Artículos de revista DQA - KAS Aldizkari artikuluak
Permanent URI for this collection
Browse
Browsing Artículos de revista DQA - KAS Aldizkari artikuluak by Title
Now showing 1 - 20 of 26
Results Per Page
Sort Options
Publication Open Access Application of eco-design and life cycle assessment standards for environmental impact reduction of an industrial product(MDPI, 2017) Navajas León, Alberto; Uriarte Elizaga, Leire; Gandía Pascual, Luis; Kimika Aplikatua; Institute for Advanced Materials and Mathematics - INAMAT2; Química AplicadaEco-design is included within the framework of the standard for “Environmental management systems—Guidelines for incorporating Eco-design” (ISO 14006:2011). Eco-design process, as defined in standard, has six steps: (i) Specify product functions; (ii) Environmental assessment of products; (iii) Strategies of improvement; (iv) Environmental objectives; (v) Product specification; and (vi) Technical solutions. Step (ii), determination of the stage or process of the product life cycle that has the highest environmental impact; this is perhaps the most controversial step because the standard does not specify which tool should be used. This lack of specification has generated some distrust with regard to eco-design, hindering its development. In order to make a trustworthy eco-design, Life Cycle Assessment (LCA) should be applied as a tool for environmental impact quantification. The main objective of this work is to apply standardised eco-design methodology for the reduction of the environmental impact of an industrial product in Spain using LCA as a tool for the environmental product assessment. LCA standardised process (ISO 14040,14044:2006) is included in the eco-design process. A glass container intended for cough syrup delivery has been selected as an industrial product to be eco-designed. Following the methodology described, the overall normalised impact decreased 35.1% when a PET container substituted a glass container. Environmental impacts have been reduced following standardised eco-design and LCA methodologies, serving as an example to industry and administration regarding how to eco-design with the confidence of obtaining reliable resultsPublication Open Access Application of gold complexes in the development of sensors for volatile organic compounds(World Gold Council, 2007) Luquin, Asunción; Elosúa Aguado, César; Vergara, Elena; Estella, Juncal; Cerrada, Elena; Bariáin Aisa, Cándido; Matías Maestro, Ignacio; Garrido Segovia, Julián José; Laguna, Mariano; Química Aplicada; Kimika Aplikatua; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta ElektronikoaTwo different kinds of sensors have been developed by using the same kind of vapochromic complexes. The vapochromic materials [Au2Ag2(C6F5)(4)L-2](n) have different colours depending on the ligand L. These materials change, reversibly, their optical properties, colour and fluorescence, in the presence of the vapours of volatile organic compounds (VOCs). For practical applications, two different ways of fixing the vapochromic material to the optical fibre have been used: the sol-gel technique and the electrostatic self-assembly method (ESA). With the first technique the sensors can even be used to detect VOCs in aqueous solutions, and using the second method it has been possible to develop nanosensors.Publication Open Access Asymmetric assembly of all‐carbon tertiary/quaternary nonadjacent stereocenters through organocatalytic conjugate addition of α‐cyanoacetates to a methacrylate equivalent(Wiley, 2016) Iriarte, Igor; Vera, Silvia; Badiola, Eider; Mielgo, Antonia; Oiarbide, Mikel; García Castillo, Jesús María; Odriozola Ibarguren, José Manuel; Palomo, Claudio; Química Aplicada; Kimika AplikatuaAn efficient, highly diastereo- and enantioselective assembly of acyclic carbonyl fragments possessing nonadjacent all-carbon tertiary/quaternary stereoarrays is reported based on a Brønsted base catalyzed Michael addition/a-protonation sequence involving a-cyanoacetates and 2,4-dimethyl-4-hydroxypenten-3-one as novel methacrylate equivalent.Publication Open Access Asymmetric propionate aldol reactions of a chiral lithium enolate accessible from direct enolization with n-butyllithium(ARKAT USA, Inc., 2005) Palomo, Claudio; Oiarbide, Mikel; Gómez Bengoa, Enrique; Mielgo, Antonia; González Rego, María Concepción; García Castillo, Jesús María; González Guerrero, Alberto; Odriozola Ibarguren, José Manuel; Bañuelos, Patricia; Linden, Anthony; Química Aplicada; Kimika AplikatuaThe presented lithium enolate-based