Optimizing both catalyst preparation and catalytic behaviour for the oxidative dehydrogenation of ethane of Ni-Sn-O catalysts

[EN] Bulk Ni-Sn-O catalysts have been synthesized, tested in the oxidative dehydrogenation of ethane and characterized by several physicochemical techniques. The catalysts have been prepared by evaporation of the corresponding salts using several additives in the synthesis gel, i.e. ammonium hydroxide, nitric acid, glyoxylic acid or oxalic acid, in the synthesis gel. The catalysts were finally calcined at 500 degrees C in air. Important changes in the catalytic behaviour have been observed depending on the additive. In fact, an important improvement in the catalytic performance is observed especially when some additives, such as glyoxylic or oxalic acid, are used. Thus the productivity to ethylene multiplies by 6 compared to the reference Ni-Sn-O catalyst if appropriate templates are used, and this is the result of an improvement in both the catalytic activity and the selectivity to ethylene. This improved performance has been explained in terms of the decrease of the crystallite size (and the increase in the surface area of catalyst) as well as the modification of the lattice parameter of nickel oxide.The authors would like to acknowledge the DGICYT in Spain (CTQ2015-68951-C3-1-R and CTQ2012-37925-C03-2) for financial support. We also thank the University of Valencia and SCSIE-UV for assistanceSolsona Espriu, BE.; López Nieto, JM.; Agouram, S.; Soriano Rodríguez, MD.; Dejoz, A.; Vázquez, MI.; Concepción Heydorn, P. (2016). Optimizing both catalyst preparation and catalytic behaviour for the oxidative dehydrogenation of ethane of Ni-Sn-O catalysts. Topics in Catalysis. 59(17-18):1564-1572. https://doi.org/10.1007/s11244-016-0674-zS156415725917-18Heracleous E, Lee AF, Wilson K, Lemonidou AA (2005) J Catal 231:159–171Heracleous E, Lemonidou AA (2006) J Catal 237:162–174Savova B, Loridant S, Filkova D, Millet JMM (2010) Appl Catal A 390:148–157Heracleous E, Lemonidou AA (2010) J Catal 270:67–75Solsona B, Nieto JML, Concepcion P, Dejoz A, Ivars F, Vazquez MI (2011) J Catal 280:28–39Skoufa Z, Heracleous E, Lemonidou AA (2012) Catal Today 192:169–176Zhu H, Ould-Chikh S, Anjum DH, Sun M, Biausque G, Basset JM, Caps V (2012) J Catal 285:292–303Skoufa Z, Heracleous E, Lemonidou AA (2012) Chem Eng Sci 84:48–56Zhu H, Rosenfeld DC, Anjum DH, Caps V, Basset JM (2015) ChemSusChem 8:1254–1263Heracleous E, Lemonidou AA (2015) J Catal 322:118–129Solsona B, Concepcion P, Demicol B, Hernandez S, Delgado JJ, Calvino JJ, Nieto JML (2012) J Catal 295:104–114Nieto JML, Solsona B, Grasselli RK, Concepción P (2014) Top Catal 57:1248–1255Popescu I, Skoufa Z, Heracleous E, Lemonidou AA, Marcu IC (2015) PCCP 17:8138–8147Zhang X, Gong Y, Yu G, Xie Y (2002) J Mol Catal A 180:293–298Popescu I, Skoufa Z, Heracleous E, Lemonidou A, Marcu I-C (2015) Phys Chem Chem Phys 17:8138–8147Nakamura KI, Miyake T, Konishi T, Suzuki T (2006) J Mol Catal A 260:144–151Solsona B, Dejoz AM, Vazquez MI, Ivars F, Nieto JML (2009) Top Catal 52:751–757Bortolozzi JP, Gutierrez LB, Ulla MA (2013) Appl Catal A 452:179–188Takeguchi T, Furukawa S, Inoue M (2001) J Catal 202:14–24Richardson JT, Turk B, Twigg MV (1996) Appl Catal 148:97–112Biju V, Khadar MA (2002) J Nanopart Res 4:247–253Van Veenendaal MA, Sawatzky GA (1993) Phys Rev Lett 70:2459–2462Vedrine JC, Hollinger G, Duc TM (1978) J Phys Chem 82:1515–1520Salagre P, Fierro JLG, Medina F, Sueiras JE (1996) J Mol Catal A 106:125–13

Groundwater and nutrient discharge through karstic coastal springs (Castelló, Spain)

