Journal of Nanoanalysis
Volume:1 Issue: 2, Aug 2014

On-line solid phase extraction (SPE) based on  nano adsorbent for pre-concentration of inorganic arsenic in water and waste water samples was developed prior to determine by hydride generation atomic absorption spectrometry (HG-AAS). By hydride generation simulation system (HGSS), the  inorganic arsenic in liquid samples changed to hydride form and pass through nano platinum multi wall carbon nanotube (3 wt % Pt, NPt-MWCNT,). The hydride form of arsenic (AsH3), pre-concentrated on NPt-MWCNTs and then completely desorption by electric heater accessory at 200oC for determining. The detection limit (LOD) and linear range of perposed method were obtained 0.4 ng L-1 and 6 –410 ng L-1 respectively(R2 = 0.9988). The relative standard deviations (%RSD) at 100 ng L-1 of analyte were found less than 5%. The capacity and efficiency  of nano adsorbent were 75 mg g-1 and 96% at  argon flow rate less than 100 ml min-1. The developed method was applied successfully to determination of ultra trace of inorganic arsenic in environmental samples by HG-AAS.

Nano-sized iron-based catalyst was prepared by the micro-emulsion method. The composition of the final nano-sized iron catalyst, in term of the atomic ratio contains: 100Fe/4Cu/2Ce. Experimental techniques of XRD, BET, TEM and TPR were used to study the phase, structure and morphology of the catalyst. Fischer-Tropsch Synthesis (FTS) reaction test was performed in a fixed bed reactor at pressure of 17 bars, temperature of 270-310°C with H2/CO ratio and GHSV 2 nl.h-1.gCat-1, respectively. The temperature of the system as a key parameter was changed and its effect on the selectivity and reaction rate was analysed. The results show that the rate of both reactions including of FTS and Water-Gas Shift (WGS) are increased by increasing temperature. For this condition, CO conversion also increased up to 89.1%.

The present study has investigated the synthesis of copper nanoparticles via copper dismutation reaction in an aqueous solution and ambient conditions. Copper (II) chloride hydrate ( ), sodium oleate (SO), sodium chloride (NaCl) and ethylene diamine (EN) have been used as copper (I, II) ions source, surfactant, chloride ions supplier and ligand, respectively. Also, an amount of hydrochloric acid (HCl) was used as a multiplier for reaction rate. To perform copper dismutation reaction in the aqueous solution, the copper (I)–chloride complexes were first prepared from  at a high concentration of chloride solution. Then, sodium oleate was added to solution as a size modifier. The reaction proceeded through the addition of ethylenediamine as a ligand to the solution. The crystalline structure, size, and morphology of the copper nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) techniques, respectively. According to the analyses, the synthesized particles are less than 20 nanometers in size and spherical in shape.

Ru/Al2O3 nano-catalysts were prepared with impregnation and microemulsion techniques. The supercritical water gasification reaction was performed at 400oC and 5-60 min. Within the tested operation conditions, the reaction residence time of 15 min was the optimum to maximize the H2 yield. It was observed that using microemulsion technique increases the total gas yield significantly. Using microemulsion technique for preparation of Ru/Al23 nano-catalyst with water to surfactant ration of 0.5, increased the hydrogen yield to 17.6 (mmol of H2/ g of bagasse), CO yield to 14.2 (mmol of CO/g of bagasse) and light gaseous hydrocarbons to 1.4 (mmol of light gaseous hydrocarbons/g of bagasse). It was observed that using micro emulsion technique increases the catalyst specific activity by a factor of 1.7 which considerably can enhance the economic aspects of the bagasse super critical water gasification technology.

Functionalization of carbon nanotube (CNT) was performed, during preparation of Fischer–Tropsch synthesis (FTS) via cobalt nanocatalysts, to modify the surface properties of CNT support. Common and functionalized CNT supported cobalt nanocatalysts were prepared using impregnation wetness method with cobalt loading of 15 wt.%. The catalysts were characterized by Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), temperature program reduction (TPR), H2 chemisorption, and transmission electron microscopy (TEM) technique. Most of the cobalt particles were homogeneously distributed inside the tubes and the rest on the outer surface of the functionalized CNT. Functionalization of CNT shifted the TPR reduction peaks to lower temperatures, improved the reduction degree, and increased the dispersion of cobalt particles and stability of catalysts. The proposed cobalt catalyst supported on functionalized CNT- (N-doped functionalized CNT) increased the FTS rate (g HC/gcat./hr), and CO conversion (%) from 0.1347, and 30 to 0.235, and 47 respectively, compared to that of the catalyst prepared by impregnation wetness method on common CNT. Catalysts supported on functionalized CNT also showed better stability.

The cross-rolling is a new process that results in significant evolutions in microstructure of the metallic sheets. In this study, an aluminium 1050 sheet was rolled up to 95% reduction in cross directions for ten passes. The rolled samples were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The rolled samples possess a high dislocation density and ultra-fine crystallite structure. In addition, an anisotropic texture was formed in the structure of material. In fact, the intensity of {220} planes of Al was extremely increased about 7500 counts per second (CPS) in cross-rolling process. In this research a new method called selected area electron diffraction (SAED) was used to determine the direction of planes. In cross-rolled samples, the rolling texture component {110} [001] was created that are known as brass texture (Bs). A regular geometric structure accompanied by ultrafine-grained observed in TEM micrographs. Ultra-fine crystalline structure is proved by rings which were obtained from SAEDs. The results show that the grain sizes are about 200 nm and 300 nm in cross-rolling and straight rolling, respectively.