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CONTENTS
Volume 3, Number 2, June 2015
 

Abstract
Crystalline Ce3+ co-doped LaPO4:RE (RE=Dy3+, Tb3+, Eu3+, Sm3+) and mix doped rare earth ions of Dy3+, Tb3+ and Eu3+ were prepared by the polyol method at 150oC. Strongly enhance luminescence intensity is obtained with the co-doping of Ce3+ with LaPO4:Dy3+ and LaPO4:Tb3+ due to charge transfer (CT) occurring from Ce3+to Dy3+ and Ce3+ to Tb3+, where as there is no significant changes in luminescence intensity of Ce3+ co-doped Eu3+ and Sm3+ doped LaPO4 samples. The luminescence color can be tuned from green to white by varying the excitation wavelength for the mix ions Ce3+, Dy3+, Tb3+ and Eu3+ doped with LaPO4.

Key Words
white emission; nanoparticle; mix ions doping; luminescence

Address
G. Phaomei: Department of Chemistry, Berhampur University, Bhanja Bihar, Odisha-760007, India
N. Yaiphaba: Department of Chemistry, D.M. College of Science, Imphal, Manipur-795001, India

Abstract
Air stable nanoparticles were prepared from cobalt sulphate using tetra butyl ammonium bromide as surfactant and sodium borohydride as reductant at room temperature. The cobalt nanocolloids in aqueous medium were found to be efficient catalysts for the degradation of toxic organic dyes. Our present study involves degradation of Methylene Blue and Rhodamine-B using cobalt nanoparticles and easy recovery of the catalyst from the system. The recovered nanoparticles could be recycled several times without loss of catalytic activity. Palladium nanoparticles prepared from palladium chloride and the same surfactant were found to degrade the organic dyes effectively but lose their catalytic activity after recovery. The cause of dye colour discharge by nanocolloids has been assigned based on our experimental findings.

Key Words
nanoparticles; chemical synthesis; dye degradation; catalytic properties; transmission electron microscopy

Address
Arijit Mondal, Asish Mondal and Debkumar Mukherjee: Department of Chemistry, Ramsaday College, Amta, Howrah 711 401, India

Abstract
Octahedral shaped single crystalline undoped and Ga-doped indium oxide nano-and microcrystals were fabricated using vapor-solid growth process. Effects of Ga doping on the crystallinity, defect structure, and optical properties of the nano-/microstructures have been studied using scanning electron microscopy, microRaman spectroscopy, transmission electron microscopy and cathodoluminescence spectroscopy. It has been observed that incorporation of Ga does not affect the morphology of In2O3 structures due to its smaller ionic radius, and similar oxidation state as that of In. However, incorporation of Ga in high concentration (~3.31 atom %) causes lattice compression, reduces optical band gap and defect induced CL emissions of In2O3 nano-/microcrystals. The single crystalline Ga-doped, In2O3 nano-/microcrystals with low defect contents are promising for optoelectronic applications.

Key Words
indium oxide; vapor-solid growth; Ga-doping; optical properties

Address
Diego Leon Sanchez: Facultad de Ciencias de la Electrónica, Universidad Autónoma de Puebla, 18 Sur y Av. San Claudio, Edif. 109, Puebla, Pue. 72570, Mexico
Jesus Alberto Ramos Ramon: Instituto de Física, Universidad Autónoma de Puebla, Apdo. Postal J-48, Puebla, Pue. 72570, Mexico
Manuel Herrera Zaldivar: Centro de Nanociencia y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, B.C. 22800, Mexico
Umapada Pal: Centro Universitario de Vinculación y Transferencia de Tecnología (CUVyTT), Universidad Autónoma de Puebla, 24 Sur, C.U., Puebla 72570, Mexico
Efraín Rubio Rosas: Centro Universitario de Vinculación y Transferencia de Tecnología (CUVyTT), Universidad Autónoma de Puebla, 24 Sur, C.U., Puebla 72570, Mexico

Abstract
Citrate ion is a commonly used reductant in metal colloid synthesis, undergoes strong surface interaction with silver nanocrystallites. The slow crystal growth observed as a result of the interaction between the silver surface and the citrate ion makes this reduction process unique compared to other chemical and radiolytic synthetic methods. The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of citrate coated Ag nanoparticles (CAgNPs) are scant. Herein, we have isolated biofilm causative bacteria and fungi from drinking water PVC pipe lines. Stable CAgNPs were prepared and the formation of CAgNPs was confirmed by UV-visible spectroscopic analysis and recorded the localized surface plasmon resonance of CAgNPs at 430 nm. Fourier transform infrared spectroscopic analysis revealed C=O and O-H bending vibrations due to organic capping of silver responsible for the reduction and stabilization of the CAgNPs. X-ray diffraction micrograph indicated the face centered cubic structure of the formed CAgNPs, and morphological studies including size (average size 50 nm) were carried out using transmission electron microscopy. The hydrodynamic diameter (60.7 nm) and zeta potential (-27.6 mV) were measured using the dynamic light scattering technique. The antimicrobial activity of CAgNPs was evaluated (in vitro) against the isolated fungi, Gram-negative and Gram-positive bacteria using disc diffusion method and results revealed that CAgNPs with 170ppm concentration are having significant antimicrobial effects against an array of microbes tested.

Key Words
C-Ag nanoparticles; antimicrobial activity; bacterial sp; fungi sp

Address
Supraja Nookala and Thimmavajjula and David Ernest: Department of Biotechnology, Thiruvalluvar University, Vellore-632001, India
Naga Venkata Krishna Vara Prasad Tollamadugu and Giridhara Krishna Thimmavajjula: Nanotechnology laboratory, Institute of Frontier Technology, Regional Agricultural Research Station, Acharya N.G. Ranga Agricultural University, Tirupati – 517 502, A.P., India

Abstract
CoFe2O4 nanotubes and porous nanorods were prepared via a simple one-pot template-free hydrothermal method and were used as an adsorbent for the removal of dye contaminants from water. The properties of the synthesized nanotubes and porous nanorods were characterized by electron diffraction, transmission electron microscopy and x-ray powder diffraction. The Adsorption characteristics of the CoFe2O4 were examined using polar red dye and the factors affecting adsorption, such as, initial dye concentration, pH and contact time were evaluated. The overall trend followed an increase of the sorption capacity reaching a maximum of 95% dye removal at low pHs of 2-4. An enhancement in the removal efficiency was also noticed upon increasing the contact time between dye molecules and CoFe2O4 nanoparticles. The final results indicated that the CoFe2O4 nanotubes and porous nanorods can be considered as an efficient low cost and recyclable adsorbent for dye removal with efficiency 94% for Cobalt ferrite nanotubes and for Cobalt ferrite porous nanorods equals 95% .

Key Words
porous nanoparticles; nanorods; dye removal; waste water treatment

Address
E. Girgis, D. Adel, C. Tharwat, O. Attallah: Solid State Physics Department, National Research Centre, 12622 Dokki, Giza, Egypt
K.V. Rao: Department of Materials Science, Royal Institute of Technology, Stockholm SE-100 44, Sweden


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