Altres ajuts: Support from the Fulbright Commission for a post-doctoral fellowship to J.G-O. (ref 2007-0516) is gratefully acknowledged. Support for the research of PM was received through the prize ICREA Academia, funded by the Generalitat de Catalunya.Discharge of groundwater and associated chemical compounds into coastal karstic regions, which are abundant in the Mediterranean basin, is envisaged to be significant. In this study, we evaluate the groundwater discharge and its nutrient load to the open karstic site of Badum (Castelló, East Spain). Salinity profiles evidenced that groundwater discharge from coastal brackish springs causes a buoyant fresher layer, as identified with thermal infrared images. Chemical tracers (radium isotopes, dissolved inorganic silicate and seawater major elements) have been used to determine a brackish groundwater proportion in coastal waters of 36% in October 2006 and 44% in June 2007. Based on a radium-derived residence time of 2.7 days in October 2006 and 2.0 days in June 2007, total SGD fluxes have been estimated in 71 500 and 187 000m³ d⁻¹, respectively, with fresh-SGD contributions representing 71% and 85%. The calculated SGD-associated nutrient fluxes, most likely of natural origin, were 1500 and 8300 μmolm⁻² d⁻¹ of DIN and 19 and 40 μmolm⁻² d⁻¹ of DIP in October 2006 and June 2007, respectively. These inputs may actually lead to or enhance P limitation, thereby altering the structure of biological communities in the area

The key role of nanocasting in gold-based Fe2 O3 nanocasted catalysts for oxygen activation at the metal-support interface

The total oxidation of propane, a representative Volatile Organic Compound, has been studied using gold-based α-Fe2O3 catalysts. Catalysts consisting of gold nanoparticles confined in nanostructured Fe2O3 prepared by a nanocasting route present the highest catalytic activity for propane total oxidation, and the activity is significantly greater than those of gold-based catalysts where iron oxide supports are prepared by other conventional methods, such as calcination. Detailed characterization and Density-functional theory (DFT) studies have been undertaken in order to explain the enhancement in catalytic properties. The presence of confined gold nanoparticles on the nanocast Fe2O3 facilitates the production of highly reactive oxygen vacancies at the metal-support interface, increasing the catalyst performance. Both the development of a microporous/mesoporous structure in the iron oxide support and the presence of a mixed surface phase of Si and Fe oxides, seem to be key parameters, being both features inherent in the nanocasting process from silica templates. Additionally, the catalytic activity is enhanced due to other positive effects, which are closely related to the nanocasting preparation method: i) a higher contact surface area between partially confined small gold nanoparticles in the internal mesoporosity of the nanostructured support and the metal oxide and; ii) a more reducible support due to the presence of more active surface lattice oxygen

A protocol for wide-scope non-target analysis of contaminants in small amounts of biota using bead beating tissuelyser extraction and LC-HRMS

This work describes a robust and powerful method for wide-scope target and non-target analysis of xenobiotics in biota samples based on bead beating tissuelyser extraction, solid phase extraction (SPE) clean-up and further detection by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). Unlike target methodologies, non-target methods usually aim at determining a wide range of still unknown substances with different physicochemical properties. Therefore, losses during the extraction process were minimised. Apart from that, the reduction of possible interferences showed to be necessary to expand the number of compounds that can be detected. This was achieved with an additional SPE clean-up step carried out with mixed-bed multi-layered cartridges. The method was validated with a set of 27 compounds covering a wide range of physicochemical properties, and further applied to the analysis of krill and fish samples. •The bead beating extraction was efficient for a wide range of organic pollutants in small quantities of biota samples. •Multi-layered solid phase extraction clean-up yield a wide xenobiotics coverage reducing matrix effects. •Method validation with 27 compounds led to a suitable method for non-target analysis of organic pollutants in biota.ICRA researchers thank funding from CERCA program. This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO): project PLAS-MED (CTM2017-89701-C3-2-R). SRM acknowledges the Ramon y Cajal program (RYC-2014-16707). This project has been funded by the Chilean Antarctic Institute through project RT_12_17. The Chilean Agency for Research and Development through the FONDAP initiative (grant no. 15150003) “Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL)”; and “Anillos de Investigación en Ciencia Antartica (grant no. ANID-PIA-ACT-INACH Anillo ACT192057). IDAEA researchers acknowledge the Spanish Ministry of Science and Innovation (Severo Ochoa, Project CEX2018-000794-S).Peer reviewe

Réaction d'hypersensibilité cutanée chez le cobaye consécutive à l'inoculation intra-dermique d'un antigène chlamydien («virus» de l'avortement de la brebis) purifié inactivé

L’inoculation intra dermique au cobaye syngénique d’un anti gène ehlamydien purifié, inactive, mélangé à l’antigène complet de Freund, détermine un état d’hypersensibilité que révèle une deuxième injection intra dermique pratiquée au sixième jour : La réaction obtenue ne fait pas intervenir d’anticorps circulants. L’état de sensibilité qu’elle traduit est transféré au cobaye neuf par injection intra-péritonéale d’une suspension en solution saline équilibrée d’un broyât de ganglions prélevés sur cobaye sensi bilisé. L’intensité des réactions obtenues montre l’importance de la réaction cellulaire dans la réponse immunitaire du cobaye à l’injection de cet antigène

Eastern Mediterranean water outflow during the Younger Dryas was twice that of the present day

