Browsing by Author "Ramalakshmi V"

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CARICA PAPAYA PEEL MEDIATED SYNTHESIS OF SILVER NANOPARTICLES AND ITS ANTIBACTERIAL ACTIVITY AGAINST HUMAN PATHOGENS
(Elsevier, 2017-10-01) Balavijayalakshmi J; Ramalakshmi V
Metallic nanoparticles are traditionally synthesized by wet chemical techniques, in which the chemicals used are quite often toxic and flammable. Ripe carica papaya peel is found to be a suitable source for green synthesis of silver nanoparticles. In the present work, a cost effective and environmental friendly technique for the green synthesis of silver nanoparticles from 1 mM silver nitrate (AgNO3) solution through the extract of ripe Carica papaya peel of various concentrations (5 ml, 10 ml, 15 ml, 20 ml, 25 ml) is described. The synthesized silver nanoparticles are characterized by using the UV–vis absorption spectroscopy, FT-IR, XRD, SEM and TEM. The formation of silver nanoparticles is confirmed by surface plasmon resonance, determined by UV–vis spectra at 400–435 nm. The shift in the absorption bands and variation in the calculated optical band gaps for the various concentrations of papaya peels extracts are also observed. The FT-IR spectra reveal that an increase in the concentration of the papaya peel extract shifts the bands to higher wavelengths. The average crystallite size for various concentrations of papaya peel extract is observed from XRD spectral analysis and is found to be around 16–20 nm, which is in good agreement with the TEM analysis. The SEM analysis shows the spherical structure of the silver nanoparticles with some agglomeration for higher concentrations of papaya peel extract. The synthesized silver nanoparticles show good antibacterial activity against human pathogens such as Escherichia coli and Staphylococcus aureus and it has many medical applications
CARICA PAPAYA PEEL MEDIATED SYNTHESIS OF SILVER NANOPARTICLES AND ITS ANTIBACTERIAL ACTIVITY AGAINST HUMAN PATHOGENS
(Elsevier /Journal of Applied Research and Technology, 2017-10-01) Balavijayalakshmi J; Ramalakshmi V
Metallic nanoparticles are traditionally synthesized by wet chemical techniques, in which the chemicals used are quite often toxic and flammable. Ripe carica papaya peel is found to be a suitable source for green synthesis of silver nanoparticles. In the present work, a cost effective and environmental friendly technique for the green synthesis of silver nanoparticles from 1 mM silver nitrate (AgNO3) solution through the extract of ripe Carica papaya peel of various concentrations (5 ml, 10 ml, 15 ml, 20 ml, 25 ml) is described. The synthesized silver nanoparticles are characterized by using the UV–vis absorption spectroscopy, FT-IR, XRD, SEM and TEM. The formation of silver nanoparticles is confirmed by surface plasmon resonance, determined by UV–vis spectra at 400–435 nm. The shift in the absorption bands and variation in the calculated optical band gaps for the various concentrations of papaya peels extracts are also observed. The FT-IR spectra reveal that an increase in the concentration of the papaya peel extract shifts the bands to higher wavelengths. The average crystallite size for various concentrations of papaya peel extract is observed from XRD spectral analysis and is found to be around 16–20 nm, which is in good agreement with the TEM analysis. The SEM analysis shows the spherical structure of the silver nanoparticles with some agglomeration for higher concentrations of papaya peel extract. The synthesized silver nanoparticles show good antibacterial activity against human pathogens such as Escherichia coli and Staphylococcus aureus and it has many medical applications.
