Green synthesis and characterization of Camellia sinensis mediated silver nanoparticles for antibacterial ceramic applications

This study focuses on the use of green synthesized silver nanoparticles (Ag-NPs) with the aid of Camellia sinensis (black tea) extract to provide antibacterial activity on ceramic structure. The synthesized Ag nanoparticles were added to the glaze used in the ceramic structures and mixed homogeneously. The homogeneous mixture was characterized by transmission electron microscopy (TEM), X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) techniques. The SPR band of the synthesized biogenic Ag NPs was observed as 422 nm during the reaction at mom temperature. TEM analysis revealed that Ag NPs were spherical and a particle size between 10 and 20 nm. Furthermore, the antibacterial properties of the homogeneous mixture (Ag NPs and glaze) were tested against Escherichia coli (E. coli, Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Biogenic Ag NPs at a concentration of 100 mu g/ml were observed to have 90%, 75%, 75%, 80% lethal effects against S. aureus, MRSA, B. Subtilis, and E. Coli bacteria, respectively. The antibacterial results of Ag NPs obtained with the help of Camellia sinensis show that they may have potential application and development in the field of ceramics. In addition, the antibacterial activity of commercially available antibiotics and the prepared Ag NPs were analyzed in ceramic glazes

Highly efficient palladium-zinc oxide nanoparticles synthesized by biogenic methods: Characterization, hydrogen production and photocatalytic activities

In this study, palladium-zinc oxide nanoparticles (Pd@ZnO NPs) from biomass were synthesized by the biogenic method. The synthesized Pd@ZnO NPs were characterized by UV–Vis, FTIR, TEM, SEM, and XRD characterization techniques. According to the TEM analysis results, NPs have a spherical structure and an average size of 8.163 nm. According to the XRD results, it was observed that the mean crystalline size of the NPs was lower than the TEM analysis. Then, hydrogen production efficiency and photocatalytic efficiency were examined to observe the catalytic efficiency of NPs. The average reusability of Pd@ZnO NPs was found to be 74% after the four cycles. According to the measurements obtained, the Ea, ΔH, and ΔS values of Pd@ZnO NPs were found to be 37.76 kJ/mol, 35.23 kJ/mol, and -172.65 J/mol.K, respectively. In addition, 75% efficiency was obtained in photodegradation studies against Rhodamine B dye using sunlight irradiation. This study can be a basis for studies on the production of edible and sustainable nontoxic energy and the removal of dyestuffs from wastewater to prevent the pollution of the environment

Bimetallic palladium-cobalt nanomaterials as highly efficient catalysts for dehydrocoupling of dimethylamine borane

In this work, we report the synthesis, characterization and application of graphene oxide stabilized PdCo nanoparticles (PdCo GO) for the dehydrocoupling of dimethylamine borane (DMAB) as a model reaction. Bimetallic graphene oxide stabilized PdCo nano particles were readily synthesized using an ultrasonic reduction technique, in which both metals of Pd and Co were reduced with GO. The dispersion of PdCo nanoparticles on the surface of GO was enhanced with the help of the ultrasonic reduction method which result in the enhancing of dispersion of both metals without any agglomeration problem. The characterization studies revealed that graphene oxide stabilized PdCo nanoparticles have a uniform, homogeneous distribution on graphene oxide and an average particle size of 3.48 +/- 0.22 nm. After fully characterization of graphene oxide stabilized PdCo nano particles, they have been tried in model reaction as a catalyst and exhibited a high catalytic performance compared the previous catalysts in literature with a TOF value of 226.80 h(-1). The investigation of kinetic parameters showed that graphene oxide stabilized PdCo nanoparticles have very high negative entropy (Delta S: -170.85 J mol(-1) K-1) value and a low activation energy value (Ea: 17.53 +/- 2 kJ mol(-1) for the model reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Graphene Oxide-Chitosan Furnished Monodisperse Platinum Nanoparticles as Importantly Competent and Reusable Nanosorbents for Methylene Blue Removal

WOS: 000446408700011In this study, the microwave assisted methodology was employed to produce uniformly distributed platinum nanoparticles decorated with graphane oxide-chitosan. The capacity of methylene blue removal of these nanohybrids at room temperature was examined via adsorption. Characterizations of these novel nanoadsorbents were accomplished using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The X-ray diffractogram of the Pt NPs@CSGO displayed an ordinary structure of face-centered cubic (FCC). Adsorbance measurement results represented significant performance increases for all these novel nanohybrids for methylene blue removal. However, Pt NPs@CSGO hybrid was one of the best nanoadsorbent compared to others produced in this study. Our results presented that the one of highest methylene blue adsorption capacity belongs to the Pt NPs@CSGO, which was 194.6 mg/g, can be considered as an outstanding capacity. Its equilibrium was accomplished in 55 min. Furthermore, all these Pt NPs are reusable materials for the methylene blue removal application because they sustained 74.02 % of the initial efficiency after six successive adsorptions-desorption cycles

Novel Chitosan-Based Nanocomposites for Dye Removal Applications

WOS: 000446408700003Monodisperse Pd nanoparticles (Pd NPs@CGO) decorated Chitosan-graphene oxide (CGO) are produced to get a nanoadsorbent material to remove methylene blue (MB) from aqueous solutions. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the Pd NPs@CGO. The spectroscopic results showed that Pd NPs@CGO has highly crystalline, monodisperse and colloidal structures. Furthermore, Pd NPs@CGO was highly efficient and stable for methylene blue removal. They provide a high adsorption capacity of 186.42 mg/g and its MB adsorption equilibrium is obtained in similar to 60 min. Nonetheless, Pd NPs@CGO are reusable and promising nanocomposites for methylene blue removal, keeping 43.05 % of the first efficacy after six adsorption-desorption cycles

