wastewater (domestic or industrial). These toxic metals affect human health and are a serious threat to the environment by the precipitation, adsorption, accumulation in the food chain and non-biodegradable nature, respectively. In the present study, treatment of industrial wastewater in terms of toxic Pb(II) removal was investigated by the using of copper oxide alginate (CuO/Alg) nanocomposite. The CuO/Alg nanocomposite was prepared by chemical reduction method in solution phase, and synthesized particles size were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The wastewater sample collected from WWTP of the local electroplating industry is located in Okhla Industrial Area, New Delhi. A series of experimental approaches have been used to remove Pb2+ from industrial wastewater with CuO/Alg nanocomposite, which includes sorbent mass, competitive ion, contact time, and SEM. The SEM image of CuO/Alg nanocomposite showed that particles had a sheet-like shape and mean diameter of about 18.09 nm. The test was performed under the batch condition to determine the adsorption rate and uptake at equilibrium from single component solution. The maximum uptake value of Pb2+ in single component solution was 118.40 mg/g from wastewater. The CuO/Alg nanocomposite identified as the most promising sorbent with an effective potential of removal of Pb2+ from wastewater is due to their high metal uptake.

Introduction and Aim: According to recent statistics, cancer is the highest cause of death in worldwide. The drugs utilized to treat cancer are not fully effective and are ultimately susceptible to resistance. Thus, there exists a need to discover more effective therapeutic agents to treat this disease. The newly emerging field of nanobiotechnology is gaining importance owing to its wide application in fields such as agriculture, medicine and industry. The present study aims at the investigation of anticancer efficiency of synthesized silver nanoparticles (AgNPs) from Enteromopha compressa, a marine alga. Materials and Methods: The brown algae E. compressa was collected from Chilika, Odisha, India, for experimental analysis. The AgNPs were synthesized from E. compressa and then characterized through UV-VIS Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS). The cell viability study, survival and DAPI straining method were conducted to ensure the anticancer activity of the synthesized AgNPs. Results: We found a distinctive peak at 446 nm owing to surface plasma resonance characteristics of synthesized AgNPs, was observed in the UV-Vis spectra. Simultaneously, the FTIR spectra confirmed the presence of various phytochemicals in E. compressa, which plays a crucial role in the formation of silver nanoparticle. Again, the XRD and TEM analysis validate the crystallinity feature of the synthesized AgNPs with an average particle size of 44.3?±?0.1.2 nm. The green synthesized AgNPs exhibited an excellent cytotoxic property against HCT-116 cell lines with >80% and >20% death of HCT-116 and FHM cells respectively occur at an AgNP dose of 200 µM. Conclusion: This study shows the E. compressa extract can be used as a reductant in the formation of spherically shaped AgNPs with an average particle size of 44 nm size and potential source for anticancer agent against HCT-116. Thus, synthesized AgNPs in this study can be a solid base for forthcoming research in the synthesis of a new medicine. Keywords: Green Synthesis; AgNPs; E. compressa; anticancer activity; colon cancer.

Multi drug resistance is increasing day by day due to misuse of antibiotics. Several potent metabolites are produced by fungi. Synthesis of silver nanoparticle (AgNPs) Due to its simple, harmless, time-saving, and cost-effective characteristics, it has acquired great popularity in recent years. A variety of analytical techniques were used to synthesize AgNPs from Aspergillus fumigatus extracts, including X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The effect of synthesis AgNPs and crude extract noted against different bacterial pathogens. Maximum antibacterial activity were noticed against tested bacteria by both fungal crude extract and (AgNPs) Maximum antibacterial activity of Ethyl acetate crude extract at 50µl concentration (12mg/1ml DMSO) showed (15mm) zone of inhibition against E.coli. While minimum antibacterial activity of Ethyl crude extract at 50µl concentration was observed against S.typhi (12mm). Highest antibacterial activity of Ethyl acetate crude extract at 100µl was noted against E.coli which showed (20mm) zone of inhibition. While (17mm) zone of inhibition was observed against S.typhi at 100µl concentration Ethyl acetate crude extract and AgNPs (25mm) zone of inhibition was observed against E.coli at 100µl concentration Ethyl acetate crude extract and AgNPs respectively. During UV-visible spectroscopy, surface Plasmon Resonance (SPR) was observed at 432 nm, which confirmed the synthesis of AgNPs. The SEM micrograph demonstrated the spherical shape of AgNPs. The results of FTIR research revealed that phenolic, carboxyl, and hydroxyl groups played a crucial role in the reduction of Ag+ ions into AgNPs, while amide linkage and amino acids stabilized AgNPs. AgNPs synthesized were XRD peaks that revealed phase purity, size, internal crystalline structure, and nature. In the pharmaceutical and medical fields, AgNPs synthesized from Aspergillus fumigatus extract could be of great importance. While, the combination of AgNPs and crude extract Aspergillus fumigatus enhances their antimicrobial effect which increase their importance in future studies Keywords: Fungal secondary metabolites, silver nanoparticles, crude extract, MDR pathogen bacteria , SEM, TEM, UV, FTIR, XRD.

In this study, an electrochemical sensor for the detection of 4-Nitrophenol (referred to as 4-NP) was developed based on templated silver nanoparticles (AgNPs) on reduced graphene oxide (rGO) nanosheets (Ag-rGO) and utilized as an electrocatalyst. It was found that the resulting composite exhibits enhanced catalytic activity towards the reduction of 4-NP. The cubic shaped AgNPs templated on rGO nanosheets has been successfully fabricated by a chemical reduction method using sodium borohydride (NaBH4), and it was well characterized through morphological and electrochemical techniques: Ultraviolet–Visible spectroscopy (UV -Vis), scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (SEM–EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and chronoamperometry. The obtained results revealed that the AgNPs scattered on rGO sheets are spherical in shape, and it’s estimated to be a dimension of ~ 60 nm in size. The prepared crystalline Ag-rGO nano sheets were further applied as an electrode material for the electrochemical examination with three electrode system to sense the hazardous material 4-NP in PBS. The electrochemical studies were conducted through CV under the condition of bare and coated electrode (Ag-rGO/GCE) with influence of concentration (4-NP from 2 to 150 mM), scan rate, reproducibility (RSD-2.87%) and stability test (4-NP-20 µM) were examined. The data reveal that the Ag-rGO/GCE exhibit highly reproducible and sustainable for the reduction of toxic 4-NP. The chronoamperometry study for current and time response was also studied at two different potentials (− 0.3 V & − 0.6 V), respectively.

Zero-valent iron nanoparticles (NZVI) were synthesized using chemical reduction method. These were applied for lead removal from water. The structural, morphological, compositional and optical studies were studied out using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). The NZVI optical energy band gap as calculated by UV absorption spectrum was 1.7 eV. The zeta potential was obtained as -32.0 mV. The biocompatibility test of NZVI was performed using MTT assay on MDCK-2 as model cell lines. Lead adsorption on NZVI was examined at different pHs, equilibrium time, temperature, and NZVI/Pb2+ concentrations. Almost 100% Pb2+ removal was achieved at NZVI dose: 0.4 g/L; Pb2+ concentration: 50 mg/L; equilibrium time: 15 min; pH 5-6; and temperature: 25°C. Pb2+ sorption kinetic data were fitted to pseudo-first and second-order kinetic equations. Pseudo-second-order kinetic equation best fitted the data. These studies clearly demonstrate NZVI as an efficient nano-adsorbent for Pb2+ removal from water. Copyright © 2017 VBRI Press