methodology is suitable for access to propionate syn-aldol motifs with high levels of stereocontrol. The reactive lithium enolate species is generated by direct treatment of a camphor-based chiral ethyl ketone with butyllithium, and is subsequently submitted to aldolization with a broad variety of aldehydes. The product aldols are obtained in uniformly high yields and high d.r. values (ranging from 91:9 to >98:2) irrespective of the aliphatic (both linear and branched chain), α,β-unsaturated, aromatic, or hetero-aromatic nature of the aldehyde employed. The crystallinity of most of the obtained adducts offers an easy access to almost 100% isomerically pure products upon a single recrystallisation. The auxiliary (1R)- (+)-camphor can be removed easily from the adducts for reuse, thereby producing the corresponding syn propionate aldols. This technology is implemented in the synthesis of a key subunit of the multi-drug resistance reversing agent hapalosin.Publication Open Access Bioavailability of heavy metals in soils amended with sewage sludge(Agricultural Institute of Canada, 2002) Morera Luzán, María Teresa; Echeverría Morrás, Jesús; Garrido Segovia, Julián José; Química Aplicada; Kimika AplikatuaThe recycling of sewage sludge to agricultural land results in the slow accumulation of potentially toxic heavy metals in soils. A greenhouse experiment was conducted to determine the bioavailability of Cu, Ni, Pb and Zn applied to soils in urban anaerobically stabilized sewage sludge. The soils were Lithic Haplumbrept (Lh), Calcixerollic Xerochrept (Cx1 and Cx2) and Paralithic Xerorthent (Px). Sunflower plants (Helianthus annuus L) were grown in. the soils following amendment with the sludge. The addition of sewage sludge markedly increased the average dry weight of the plants in the soils that had lower yields without sludge addition (Lh, Cx2, and Px). The acid pH of the Lh soil favoured the bioavailability of Zn from sewage sludge. The bioavailability of Cu was greater in the alkaline soils than in the acidic soil (Lh), which can be attributed to the high organic matter content of the Lh soil which complexes Cu and impairs its uptake by the plants. The concentration of metals in the plants increased with the sewage sludge dose. The effect of the soil type on the metal concentration in plants was greater that the effect of the dose.Publication Open Access Catalytic hydroprocessing of lignin β-O-4 ether bond model compound phenethyl phenyl ether over ruthenium catalysts(Springer, 2017) Gómez Monedero, B.; Faria, J.; Bimbela Serrano, Fernando; Ruiz, M. P.; Química Aplicada; Kimika AplikatuaThe catalytic hydroprocessing of phenethyl phenyl ether (PPE), a model compound of one of the most significant ether linkages within lignin structure, β-O-4, has been studied. Reactions were carried out using two ruthenium-based catalysts, supported on different materials: 3.8 wt.% Ru/C and 3.9 wt.% Ru/Al2O3. Aiming at studying the reaction mechanism, experiments were carried out at 150 °C and 25 bar in H2 atmosphere, with varying feed to catalyst mass ratios and reaction time. Differences between the relative importance of the steps of the mechanism were observed when using those two catalysts. The most significant finding was the predominance of the cleavage of Cβ-O bonds compared to the cleavage of the Caryl-O when using Ru/Al2O3 as catalyst; whereas with Ru/C, the two routes were nearly equivalent. It has been observed that the kinetic model describes the general tendencies of consumption and formation of the different products, but some over/under estimation of concentrations occurs. Finally, the effect of temperature was also explored by carrying out reactions at 100 and 125 °C, observing that decreasing temperature from 150 to 125 or 100 °C favored the dimer hydrogenation route versus the hydrogenolysis of the ether bonds.Publication Open Access Encuesta de satisfacción de un proyecto de mejora de calidad del servicio aragonés de salud(Universidad de Murcia, 2015) Bimbela Serrano, María Teresa; Bimbela Serrano, Fernando; Bernués Vázquez, Luis; Ciencias; ZientziakIntroducción: Según el informe de 2008 del Sistema Nacional de Salud, existe un 4,7% de los usuarios que opina que el sistema sanitario debería rehacerse por completo y casi un 27%, que es necesario introducir cambios importantes para su mejora. Hipótesis: El desarrollo de un programa específico de control de peso para pacientes obesos en Atención Primaria mejora la calidad de la actuación percibida por el paciente de Atención Primaria. Objetivos: