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In this paper, we report an easy route for preparing new metal nanorod-polymer composites consisting of gold nanorods, Au NRs, and temperature responsive copolymer "microgel" particles. The microgel particles of ~200 nm in size, which contain carboxylic acid groups, were prepared by surfactant-free emulsion polymerization of a selected mixture made of N-isopropylacylamide and acrylic acid in the presence of a cross-linker N,N0-methylenebisacrylamide. The electrostatic interactions between the cationic cetyltrimethylammonium bromide (CTAB) stabilized Au NRs and anionic microgel particles were expected to occur in order to prepare stable Au NRs-microgel composite particles. The optical and structural characterization of the composite was achieved using UV-Vis spectroscopy, Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and dynamic light scattering (DLS). TEM image shows that Au NRs are attached on the surface of the microgel particles. Dynamic light scattering measurements prove that the composite particles are temperature responsive, which means the particles undergo a decrease in size as the temperature increases above its phase transition temperature. In vitro cytotoxicity of the composite materials were tested by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Lactate dehydrogenase (LDH), and hemolysis assay, which showed non-toxicity (biocompatibility). [ABSTRACT FROM AUTHOR]

This paper collects experimental data and mathematical modelling of Nd(III), Tb(III) and Dy(III) solvent extraction with an ionic liquid prepared from Aliquat 336 (Methyl-tri(octyl/decyl)ammonium chloride) and Oleic Acid (AliOle). Extraction experiments were carried out to evaluate the effect of chloride anion in aqueous phase, AliOle and REE concentrations over the extraction extension. Mathematical models computed with Matlab software were derived from the mass balances and chemical equilibria involved in the extraction system of Neodymium(III), Terbium(III) and Dysprosium(III) individually. The optimized equilibria parameters proposed fit accurately the experimental data and allowed us to predict the extraction extension of each metal from an aqueous mixture. [ABSTRACT FROM AUTHOR]

The synthesis of mono-sized silica nanoparticle with mesostructures via sol-gel method by employing ammonium polycarboxylate (APC) surfactant has investigated. The major aim of this paper is to introduce APC as an appropriate surfactant to control nucleation and growth of nanoparticles during hydration and condensation steps of the sol-gel process. Dynamic light scattering (DLS) results indicated that the particle in the sol containing APC had an average particle size about 10 nm. The bonds of prepared silica nanoparticles were studied by IR spectroscopy and X-ray photoelectron spectroscopy (XPS). The result of scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM) confirmed that applying APC could sufficiently induce the mass transfer during the synthesis process, this claim have also verified according to the particle size analysis. Resulting information also approved the synthesis of spherical and mono-sized nanoparticle with an average particle size of 25 nm. Furthermore, the synthesized nanoparticles possessed a mesostructured characteristic due to leaving of APC organic components during final heat treatment. N 2 adsorption/desorption porosimetry indicated that the particles were comprised of mesopores with an average pore size of 2.5 nm and specific surface area of 1015 m 2 g −1 . This strategy could be readily applied to prepare an engineered product of silica nanoparticles with uniform spherical morphology and mesostructure. [ABSTRACT FROM AUTHOR]

This paper reports the phase equilibrium temperature and dissociation heat of ionic semiclathrate hydrate formed with tetrabutylammonium butyrate (TBABu). The temperature – composition phase diagram of the TBABu hydrate was determined in the mass fraction from 0.10 to 0.44. The highest equilibrium temperature of TBABu hydrate was 15.4 °C in the mass fraction range from 0.35 to 0.37. On the dissociation heat of DSC measurements, a single heat flow peak of TBABu hydrate excluding ice melting peak was observed at all the mass fraction systems. The largest dissociation heat was 184.9 ± 3.1 kJ/kg at the mass fraction 0.36. TBABu hydrate could potentially be used as a thermal energy storage material. [ABSTRACT FROM AUTHOR]

The paper presents a technique for the synthesis of molybdenum carbide using mechanical activation of carbon black, which was impregnated with a 20% aqueous solution of ammonium heptamolybdate (AHM) using the incipient wetness technique, in an inert medium at a 100 g acceleration of milling bodies for 30 min. The mechanically activated carbide-containing composites were calcined in an inert medium at 800 °C. The composites were examined by a range of physical methods. It was shown that the mechanically activated composite consists of molybdenum carbide, iron oxide and iron carbide (about 4–8% according to AES-ICP). The phase addition method was used to determine the quantitative content of Мо 2 С, which was equal to 7.2 wt% in the calcined sample. Catalytic testing of mechanically activated molybdenum carbide in the partial oxidation of methane showed that the carbide-containing catalyst provides a 48–60% conversion of methane and an 83–85% selectivity for the target product (CO). [ABSTRACT FROM AUTHOR]

In this paper the interfacial behavior of aqueous solutions of cationic gemini surfactants of the, N,N′-bis(dimethylalkyl)-α,ω-alkanediammoniumdibromide type (known as the 12-s-12 series), in the absence and presence of ZnO nanoparticles was studied. Equilibrium and dynamic interfacial tension between n- decane and aqueous surfactant solutions were investigated. It was concluded that the synergistic effect between surfactants and nanoparticles increases the surfactant efficiency with respect to reducing the interfacial tension. Moreover, the magnitude of the effect of ZnO nanoparticles on the interfacial tension decreases with increasing length of the spacer group in the gemini surfactant structure. Dynamic studies illustrate that the migration mechanism of gemini surfactants (regardless of the presence of ZnO) from the bulk to the interface was controlled by both diffusion and adsorption. The effect of spacer length on the contact angle and emulsion stability both with and without nanoparticles was also studied. [ABSTRACT FROM AUTHOR]

