Silver Decorated Carbon Nanospheres as Effective Visible Light Photocatalyst

2013 ◽  
Vol 1509 ◽  
Author(s):  
W. Armstrong ◽  
B. Sapkota ◽  
S. R. Mishra
Keyword(s):  
Silver Nanoparticles ◽  
Visible Light ◽  
Amorphous Carbon ◽  
Uv Light ◽  
Low Cost ◽  
Hollow Spheres ◽  
Weight Ratio ◽  
Carbon Nanospheres ◽  
Visible Light Photocatalyst ◽  
Vis Spectroscopy

AbstractThe objective of this study was to assess usability of silver nanoparticles loaded on amorphous carbon (Ag-C) hollow nanospheres for the removal of Methylene Blue (MB) molecules from aqueous solutions. Using microwave technique, silver nanoparticles of different weight ratio was deposited onto amorphous carbon templates. The carbon hollow spheres were derived from glucose using hydrothermal technique. Interestingly crystallite size of Ag decreased with the silver loading on carbon nanospheres. Using UV-vis spectroscopy, the kinetics of MB removal from the solution was assessed. The degradation of MB followed pseudo-first-order kinetics. The obtained results showed that Ag-C particles are efficient MB degradation agent with the rate constant as high as 0.19 m-1 under visible light and 0.041 m -1 under UV light. Thus Ag-C particles are good alternative as low-cost scavenger of dye molecules in wastewater treatments.

scholarly journals Antifungal and Cytotoxic Evaluation of Photochemically Synthesized Heparin-Coated Gold and Silver Nanoparticles

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2849
Author(s):  
María del Pilar Rodriguez-Torres ◽  
Luis Armando Díaz-Torres ◽  
Blanca E. Millán-Chiu ◽  
René García-Contreras ◽  
Genoveva Hernández-Padrón ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Candida Parapsilosis ◽  
Uv Light ◽  
Chloroauric Acid ◽  
Gold And Silver Nanoparticles ◽  
Issatchenkia Orientalis ◽  
Microdilution Method ◽  
Metal Precursors ◽  
Photochemical Method ◽  
Vis Spectroscopy

Heparin-based silver nanoparticles (AgHep-NPs) and gold nanoparticles (AuHep-NPs) were produced by a photochemical method using silver nitrate and chloroauric acid as metal precursors and UV light at 254 nm. UV–Vis spectroscopy graphs showed absorption for AgHep-NPs and AuHep-NPs at 420 nm and 530 nm, respectively. TEM revealed a pseudospherical morphology and a small size, corresponding to 10–25 nm for AgHep-NPs and 1.5–7.5 nm for AuHep-NPs. Their antifungal activity against Candida albicans, Issatchenkia orientalis (Candida krusei), and Candida parapsilosis was assessed by the microdilution method. We show that AgHep-NPs were effective in decreasing fungus density, whereas AuHep-NPs were not. Additionally, the viability of human gingival fibroblasts was preserved by both nanoparticle types at a level above 80%, indicating a slight cytotoxicity. These results are potentially useful for applications of the described NPs mainly in dentistry and, to a lesser extent, in other biomedical areas.

scholarly journals Study of Antibacterial Properties of Ziziphus mauritiana based Green Synthesized Silver Nanoparticles against Various Bacterial Strains

2020 ◽  
Vol 12 (4) ◽  
pp. 1484 ◽  
Author(s):  
M. Asimuddin ◽  
Mohammed Rafi Shaik ◽  
Neeshat Fathima ◽  
M. Shaistha Afreen ◽  
Syed Farooq Adil ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Metallic Nanoparticles ◽  
Low Cost ◽  
Preliminary Investigation ◽  
Antibacterial Properties ◽  
Silver Ions ◽  
Ziziphus Mauritiana ◽  
Bacterial Strains ◽  
Vis Spectroscopy ◽  
Ft Ir

