The effect of the synthesis method over the catalytic behavior was investigated in Pt and PtSn catalysts. Catalysts synthesized using the one-step sol−gel method (OSSGM) were compared with those synthesized by conventional impregnation in the n-heptane reforming reaction at 500 °C and 1 atm, showing that the one-step sol−gel synthesis enhances both the activity and the resistance to deactivation by coking. The formation of coordinatively unsaturated aluminum (AlV) in the materials is promoted by the OSSGM, and it can be related to the increment in both their acidity and their platinum dispersion. Therefore, the bifunctionality of the catalysts, measured as the metal/acid site ratio (Ψ parameter), was also correlated to the AlV species. Higher values of Ψ implied a higher resistance to deactivation, higher rates of toluene production, and an inhibition of benzene induced by the OSSGM.

The aim of this contribution is to provide a comprehensive comparison between chitosan and Moringa oleifera seed flour (MOSF) as coagulant-flocculants. MOSF was obtained as a byproduct in a biodiesel process. Turbidity and heavy metal ion removal, using both ecofriendly materials, was assessed. Jar tests were performed on samples taken from river water, agricultural wastewater, and mixed wastewater (contaminated with agricultural and urban residues). Bioflocculant dosages within the range of 0.005-20 mg L À1 were tested. Irrespective of the initial turbidity, the optimal dosage of chitosan and MOSF for decreasing turbidity in river water was 1 and 5 mg L À1 , respectively. Furthermore, from river water, Pb removal up to 95% was achieved irrespective of the bioflocculant; for Mn removal, MOSF performed better than chitosan, with the adsorbent trapping close to 90% of this metal. MOSF decreased turbidity levels and heavy metal content (Mn and Pb) to under the permissible limits (Mexican environmental regulation for potable water, NOM-127-SSA1-1994). Additionally, kinetic data were fitted to kinetic models of adsorption for the pollutants. For agricultural wastewater, a chitosan dosage of 10 mg L À1 reduced turbidity to 5-10 nephelometric turbidity units (NTU), and a MOSF dosage of 10 mg L À1 decreased the turbidity to values lower than 5 NTU. For the mixed wastewater, chitosan achieved a high turbidity removal, while MOSF was not suitable.

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Objetivos: Seleccionar de entre los ecotipos de M. oleifera introducidos al Estado de Sinaloa, los más aptos para la producción de biomasa, semilla y aceite, y caracterizarlos químicamente. Diseño /metodología/aproximación: se estableció un huerto con 48 árboles de 6 ecotipos de M. oleifera distribuidos al azar. A los 16 meses de edad se determinaron los rendimientos agronómicos de tallos, hojas y semillas, la composición proximal de cada fracción, el perfil lignocelulósico de tallos y el contenido de ácidos grasos del aceite de la semilla. Resultados: Se encontraron diferencias significativas entre ecotipos para todos los parámetros, encontrándose que “Sinaloa” produjo la mayor cantidad de semilla y “Mojolo” los mayores rendimientos de tallos y hojas. El análisis proximal mostró el mayor contenido lípidos en semilla (48.2%) y de ácido oleico en el aceite del ecotipo “Elota”. El perfil de los componentes de la lignocelulosa de tallos indicó que “Sonora”, “Elota” y “Sinaloa” tienen la mayor proporción de holocelulosa. “Sinaloa” obtuvo los más altos rendimientos por hectárea de semilla y aceite, mientras que, de la hoja, el ecotipo “Mojolo” logró la más alta productividad por hectárea de proteínas, lípidos y carbohidratos. Limitaciones /implicaciones: este estudio sólo es comparativo y comprende 16 meses en cultivo no intensivo. Hallazgos/conclusiones: El ecotipo “Mojolo”  fue el mejor para la producción de biomasa y “Sinaloa” para semilla y aceite. El ecotipo “Elota” presentó los mayores porcentajes de aceite en la semilla. Se sugiere la experimentación con cruzas entre ellos para buscar mejoras genéticas

Catalysis Non Catalytic SMP 2 Reaction time 0.5-4h 0.5-5.5h 1-8h 120-240s Operation conditions 0.1 MPa, 30-65 ºC 0.1-5 MPa, 30-200 ºC 0.1 Mpa, 35-40 ºC >25Mpa, >239.4 ºC Catalyst Acid/base Metal oxides o carbonates Lipase Non Free fatty acid Soap formation Esters Esters Esters Water Interfere No interfere No interfere Act as catalyst to the process Yield Normal Low to normal Low to normal High Purification Difficult Easy Easy Very easy Downstream Water Non Non Non Glycerol purity Low Low to normal Normal High Process Complex Normal Simple Simple Capital cost Low Medium High Very high Operation cost High High Normal High

Abstract:The design and building of new alternative fuel plants is an increasing necessity to replace old technology and non-renewable fossil fuels. To optimize the performance of these plants and to obtain an economically feasible production of these types of fuels, it is necessary to have a total control of each variable involved in the process of production and how these factors affect the yield of fuel production. In this paper it is proposed a model of a digester to generate gas using a Vensim software designed to generate simulations in dynamic state. This simulation was developed using differential equations to model the behavior at each stage of the process and auxiliary conditions to complement the mathematical description of the model. The main factors in the biogas production are the retention time and the methanogen mortality ratio. For retention time lower than 10 h the process loses effectiveness due to bacterial growth is not completed efficiently, but a high retention time involves a bigger reactor and the yield of production decreases considerably for retention time higher than 40 h. The best yields were obtained for a mortality ratio in methanogen and acidogenic bacteria lower than 0.2 and a retention time of 30 h with a final production of 3.33 L by each kilogram of biomass.