Browsing by Author "Karimi, Fatemeh"

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Efficient Green Photocatalyst of Silver-Based Palladium Nanoparticles for Methyle Orange Photodegradation, Investigation of Lipid Peroxidation Inhibition, Antimicrobial, and Antioxidant Activity
(Pergamon-elsevier Science Ltd, 2022) Karimi, Fatemeh; Rezaei-savadkouhi, Negin; Aygun, Aysenur; Tiri, Rima Nour Elhouda; Meydan, Ismet; Aghapour, Elaheh; Ucar, Mustafa
Nanotechnology is an interdisciplinary study that has been developing worldwide in recent years and has a serious impact on human life. The fact that the nanoparticles of plant origin are clean, non-toxic, and biocom-patible has enabled new fields of study. The Hibiscus sabdariffa (H. sabdariffa) plant has been attracted by sci-entists because of its impact on health and many other areas. The lipid peroxidation inhibiting activity, antioxidant properties, and antimicrobial properties of H. sabdariffa plant with Ag-Pd metal was ditermined. For the total phenolic component, gallic acid was used as the standard and quarcetin was used for the total flavonoid. The lipid peroxidation inhibition activity of Ag-Pd NPs in ethanol extract was found to be very well compared to the positive control (BHA). The lowest and highest concentrations of DPPH radical scavenging activity were 82.178-97.357%, whereas for BHA these values were found to be 84.142-94.142%. The highest concentration of Ag-Pd NPs at 200 mu g/mL the DPPH radical quenching activity was higher than BHA. Ag-Pd NPs showed a good antimicrobial activity against certain pathogenic microorganisms such as Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, which are the causative agents of various diseases in humans. The photodegradation activity of Ag-Pd NPs also investigated against Methyl orange dye (MO) under sunlight irradiation for 120 min and was found to be as 67.88%
One-Step Synthesized Biogenic Nanoparticles Using Linum Usitatissimum: Application of Sun-Light Photocatalytic, Biological Activity and Electrochemical H2o2 Sensor
(Academic Press inc Elsevier Science, 2023) Karimi, Fatemeh; Tiri, Rima Nour Elhouda; Aygun, Aysenur; Gulbagca, Fulya; Ozdemir, Sadin; Gonca, Serpil; Sen, Fatih
This study aimed to synthesize Ag NPs as a green catalyst for photocatalytic activity and to examine their bio-logical activities. It was determined that they have high activity in catalytic and biological activities. The green synthesis which is an environmentally friendly and inexpensive method was used to synthesize Ag-NPs using Linum usitatissimum as a reducing agent. Transmission electron microscopy (TEM), infrared to Fourier transform infrared (FTIR) spectroscopy, UV-Visible (UV-Vis) spectroscopy, and X-ray diffraction (XRD) were used to characterize the Ag NPs. In UV-Vis examination, Ag-NPs had intense peaks in the 435 nm region. The anti-bacterial activity of Ag NPs was investigated, and Ag NPs showed a high lethal effect against S. aureus, E. coli, B. subtilis, and MRSA. In addition, Ag NPs were tested for anticancer activity against the HT-29 colon cancer cell line, MDA-MB-231 breast cancer cell line, healthy cell line L929-Murine Fibroblast cell Lines, and MIA PaCa-2 human pancreatic cancer cell line at various concentrations (1-160 mu g/mL) and showed a high anti-cancerogenic properties against MDA-MB-231 cells. Ag NPs showed the ability of DNA cleavage activity. Also, the antioxidant activity of Ag NPs against DPPH was found to be 80% approximately. Furthermore, the pho-tocatalytic activity of Ag NPs against methylene blue (MB) was determined to be 67.13% at the 180th min. In addition, it was observed that biogenic Ag NPs have high electrocatalytic activity for hydrogen peroxide (H2O2) detection. In the sensor based on Ag NPs, linearity from 1 mu M to 5 mu M was observed with a detection limit (LOD) of 1.323 mu M for H2O2. According to these results, we conclude that the biogenic Ag NPs synthesized using Linum usitatissimum extract can be developed as an efficient biological agent as an antibacterial and anticancer also can be used as a photocatalyst for industrial wastewater treatment to prevent wastewater pollution.
Palladium Based Bimetallic Nanocatalysts: Synthesis, Characterization and Hydrogen Fuel Production
(Elsevier Sci Ltd, 2023) Ni, Kaijie; Wu, Yingji; Karimi, Fatemeh; Gulbagca, Fulya; Seyrankaya, Abdullah; Altuner, Elif Esra; Sen, Fatih
In this study, Palladium dopped Copper oxide nanoparticles (CuO@Pd NPs) were synthesized by an environmentally friendly green synthesis method for hydrogen production experiments. Characterizations of synthesized nanoparticles; UV-vis Spectroscopy to characterize the optical properties, Scanning Electron Microscopy (SEM) to determine the morphology and particle size of the particles, Fourier Transform Infrared Spectroscopy (FTIR) for the analysis of organic groups, and X-ray Diffraction Spectroscopy (XRD) for the crystal lattice type analysis were used. As a result of the UV-vis Spectroscopy characterization of the synthesized nanoparticles, an absorption peak compatible with metals visible at 422 nm was observed. According to the XRD analysis results, the crystal size observed in the cubic phase was calculated as approximately 4.426 nm. According to the results of the SEM analysis the average particle size of the cubic nanoparticles was seen as 26.2 nm. The catalytic properties of CuO@Pd NPs were determined by the sodium borohydride hydrolysis reaction. As a result of catalyst, substrate, temperature, and reusability experiments, some activation parameters required for a catalytic reaction of nanoparticles were calculated. The activation energy of CuO@Pd NPs was calculated as 37.39 kJ/mol, enthalpy change as 34.84 kJ/mol, and entropy change as -189.8 J/mol.K. TOF, which is an indicator of hydrogen efficiency, was calculated as 1513.4 h-1. Reusability experiments were carried out in 4 cycles and the catalytic activity of CuO@Pd NPs was measured as 70 %. In light of these results, it was seen that nanoparticles provide optimal conditions for a catalytic reaction.