Valorar la influencia de un proyecto de mejora de calidad de Atención Primaria en los resultados globales de una encuesta de satisfacción de los usuarios de dicha Zona Básica de Salud. Material y Métodos: Estudio prospectivo de intervención cuasiexperimental centrado en el tratamiento de la obesidad en Atención Primaria realizado desde Enero de 2012 a Diciembre 2013, en cuya evaluación final se realizó una encuesta autoadministrada de Satisfacción de los usuarios y se comparó con los resultados obtenidos con el mismo cuestionario por el Servicio Aragonés de Salud en dicha Zona Básica de Salud. Para el análisis estadístico de estos datos se empleó el programa informático SPSS.15. Resultados principales: Se observa un aumento destacable en los apartados ‘Interés del personal de enfermería’, ‘Satisfacción de los cuidados sanitarios’ (medicina y enfermería) y ‘Solución dada a problemas’. No hubo aspectos negativos y el 100% de los encuestados expresó una satisfacción general y un 88% destacó el aspecto de la paciencia del profesional hacia los pacientes. Conclusión: El proyecto de mejora de calidad realizado con pacientes crónicos de la consulta de enfermería de Atención Primaria, ha sido valorado muy satisfactoriamente, llegando a mejorar la puntuación de los resultados globales del Sistema Aragonés de Salud en esta Zona Básica de Salud.Publication Open Access Estrategias del alumnado de Educación Secundaria para estimar la densidad(Universitat Autònoma de Barcelona, 2018) Napal Fraile, María; Echeverría Morrás, Jesús; Zulet González, Amaia; Santos Cervera, Leyre; Ibarra Murillo, Julia; Psicología y Pedagogía; Psikologia eta Pedagogia; Química Aplicada; Kimika AplikatuaLa densidad, o concentración de materia, es un concepto muy relevante pero que genera muchas dificultades de comprensión. Para medir la competencia en la estimación de la densidad del alumnado de la ESO, se pasó un cuestionario acompañado de un juego de materiales a 196 alumnos de los cuatro cursos de la ESO en dos colegios. La estimación de la densidad depende del peso percibido, el tamaño o la viscosidad, lo que a veces lleva a estimaciones erróneas. En todos los cursos, más del 40 % de los alumnos consideran la densidad como una propiedad extensiva; en torno a un 50 % usan modelos –no siempre coherentes– más cercanos a una propiedad intensiva y específica. Existen además dificultades para predecir los cambios en densidad con el estado de agregación o la temperatura, lo que sugiere que deben introducirse cambios en su enseñanza.Publication Open Access Fiber optic sensors based on hybrid phenyl-silica xerogel films to detect n-hexane: determination of the isosteric enthalpy of adsorption(Beilstein-Institut, 2017) Echeverría Morrás, Jesús; Calleja, Ignacio; Moriones Jiménez, Paula; Garrido Segovia, Julián José; Kimika Aplikatua; Institute for Advanced Materials and Mathematics - INAMAT2; Química Aplicada; Gobierno de Navarra / Nafarroako Gobernua, 269/01/08We investigated the response of three fiber optic sensing elements prepared at pH 10 from phenyltriethoxysilane (PhTEOS) and tetraethylsilane (TEOS) mixtures with 30, 40, and 50% PhTEOS in the silicon precursor mixture. The sensing elements are referred to as Ph30, Ph40 and Ph50, respectively. The films were synthesized by the sol–gel method and affixed to the end of optical fibers by the dip-coating technique. Fourier transform infrared spectroscopy, N2 adsorption–desorption at 77 K and X-ray diffraction analysis were used to characterize the xerogels. At a given pressure of n-hexane, the response of each sensing element decreased with temperature, indicating an exothermic process that confirmed the role of adsorption in the overall performance of the sensing elements. The isosteric adsorption enthalpies were obtained from the calibration curves at different temperatures. The magnitude of the isosteric enthalpy of n-hexane increased with the relative response and reached a plateau that stabilized at approximately −31 kJ mol−1 for Ph40 and Ph50 and at approximately −37 kJ mol−1 for Ph30. This indicates that the adsorbate–adsorbent interaction was dominant at lower relative pressure and condensation of the adsorbate on the mesopores was dominant at higher relative pressure.Publication Open Access Gold supported on CuOₓ/CeO₂ catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)(Elsevier, 2014) Laguna, O. H.; Hernández, W. Y.; Arzamendi Manterola, María Cruz; Gandía Pascual, Luis; Centeno, M. A.; Química Aplicada; Kimika AplikatuaHydrogen produced from the conversion of