Eastern Mediterranean deep-intermediate convection was highly sensitive to varying inputs of fresh water fluxes associated with increased rainfall during the African Humid period (15-6 kyr Before Present). Here we investigate changes in the water-outflow from the Eastern Mediterranean Sea since the last deglaciation using neodymium isotope ratios. Our results indicate enhanced outflow during the Younger Dryas, two times higher than present-day outflow and about three times higher than during the last Sapropel. We propose that the increased outflow into the western Mediterranean over the Younger Dryas was the result of the combined effect of 1) enhanced climate-driven convection in the Aegean Sea and 2) reduced convection of western deep water during this period. Our results provide solid evidence for an enhanced Younger Dryas westward flow of Eastern Mediterranean sourced waters in consonance with an intensification of Mediterranean water-outflow during a weakened state of the Atlantic circulatio

A user-friendly web portal for T-Coffee on supercomputers

<p>Abstract</p> <p>Background</p> <p>Parallel T-Coffee (PTC) was the first parallel implementation of the T-Coffee multiple sequence alignment tool. It is based on MPI and RMA mechanisms. Its purpose is to reduce the execution time of the large-scale sequence alignments. It can be run on distributed memory clusters allowing users to align data sets consisting of hundreds of proteins within a reasonable time. However, most of the potential users of this tool are not familiar with the use of grids or supercomputers.</p> <p>Results</p> <p>In this paper we show how PTC can be easily deployed and controlled on a super computer architecture using a web portal developed using Rapid. Rapid is a tool for efficiently generating standardized portlets for a wide range of applications and the approach described here is generic enough to be applied to other applications, or to deploy PTC on different HPC environments.</p> <p>Conclusions</p> <p>The PTC portal allows users to upload a large number of sequences to be aligned by the parallel version of TC that cannot be aligned by a single machine due to memory and execution time constraints. The web portal provides a user-friendly solution.</p

Chemical, Structural, and Morphological Changes of a MoVTeNb Catalyst during Oxidative Dehydrogenation of Ethane

MoVTeNb mixed oxide, a highly active and selective catalyst for the oxidative dehydrogenation of ethane to produce ethylene, exhibits the so-called M1 and M2 crystalline phases. The thermal stability of the MoVTeNb catalytic system was assessed under varying reaction conditions; to this end, the catalyst was exposed to several reaction temperatures spanning from 440 to 550 °C. Both the pristine and spent materials were analyzed by several characterization techniques. The catalyst was stable below 500 °C; a reaction temperature of ≥500 °C brings about the removal of tellurium from the intercalated framework channels of the M1 crystalline phase. Rietveld refinement of X-ray diffraction patterns and microscopy results showed that the tellurium loss causes the progressive partial destruction of the M1 phase, thus decreasing the number of active sites and forming a MoO2 crystalline phase, which is inactive for this reaction. Raman spectroscopy confirmed the MoO2 phase development as a function of reaction temperature. From highresolution transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses it was noticed that tellurium departure occurs preferentially from the end sides of the needlelike M1 crystals, across the [001] plane. Detailed analysis of a solid deposited at the reactor outlet showrf that it consisted mainly of metallic tellurium, suggesting that the tellurium detachment occurs via reduction of Te4+ to Te0 due to a combination of reaction temperature and feed composition. Thus, in order to sustain the catalytic performance exhibited by MoVTeNb mixed oxide, hot spots along the reactor bed should be avoided or controlled, maintaining the catalytic bed temperature below 500 °C.This work was financially supported by the Instituto Mexicano del Petroleo.Valente, JS.; Armendariz-Herrera, H.; Quintana-Solorzano, R.; Del Angel, P.; Nava, N.; Masso Ramírez, A.; López Nieto, JM. (2014). Chemical, Structural, and Morphological Changes of a MoVTeNb Catalyst during Oxidative Dehydrogenation of Ethane. ACS Catalysis. 4:1292-1301. doi:10.1021/cs500143jS12921301

Enzyme-linked immunosorbent assay with a Salmonella enteritidis antigen for differentiating infected from vaccinated poultry

The specificity and sensitivity of indirect ELISA, based on the use of four different antigenic extracts obtained from a clinical isolate of Salmonella enteritidis, were compared with those obtained with the gm-flagellin based ELISA (IDEXX). A total of 116 serum samples from salmonellae free, naturally infected and vaccinated hens were studied. The results showed that the indirect ELISA, based on lipopolysaccharide (LPS), O-polysaccharide (PS) or membrane sediment (SD) antigens, enable the identification of a greater number of infected birds and discriminated field antibody responses from vaccinal ones better than the commercial IDEXX test. The indirect ELISA that used a O-polysaccharide rich fraction (PS) proved to be the most specific and sensitive test, suggesting that this indirect ELISA could be used to confirm IDEXX results, especially when the differentiation between vaccinated and infected poultry is required