Effect of sulfur and nitrogen dioxides on the performance of a proton exchange membrane fuel cell

There is presently much interest in the clean and efficient generation of energy by proton exchange membrane fuel cells (PEMFC), using hydrogen as fuel. The generation of hydrogen by the reforming of other fuels, anaerobic fermentation of residual waters and other methods, often produce contaminants that affect the performance of the cell. In this work, the effect of gaseous SO2 and NO2 on the performance of a H2/O2 single PEMFC is studied. The results show that SO2 decreases irreversibly the performance of the cell under operating conditions, while NO2 has a milder effect that allows the recovery of the system.FAPESPCNP

Effect of temperature on the electro-oxidation of ethanol on platinum

We present in this work an experimental investigation of the effect of temperature (from 25 to 180 ºC) in the electro-oxidation of ethanol on platinum in two different phosphoric acid concentrations. We observed that the onset potential for ethanol electro-oxidation shifts to lower values and the reaction rates increase as temperature is increased for both electrolytes. The results were rationalized in terms of the effect of temperature on the adsorption of reaction intermediates, poisons, and anions. The formation of oxygenated species at high potentials, mainly in the more diluted electrolyte, also contributes to increase the electro-oxidation reaction rate.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Pesquisa (CNPq

Carbon monoxide oxidation on Pt-Ru electrocatalysts supported on high surface area carbon

This find is registered at Portable Antiquities of the Netherlands with number PAN-0000787

Three years of harvest with the vector vortex coronagraph in the thermal infrared

For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 to 13 {\mu}m). Our AGPMs were first installed on VLT/NACO and VLT/VISIR in 2012, followed by LBT/LMIRCam in 2013 and Keck/NIRC2 in 2015. In this paper, we review the development, commissioning, on-sky performance, and early scientific results of these new coronagraphic modes and report on the lessons learned. We conclude with perspectives for future developments and applications.Comment: To appear in SPIE proceedings vol. 990

Energy recovery from winery wastewater using a dual chamber microbial fuel cell

BACKGROUND Microbial fuel cells (MFCs) can treat agro-industrial wastewater, but only a few studies have reported the treatment of winery waste and much work is needed in order to develop this interesting application of MFC technology, in particular in evaluating how the unfavorable COD/N and COD/P ratios may affect the MFC performance. In this work, a dual chamber MFC was used to treat real effluents from wine processing factories. RESULTS The MFC was not efficient in terms of COD removal, even when nutrients concentration was increased and daily removals which oscillated around 1000 mg L-1 d-1 were observed during the complete experimental period, with COD removals around 17%. Increases in the phosphorus and nitrogen concentrations positively influenced the production of electricity. By increasing the concentration of phosphorus and nitrogen, Coulombic efficiency was increased from 2% to almost 15%, and maximum power density from 105 to 465 mW m-2. CONCLUSIONS Results demonstrate that electricity can be produced efficiently and that the unbalanced nutrients/COD ratio is a major challenge in the treatment of winery wastewater, in spite of the very high organic load contained in this type of wastewater. © 2015 Society of Chemical IndustryANTECEDENTES Las celdas de combustible microbianas (MFC) pueden tratar aguas residuales agroindustriales, pero solo unos pocos estudios han informado el tratamiento de residuos de bodegas y se necesita mucho trabajo para desarrollar esta interesante aplicación de la tecnología MFC, en particular en la evaluación de cómo la DQO desfavorable / Las relaciones N y COD / P pueden afectar el rendimiento del MFC. En este trabajo, se utilizó un MFC de doble cámara para tratar efluentes reales de las fábricas de procesamiento de vino. RESULTADOS El MFC no fue eficiente en términos de remoción de DQO, aun cuando se incrementó la concentración de nutrientes y se observaron remociones diarias que oscilaron alrededor de 1000 mg L -1 d -1 durante todo el período experimental, con remociones de DQO alrededor del 17%. Los aumentos en las concentraciones de fósforo y nitrógeno influyeron positivamente en la producción de electricidad. Al aumentar la concentración de fósforo y nitrógeno, la eficiencia de Coulombic se incrementó del 2% a casi el 15% y la densidad de potencia máxima de 105 a 465 mW m -2 . CONCLUSIONES Los resultados demuestran que la electricidad se puede producir de manera eficiente y que la relación desequilibrada nutrientes / DQO es un gran desafío en el tratamiento de las aguas residuales de bodegas, a pesar de la altísima carga orgánica contenida en este tipo de aguas residuales. © 2015 Sociedad de la Industria Químic