Catalytic activity evaluation for hydrogen production via autothermal reforming of methane

A nickel catalyst (5.75 wt.%) supported on gamma-alumina was evaluated through autothermal reforming of methane (ATR). The reforming process was pointed to hydrogen production, following thermodynamic and stoichiometric predictions. The catalyst was characterised by several methods including atomic absorption spectroscopy (AAS), B.E.T.-N₂, X-ray diffraction (XRD), scanning electron microscope (SEM) and thermal analyses (thermogravimetry, TG; derivate thermogravimetry, DTG; and differential thermal analysis, DTA). Experimental evaluations in a fixed-bed reactor (1023–1123 K, 1.00 bar, 150–400 cm³/min feed) presented methane conversions in the range of 40–65%. The effluent mixtures provided hydrogen yields in the range of 78–84%, carbon monoxide 3–14%, and carbon dioxide 5–18%. High molar H₂/CO ratios, ranging from 8 to 90, were obtained. Operating autothermal conditions (excess of steam, 1023–1123 K, 1.00 bar) provided low coke formation and high hydrogen selectivity (81%) for methane reforming.     

Tuna (Thunnus thynnus) glazed with hydrocolloids as alternative of edible coatings and storaged at -10 degrees C

Numerous studies have been focused to natural ingredients to maintain the quality and shell life of foods. Edibles coating, biodegradable ingredients, such as hydrocolloids and proteins can be used for coating fish with the purpose to suppress changes of quality during frozen storage. At the present time several developing of edibles packing, like glaze using hydrocolloids, (gelatin, carrageen, starch), that besides acts as protective film for food, they are economic, can be ingested by the consumer without toxicity risk, help to preserve organoleptics and nutritional characteristics of the product and, being biodegradable they contribute to the conservation of the atmosphere. The objective of the present study was to evaluate the incorporation ofhydrocolloids in the glazing tuna process as alternative of packing, to enhance its physical and chemical characteristics. Samples of tuna was glazed incorporating to its solutions of carrageen at 0.05, 0,1 and 0.15%, and gelatin at 0.5, 1%. The samples were shaped as square (15 cm3), frozen al -30 degrees C and glazed incorporating hydrocolloids submerging the sample its solutions at 0 degrees C by 30 seconds and storage at -10 degrees C by 0, 15 and 30 days. Proximal analysis results, soluble proteins, TBA, and color showed that all the samples glazed with hydrocolloids decrease deterioration of the tuna products respect to samples glazed without hydrocolloids; concluding that glazing adding hydrocolloids protects tuna for loss humidity and delays degradation of proteins. Moreover, carrageen shows to a better performance at the concentrations of 0.05% compared with the gelatin and the starch.     

Surface acidity of novel mesostructured silicas with framework aluminum obtained by SBA-16 related synthesis

A novel SBA-16-related synthesis of mesostructured silica containing framework aluminum is reported here. This material was successfully synthesized using aluminum sulphate and the pH-adjusting method. The structural and porosity properties of this novel material were studied by X-ray diffraction and N₂ adsorption at 77 K. The Al insertion was determined by ²⁷Al-MAS-NMR and the acidity was monitored by infrared spectroscopy of CO adsorption at 100 K.     

Growth of Ag, Au, Cu, and Pt nanostructures on surfaces by micropatterned laser-image formations

Silver, gold, copper and platinum nanoparticles (NPs) were grown on surfaces in the form of patterns by the exposure of laser radiation onto droplets of metal ion solutions and the aid of a reducing agent. The generation of patterns from metallic NPs was achieved by combining induced growth of NPs and nanostructures by laser incidence directly on surfaces and optical image formation techniques for transferring the patterns. Near-UV (363.8 nm) and visible (532 nm) laser wavelengths were used for the laser-induced growth of NPs into microstructures on glass, quartz, stainless steel, silicon, and gold-on-silicon substrates. The sizes of the patterns formed were on the micrometer scale and the sizes of the transferred patterns were on the millimeter scale. The patterns formed were generated by optical transference of image and interference of laser beams. Ag and Au substrates were highly active in surface enhanced Raman spectroscopy (SERS). The enhanced Raman activity was measured for SERS probe molecules: 9H-purin-6-amine (adenine) and 1,2-bis (4-pyridyl)-ethane analytes on Ag and Au substrates, respectively. The enhancement factors obtained were 1.8×10(5) and 6.2×10(6), respectively.