INTERNATIONAL NANO LETTERS (INL)
Year:2014 | Volume:4 | Issue:2|Papers Count:8

We report the low temperature synthesis of CdE (E=S, Se and Te) semiconductor nanoparticles capped by anacardic acid, an environmentally benign naturally occurring capping ligand. The cadmium chalcogenide nanoparticles were synthesized by reacting the reduced chalcogen powder with cadmium chloride to form the corresponding bulk material which was then dispersed in tri-n-octylphosphine (TOP) and thermolysed in anacardic acid. The low temperature of the reaction and the use of a naturally occurring oil solvent make this a relatively green synthetic route. The optical properties of the anacardicacid-capped cadmium chalcogenide particles show evidence of quantum confinement. The particles were characterized by X-ray diffraction and electron microscopy techniques.

Pesticides are deliberately used for controlling the pests in agriculture and public health, due to which, a part of it is present in the drinking water. Due to their widespread use, they are present in both surface and ground water. Most of the pesticides are resistant to biodegradation and are found to be carcinogenic in nature even at trace levels. Conventional methods of pesticide removal are disadvantageous due to their inherent time consumption or expensiveness. Nanoparticles alleviate both of these drawbacks and hence, they can be effectively utilized for the mineralization of pesticides. To prevent the presence of nanoparticles in the purified water after mineralization of pesticides, they need to be incorporated on a support. In earlier studies, researchers employed activated carbon and alumina as support for silver nanoparticles in pesticide mineralization. However, not many studies have been carried out on polymeric membranes as support for silver nanoparticles in the mineralization of pesticides (chlorpyrifos and malathion). With this in view, a detailed study has been carried out to estimate the mineralization potential of silver nanoparticles (synthesized using glucose) supported on cellulose acetate membrane. It is observed that the silver nanoparticles can effectively mineralize the pesticides, and the concentration of nanoparticles enhances the rate of mineralization.

This study includes of syntheses and characteristics functionalized single-walled carbon nanotubes (SWCNTs) with amide group using thionyl chloride and NH3. First SWCNTs in H2SO4 and HNO3, solved and the solution obtained ultrasound was to reach the equilibrium temperature to functionalization of carboxylate single walled carbon nanotubes (SWCNT-COOH). Then using thionyl chloride with (SOCl2) and DMF the mixture was refluxing. SWCNT-COCl was obtained from the previous step with ammonia (NH3), and DMF as solvent, and the mixture was refluxing. The black solid obtained was placed overnight in the oven to dry. Carbon nanotubes were expected at this stage to have a functional group CONH2. All new chemical bonding products were identified by FTIR and observations using scanning electron microscopy (SEM) were confirmed. SWCNT-COOH functionalized carbon nanotubes have a relatively smooth surface and thin Stowe and the SEM image of the SWCNT-NH2; a thin layer of hope is clearly placed on the surface of SWCNTCOOH and its diameter is increased.

The present investigation deals with the facile synthesis and characterization of chitosan (CTS) -based zinc oxide (ZnO) nanoparticles (NPs) and their antimicrobial activities against pathogenic microorganisms. ZnO–CTS NPs were synthesized through two different methods: nano spray drying and precipitation, using various organic compounds (citric acid, glycerol, starch and whey powder) as stabilizers. Both the synthesis methods were simple and were devoid of any chemical usage. The detailed characterization of the NPs was carried out using UV–Vis spectroscopy, dynamic light scattering particle size analysis, zeta potential measurements and scanning electron microscopy, which confirmed the fabrication of NPs with different shapes and sizes. Antimicrobial assay of synthesized ZnO–CTS NPs was carried out against different pathogenic microbial strains (Candida albicans, Micrococcus luteusand Staphylococcus aureus). The significant (p<0.05) inhibition of growth was observed for both M. luteus and S. aureus with ZnO–CTS NPs (with a concentration ranging from 0.625 to 0.156 mg/ml) as compared to control treatment. ZnO–CTS NPs also showed significant biofilm inhibition activity (p<0.05) against M.luteusand S. aureus. The study demonstrated the potential of ZnO–CTS NPs as antimicrobial and antibiofilm agents.

Plasmonic Fano resonances arise in bimetallic layered nanostructures (metal–dielectric–metal and dielectric–metal–dielectric–metal) are studied theoretically as the function of their geometrical parameters. Multiple Fano resonances are generated in these nanostructures where several subradiant dark modes appear due to the geometrical symmetry breaking induced by offsetting different layers. The plasmonic responses of the proposed nanoparticles with equal volumes are compared and multiple Fano resonances with large modulation depths are obtained in metal–dielectric–metal structure which is highly suitable for multi-wavelength sensing and plasmon line shaping. However, the dielectric–metal–dielectric–metal nanostructure is found to provide a slightly better tunability of higher-order plasmonic modes compared to metal–dielectric–metal nanostructure due to which it can be useful for biomedical applications.

The potential applications of one-dimensional nanostructured materials widely depend on their shape and size. This paper deals with a method for synthesizing and characterizing silver nanowires through an organic solution. The so-called polyol method was used to synthesize silver nanowires in which ethylene glycol was used as both media and the reducing agent. Adequate CuCl2/ethylene glycol solution is used to prohibit chemical etching by the oxygen on nanowires surfaces. The effects of CuCl2 concentration and the addition rate of AgNO3 were examined. It was revealed that by optimizing the parameters, silver nanowires with aspect ratios of up to 32 are accessible. To characterize the structure and morphology of nanowires, X-ray powder diffraction, UV–Vis spectroscopy, scanning electron microscopy and atomic force microscopy were used.

A complete green chemical reaction between aurochloric acid and tea polyphenols resulted in the reduction of Au3+®Au0. The reaction was carried out in a Teflon-coated bomb digestion vessel at 200oC. It was observed that with increasing the reaction time from 1 to 5 h, the shape of the nanoparticles changed from sphericalto rod-like structures. The reaction was followed with the help of UV–vis spectrometer, which showed a single absorption peak at 548 nm for 1-h reaction product and two peaks for a 5-h reaction product at 533 and 745 nm corresponding to the transverse and longitudinal surface plasmon resonance bands. Microstructures obtained from transmission electron microscope revealed that the samples obtained after 1-h reaction are predominantly spherical in shape with an average size of 15 nm. Whereas samples obtained after 5 h of reaction exhibited rod-like structures with an average size of 45 nm.

Ferrite–folic acid (FA) nanohybrids were synthesized and characterized by various analytical tools like Fourier transform infrared spectroscopy, UV–Visible spectroscopy, fluorescence spectroscopy, field emission scanning electron microscopy, X-ray diffraction analysis and vibrating sample measurement techniques. After the nanohybrid formation, both the crystallinity and the magnetization values of ferrite were disturbed due to the surface functionalization of ferrite by FA. The role of nanohybrid on the structure–property relationship of starch, particularly the sedimentation of starch under three different pHs, was evaluated. Again the magnetization value of Fe3O4–FA/starch nanocomposite system was reduced due to the encapsulation effect. The sedimentation velocity of starch under the influence of nanohybrid was enhanced in the acidic medium.