CHEMICAL FUNCTIONALIZATION OF OLIGOSACCHARIDE MOLECULES AS AN DETECTION AGENT FOR THE SENSITIVE DETECTION OF NITROPHENOL ISOMER USING COPPER OXIDE NANOPARTICLES DECORATED REDUCED GRAPHENE OXIDE NANOSHEET
(Department of Mechanical Engineering, NIT, Trichy., 2019-09-09) Ramalakshmi V; Balavijayalakshmi J
The present work describes the synthesis of beta-cyclodextrin (β-CD) functionalized copper oxide nanoparticles (CuONPs) encapsulated reduced graphene oxide (rGO) nanosheets (rGONS/β-CD/CuO) for the electrochemical detection of nitrophenol isomer such as ortho-nitrophenol. The chemical functionalization of stabilizing agent with the synthesized rGONS/CuO nanocomposites and the polymer stabilized rGONS/CD/CuO nanocomposites are investigated using FT-IR, XRD, SEM and TEM analysis. The morphological analysis confirms that oligosaccharide molecules are functionalized on the rGONS surface and also the encapsulated spherical shaped CuONPs on the rGONS/β-CD surface. The electrochemical study shows that the rGONS/β-CD/CuO/GCE exhibits a good electrochemical behaviour for the reduction of nitrophenol isomer. It shows good linear range of detection for ortho-nitrophenol with a sensitivity of 2.3 mAμM-1cm-2. The enhancement in the electrochemical behaviour of rGONS may be due to the host guest recognition and catalytic properties of β-CD and CuONPs respectively.
DECORATION AND FUNCTIONALIZATION OF GRAPHENE OXIDE NANOCOMPOSITES FOR SENSING APPLICATIONS
(Royal Book publishers / PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) Ramalakshmi V; Balavijayalakshmi J
In the present work, β-cyclodextrin functionalized reduced graphene oxide-silver nanocomposites (GO-β-CD-Ag) are effectively synthesized using wet chemical method. The GO-β-CD nanocomposites are initially produced via hydrazine reduction. The various concentrations (0.002 M, 0.004 M, 0.006 M, 0.008 M and 0.01 M) of silver nanoparticles are decorated on the GO-β-CD surface by the reduction of silver nitrate with sodium borohydrate as a reducing agent. The produced GO-β-CD-Ag nanocomposites are well characterized using XRD, SEM and EDAX analysis. The XRD results firmly established that the β-CD molecules are satisfactorily coated on the rGO surface and also the Ag nanoparticles with an average size of 23 nm are evenly decorated on the GO-β-CD surface. The GO-β-CD-Ag nanocomposites modified glassy carbon electrode is captivated for the selective detection of o-Nitrophenol. Cyclic voltammetry test is employed to determine the presence of o-Nitrophenol compound. The result shows the oxidation and reduction potential for o-Nitrophenol at -0.25 V and -0.5 V respectively, indicating the successful determination of o-Nitrophenol by using the GO-CD-Ag nanocomposite modified electrode.
DECORATION AND FUNCTIONALIZATION OF GRAPHENE OXIDE NANOCOMPOSITES FOR SENSING APPLICATIONS
(Materials today: Proceedings, 2019) Ramalakshmi V; Balavijayalakshmi J
In the present work, β-cyclodextrin functionalized reduced graphene oxide-silver nanocomposites (GO-β-CD-Ag) are effectively synthesized using wet chemical method. The GO-β-CD nanocomposites are initially produced via hydrazine reduction. The various concentrations (0.002 M, 0.004 M, 0.006 M, 0.008 M and 0.01 M) of silver nanoparticles are decorated on the GO-β-CD surface by the reduction of silver nitrate with sodium borohydrate as a reducing agent. The produced GO-β-CD-Ag nanocomposites are well characterized using XRD, SEM and EDAX analysis. The XRD results firmly established that the β-CD molecules are satisfactorily coated on the rGO surface and also the Ag nanoparticles with an average size of 23 nm are evenly decorated on the GO-β-CD surface. The GO-β-CD-Ag nanocomposites modified glassy carbon electrode is captivated for the selective detection of o-Nitrophenol. Cyclic voltammetry test is employed to determine the presence of o-Nitrophenol compound.The result shows the oxidation and reduction potential for o-Nitrophenol at -0.25 V and -0.5 V respectively, indicating the successful determination of o-Nitrophenol by using the GO-CD-Ag nanocomposite modified electrode.
