Browsing by Author "Gunduz, Meliha Koldemir"

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An Environmental Approach for the Photodegradation of Toxic Pollutants From Wastewater Using Pt-Pd Nanoparticles: Antioxidant, Antibacterial and Lipid Peroxidation Inhibition Applications
(Academic Press inc Elsevier Science, 2022) Seckin, Hamdullah; Tiri, Rima Nour Elhouda; Meydan, Ismet; Aygun, Aysenur; Gunduz, Meliha Koldemir; Sen, Fatih
Background: Green synthesis is an effective and friendly method for the environment, especially in recent years has been used in many areas. It finds application opportunities in many fields such as physics, chemistry, electronics, food, and especially health and is the subject of intensive studies in this field. Objectives: The synthesized Pt-Pd NPs were aimed to be used as a bio-based photocatalyst under sunlight to prevent wastewater pollution. In addition, it is aimed to use Pt-Pd NPs as biological agents in different applications in the future. Methods: In this study, the platinum-palladium nanoparticles were synthesized by the extract of Hibiscus sabdariffa, the characterization of the nanoparticles was carried out by different methods (ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), infrared transform spectroscopy atomic force microscopy (AFM), and ray diffraction (XRD) analysis). And we discussed several different parameters related to human health by obtaining platinum-palladium bimetallic nanoparticles (Pt-Pd NPs) with a green synthesis method. These parameters are antioxidant properties (total phenolic, flavonoid, and DPPH scavenging activity), antibacterial activity, and lipid peroxidation inhibition activity. Gallic acid was used as standard phenolic, and quercetin was used as standard flavonoid reagents. The newly synthesized Hibiscus sabdariffa mediated green synthesized Pt-Pd NPs were compared with gram-positive and gram-negative bacteria, the high antibacterial activity was shown by gram-positive bacteria. The photodegradation of Pt-Pd NPs was carried out against MB dye for 180 min. Results: TEM results show that the average size of Pt-Pd NPs is around 4.40 nm. The total amount of phenolic compounds contained in 0.2 mg/ml of Pt-Pd NPs was equivalent to 14.962 +/- 7.890 mu g/ml gallic acid and the total amount of flavonoid component was found to be equal to 28.9986 +/- 0.204 mu g/ml quercetin. Hibiscus sabdariffa mediated green synthesized Pt-Pd NPs was found to have very effective for lipid pemxidation inhibition activity in the FeCl2-H2O2 system. The maximum DPPH scavenging activity was determined as 97.35% at 200 mu g/mi. The photocatalytic activity of Pt-Pd NPs was analysed against Methylene blue (MB) and the maximum degradation percentage was observed to be 83.46% at 180 min. Conclusions: The biogenic Pt-Pd NPs showed a high effective photocatalytic and biological activity.
Production of Plant-Based Zno Nps by Green Synthesis; Anticancer Activities and Photodegradation of Methylene Red Dye Under Sunlight
(Springer Heidelberg, 2024) Demir, Canan; Aygun, Aysenur; Gunduz, Meliha Koldemir; Altinok, Bahar Yilmaz; Karahan, Tugba; Meydan, Ismet; Sen, Fatih
Discharging wastewater from factories into streams without cleaning them causes environmental pollution and threatens the health of living beings. The photocatalysis method developed for easy, fast, and low-cost wastewater cleaning attracts considerable attention and therefore needs to synthesize efficient photocatalysts. In addition, the synthesized non-toxic catalysts can be tested as anticancer agents and may be suitable candidates to solve the issues facing cancer therapy today. Therefore, the synthesis of biogenic nanomaterials has gained importance. Plant-mediated green synthesis stands out in the simple, fast, cheap, and non-toxic production of nanoparticles (NPs). NPs produced by green synthesis are frequently used in biological applications such as anticancer and photocatalyst applications for cleaning wastewater. In this article, zinc oxide nanoparticles (ZnO NPs) were obtained using Zingiber officinale extract. The plant extract functions as a reducing, capping, and stabilizing agent in the green production of ZnO NPs. The synthesis of ZnO NPs was characterized using UV-Vis spectroscopy, FTIR, XRD, and TEM. TEM results show that ZnO NPs have sizes in the range of 10-45 nm. The anticancer activity of ZnO NPs was examined against HT29 (ATCC (R) HTB-38 (TM)) colorectal cancer cell line and HepG2 (ATCC (R) HB-8065 (TM)) hepatocellular cancer cell line by MTT assay. The IC50 values of ZnO NPs against HT29 and HepG2 cancer cell lines after 48 h were calculated as 20 mu g/mL and 45 mu g/mL, respectively. Additionally, the photocatalytic activity of ZnO NPs was tested against methylene red azo dye under sunlight and 87.96% (pH 7) photodegradation was obtained at the end of the 120th minute. It is predicted that ZnO NPs can be used effectively in both anticancer studies and environmental improvement.