Browsing by Author "Devadiga, A."

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Highly stable silver nanoparticles synthesized using Terminalia catappa leaves as antibacterial agent and colorimetric mercury sensor
(2017) Devadiga, A.; Vidya, Shetty, K.; Saidutta, M.B.
Silver nanoparticles (AgNPs) were synthesized using the aqueous extract of an agrowaste: Terminalia catappa leaves. The AgNPs were characterized using UV VIS spectroscopy, Transmission electron microscopy, Scanning electron microscopy, Fourier Transmission Infrared spectroscopy and Dynamic light scattering analysis. AgNPs were monodispersed, crystalline, quasi-spherical with average size of ?11 nm and were encapsulated with capping agents present in the extract. The AgNPs were stable with the zeta potential value of ?36.7 mV. These AgNPs exhibited significant antibacterial activity against water borne pathogens and could be used as colorimetric sensors for the detection of trace levels of mercury, indicating their multifaceted application in antibacterial coating, water treatment and as colorimetric mercury sensors. The overall synthesis process emphasizes on the agrowaste utilization for the green synthesis of AgNPs. 2017 Elsevier B.V.
Highly stable silver nanoparticles synthesized using Terminalia catappa leaves as antibacterial agent and colorimetric mercury sensor
(Elsevier B.V., 2017) Devadiga, A.; Shetty K, K.V.; Saidutta, M.B.
Silver nanoparticles (AgNPs) were synthesized using the aqueous extract of an agrowaste: Terminalia catappa leaves. The AgNPs were characterized using UV–VIS spectroscopy, Transmission electron microscopy, Scanning electron microscopy, Fourier Transmission Infrared spectroscopy and Dynamic light scattering analysis. AgNPs were monodispersed, crystalline, quasi-spherical with average size of ?11 nm and were encapsulated with capping agents present in the extract. The AgNPs were stable with the zeta potential value of ?36.7 mV. These AgNPs exhibited significant antibacterial activity against water borne pathogens and could be used as colorimetric sensors for the detection of trace levels of mercury, indicating their multifaceted application in antibacterial coating, water treatment and as colorimetric mercury sensors. The overall synthesis process emphasizes on the agrowaste utilization for the “green” synthesis of AgNPs. © 2017 Elsevier B.V.
Solar photocatalytically active, engineered silver nanoparticle synthesis using aqueous extract of mesocarp of Cocos nucifera (Red Spicata Dwarf)
(2017) Sumi, M.B.; Devadiga, A.; Shetty, K.V.; Saidutta, M.B.
Silver nanoparticles synthesised using aqueous extract of Cocos nucifera (CN) mesocarp were evaluated for their photocatalytic activity under solar irradiation. The silver nanoparticles were synthesised by a green method of harnessing bioactive phytocomponents from the mesocarp of Cocos nucifera. Large-scale application of this process necessitates the manoeuvering of the process parameters for increasing the conversion of silver ions to nanoparticles. Process parameters influencing the morphological characteristics of silver nanoparticles such as precursor salt concentration and pH of the synthesis mixture were studied. The crystalline nanoparticles were characterised using UV-vis spectroscopy, XRD, FTIR, SEM and EDX analysis. CN extract and 5 mM silver nitrate solution at a ratio of 1:4 (v/v) in the synthesis mixture was found to be the optimum. Alkaline initial pH of the synthesis mixture was found to favour the synthesis of smaller sized monodispersed silver nanoparticles. Solar energy was harnessed for the photocatalytic degradation of Malachite green dye using silver nanoparticles obtained through the green synthesis method. Overall process aims at utilisation of naturally available resource for the synthesis of silver nanoparticles as well as the degradation of dyes using these nanoparticles, making it useful in the treatment of wastewater. 2016 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Solar photocatalytically active, engineered silver nanoparticle synthesis using aqueous extract of mesocarp of Cocos nucifera (Red Spicata Dwarf)
(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2017) Sumi, M.B.; Devadiga, A.; Shetty K, V.K.; Saidutta, M.B.