A FACILE APPROACH TO SYNTHESIZE GRAPHENE OXIDE AND REDUCED GRAPHENE OXIDE NANOMATERIALS
(BIT, Sathyamangalam, 2017-08-17) Ramalakshmi V; Yuvashree S; Balavijayalakshmi J
Technology research in nanotechnology promises breakthroughs in areas such as materials and manufacturing nanoelectronics, medicine, healthcare, energy, biotechnology, information technology, and national security. One of the crucial bottlenecks for the application of graphene-based systems in materials science is their mass production. Meeting the requirements, graphene oxide (GO) has been considered widely as a prominent precursor and a starting material for the synthesis of this processable material [1]. This work describes the synthesis and characteristic analysis of Graphene oxide (GO) and reduced graphene oxide. Graphene Oxide (GO) is synthesized in large quantity from Natural Flake Graphite (NFG) by modified Hummer’s method. The synthesized GO is chemically reduced to Reduced Graphene Oxide (RGO) using hydrazine monohydrate as reducing agent via wet chemical method. The synthesized samples are characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction analysis (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDS). The characterized samples have been tested for the removal of dye from water in water purification process.
A FACILE SYNTHESIS AND INVESTIGATION ON METAL OXIDE NANOPARTICLES EMBELLISHED GRAPHENE OXIDE NANOCOMPOSITES
(Royal Book publishers / PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) Ramalakshmi V; Balavijayalakshmi J; Roshini P
Graphene is a flat monolayer of carbon atoms with sp2-hybridized two-dimensional carbon structure. Graphene’s fascinating high conductivity, superior electron mobility, extremely high specific surface area and easy functionalization make graphene a good substrate to yield graphene-based nanocomposites. Metal oxides nanomaterials have considerable attention due to their unique properties that can be used for designing advanced nanodevices. Thus, in the present study metal oxide nanoparticles embellished graphene oxide nanosheets (GNs) is synthesized and characterized. The graphene oxide nanosheets are produced by modified Hummer’s method. The metal oxide nanoparticles are loaded on the synthesized graphene oxide nanosheets via chemical reduction method. The metal oxide nanoparticles embellished graphene oxide nanosheets are characterized using Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction analysis and Field emission scanning electron microscopy (FE-SEM). The structural properties of the synthesized nanocomposites are characterized using X-Ray diffraction analysis and the result confirms that the synthesized nanocomposites are well crystalline. The morphology of synthesized nanocomposites is analyzed using field emission scanning electron microscopy analysis.
IMPACT OF ENCAPSULATED METAL NANOPARTICLES ON POLYMER FUNCTIONALIZED GRAPHENE NANOCOMPOSITES FOR ITS SENSING APPLICATIONS
(Centre for NanoScience and Technology, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Hyderabad, 2018-10-04) Balavijayalakshmi J; Ramalakshmi V
The present work describes the synthesis of beta cyclodextrin functionalized silver nanoparticles encapsulated graphene oxide nanocomposite for the sensitive electrochemical detection of nitrophenol (NP) isomers. The functionalization and encapsulation of graphene oxide surface using beta cyclodextrin and silver nanoparticles are done by using chemical reduction of graphene oxide, beta cyclodextrin and silver nitrate chemical reagents. The physico-chemical properties of synthesized GO-CD-Ag nanocomposites are investigated using XRD, SEM, TEM and RAMAN analytical techniques [1]. The SEM and TEM morphological analysis confirms that the beta cyclodextrin molecules are effectively covered on the surface of graphene oxide nanosheets and also the silver nanoparticles are uniformly encapsulated on the surface of beta cyclodextrin functionalized graphene oxide nanosheets. The synthesized GO-CD-Ag nanocomposite modified GCE is employed for the sensitive detection of nitrophenol isomer such as para-nitrophenol (p-NP) and meta-nitrophenol (m-NP). The cyclic voltammetry studies show that the GO-CD-Ag nanocomposite modified GCE exhibits a good electrochemical behaviour for the reduction of p-NP and m-NP isomers in PBS solution [2]. The enhancement in the electrochemical behaviour of graphene oxide may be due to the host guest recognition properties of beta cyclodextrin and electronic properties of silver nanoparticles. The synthesized GO-CD-Ag nanocomposite modified electrochemical sensor exhibits the linear detection limits of 25 mm and 15 mm for p-NP and m-NP, respectively.