Due to their low cost and environmentally friendly nature, plant extracts based methods have gained significant popularity among researchers for the synthesis of metallic nanoparticles. Herein, green synthesis of silver nanoparticles was performed using the aqueous solution of Ziziphus mauritiana leaves extract (ZM-LE) as a bio-reducing agent. The as-obtained silver nanoparticles were characterized by using UV-Vis spectroscopy, XRD (X-ray diffraction), TEM (transmission electron microscopy), and FT-IR (Fourier-transform infrared spectroscopy). In addition, the effects of the concentrations of the leaves extract, silver nitrate, and the temperature on the preparation of nanoparticles were also investigated. In order to determine the nature of secondary metabolites present in leaves extract, a preliminary investigation of phytoconstituents was carried out using different methods including Folin-Ciocalteu and AlCl3 methods. The results have indicated the presence of a considerable amount of phenolic and flavonoid contents in the leaves extract, which are believed to be responsible for the reduction of silver ions and stabilization of resulting nanoparticles. Indeed, the FT-IR spectrum of silver nanoparticles also confirmed the presence of residual phytomolecules of leaves extract as stabilizing ligands on the surface of nanoparticles. The antibacterial properties of as-obtained silver nanoparticles were tested against various bacterial strains including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis. The nanoparticles strongly inhibited the growth of S. aureus with a minimum inhibitory concentration (MIC) of 2.5 μg/ml and moderately inhibited the growth of E. coli with a MIC of 5 μg/ml.

Synthesis and characterization of silver nanoparticles using as a reducing agent plant extract of Dandelion (Taraxacun officianale)

2019 ◽  
pp. 11-17
Author(s):  
Lidia Meléndez-Balbuena ◽  
Eric Reyes-Cervantes ◽  
Blanca Martha Cabrera-Vivas ◽  
Maribel Arroyo
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extract ◽  
Plant Extracts ◽  
Low Cost ◽  
Coli Strain ◽  
Reducing Agent ◽  
Force Microscopy ◽  
Yellow Color ◽  
Golden Yellow ◽  
Vis Spectroscopy

The objective of this work was to synthesize the synthesis of silver nanoparticles using as a reducing agent of ionic silver the plant extract of Dandelion (Taraxacun officianale), vegetable of high availability and low cost, as an alternative to the processes conventional, based on the antioxidant capacity of plant extracts that reduce metals in solution. The nanoparticles prepared by this method were characterized by the golden yellow color characteristic of silver nanoparticle solutions. Measurements with UV-Vis spectroscopy of aqueous solutions of Ag1 + ions after coming into contact with plant extracts of Dandelion at different pHs showed an intense absorption band around 400-450 nm, characteristic of the resonance of the Plasmon of silver nanoparticles. Through the scanning of the samples by means of AFM (atomic force microscopy), morphological information of the nanoparticles is obtained, from 3D topographic images of them, such as distribution, size and shape of the silver nanoparticles. Finally, its antibacterial activity was tested against the Escherichia coli strain.

Synthesis and Characterization of Attapulgite Clay Coated Ag/AgBr/TiO2 Visible Light Photocatalyst

2010 ◽  
Vol 178 ◽  
pp. 285-290 ◽  
Author(s):  
Xu Gu ◽  
Jin Long Jiang ◽  
Dong Li
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
High Efficiency ◽  
Catalyst Activity ◽  
Precipitation Method ◽  
High Dispersion ◽  
X Ray Diffraction ◽  
Visible Light Photocatalyst ◽  
Vis Spectroscopy ◽  
Attapulgite Clay

Attapulgite clay coated Ag/AgBr/TiO2 visible light photocatalyst was prepared by an impregnation-deposition-precipitation method. The catalyst was characterized via powder X-ray diffraction (XRD), TEM, UV-Vis spectroscopy, and EMAX, and their photocatalytic activity was examined by degradation of methylene blue in water under sunlight. The results showed that the catalyst exhibited high efficiency for the degradation of methylene blue and the catalyst activity maintained effectively after successive cyclic experiments under sunlight, attributed to adsorption of dye on attapulgite clay and high dispersion of AgBr and TiO2 nano-sized particles on the surface of attapulgite clay.