In this paper we report the synthesis, the crystal structure and the optical response of APbX 3 (A=MA, DMA, and TMA; X=I, Br) hybrid organic-inorganic materials including some new phases. We observe that as the cation group increases in size, the optical absorption edge shifts to higher energies with energy steps which are systematic and independent on the anion. A linear correlation between the optical bad gap and the tolerance factor has been shown for the series of samples investigated. [ABSTRACT FROM AUTHOR]

This paper reports the solvothermal synthesis of MoS nanospheres and nanosheets. The nanospheres were obtained using ammonium polysulfide as a sulfur source and have a mean diameter of about 100 nm. The nanosheets were assembled from a few lamellar layers and were obtained using thiourea as a sulfur source. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used in order to characterize the prepared powders. Conglomerate size and stability of the synthesized samples in hexane were studied with zeta potential. The four-ball method was used to assess the lubricating effect when these materials were used as additives in engine oil dispersions. The topography of the wear scar was analyzed using SEM, EDX, and 3D surface profilometry. The tribological properties of base engine oil containing the nanomaterials penetrated more easily into the interface space, and it formed a tribo-film at contact interface. The tribological performance showed that the synthesized nanosheets had superior anti-wear and friction-reducing properties as a lubrication additive compared with nanospheres, and the wear scar of balls lubricated with nanospheres revealed larger width compared to nanosheets. From the results, it is observed that nanosheets dispensed in oil have better tribological performance compared to nanospheres oil in terms of capability to reduce wear. [ABSTRACT FROM AUTHOR]

The homogeneous catalytic oxidation of ammonium sulfite in a microporous tube-in-tube microchannel reactor (MTMCR) was studied in this paper. It was found that the oxidation rate of ammonium sulfite in the MTMCR is 360 times higher than that in a packing column and could be further boosted about 4-6 times by the Co2+ catalyst. The effects of different operating parameters on the oxidation of ammonium sulfite were investigated. Experimental results indicated that the oxidation ratio of ammonium sulfite increased with the increase of the oxygen volumetric flow rate, but decreased with the increase of the liquid volumetric flow rate and sulfite concentration, and a smaller micropore size and annular channel width resulted in a higher oxidation ratio of ammonium sulfite. The oxidation ratio reached 80% under the optimum operating conditions in the catalytic oxidation process. This study reveals that the MTMCR is a potential intensification device for the oxidation process of ammonium sulfite. [ABSTRACT FROM AUTHOR]

This paper investigates the catalytic properties of the iridium catalysts supported on modified silicalite-1. Post-synthesis modification of silicalite-1, with solutions of ammonium compounds (NH4F and NH4OH), appeared to be an efficient method to generate the acidic sites in starting support. The modification of support led not only to changes in its acidity but also its porosity—formation of additional micro- and mesopores. The novel materials were used as supports for iridium. The iridium catalysts (1 wt.% Ir) were characterized by N2 adsorption/desorption measurements, temperature-programmed reduction with hydrogen (TPR-H2), H2 chemisorption, transmission electron microscopy (TEM), temperature-programmed desorption of ammonia (TPD-NH3), X-ray photoelectron spectroscopy (XPS) and tested in the hydrogenation of toluene reaction. The catalytic activity of iridium supported on silicalite-1 treated with NH4OH (higher porosity of support, better dispersion of active phase) was much higher than that of Ir supported on unmodified and modified with NH4F silicalite-1. [ABSTRACT FROM AUTHOR]

Due to the special properties of the ammonium salts, ammonium acetate and ammonium citrate were used to explore the best leaching conditions of rare earth with compound ammonium carboxylate. This paper explored the influence of the molar ratio, ammonium concentration, experimental temperature, and pH of the compound leaching agents on the leaching efficiency of rare earth and aluminum, and it analyzed the leaching process based on the leaching kinetics, which provides a new method for leaching rare earth from the weathered crust elution-deposited rare earth ore. The results showed that under the conditions where the molar ratio of ammonium acetate and ammonium citrate was 7:3 and the ammonium concentration was 0.15 mol/L, the leaching efficiency of rare earth was the highest when the pH of leaching agent was 4.0 and the experimental temperature was 313 K. Meanwhile, when CH3COONH4 and (NH4)3Cit were used to leach rare earth ore, the leaching reaction kinetics equation of rare earth and aluminum were obtained. In the temperature range of 283–323 K, the apparent activation energy of rare earth was 14.89 kJ/mol and that of aluminum was 19.17 kJ/mol. The reaction order of rare earth was 0.98 and that of aluminum was 0.79. The results were in accordance with the shrinking core model and indicate that the concentration of the leaching agent had a greater influence on rare earth than aluminum. This process can reduce the use of ammonium salt, and it is of great significance to extract rare earth elements from weathered crust elution-deposited rare earth ore and improve the utilization rate of resources. [ABSTRACT FROM AUTHOR]