INFLUENCE OF GOLD NANOPARTICLE CONCENTRATION ON POLYMER FUNCTIONALIZED REDUCED GRAPHENE NANOSHEETS AND ITS ELECTROCHEMICAL SENSING PERFORMANCE
(IOP Publishing / Material research express, 2019-04-05) Ramalakshmi V; Balavijayalakshmi J
The different concentrations (0.002 M, 0.004 M, 0.006 M, 0.008Mand 0.01M) of gold nanoparticles encapsulated β-cyclodextrin functionalized reduced graphene oxide nanocomposites (rGONS/β-CD/Au) synthesized via wet chemical method is reported. The synthesized rGONS/β-CD/Au nanocomposites are investigated using FTIR, XRD, SEM, EDS andTEManalysis. The FTIR spectra reveal that the blue shift in the bands may be due to the intermolecular interaction between reduced graphene oxide and cyclodextrin. FromXRDanalysis the average crystallite size is found to be around 10 nm, which is in good agreement withTEManalysis. The SEM analysis shows the spherical structure of the gold nanoparticles. The glassy carbon electrode (GCE) modified with the synthesized rGONS/β-CD/Au nanocomposites of 0.006Mconcentration is employed for the sensitive detection of different nitrophenols such as ortho-nitrophenol (o-NP), para-nitrophenol (p-NP) and metanitrophenol (m-NP) by using electrochemical techniques and the result displays a wide detection range for all the nitrophenol isomers.
INVESTIGATION ON EMBELLISHMENT OF METAL NANOPARTICLES ON GRAPHENE NANOSHEETS AND ITS SENSING APPLICATIONS
(Centre for Crystal Growth, VIT University, Vellore, 2017-10-09) Ramalakshmi V; Balavijayalakshmi J
Nanotechnology promises breakthroughs in areas such as manufacturing nanoelectronics, medicine and healthcare, energy, biotechnology, information technology, and national security. The present work describes a general approach for the preparation of cyclodextrin functionalized (CD) graphene oxide nanosheets (GNs) for the embellishment of different concentrations of silver nanoparticles (Ag) on the surface of GNs. The graphene oxide nanosheets are synthesized by modified Hummer’s method. Firstly, CD/RGO nanosheets are synthesized through hydrazine reduction. The different concentrations of Ag nanoparticles are loaded on the CD/RGO nanosheets by the reduction of AgNO3 with NaBH4 as reducing agent. The synthesized CD/RGO/Ag nanocomposites are well characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectroscopy and EDAX analysis. The results confirmed that the CD is effectively covered on the RGO surface and the Ag nanoparticles are uniformly decorated on the CD/RGO nanosheets [1]. The modified glassy carbon electrode was employed for the selective determination of phenolic compounds. Cyclic voltammetry measurements suggested that the CD/RGO/Ag nanocomposites exhibits an excellent electrochemical activity towards oxidation of phenolic compounds due to the host-guest recognition and enrichment capability of β-CD as well as the outstanding electronic properties of RGO and Ag nanoparticles [2].