Green Synthesis of Biopolymer-Silver Nanocomposites for Gas Sensing

2016 ◽  
Vol 99 ◽  
pp. 54-60 ◽  
Author(s):  
Shilpa A. Pande
Keyword(s):  
Silver Nanoparticles ◽  
Optical Sensors ◽  
Gas Sensing ◽  
Low Cost ◽  
Research Work ◽  
Trisodium Citrate ◽  
Nanocomposite Films ◽  
Sem Images ◽  
Natural Polysaccharide ◽  
Vis Spectroscopy

In this research work, a very simple, low cost eco-friendly method is presented for the synthesis of silver nanoparticles to be used in colorimetric optical sensors based on localized SPR (LSPR) measurement for gas ammonia. Silver nitrate salts are reduced using gaur gum which acts as a capping and reducing agent. Commonly used reducing agents such as trisodium citrate or sodium borohydride are replaced by a more environmental friendly natural polysaccharide. Nanocomposite films of ~ 1.5 μm thicknesses were fabricated using Gaur Gum and silver nanoparticles. The uniformity of nanoparticles size was measured by SEM and TEM, while face centred cubic structure of crystalline silver nanoparticles was characterized using the X-ray diffraction technique. The optical properties of the composite film were tested by UV-VIS Spectroscopy. The formation of Gaur Gum/silver nanocomposite films was confirmed using SEM images. Also the resistivity of nanocomposite thin film was measured which could be then used for gas sensing application.

Surface Modified Titania Visible Light Photocatalyst Powders

2010 ◽  
Vol 162 ◽  
pp. 49-75 ◽  
Author(s):  
Dariusz Mitoraj ◽  
Horst Kisch
Keyword(s):  
Visible Light ◽  
Low Cost ◽  
Titanium Hydroxide ◽  
Main Group Elements ◽  
Visible Light Photocatalyst ◽  
The Earth ◽  
Visible Part ◽  
Doped Titania ◽  
Surface Modified ◽  
Organic Sensitizers

Titanium dioxide has received great attention both in fundamental and applied photocatalysis due to its low cost, non-toxicity, and stability against photocorrosion [ - ]. Unfortunately it can utilize only the very small UV part (about 3%) of solar light arriving at the earth surface. However, also the visible part (λ > 400 nm) may induce photocatalysis if titania is modified by transition or main group elements. Accordingly, many publications appeared in the last 20 years dealing with the problem of sensitizing titania for visible light photooxidation reactions. This may be achieved by doping, which means substitution of lattice ions, and by surface modification. In many cases authors not clearly differentiate between these two possibilities and so called doped titania quite often is a surface modified material. The latter is easily prepared by heating titania or its precursor compounds like titanium hydroxide in the presence of a modifier at temperatures in the range of 100 – 500 °C. In the following we summarize our work in this field using inorganic and organic sensitizers.

scholarly journals Immobilization of Lipase on Silver Nanoparticles via Adhesive Polydopamine for Biodiesel Production

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Kanchana Dumri ◽  
Dau Hung Anh
Keyword(s):  
Silver Nanoparticles ◽  
Soybean Oil ◽  
Low Cost ◽  
Immobilized Lipase ◽  
Complex Surface ◽  
Biodiesel Production ◽  
Alternative Source ◽  
Covalent Bonds ◽  
Chromatography Analysis ◽  
Vis Spectroscopy

Biodiesel production technology is competitive in terms of low cost and alternative source of energy which should be not only sustainable but also environmentally friendly. Designing of the lipase immobilization for biodiesel production has a remarkable impact and is still challenging. In this work, biodiesel production from soybean oil was enhanced and facilitated by using a novel biocatalyst consisting of commercial lipase (EC 3.1.1.3), silver nanoparticles, and polydopamine. Silver nanoparticles (AgNPs) were synthesized with a size range of 10–20 nm. Polydopamine (PD) was delivered by the self-polymerization of dopamine in 10 mM Tris-HCl pH 8.5 and simultaneously coated the AgNPs to form a PD/AgNPs complex. Lipase was immobilized on the PD/AgNPs complex surface via covalent bonds to form a tailor-made biocatalyst consisting of immobilized lipase/PD/AgNPs complex (LPA). The formation and morphology of each composition were characterized by UV-Vis spectroscopy and scanning electron microscope (SEM). Significantly, gas chromatography analysis showed a remarkable biodiesel production yield of 95% by using the LPA complex at 40°C for 6-hours reaction time, whereas the yield was 86% when using free lyophilized lipase. The LPA complex was apparently reusable after 7 batches and the latter conversion rate of soybean oil was decreased by only 27%.