hydrocarbons or alcohols contains variable amounts of CO that should be removed for some applications such as feeding low-temperature polymer electrolyte membrane fuel cells (PEMFCs). The CO preferential oxidation reaction (PROX) is particularly well-suited for hydrogen purification for portable and on-board applications. In this work, the synthesis and characterization by XRF, BET, XRD, Raman spectroscopy and H2-TPR of a gold catalyst supported on a coppercerium mixed oxide (AuCeCu) for the PROX reaction are presented. The comparison of this catalyst with the copper–cerium mixed oxide (CeCu) revealed that the experimental procedure used for the deposition of gold gave rise to the loss of reducible material by copper lixiviation. However, the AuCeCu solid was more active for CO oxidation at low temperature. A kinetic study has been carried over the AuCeCu catalyst for the PROX reaction and compared with that of the CeCu catalyst. The main difference between the models affected the contribution of the CO adsorption term. This fact may be related to the surface electronic activity produced by the interaction of the cationic species in the AuCeCu solid, able to create more active sites for the CO adsorption and activation in the presence of gold.Publication Open Access Hydrogen production from water electrolysis: current status and future trends(IEEE, 2012) Ursúa Rubio, Alfredo; Gandía Pascual, Luis; Sanchis Gúrpide, Pablo; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Química Aplicada; Kimika AplikatuaThis paper reviews water electrolysis technologies for hydrogen production and also surveys the state of the art of water electrolysis integration with renewable energies. First, attention is paid to the thermodynamic and electrochemical processes to better understand how electrolysis cells work and how they can be combined to build big electrolysis modules. The electrolysis process and the characteristics, advantages, drawbacks, and challenges of the three main existing electrolysis technologies, namely alkaline, polymer electrolyte membrane, and solid oxide electrolyte, are then discussed. Current manufacturers and the main features of commercially available electrolyzers are extensively reviewed. Finally, the possible configurations allowing the integration of water electrolysis units with renewable energy sources in both autonomous and grid-connected systems are presented and some relevant demonstration projects are commented.Publication Open Access Influence of the power supply on the energy efficiency of an alkaline water electrolyser(Elsevier, 2009) Ursúa Rubio, Alfredo; Marroyo Palomo, Luis; Gubía Villabona, Eugenio; Gandía Pascual, Luis; Diéguez Elizondo, Pedro; Sanchis Gúrpide, Pablo; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza; Química Aplicada; Kimika Aplikatua; Gobierno de Navarra / Nafarroako GobernuaElectric energy consumption represents the greatest part of the cost of the hydrogen produced by water electrolysis. An effort is being carried out to reduce this electric consumption and improve the global efficiency of commercial electrolysers. Whereas relevant progresses are being achieved in cell stack configurations and electrodes performance, there are practically no studies on the effect of the electric power supply topology on the electrolyser energy efficiency. This paper presents an analysis on the energy consumption and efficiency of a 1 N m3 h1 commercial alkaline water electrolyser and their dependence on the power supply topology. The different topologies of power supplies are first summarised, analysed and classified into two groups: thyristor-based (ThPS) and transistor-based power supplies (TrPS). An Electrolyser Power Supply Emulator (EPSE) is then designed, developed and satisfactorily validated by means of simulation and experimental tests. With the EPSE, the electrolyser is characterised both obtaining its I–V curves for different temperatures and measuring the useful hydrogen production. The electrolyser is then supplied by means of two different emulated electric profiles that are characteristic of typical ThPS and TrPS. Results show that the cell stack energy consumption is up to 495 W h N m3 lower when it is supplied by the TrPS, which means 10% greater in terms of efficiency.Publication Open Access Kinetic analysis and CFD simulations of the photocatalytic production of hydrogen in silicone microreactors from water-ethanol mixtures(Elsevier, 2017) Castedo, Alejandra; Uriz Doray, Irantzu; Soler, Lluís; Gandía Pascual, Luis; Llorca Piqué, Jordi; Kimika