INVESTIGATION ON EMBELLISHMENT OF METAL NANOPARTICLES ON GRAPHENE NANOSHEETS AND ITS SENSING APPLICATIONS
(‎Magnolithe GmbH / Mechanics, Material Science and Engineering, 2018) Ramalakshmi V; Balavijayalakshmi J
In the present work, β-cyclodextrin functionalized reduced graphene oxide-silver nanocomposites (GO-β-CD-Ag) are successfully synthesized using wet chemical technique. The GO-β-CD nanocomposites are firstly synthesized via hydrazine reduction. The different concentrations (0.002 M, 0.004 M, 0.006 M, 0.008 M and 0.01 M) of silver nanoparticles are embellished on the GO-β-CD surface by the chemical reduction of silver nitrate with sodium borohydrate as a reducing agent. The synthesized GO-β-CD-Ag nanocomposites are characterized using XRD, SEM and EDAX techniques. The XRD results confirmed that the β-CD molecules are effectively coated on the rGO surface and also the Ag nanoparticles with an average size of 23 nm are uniformly decorated on the GO-β-CD surface. The GO-β-CD-Ag nanocomposites modified glassy carbon electrode is employed for the selective determination of o-Nitrophenol. Cyclic voltammetry test is performed to determine the presence o-Nitrophenol compound. The result shows the oxidation and reduction potential for o-Nitrophenol at -0.25 V and -0.45 V respectively, suggests the successful determination of o-Nitrophenol by using the GO-CD-Ag nanocomposite modified electrode.
INVESTIGATION ON STRUCTURAL AND MORPHOLOGICAL ANALYSIS OF ZINC OXIDE ENSEMBLED GRAPHENE OXIDE ELECTRODE MATERIAL
(Institute of Applied Science & Computations / Journal of Applied Science and Computations, 2018) Ramalakshmi V; Balavijayalakshmi J
Graphene has received considerable attention of all researchers employing globally in the area of materials science and technology. In this present work, Zinc oxide nanoparticles (GO-ZnO) anchored graphene oxide nancomposite is synthesized using chemical reduction method. The synthesized GO-ZnO nanocmopsites are subjected to FT-IR, XRD, SEM and EDAX techniques, in order to examine the functional, structural, morphological and elemental analysis. The X-ray diffraction analysis confirms the anchoring of well crystalline zinc oxide nanoparticles with the crystallite size of about 19 nm on the surface of graphene oxide. SEM analysis reveals the formation of spherical shape zinc oxide nanoparticles on the layered structured surface of graphene oxide. The enhanced electrochemical sensing property of the GO-ZnO nanocomposites is studied using cyclic voltammetry analysis. A glassy carbon electrode (GCE) modified with GO-ZnO nanocomposites (GO-ZnO/GCE) is fabricated for the rapid detection of onitrophenol. Under the optimal conditions, the GO-ZnO/GCE modified electrode shows the reduction potential at -0.6 V for the concentration of 220 μM of o-Nitrophenol in PBS buffer solution.
POLYMER FUNCTIONALIZED REDUCED GRAPHENE OXIDE BASED NICKEL NANOPARTICLES AS HIGHLY EFFICIENT DYE CATALYST FOR WATER REMEDIATION
(International and Interuniversity Centre for Nanoscience and Nanotechnology (IIUCNN), Mahatma Gandhi University, Kottayam, Kerala, 2018-05-11) Ramalakshmi V; Balavijayalakshmi J
The present work describes the synthesis and characterization of reduced graphene oxide based nickel nanoparticles containing beta cyclodextrin composite and its application for removal of textile dye from aqueous medium. For this purpose graphene oxide is produced by modified Hummer’s method, then after, GO-CD and GO-CD-Ni nanocomposites are synthesized via wet chemical method. The synthesized adsorbents (GO, GO-CD and GO-CD-Ni) are characterized using different characterization techniques such as FT-IR, XRD, FE-SEM. Also, the various parameters affecting dye removal like pH, contact time, amount of adsorbents and initial dye concentrations are investigated. The synthesized adsorbents exhibits excellent adsorption performance for the removal of textile dyes. The adsorption process is pH dependent and the adsorption capacity is increased with the increase in contact time and with that of adsorbent dosage.