Silver nanoparticles synthesised using aqueous extract of Cocos nucifera (CN) mesocarp were evaluated for their photocatalytic activity under solar irradiation. The silver nanoparticles were synthesised by a green method of harnessing bioactive phytocomponents from the mesocarp of Cocos nucifera. Large-scale application of this process necessitates the manoeuvering of the process parameters for increasing the conversion of silver ions to nanoparticles. Process parameters influencing the morphological characteristics of silver nanoparticles such as precursor salt concentration and pH of the synthesis mixture were studied. The crystalline nanoparticles were characterised using UV-vis spectroscopy, XRD, FTIR, SEM and EDX analysis. CN extract and 5 mM silver nitrate solution at a ratio of 1:4 (v/v) in the synthesis mixture was found to be the optimum. Alkaline initial pH of the synthesis mixture was found to favour the synthesis of smaller sized monodispersed silver nanoparticles. Solar energy was harnessed for the photocatalytic degradation of Malachite green dye using silver nanoparticles obtained through the green synthesis method. Overall process aims at utilisation of naturally available resource for the synthesis of silver nanoparticles as well as the degradation of dyes using these nanoparticles, making it useful in the treatment of wastewater. © 2016 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Synthesis of silver nanoparticles using medicinal Zizyphus xylopyrus bark extract
(2015) Sumi, Maria, B.; Devadiga, A.; Shetty, Kodialbail, V.; Saidutta, M.B.
In the present paper, biosynthesis of silver nanoparticles using Zizyphus xylopyrus bark extract is reported. Z. xylopyrus bark extract is efficiently used for the biosynthesis of silver nanoparticles. UV Visible spectroscopy showed surface plasmon resonance peaks in the range 413 420 nm confirming the formation of silver nanoparticles. Different factors affecting the synthesis of silver nanoparticles like methodology for the preparation of extract, concentration of silver nitrate solution used for biosynthesis and initial pH of the reaction mixture were studied. The extract prepared with 10 mM AgNO3 solution by reflux extraction method at optimum initial pH of 11, resulted in higher conversion of silver ions to silver nanoparticles as compared with those prepared by open heating or ultrasonication. SEM analysis showed that the biosynthesized nanoparticles are spherical in nature and ranged from 60 to 70 nm in size. EDX suggested that the silver nanoparticles must be capped by the organic components present in the plant extract. This simple process for the biosynthesis of silver nanoparticles using aqueous extract of Z. xylopyrus is a green technology without the usage of hazardous and toxic solvents and chemicals and hence is environment friendly. The process has several advantages with reference to cost, compatibility for its application in medical and drug delivery, as well as for large-scale commercial production. 2014, The Author(s).
Synthesis of silver nanoparticles using medicinal Zizyphus xylopyrus bark extract
(Springer Nature, 2015) Babu, B.; Devadiga, A.; Shetty K, V.K.; Saidutta, M.B.
In the present paper, biosynthesis of silver nanoparticles using Zizyphus xylopyrus bark extract is reported. Z. xylopyrus bark extract is efficiently used for the biosynthesis of silver nanoparticles. UV–Visible spectroscopy showed surface plasmon resonance peaks in the range 413–420 nm confirming the formation of silver nanoparticles. Different factors affecting the synthesis of silver nanoparticles like methodology for the preparation of extract, concentration of silver nitrate solution used for biosynthesis and initial pH of the reaction mixture were studied. The extract prepared with 10 mM AgNO3 solution by reflux extraction method at optimum initial pH of 11, resulted in higher conversion of silver ions to silver nanoparticles as compared with those prepared by open heating or ultrasonication. SEM analysis showed that the biosynthesized nanoparticles are spherical in nature and ranged from 60 to 70 nm in size. EDX suggested that the silver nanoparticles must be capped by the organic components present in the plant extract. This simple process for the biosynthesis of silver nanoparticles using aqueous extract of Z. xylopyrus is a green technology without the usage of hazardous and toxic solvents and chemicals and hence is environment friendly. The process has several advantages with reference to cost, compatibility for its application in medical and drug delivery, as well as for large-scale commercial production. © 2014, The Author(s).