scholarly journals H2Ti3O7 Nanotubes Decorated with Silver Nanoparticles for Photocatalytic Degradation of Atenolol

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Mariana Hinojosa-Reyes ◽  
Roberto Camposeco-Solís ◽  
Facundo Ruiz ◽  
Nereyda Niño Martínez ◽  
Vicente Rodríguez González ◽  
...  

The photocatalytic degradation/adsorption process of the β-blocker atenolol (ATL) under UV irradiation is described using two types of silver decorated catalysts: silver/titania and silver/titanates. The silver ions were reduced on the surface of TiO2-P25-Degussa using gallic acid. Silver/titanates were prepared by a microwave-assisted hydrothermal method using the silver/titania as the starting material to obtain the hydrogen titanate (H2Ti3O7) structure with tubular morphology. These materials were characterized by X-ray diffraction, UV-Vis spectroscopy, N2 physisorption, temperature programmed reduction, TEM, and FTIR spectroscopy. During the photocatalytic process, the ATL molecules were completely converted to amino-diol byproducts. It is the first time that these materials have been applied during the photocatalytic process in the degradation of pharmaceuticals products. The success of the silver nanoparticles (2 nm) consists of the homogeneous distribution over the surface of titanate nanotubes inhibiting the hole/electron recombination promoting the oxidation process. The Ag@H2Ti3O7 with a concentration of silver as 1.0% shows the highest adsorption/degradation of ATL than the Ag@TiO2 and the P25-Degussa. The great performance in the reuse test consists in the strong attachment of the silver nanoparticles on the titanium surface that inhibits the silver lixiviation during the photocatalytic tests.

Author(s):  
Shyla Marjorie Haqq ◽  
Amit Chattree

  This review is based on the synthesis of silver nanoparticles (AgNPs) using a green approach which is biofabricated from various medicinal plants. AgNPs were prepared from the various parts of the plants such as the flowers, stems, leaves, and fruits. Various physiochemical characterizations were performed using the ultraviolet (UV)-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy. AgNPs were also used to inhibit the growth of bacterial pathogens and were found to be effective against both the Gram-positive and Gram-negative bacteria. For the silver to have antimicrobial properties, it must be present in the ionized form. All the forms of silver-containing compounds with the observed antimicrobial properties are in one way or another source of silver ions. Although the antimicrobial properties of silver have been known, it is thought that the silver atoms bind to the thiol groups in enzymes and subsequently leads to the deactivation of enzymes. For the silver to have antimicrobial properties, it must be present in the ionized form. The study suggested that the action of the AgNPs on the microbial cells resulted into cell lysis and DNA damage. AgNPs have proved their candidature as a potential antibacterial against the multidrug-resistant microbes. The biological agents for synthesizing AgNPs cover compounds produced naturally in microbes and plants. Reaction parameters under which the AgNPs were being synthesized hold prominent impact on their size, shape, and application. Silver nanoparticle synthesis and their application are summarized and critically discussed in this review.


2019 ◽  
Vol 8 (3) ◽  
pp. 576-585

In the present study silver nanoparticles (AgNPs) have been synthesized through the cell-free extracts of the rooftop dwelling cyanobacterium Scytonema geitleri HKAR-12. UV-VIS spectroscopy, FTIR, X-ray diffraction, SEM and TEM were used for the determination of morphological, structural and optical properties of synthesized AgNPs. Extracts of Scytonema geitleri HKAR-12 have the ability to reduce AgNO3 to Ag0. Sharp peak at 422 nm indicated the rapid synthesis of AgNPs. FTIR results showed the presence of different groups responsible for the reduction of AgNO3 to AgNPs. XRD pattern confirmed the crystalline nature of AgNPs. SEM showed the bead shape structure of AgNPs. TEM confirmed the actual size of AgNPs to be ranging between 9-17 nm. AgNPs showed antibacterial activity against Pseudomonas aeruginosa, Escherichia coli strain1 and E. coli strain 2 and 11 μg/mL of AgNPs effectively inhibited the growth of MCF-7 cells. Hence, Scytonema geitleri HKAR-12, isolated from the rooftop could serve as a desirable biological candidate for convenient and cheap production of AgNPs having antimicrobial and anti-cancerous properties.