An efficient visible-light photocatalyst made from a nonpolar layered semiconductor by grafting electron-withdrawing organic molecules to its surface

2016 ◽  
Vol 52 (92) ◽  
pp. 13507-13510 ◽  
Author(s):  
Benyan Xu ◽  
Yang An ◽  
Yuanyuan Liu ◽  
Baibiao Huang ◽  
Xiaoyan Qin ◽  
...  
Keyword(s):  
Visible Light ◽  
Organic Molecules ◽  
Uv Light ◽  
Layered Semiconductor ◽  
Visible Light Photocatalyst ◽  
Chemically Modified

The UV-light responsive Bi2O2(HCOO)2 (BFM) becomes an efficient visible-light photocatalyst when it is chemically modified with 4-substituted electron-withdrawing thiophenolates −S-C6H4Z.

scholarly journals ANTIMICROBIAL AND ANTICANCER ACTIVITY OF SILVER NANOPARTICLES FROM EDIBLE MUSHROOM: A REVIEW

2017 ◽  
Vol 10 (3) ◽  
pp. 37 ◽  
Author(s):  
Priyadarshni Karuppiah Chandran ◽  
Mahalingam Pambayan Ulagan
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Low Cost ◽  
Nanoparticle Synthesis ◽  
Colon Adenocarcinoma ◽  
Breast Adenocarcinoma ◽  
Metallic Silver ◽  
Liver Carcinoma ◽  
X Ray ◽  
Vis Spectroscopy

ABSTRACTBiologically inspired nanoparticle synthesis is currently a rapid expanding area of research in nanotechnology. Nanoparticle synthesis utilizing thebioresources such as plants and microbes appears to be a viable, low-cost, and eco-friendly approach. Especially mushrooms can be used for largescalesynthesis of silver nanoparticles as mushroom produces many proteins that reduce the silver nitrate during the biosynthesis. Silver nanoparticlescan be characterized using ultraviolet-visible (UV-VIS) spectroscopy, fourier transform infrared spectroscopy, X-ray diffraction, scanning electronmicroscopy, energy dispersive X-ray, and transmission electron microscope. Silver nanoparticles possess high antibacterial activity since silver indifferent forms has been extensively used as a medicine for curing diseases and promote wound healing. Silver nanoparticles have high surfacespecific area, which will lead to excellent antimicrobial activity as compared with bulk metallic silver. Further, the silver nanoparticles show anticanceractivity against various cell lines such as human epidermoid larynx carcinoma (HEP-2), colon adenocarcinoma (HCT-116), breast adenocarcinoma(MCF-7), liver carcinoma (Hep-G2), and intestinal adenocarcinoma (Caco2) were well documented. This review intends to present green synthesis ofsilver nanoparticles and their application as antimicrobial and anticancer agents.Keywords: Silver nanoparticles, Bioresources, Mushroom, Antimicrobial activity, Anticancer property.

Size Effect of Silver Nanoparticle Melted into ZnO Nanorods for Photocatalytic Activity

2013 ◽  
Vol 284-287 ◽  
pp. 367-374
Author(s):  
Jung Jie Huang ◽  
Ching Hsun Chao ◽  
Chao Nan Chen ◽  
Chun Fa Hsu ◽  
Ming Wei Tsai
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Silver Nanoparticles ◽  
Photocatalytic Activity ◽  
Size Effect ◽  
Silver Nanoparticle ◽  
Uv Light ◽  
Zno Nanorods ◽  
Zno Nanorod ◽  
Vis Spectroscopy

Ag/ZnO nanorod structure was synthesized by using the hydrothermal method to grow ZnO nanorods and melted silver nonoparticles into ZnO nanorods by thermal annealing process in vacuum at 700 oC. The photocatalytic activity for methylene blue decolorization is enhanced by silver nanoparticles melted into a ZnO nanorod structure owing to the formation of Schottky barrier near the Ag/ZnO interface prolongs the recombination of electron-hole pairs effectively. The size effect of silver nanoparticles in the Ag/ZnO nanorod structure for photocatalytic activity was discussed which was changed from 12 to 34 nm. The smaller silver nanoparticle size sample shows better decolorization efficiency of methylene blue solution owing to the higher surface area of Ag/ZnO nanoroad. Ag/ZnO nanorod films have been characterized by X-ray diffraction (XRD), UV-vis spectroscopy, field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The dye decolorization significantly increased from 69 to 99 % after UV light irradiation for 8 hr by the optimum Ag/ZnO nanorod film.

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