Aplikatua; Institute for Advanced Materials and Mathematics - INAMAT2; Química AplicadaSilicone microreactors containing microchannels of 500 μm width in a single or triple stack configuration have been manufactured, coated with an Au/TiO2 photocatalyst and tested for the photocatalytic production of hydrogen from water-ethanol gaseous mixtures under UV irradiation. Computational fluid dynamics (CFD) simulations have revealed that the design of the distributing headers allowed for a homogeneous distribution of the gaseous stream within the channels of the microreactors. A rate equation for the photocatalytic reaction has been developed from the experimental results obtained with the single stack operated under different ethanol partial pressures, light irradiation intensities and contact times. The hydrogen photoproduction rate has been expressed in terms of a Langmuir-Hinshelwood-type equation that accurately describes the process considering that hydrogen is produced through the dehydrogenation of ethanol to acetaldehyde. This equation incorporates an apparent rate constant (kapp) that has been found to be proportional to the intrinsic kinetic rate constant (k), and that depends on the light intensity (I) as follows: kapp = k·I0.65. A three-dimensional isothermal CFD model has been developed in which the previously obtained kinetic equation has been implemented. The model adequately describes the production of hydrogen of both the single and triple stacks. Moreover, the specific hydrogen productions (i.e. per gram of catalyst) are very close for both stacks thus suggesting that the scaling-up of the process could be accomplished by simply numbering-up. However, small deviations between the experimental and predicted hydrogen production suggest that a fraction of the radiation is absorbed by the microreactor components which should be taken into account for scaling-up purposes.Publication Open Access Kinetics of the acid-catalyzed hydrolysis of tetraethoxysilane (TEOS) by 29Si NMR spectroscopy and mathematical modeling(Springer, 2018) Echeverría Morrás, Jesús; Moriones Jiménez, Paula; Arzamendi Manterola, María Cruz; Garrido Segovia, Julián José; Gil Idoate, María José; Cornejo Ibergallartu, Alfonso; Martínez Merino, Víctor; Química Aplicada; Kimika Aplikatua; Institute for Advanced Materials and Mathematics - INAMAT2Tetraethoxysilane (TEOS) is widely used to synthesize siliceous material by the sol–gel process. However, there is still some disagreement about the nature of the limiting step in the hydrolysis and condensation reactions. The goal of this research was to measure the variation in the concentration of intermediates formed in the acid-catalyzed hydrolysis by 29Si NMR spectroscopy, to model the reactions, and to obtain the rate constants and the activation energy for the hydrolysis and early condensation steps. We studied the kinetics of TEOS between pH 3.8 and 4.4, and four temperature values in the range of 277.2–313.2 K, with a TEOS:ethanol:water molar ratio of 1:30:20. Both hydrolysis and the condensation rate speeded up with the temperature and the concentration of oxonium ions. The kinetic constants for hydrolysis reactions increased in each step kh1 < kh2 < kh3 < kh4, but the condensation rate was lower for dimer formation than for the formation of the fully hydrolyzed Si(OH)4. The system was described according to 13 parameters: six of them for the kinetic constants estimated at 298.2 K, six to the activation energies, and one to the equilibrium constant for the fourth hydrolysis. The mathematical model shows a steady increase in the activation energy from 34.5 kJ mol−1 for the first hydrolysis to 39.2 kJ mol−1 in the last step. The activation energy for the condensation reaction from Si(OH)4 was ca. 10 kJ mol−1 higher than the largest activation energy in the hydrolytic reactions. The decrease in the net positive charge on the Si atom contributes to the protonation of the ethoxy group and makes it a better leaving group.Publication Open Access Lipogenic enzyme activity in growing Rasa Aragonesa lambs(CIHEAM, 1995) Arana Navarro, Ana; Soret Lafraya, Beatriz; Corroza Muro, Manuel; Mendizábal Aizpuru, José Antonio; Mendizábal Múgica, Francisco Javier; Horcada, Alberto; Eguinoa Ancho, Paola; Purroy Unanua, Antonio; Producción Agraria; Nekazaritza Ekoizpena; Química Aplicada; Kimika AplikatuaThe lipogenic enzyme activity of the following enzymes was studied: Glycerol 3-phosphate dehydrogenase (G3PDH), fatty acids synthetase (FAS), NADP-Malate dehydrogenase (ME) and Glucose 