Nanotechnology

Enhancement of photocatalytic activity of titania in the visible region and stabilization of anatase phase are significant from the view point of water pollution abatement, since this will enable solar light mediated processes to be scaled up to meet industrial requirements. Recent research has focused on designing nano titania based catalytic systems due to the large surface areas and improved photogeneration of oxidant-reductant species that the nano particles offer. There are several methods for the synthesis of nanoTiO2. Compared to bare TiO2, metal ion doped TiO2 is advantageous, as the doped metal ion alters the band gap and surface adsorption properties. Iron, zinc, cadmium, lanthanum, cerium, cobalt and nickel ions doped TiO2 have been reported in the literature for photocatalytic application. In this context, the present study aims at the co-doping of nano titania with a transition metal ion and a rare earth metal ion. Copper and Samarium ions have been chosen for this purpose as this co-doping has not been reported in the literature so far. In this paper we have synthesized Cu and Sm ions co-doped nano titania prepared by the sol-gel method. This catalyst was characterized by FTIR, XRD, TGA, SEM and UV- visible to analyze the band gap chatacteristics and the effect of calcination on the photodegradation of 4CP

The thermal evaporation system type (Edwards) has been used to evaporate high purity (99.9 %) silver on glass substrates at room temperature under low pressure (about 10-6 torr) for different thickness (50, 75, 100, 125 and 150) nm. Using a rapid thermal oxidation (RTO) of Ag film at oxidation temperature 350 oC and different oxidation times, Ag2O thin film was prepared. The optical properties of Ag2O film were investigated and compared with other published results. The gas response behaviors of the p-Ag2O/PSi/c-Si – based gas sensor to H2 gas were investigated. The film gas response dependence on the temperature and test gas concentration was tested.

The titanium dioxide powder was prepared on p-type porous silicon by sol-gel process. The morphology of TiO2 sensing film surface was imaged by atomic force microscope (AFM) model AA3000 SPM from Angstrom Advanced Inc. The average roughness of the film surface is 25 nm. The X-ray diffraction (XRD) patterns shows of TiO2nano-particalprepared by the solgel method arepolycrystalline, the anatase phase with the preferential orientation of the crystallites along the [101] direction,at2? =25.253°theresultisinagreementwiththe ASTM Card (PDF 21-1272).The resistance of the TiO2nano-partical sensors reduces with the presence of vapor ethanol.

Synthesis of a nanocomposite hydrogel P-PAMPS-PAAm/ZnO, has been made by the polymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and acrylamide (AAm) in the presence of pectin (P) and zinc oxide (ZnO) using microwave irradiation technique. FTIR, XRD, SEM and TEM studies indicated the formation of a gel network and incorporation of ZnO particles within gel structure. The system was evaluated for adsorption of Cu (II) and Pb(II) ions from aqueous solutions. About 77 mgg-1 of Cu(II) and 125 mgg-1 of Pb(II) could be adsorbed from aqueous solutions. Different isotherm models have been employed to study the adsorption process and the data is found to fit well with Langmuir isotherm model. The kinetic studies revealed a second-order adsorption process. About 95% of the metal ions adsorbed could be stripped in acidic medium of pH 1.2 indicating the reusability of the gel.

Fluorine-doped Tin Oxide (FTO) thin films supported on glass substrates have been fabricated by employing Ultrasonic Spray Pyrolysis (USP) technique. Precursor solution for the spraying was prepared by placing NH4F and SnCl2.2H2O at a weight ratio of 1 to 9 in a solution of acetic acid ? and distilled water. Three films of different thicknesses were prepared corresponding to spray times of 10, 20, and 30 minutes, resulting in 13, 22, and 45 nm thick films. The optical, structural, morphological, and electrical properties of the fabricated films have been investigated. X-ray diffraction studies revealed a polycrystalline fluorine-tin oxide phase with monoclinic crystalline structure, predominantly with (201), (130), (222), and (510) oriented films. The measured sheet resistances of the films were 38 ?/cm, 150 ?/cm, and 300 ?/cm and the highest measured optical transmittance in the visible range were 87.4%, 70% , and 36% respectively.

Sample pretreatment methods, such as separation / preconcentration prior to the determination of metal ions have developed rapidly due to the increasing need for accurate and precise measurements at extremely low levels of ions in diverse matrices. The development of new sorbents and their application in preconcentration methods for determination of trace analytes is subject of great interest. This review summarizes and discusses several analytical methods involving the preparation and use of new solid phase extractant. A literature survey of the last ten years offering a critical review of these new sorbents available for use in trace analyte enrichment is provided.

In recent time, copper nanoparticles (Cu-NPs) are versatile nanomaterials that find wide array of utilizations in biomedicine, molecular biology, dentistry, dye degradation, catalysis, among others. The aim of this study is to assess the quality of Cu-NPs synthesized from copper tailings and reagent grade copper salt. Chemical reduction method was used to synthesize Cu NPs from copper tailings and reagent grade copper salt using sodium tetrahydroborate (NaBH4) as the reducing agent. The synthesized copper nanoparticles were characterized using different analytical techniques such as: quantitative X-ray Diffraction (XRD), scanning electron microscopy (SEM), X-Fluorescence spectroscopy (XRF), Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric analysis (TGA). The results of XRD identified three major mineral phases tenorite Syn, garnet and quartz in tailing (87.3%, 7.8%, and 4.9%) and reagent grade salt (90%, 6%, and 4%) respectively and confirmed the formation of face-centered cubic (FCC) metallic copper. SEM revealed irregular shape particle morphology with rough surface and particle of 31.3 nm for Cu tailings and 37.6 nm for Reagent Cu nanoparticles. XRF revealed high elemental composition of copper in both synthesized nanoparticles from tailings and reagent salt with 85.15% and 85.98% respectively, BET surface area are 342.11 m2/g and 464.95 m2/g for Cu tailings and reagent salts respectively, and FTIR revealed the specific functional groups O-H, C=O, C-O and Cu-O stretching for both tailings and reagent grade Cu-NPs. However, this type of study has not been reported in an accredited journal. Thermogravimetric analysis (TGA) confirms the thermal stability of these Cu-NPs up to 325 °C. In conclusion, synthesized TCu-NPs and and RCu-NPs were pure, highly crystalline, nano-sized and the quality of the nanoparticles from tailings was slightly lesser than the reagent grade salt due to the presence of impurities. KEYWORDS: Copper tailing, reagent grade copper salt, chemical reduction, copper nanoparticles, characterization

In this paper we report on the synthesis of single-crystal Mg2B2O5 nanowires by heating the precursor powder made of disodium tetraborate decahydrate and magnesium chloride dihydrate at 8500C. The as-received nanowires possess smooth surface with diameters varying between 25 and 40 nm. Also Mg2B2O5 nanorods doped with Eu were synthesized by firing a mixture powder of the above obtained Mg2B2O5 nanowires and Eu2O3 in air atmosphere. The as synthesized Mg2B2O5:Eu nanorods have diameters varying between 110 and 130 nm. The structural and compositional characteristics of the as-synthesized products have been investigated by XRD, SEM, TEM, EDX, and SAED techniques. Photoluminescence investigations reveal that both Eu+3 and Eu+2 can coexist in Mg2B2O5 nanorods. Eu2 display a violet emission beak at 412 nm and Eu3+ display broad emissions centered at 538 and 615 nm.