SILVER NANOCOMPOSITES DECORATED REDUCED GRAPHENE OXIDE NANOSHEETS FOR ELECTROCHEMICAL SENSOR APPLICATIONS
(Oriental Scientific Publishing Company / Oriental journal of Chemistry, 2018-12-25) Ramalakshmi V; Balavijayalakshmi J
Recently, metal nanoparticles incorporated carbon nanostructures have tremendous applications in the field of nanosensor and technologies. In the proposed work, silver nanoparticles (Ag) decorated reduced graphene oxide nanosheets (rGONS) (rGONS-Ag) are synthesized and developed for the sensitive detection of ortho-Nitrophenol (o-NP) using electrochemical techniques. The rGONS-Ag nanocomposites are synthesized through chemical reduction method. The physical and electrochemical behaviour of the synthesized rGONS-Ag nanocomposites are characterized by using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray spectroscopy (EDAX), Transmission electron microscopy (TEM) and Cyclic voltammetry (CV) techniques. The X-ray diffraction analysis reveals the formation of well crystalline silver nanoparticles (AgNp’s) on the surface of rGO nanosheets with the crystallite size of about 22.775 nm. The morphological analysis reveals the formation of well distributed cubic shape AgNp’s on the surface of rGO nanosheets. The rGONS-Ag nanocomposites modified glassy carbon electrode (GCE) shows the good electrochemical detection performance for ortho-Nitrophenol (o-NP) with the linear detection range from 2 mM to 8 mM and with the sensitivity of about 0.221 mA mM-1 cm-2.
STRUCTURAL AND MORPHOLOGICAL INVESTIGATION ON THE GRAPHENE OXIDE NANOSHEETS FUNCTIONALIZED TRIMETALLIC NANOPARTICLES
(Vizhi Chudar Pathippagam / Anna University, Chennai, 2017-01-06) Ramalakshmi V; Balavijayalakshmi J
In recent years, the trimetallic nanoparticles (NPs) are of having great interest because of their novel properties and applications. Trimetallic nanoparticles have improved physicochemical properties compared to their monometallic nanoparticles. Among the other metallic NPs, trimetallic NPs possess scientific and industrial importance because of their unique properties namely, magnetic, optical, electronic, and catalytic for practical applications [1]. In the present paper, the attempt has been made to synthesize trimetallic Au-Ag/Ni nanocomposites on β-cyclodextrin functionalized reduced nano graphene sheets (β-CD-NGS) as the platform. Graphene, a two-dimensional structure consists of sp2 hybridized carbon closely packed honeycomb lattices. It is considered as a basic building block for graphitic materials with all other dimensionalities [2]. It has considerable heed on both the experimental and theoretical fields because of its unique nanostructure and a variety of attracting thermal, mechanical, electrical properties. Based on these remarkable properties of graphene, these graphene nanosheets can be used as an ideal building block for nanocomposites and are broadly applied in many technological fields such as nanophotonics, sensors, catalysis, and supercapacitors [3]. But during the reduction process of graphene oxide (GO) to nano graphene sheets (NGS), NGS tends to agglomerates via Vander Waals interactions, due to the loss of oxygen containing functional groups in GO, and it is difficult for many potential applications. To overcome this problem, the β-Cyclodextrin (β-CD) is introduced into the graphene oxide before the reduction process is fully completed. The introduced β -CD onto the surface of NGS prevents the agglomeration of the NGS and improves the solubility of the β-CD-NGs in water [3]. This new composite have individual properties of two materials, such as large surface area and high conductivity of GO and supramolecular recognition and enrichment capability of β-CD. It is a macrocyclic allied oligosaccharides composed of seven glucose units. It is toroidal in shape with a hydrophobic inner cavity and a hydrophilic exterior which provides water solubility. The characteristic of β-CD facilitates them to selectively bind various organic, inorganic, and biological guest molecules into their cavities to form stable host guest inclusion complexes and also exhibits high molecular selectivity and enantioselectivity. Therefore, β-CD functionalized NGS are used as a platform for the preparation of nanocomposites [4]. In recent