in Wiley Online Library (wileyonlinelibrary.com)The sonochemical synthesis and characterization of highly active and stable Ni nanoparticles supported on TiO 2 as a CO methanation catalyst for the production of synthetic natural gas are reported. The catalyst synthesized by sonication showed higher activity for CH 4 formation than the catalyst synthesized via the conventional wet impregnation method. The activation energy was found to be 79 and 94 kJ mol 21 for the catalyst synthesized with sonication and wet impregnation method, respectively. The combined results of x-ray photoelectron spectroscopy and x-ray diffraction show that the enhancement in activity of the sample synthesized by sonication method is due to partial substitution of Ni in TiO 2 lattice. This creates oxide vacancies and facilitates hydrogen adsorption and spillover from nickel to support. H 2temperature-programmed reduction study corroborates the intimate contact of Ni with support, thus rendering strong metal support interactions. The mechanism involving Langmuir-Hinshelwood kinetics with hydrogen-assisted CO dissociation was used to correlate experimental data.The catalytic activity measurement was performed at atmospheric pressure in a tubular quartz reactor (4-mm ID and length of 30 cm) over 0.5 g of catalyst (40-80 mesh) Figure 4. H 2 -TPR profile for (a) 23%Ni/TiO 2 (imp), (b) 23%Ni/TiO 2 (sonic), and (c) nickel oxide.Figure 5. Percentage (a) CO conversion, (b) CH 4 selectivity, and (c) CH 4 yield plot on various TiO 2modified catalysts.

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Copper and zinc were extracted from salicylate solution into Aliquat 336 dissolved in toluene and determined in the organic phase spectrophotometrically using 1-(2-pyridylazo)-2-naphthol. The determination of copper and zinc was also carried out titrimetrically or by atomic absorption spectrometry after stripping the metal ions from the organic phase. The method permits the determination of copper and zinc in environmental and pharmaceutical samples. The standard deviation and relative standard deviation are 0.052 micrograms and 0.69%, respectively, for copper and 0.041 micrograms and 0.60%, respectively, for zinc.

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