6-phosphate dehydrogenase (G6PDH) in five fat depots (omental, OM; mesenteric, MES; kidney knob and channel, KKC; subcutaneous, SC; intermuscular, IM) in 45 male Rasa Aragonesa lambs divided into three groups of 15 lambs (G12, G24, G36). They were slaughtered respectively at 11.70 ± 0.67; 24.50 ± 0.57 and 35.80 ± 1.74 kg of live weight (LW) and at 32 ± 5; 89 ± 8, and 123 ± 8 days old. The G12 lambs were slaughtered on the day of weaning, having consumed solely their mother's milk; those in the G24 and G36 groups were weaned at 16.20 ± 1.32 and 18.30 ± 2.46 kg LW respectively, were fed from then onward concentrated fodder and barley straw ad libitum until they were slaughtered. Between 24 and 36 kg LW an increase in the activity of the G3PDH and FAS lipogenic enzymes was observed. The increasine the 'de novo' synthesis (FAS) at 36 kg LW was matched by G6PDH activity, which indicates greater use of acetate as a precursor of fatty acids. Furthermore, the maintenance of ME activity during the period studied would indicate that the glucose rate utilization for the fatty acids synthesis was not modified throughout this period.Publication Open Access Microwave-assisted pillaring of a montmorillonite with al-polycations in concentrated media(MDPI, 2017) González, Beatriz; Pérez, Alba Helena; Trujillano, Raquel; Gil Bravo, Antonio; Vicente, Miguel Ángel; Química Aplicada; Kimika AplikatuaA montmorillonite has been intercalated with Al3+ polycations, using concentrated solutions and clay mineral dispersions. The reaction has been assisted by microwave radiation, yielding new intercalated solids and leading to Al-pillared solids after their calcination at 500 °C. The solids were characterized by elemental chemical analysis, X-ray diffraction, FTIR spectroscopy, thermal analyses, and nitrogen adsorption. The evolution of the properties of the materials was discussed as a function of the preparation conditions. Microwave treatment for 2.5 min provided correctly pillared solids.Publication Open Access Mobility of heavy metals in soils amended with sewage sludge(Agricultural Institute of Canada, 2001) Morera Luzán, María Teresa; Echeverría Morrás, Jesús; Garrido Segovia, Julián José; Química Aplicada; Kimika AplikatuaSewage sludges added to arable land can improve soil fertility and physical properties. However, the concentrations of heavy metals commonly found in sludges limits their application to soil. The purpose of this paper is to evaluate the mobility of heavy metals (Cd, Cu, Ni, Pb and Zn) in four soils amended with different rates (0, 80, 60 and 320 t ha-1) of anaerobically stabilized urban sewage sludge. Total metal content in the sewage sludge was Zn much greater than Cu > Pb > Ni much greater than Cd. Sludge, soils and sludge-soil mixtures were fractionated by the Tessier sequential extraction procedure. The fractions extracted by H2O2/HNO3 and NH2OH.HCl were the most abundant pools for metals under study. The apparent mobility of metals in the sludge was Zn approximate to Cd approximate to Ni > Pb > Cu. The addition of sewage sludge in soils increased the percentages of metal extracted in non-residual fractions. ANOVA showed that the most significant increases were those of Zn, followed by Cu and Pb; there were no statistical differences (P < 0.05) for Ni and Cd. Exchangeable Zn from sludge was immobilized in basic soils. The other trace metals showed no fraction redistribution. The soils and sludge-treated soil samples were also extracted with EDTA and DTPA. Extraction with EDTA was more sensitive to soil type, whereas extraction with DTPA showed wider variation with metals. Both chelates seemed to be more effective to assess the mobility of metals added with the sludges at low concentrations than the Tessier's chemical partitioning.Publication Open Access Navarra y China. Punto de partida(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2006) Sánchez Fernández, Carlos; Química Aplicada; Kimika AplikatuaEs cierto, y no nos equivocamos al decir que China es diferente. Esta diferencia hace que insistamos una y otra vez en que China es, si no el lugar más difícil para hacer negocios, sí uno de los más difíciles. Pero, a parte de los problemas que nos podamos encontrar en cualquier otro país, es esa DIFERENCIA la que nos va a dar más quebraderos de cabeza. Ese llamado choque cultural, diferente mentalidad o idiosincrasia particular del pueblo asiático Pero claro, China es el país del momento. Tiene un crecimiento nunca visto en otro país y una política diseñada por sus dirigentes a medio-largo