2014 ◽  
Vol 2 (4) ◽  
pp. 510-515
Author(s):  
Hala Moustafa Ahmed

The present study mainly focuses of combined action of Nepali hog plum as well as citrate synthesized silver nanoparticles (AgNPs) and Amikacin, as an antibiotic. The synergistic actions of citrate stabilized silver nanoparticles (AgNPs with chem) were compared with that of Nepali hog plum Choerospondia saxillaris (Lapsi) synthesized silver nanoparticles (AgNPs with plant), together with action of antibiotic onselected bacterial strains of Salmonella typhi. The synthesized AgNPs were characterized through UV-Vis spectroscopy, Transmission electronmicroscopy and X-ray diffraction technique. The size of the synthesized silver nanoparticles was measured by Transmission Electron Microscope (TEM) and X-ray diffraction (XRD).DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11127 Int J Appl Sci Biotechnol, Vol. 2(4): 510-515 


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Edwina Olohirere Uzunuigbe ◽  
Abidemi Paul Kappo ◽  
Sixberth Mlowe ◽  
Neerish Revaprasadu

Synthesizing nanoparticles with the less environmentally malignant approach using plant extract is of great interest; this is because most of the chemical approaches can be very costly, toxic, and time-consuming. Herein, we report the use of Acacia senegal leaf extracts to synthesize silver nanoparticles (AgNPs) using an environmentally greener approach. Silver ions were reduced using the bioactive components of the plant extracts with observable colour change from faint colourless to a brownish solution as indication of AgNP formation. The structural properties of the as-synthesized AgNPs were characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV-Vis absorption spectrum. Antimicrobial assessment of the as-synthesized AgNPs was explored on some strains of gram-positive and gram-negative bacteria. The obtained results indicate that the as-synthesized AgNPs are pure crystallite of cubic phase of AgNPs, fairly dispersed with a size range of 10–19 nm. The AgNPs were found to be small in size and exhibit significant antibacterial activities, suggesting that the as-synthesized AgNPs could be used in the pharmaceutical and food industries as bactericidal agents.


2020 ◽  
Vol 7 (7) ◽  
pp. 200065 ◽  
Author(s):  
Siti Nur Aishah Mat Yusuf ◽  
Che Nurul Azieyan Che Mood ◽  
Nor Hazwani Ahmad ◽  
Doblin Sandai ◽  
Chee Keong Lee ◽  
...  

Background : Silver nanoparticles (AgNPs) are widely used in food industries, biomedical, dentistry, catalysis, diagnostic biological probes and sensors. The use of plant extract for AgNPs synthesis eliminates the process of maintaining cell culture and the process could be scaled up under a non-aseptic environment. The purpose of this study is to determine the classes of phytochemicals, to biosynthesize and characterize the AgNPs using Clinacanthus nutans leaf and stem extracts. In this study, AgNPs were synthesized from the aqueous extracts of C. nutans leaves and stems through a non-toxic, cost-effective and eco-friendly method. Results : The formation of AgNPs was confirmed by UV-Vis spectroscopy, and the size of AgNP-L (leaf) and AgNP-S (stem) were 114.7 and 129.9 nm, respectively. Transmission electron microscopy (TEM) analysis showed spherical nanoparticles with AgNP-L and AgNP-S ranging from 10 to 300 nm and 10 to 180 nm, with average of 101.18 and 75.38 nm, respectively. The zeta potentials of AgNP-L and AgNP-S were recorded at −42.8 and −43.9 mV. X-ray diffraction analysis matched the face-centred cubic structure of silver and was capped with bioactive compounds. Fourier transform infrared spectrophotometer analysis revealed the presence of few functional groups of phenolic and flavonoid compounds. These functional groups act as reducing agents in AgNPs synthesis. Conclusion : These results showed that the biogenically synthesized nanoparticles reduced silver ions to silver nanoparticles in aqueous condition and the AgNPs formed were stable and less toxic.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Preetha Devaraj ◽  
Prachi Kumari ◽  
Chirom Aarti ◽  
Arun Renganathan