years metal nanoparticles (Au, Ag) have been used for many potential applications, because of their high surface to volume ratio and good catalytic activity compared to their respective bulk metals. The noble metals (Au, Pd, Pt etc.) doped with non-noble metals (Fe, Co, Ni etc.) is an admirable approach to intensify the catalytic activity and the sensitivity of nanomaterials [5]. The synthesized nanocomposites are characterized using UV-Vis, FT-IR, XRD, EDX and SEM analysis. Synthesized Pure NGS, β-CD, β-CD-NGS and β-CD-NGS-(Au-Ag/Ni) nanocomposites are characterized using UV-Vis spectroscopy. According to the UV-Vis spectral analysis, the absorption band for pure NGS are obtained around 240 nm and 300 nm for π-π* transition of the atomic C-C bonds and n-π* transitions of aromatic C-C bonds respectively and for β –CD the major peak observed around 260 nm. In the β-CD-NGS spectra, an absorption peak at 260 nm is observed, indicating the successful synthesis of β-CD-NGS. The UV-Vis spectra of β-CD-NGS-(Au-Ag/Ni) nanocomposite confirm the presence of all formed composites [3]. FT-IR spectra of pure NGS, β-CD, β-CD-NGS and β-CD-NGS-(Au-Ag/Ni) nanocomposites are recorded. From the results, the transmission bands of pure NGS obtained around 1100 cm-1, 1600 cm-1 and 3400 cm-1 may correspond to the bending vibrations of coupled C–C/C–O, O–H and O–H stretching vibration respectively. The FT-IR spectra of β-CD-NGS exhibits spectra for β-CD around 940 cm-1, 700 cm-1 and 570 cm-1 may due to the skeletal vibration and pyranose ring vibrations respectively, which is in good agreement with the pure β-CD spectrum. The main absorption peaks of pure NGS are also observed and it confirms the presence of β-CD molecules on the surface of GNS. The FT-IR spectra of β-CD-NGS-(Au-Ag/Ni) nanocomposites also confirm the presence of all the functional groups of synthesized nanocomposites [6]. The crystalline nature of the synthesized nanocomposites is studied using XRD analysis. By observing the sharp crystalline XRD peaks, the formation of pure nanoparticles without any impurities are confirmed .The microstructure of the Pure NGS, β-CD, β-CD-NGS and β-CD-NGS-(Au-Ag/Ni) nanocomposites are investigated by SEM analysis. In the SEM image of β-CD-NGS-(Au-Ag/Ni) nanocomposites, the bright spots are observed, which confirms the formation of trimetallic nanoparticles on CD-NGS [4]. The EDX spectrum of the prepared β-CD-NGS-(Au-Ag/Ni) nanocomposites confirms the presence of the β-CD, NGS, Au, Ag, Ni element in the prepared nanocomposites [7]. The as-synthesized nanocomposites may have many potential applications in removal of dye pollutants and waste water treatment technologies etc.
SYNTHESIS OF SILVER NANOPARTICLES USING NATURAL REDUCING AGENTS
(Sastra University, Thanjavur, 2015-01-29) Balavijayalakshmi J; Ramalakshmi V
Green synthesis of nanoparticle is a novel way to synthesize nanoparticles by using biological sources. It is gaining attention due to its cost effective, eco friendly and large scale production possibilities. Silver nanoparticles are usually synthesized by chemicals which are quite toxic and flammable in nature. This study deals with an environmental friendly and biosynthesis process of antibacterial silver nanoparticles from 2mM aqueous AgNO3 using extract of carica papaya peel, well adorned for its wide availability and medical property. It is observed that the use of ripe carica papaya peel extract makes a fast and convenient method for the synthesis of silver nanoparticles and can reduce silver ions into silver nanoparticles without using any severe conditions. The formation and characterisation of silver nanoparticles (AgNPs) are confirmed by UV-Vis spectroscopy, Scanning electron microscopy (SEM), X-Ray diffraction (XRD), Fourier Transmission infrared spectroscopy (FTIR). Fourier transform infrared spectroscopy analysis revealed that bio molecules are involved in the synthesis and capping of silver nanoparticles. The XRD analysis confirmed that the silver nanoparticles (AgNPs) are crystalline in nature. The morphology of the AgNPs is studied using SEM analysis. The silver nanoparticles synthesized via green route are highly toxic to multidrug resistant human pathogens hence it has a great potential in biomedical application.