International Journal of Nanoparticles (8 papers in press)
Biosynthesis of Silver Nanoparticles Using Unriped Carica Papaya Fruit Extract with Different PH Conditions
by Hooi Chien Ng, Cheng Seong Khe, Azizan Aziz, Zulkifli Merican Aljunid Merican, Rajalingam Sokkalingam, Thiam Leng Chew, Chin Wei Lai
Abstract: Silver nanoparticles were successfully synthesized at room temperature from silver nitrate using unripe Carica papaya fruit extract as a reducing and capping agent. pH of the reaction solution was adjusted with the addition of sodium hydroxide from pH 5.6 (original pH of the broth) to pH 6.5, pH 7.5 and pH 8.5. Quasi spherical silver nanoparticles were obtained across the studied pH range. The average particle size obtained decreased from 34 nm to 15 nm as the pH of the solution increased from 5.6 to 8.5. From the observations and ultra violetvisible spectrophotometer analysis, the rate of reduction and formation of silver nanoparticles increased as the pH increased. The crystalline nature of the as-synthesized silver nanoparticles in a cubic structure was confirmed by the peaks in X-ray diffraction and selected area electron diffraction. From Fourier transform infrared spectra, it was found that proteins in unripe papaya fruit extract were strongly bounded to the surface of silver nanoparticles as a capping agent. The thin layer of protein coating also further confirmed under high resolution transmission electron microscope. A plausible formation mechanism has been briefly proposed.
Keywords: Biosynthesis; silver nanoparticles; Carica papaya fruit extract; pH; twinning.
Microalgae harvesting of nannochloropsis sp.using polyethersulfone/ lithium chloride/ functionalized multiwall carbon nanotube membranes fabricated via temperature induced phase inversion and non-solvent induced phase inversion
by Nur Farahah Mohd Khairuddin, Ani Idris, Muhammad Irfan, Teo Chee Loong
Abstract: Microalgae are a promising renewable source especially for producing biofuels and other high value products. Biofuel and biomass production involves several steps from cultivation, harvesting and extraction. Recent technology has used ultrafiltration membrane for microalgae harvesting but are faced with adverse effect of microalgae fouling. In the present study, nannochloropsis sp. harvesting was performed using an ultrafiltration hybrid membrane made of polyethersulfone (PES) blended with the two additives namely lithium chloride (LiCl) and functionalized multiwall carbon nanotube (F-MWCNT). The membranes were prepared via two methods; non-solvent induced phase separation (NIPS) and temperature induced phase separation (TIPS). The membrane performances were evaluated in terms of membrane flux and fouling for the use of microalgae harvesting. The FESEM analysis showed that the morphology of the hybrid PES-MWCNT-LiCl membranes was very much influenced by the phase separation method. Flux rates of the membranes improved dramatically with increasing amount of additives when prepared using TIPS. A 100% microalgae separation from cultivated solution without major fouling (more than 80% flux recovery) was successfully achieved.
Keywords: membrane; multiwall carbon nanotube; lithium salt; nannochloropsis algae.
Structural Transformation of Polymeric and Cationic Capped Zirconia Nanoparticles with Temperature
by Sreedevi R Mohan, Uma Maheswari A, Sivakumar Manickam
Abstract: The phase transformation mechanisms of zirconia nanocrystals obtained on thermal treatment of polyvinylpyrrolidone (PVP) and cetyltrimethylammoniumbromide (CTAB) capped hydrous amorphous zirconia (HAZ) on thermal treatment are investigated. In PVP assisted synthesis, tetragonal zirconia nanoparticles formation is the predominant one as compared to CTAB assisted synthesis. The decomposition of surfactants capped on HAZ with temperature (526 oC for PVP and 466 oC for CTAB) and subsequent interaction of the by-products with zirconia nanoparticles are responsible for tetragonal to monoclinic phase transformation. The decomposition temperature of capped surfactants is observed from thermogravimetric analysis (TGA) and subsequent interaction of byproducts with zirconia nanoparticles at different temperatures is investigated from FTIR spectra. Further the structure of nanoparticles annealed at different temperatures is investigated using XRD, micro Raman and photoluminescence (PL) analysis.
Keywords: Zirconia nanoparticles; Phase transformation; Annealing; Surfactant; Mineralizer.
Production of nano structure iron powder from blue dust
by Kamlesh Kumar
Abstract: One of the great triumph in the field of Nano materials and metal by Nano technology is the success in developing of nano sized iron powder from iron ore concentrate (Blue Dust). NMDC has taken an initiative to utilize high-grade blue dust to produce value added product i.e. Nano structure iron powder (NSIP), which can fetch high value. After the up gradation of blue dust by physical method, the samples were leached by acid to produce value added product from blue dust. This was followed by leaching, precipitation, drying, reduction, grinding in argon atmosphere and characterized by SEM, XRD etc to confirm its nano character. This value added product having less than 100 nanometers size has its applications in computer engineering, electronics, instrument making, medicine, catalysis etc. Component made from Nano structured materials have attracted large attention due to their high strength, excellent functional properties, better corrosion resistance, reduced sintering temperatures, etc. Paper contains preparation of nanosized particles (less than 100 nanometers) is connected to influence the dimensional effect on their physical, chemical, Mechanical and other properties.