Cannonball (Couroupita guianensis) is a tree belonging to the family Lecythidaceae. Various parts of the tree have been reported to contain oils, keto steroids, glycosides, couroupitine, indirubin, isatin, and phenolic substances. We report here the synthesis of silver nanoparticles (AgNPs) using cannonball leaves. Green synthesized nanoparticles have been characterized by UV-Vis spectroscopy, SEM, TEM, and FTIR. Cannonball leaf broth as a reducing agent converts silver ions to AgNPs in a rapid and ecofriendly manner. The UV-Vis spectra gave surface plasmon resonance peak at 434 nm. TEM image shows well-dispersed silver nanoparticles with an average particle size of 28.4 nm. FTIR showed the structure and respective bands of the synthesized nanoparticles and the stretch of bonds. Green synthesized silver nanoparticles by cannonball leaf extract show cytotoxicity to human breast cancer cell line (MCF-7). Overall, this environmentally friendly method of biological silver nanoparticles production provides rates of synthesis faster than or comparable to those of chemical methods and can potentially be used in various human contacting areas such as cosmetics, foods, and medical applications.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
P. Shivakumar Singh ◽  
G. M. Vidyasagar

The present work investigated the biosynthesis of silver nanoparticles using Annona reticulata leaf aqueous extract. The biosynthesised silver nanoparticles were confirmed by visual observation and UV-Vis spectroscopy. Appearance of dark brown colour indicated the synthesis of silver in the reaction mixture. The silver nanoparticles were found to be spherical, rod, and triangular in shape with variable size ranging from 23.84 to 50.54 nm, as evident by X-ray diffraction studies, TEM. The X-ray diffraction studies, energy dispersive X-ray analysis, and TEM analysis indicate that the particles are crystalline in nature. The nanoparticles appeared to be associated with some chemical compounds which possess hydroxyl and carbonyl groups, confirmed by FTIR. This is the first and novel report of silver nanoparticles synthesised from Annona reticulata leaves extract and their antidermatophytic activity.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Abhishek Kaler ◽  
Sanyog Jain ◽  
Uttam Chand Banerjee

Rapidly developing field of nanobiotechnology dealing with metallic nanoparticle (MNP) synthesis is primarily lacking control over size, shape, dispersity, yield, and reaction time. Present work describes an ecofriendly method for the synthesis of silver nanoparticles (AgNPs) by cell free extract (CFE) ofSaccharomyces boulardii. Parameters such as culture age (stationary phase growth), cell mass concentration (400 mg/mL), temperature (35°C), and reaction time (4 h), have been optimized to exercise a control over the yield of nanoparticles and their properties. Nanoparticle (NP) formation was confirmed by UV-Vis spectroscopy, elemental composition by EDX (energy dispersive X-rays) analysis, and size and shape by transmission electron microscopy. Synthesized nanoparticles had the size range of 3–10 nm with high negative zeta potential (−31 mV) indicating excellent stability. Role of proteins/peptides in NP formation and their stability were also elucidated. Finally, anticancer activity of silver nanoparticles as compared to silver ions was determined on breast cancer cell lines.


A simple eco friendly preparation of reduced graphene oxide from graphene oxide using strawberry extract is reported. As prepared reduced graphene oxide were characterized by X-Ray Diffraction, UV-Vis spectroscopy, Scaning electron microscopy and degradation performane of MB. The reduced graphene oxide was effectively degradation of MB.


2020 ◽  
Vol 12 (4) ◽  
pp. 1484 ◽  
Author(s):  
M. Asimuddin ◽  
Mohammed Rafi Shaik ◽  
Neeshat Fathima ◽  
M. Shaistha Afreen ◽  
Syed Farooq Adil ◽  
...  

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.


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