plazo que parece dar sus frutos. ¿Quién iba a pensar hace 25 años que China en este período iba a multiplicar su PIB por 7 a un crecimiento del 8% o 10% anual? ¿Quién podía prever que hoy tendría una economía de mercado en vez de una economía planificada? Y ahora tienen por delante otra serie de retos como son las diferencias de renta entre individuos y regiones, la creación de un consumo interno, el aumento del paro, la reforma de la banca pública, las nacionalidades, la corrupción... pero, China ha demostrado saber cómo hacer las cosas en estos últimos 25 años, así que creo que merecen nuestra confianza, sabrán como seguir haciendo las cosas durante los siguientes 25 años al menos. Frente a esta expectativa, ¿Cómo debemos posicionarnos en China desde Navarra.Publication Open Access Outstanding performance of rehydrated Mg-Al hydrotalcites as heterogeneous methanolysis catalysts for the synthesis of biodiesel(Elsevier, 2018) Navajas León, Alberto; Campo Aranguren, Idoia; Moral Larrasoaña, Ainara; Echave, Javier; Sanz Iturralde, Oihane; Montes, Mario; Odriozola, José Antonio; Arzamendi Manterola, María Cruz; Gandía Pascual, Luis; Química Aplicada; Kimika Aplikatua; Institute for Advanced Materials and Mathematics - INAMAT2There is still a need for active, selective and stable heterogeneous catalysts for the synthesis of biodiesel. In this work, magnesium-aluminium hydrotalcites with Mg/Al molar ratios within the 1.5–5 range were synthesized by coprecipitation and used as transesterification catalysts for the synthesis of biodiesel. The mixed oxides obtained after calcination recovered the hydrotalcite structure in the form of meixnerite after rehydration in boiling water. The solids were characterized by XRD, TGA, N2 adsorption-desorption, and SEM. Basic properties were assessed by means of Hammett indicators and CO2-TPD. Rehydrated materials with the highest Mg/Al ratios showed some distinctive features: low surface area, well defined flake-like crystals, high basicity and strong basic sites with H_ values above 11. They were also the most active catalysts allowing to achieve 51–75% sunflower oil methanolysis conversion after 8 h of reaction under mild conditions (60 °C, 1 atm), methanol/oil molar ratio of 12 using between 2 and 6 wt% of catalyst. The conversion increased up to 96% (92% fatty acid methyl esters yield) using 2 wt% catalyst and methanol/oil molar ratio of 48. Catalyst leaching was not a serious problem with these solids that could be reutilized maintaining very good activities. A general accordance between solids basic properties and their catalytic performance has been observed. These results are among the best reported in the literature for heterogeneous methanolysis catalysts and have been attributed to the high basicity of the rehydrated solids and the presence of strong and accessible basic sites probably consisting in interlayer hydroxide anions at the edges of the crystals.Publication Open Access Preparation of Al/Fe-pillared clays: effect of the starting mineral(MDPI, 2017) Muñoz Alvear, Helir Joseph; Blanco, Carolina; Gil Bravo, Antonio; Vicente, Miguel Ángel; Galeano, Luis Alejandro; Química Aplicada; Kimika AplikatuaFour natural clays were modified with mixed polyoxocations of Al/Fe for evaluating the effect of the physicochemical properties of the starting materials (chemical composition, abundance of expandable clay phases, cationic exchange capacity and textural properties) on final physicochemical and catalytic properties of Al/Fe-PILCs. The aluminosilicate denoted C2 exhibited the highest potential as starting material in the preparation of Al/Fe-PILC catalysts, mainly due to its starting cationic exchange capacity (192 meq/100 g) and the dioctahedral nature of the smectite phase. These characteristics favored the intercalation of the mixed (Al13x/Fex)7+ Keggin-type polyoxocations, stabilizing a basal spacing of 17.4 Å and high increase of the BET surface (194 m2/g), mainly represented in microporous content. According to H2-TPR analyses, catalytic performance of the incorporated Fe in the CatalyticWet Peroxide Oxidation (CWPO) reaction strongly depends on the level of location in mixed Al/Fe pillars. Altogether, such physicochemical characteristics promoted high performance in CWPO catalytic degradation of methyl orange in aqueous medium at very mild reaction temperatures (25.0 1.0 C) and pressure (76 kPa), achieving TOC removal of 52% and 70% of azo-dye decolourization in only 75 min of reaction under very low concentration of clay catalyst (0.05 g/L).