Keywords: Blue dust; Leaching; precipitation; minerals; Drying; high strength; sodium hydroxide.
Structural and electrical studies of Mn-Ni mixed nanoferrites
by Elangbam Chitra Devi, Ibetombi Soibam
Abstract: Mn-Ni mixed spinel nanoferrites with varying nickel concentration (0.1, 0.2, 0.3, 0.4, and 0.5) were prepared by co-precipitation method. The spinel phase formation was confirmed by XRD and FTIR. Microstructure and compositional analysis were done by SEM and EDX respectively. Room temperature dielectric properties, resistivity and ac-conductivity were studied. The nanoferrites possess a very high dielectric constant. Dielectric loss tangent decreases with increase in nickel concentration and a broad peak appears for higher nickel concentration (0.2, 0.3, 0.4 and 0.5). Variation in dc-resistivity with nickel concentration goes in agreement with the variation of dielectric constant. Frequency variation of ac-conductivity for different nickel concentration shows dispersion at higher frequencies for different Ni concentration. Conduction mechanism has been explained on the basis of hopping electron model of ferrites.
Keywords: Spinel ferrites; dielectric property; ac-conductivity; SEM.
Greener Synthesis of Silver Nanoparticle from Chordia Dichotoma Leaf Extract and its Antimicrobial Activity
by Kalainila P, Ernest Ravindran R S, Hemachandran V
Abstract: Greener synthesis of silver nanoparticles (AgNPs) using the leaf extract of Chordia dichotoma. After the addition of leaf extract into the silver nitrate solution the color change was observed that clearly confirms the formation of AgNPs. The synthesized AgNPs undergo the surface plasmon resonance (SPR) effect for the size reductions were confirmed by the formation of peak at 431 nm from UV-Visible Spectroscopy (UV-Vis). The stability of the nanoparticles were studied at different time interval (0 to 72 h) using UV- visible spectroscopy and found to stable. FTIR analysis was performed to identify the active biomolecules that were responsible for the reduction of AgNPs. The synthesized particles were found to be spherical in shape and are in the average size range to nm and were observed to be monodispersed hence it proves that the particles were stable.
Keywords: Bio-reduction; Chordia dichotoma; Silver nanoparticle and Antimicrobial activity.
Phytofabrication, Characterization and Antimicrobial Studies of Gold Nanoparticles Using Cannabis sativa (Bhang), Leaf Extract
by Neeraj Sharma, SHAILENDRA PRATAP SINGH
Abstract: Phytofabrication of gold nanoparticles by plant extract of cannabis sativa is at present under exploitation for the reason that to develop environmentally benign nanoparticles synthesis to avoid adverse effects in biomedical applications. Different concentrations of ethanolic leaf extract of the plant were reacted with aqueous solution of HAuCl4•4H2O. A fixed ratio of plant extract and metal ion was mixed which in turn showed the change in colour of the solution leading to the inference that nanoparticles are formed. Thecharacterization of nanoparticles was done by UV-vis Spectrophotometer, FTIR, and TEM. The particles synthesized were of the size ranging from 20-100 nm. The solution showed a peak at 560 nm on UV-VIS spectrum corresponding to the surface Plasmon resonance of gold nanoparticles. The shape of the nanoparticles was spherical according to Transmission electron microscopy.In these studies, the antimicrobial studies of the AuNPS were exploited against different micro-organisms. The results of UV-VIS,FT-IR and TEM confirm that the leaves extract of Cannabis sativa can be used to produce gold nanoparticles with significant amount of antimicrobial activity.
Keywords: Gold Nanoparticles; Leaf Extract; Anti-Oxidant; Cannabis sativa, TEM, FTIR, UV –VIS
Special Issue on: CIMDD 2013 Behaviour of Materials
Electrical properties of Nanoscale Field Effect Transistor
by Sana Kausar, Shirish Joshi
Abstract: In this paper structure of a H-passivated silicon nanowire along direction with hexagonal cross section is defined by using Virtual nanolab(VNL), and set up a nanoscale field effect transistor (FET) structure with a wrap-around gate. Then the transmission spectrum and conductance is computed as the gate bias is varied. The device characteristic curve and conductance with respect to gate voltage is studied. Also effect of doping of Al atom on characteristic curve and conductance of nanoscale field effect transistor is analyzed.
Keywords: DFT; GGA; nanowire.