Hydrothermal-assisted synthesis of Co-doped ZnO nanoparticles catalyst for sodium borohydride dehydrogenation and photodegradation of organic pollutants in water

In recent years, studies on dye removal and hydrogen energy have gained momentum. However, these studies are still not in the desired position. Existing biological and physical methods for dye removal are quite inadequate. In hydrogen production, the efficiency is very low when a catalyst is not used. It is important to obtain inexpensive catalysts for both purposes. For this purpose, Cobalt doped Zinc oxide nanoparticles (Co-doped ZnO NPs) were synthesized using a one-pot flash combustion approach. The photocatalytic activity and hydrolysis process of the produced catalyst on NaBH4 were evaluated. The photocatalytic activity of Co-doped ZnO NPs was investigated for decolorization against certain dyes under sunlight irradiation. Co-doped ZnO NPs were analyzed for hydrogen production from NaBH4 hydrolysis. It has been determined that the nanomaterial has a superior catalytic activity with Turnover frequency (TOF) of 1682.3 min−1, 32.45 kJ/mol enthalpy (∆E),-158.4 J/mol.K entropy (∆S), and 34.94 kJ/mol activation energy (EA) obtained as a result of the hydrolysis reaction of Co-doped ZnO NPs. Their reusability was found to be 72.5% at the 4th cycle. The photocatalytic activity of the Co-doped ZnO NPs was found 81.22% (120 min) and 86.98% (90 min) against RhB and MB dyes, respectively. According to the results obtained, it has been seen that Co-doped ZnO NPs are reusable catalysts with high catalytic activity for hydrogen production as a clean energy source. At the same time, it was emphasized that a photocatalyst with high catalytic activity was obtained for wastewater treatment

An environmental approach for the photodegradation of toxic pollutants from wastewater using Pt-Pd nanoparticles: Antioxidant, antibacterial and lipid peroxidation inhibition applications

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

Binary Palladium-Nickel/Vulcan carbon-based nanoparticles as highly efficient catalyst for hydrogen evolution reaction at room temperature

WOS: 000473840800010Herein, Palladium-Nickel alloy nanoparticles assembled on Vulcan carbon composites (PdNi@VC) have been reported as highly efficient, stable and durable catalyst for the hydrogen evolution from dimethylamine borane. Palladium-Nickel alloy nanoparticles assembled on Vulcan carbon composites were prepared using ultrasonic reduction technique and characterized using some analytical methods. The characterization analyses revealed that Palladium-Nickel alloy nanoparticles assembled on Vulcan carbon composites have a monodisperse metal distribution and crystalline structure. Some catalytic experiments were performed, and some activation parameters such as activation energy (Ea=40.05 +/- 2 kJ/mol), activation entropy (Delta S =-132.11 +/- 1 J mol(-1) K-1) and activation enthalpy (Delta H =37.55 +/- 1 kJ mol(-1)) were calculated for catalytic reaction of dimethylamine borane. The turnover frequency (TOF) value of Palladium-Nickel alloy nanoparticles assembled on Vulcan carbon composites was found to be 283.48 h(-1), having one of the best catalytic activities among the previous heterogenous catalysts tested for dimethylamine borane (DMAB) catalytic reaction. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.DEU-BAPDokuz Eylul University [KB.FEN.040]The authors would like to thank to DEU-BAP (2017.KB.FEN.040) for the financial support

Photocatalytic investigation of textile dyes and E. coli bacteria from wastewater using Fe3O4@MnO2 heterojunction and investigation for hydrogen generation on NaBH4 hydrolysis

© 2023 Elsevier Inc.Various impurities found nowadays in water can be detrimental to human health. This work focused on utilizing Fe3O4@MnO2 nanocomposite for cleaning organic contaminants from water, including rhodamine B (RhB) and Escherichia coli (E. coli). Analysis methods such as XRD, UV–vis, TEM, and FTIR were used to describe the nanocomposite. The results showed that the developed nanocomposite has good photocatalytic activity against pollutants in wastewater. The E. coli was destroyed after 90 min, and the RhB photodegradation rate was 75%. Moreover, the Fe3O4@MnO2 efficiency as a catalyst for producing hydrogen as an alternative energy source was tested. According to the calculations, the nanomaterial's turnover frequency, activation energy, enthalpy, and entropy are 1061.3 h−1, 28.93 kJ/mol, 26.38 kJ/mol, and −128.41 J/mol.K, respectively. Four reusability tests were completed, and the average reusability was 78%. The obtained data indicated the excellent potential for the developed Fe3O4@MnO2 nanomaterial to act as an adsorbent, thus representing an alternative to the classical depollution methods. This study showed that nanoparticles have a photocatalytic effect against pathogenic bacteria and RhB azo dye in polluted waters and offer an effective catalytic activity to produce hydrogen as an alternative energy source

Efficient green photocatalyst of silver-based palladium nanoparticles for methyle orange photodegradation, investigation of lipid peroxidation inhibition, antimicrobial, and antioxidant activity

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