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Reñones, Patricia; Moya, Alicia; Fresno, Fernando; Collado, Laura; Vilatela, Juan J.; de la Peña O’Shea, Víctor A. (Journal of CO2 Utilization (ELSEVIER), April 18, 2016)[+][-]
Resumen: In this research work, the gas phase CO2 photocatalytic reduction using water as electron donor has been performed using hierarchical assemblies of mesoporous TiO2 1-D nanofibres synthesised by a combination of electrospinning and sol–gel methods. In order to compare the effect of the crystallisation step on oxygen vacancies and conductivity, two different annealing conditions have been undertaken: under a high Ar flow (“TiO2 Fibres-A” sample) and under static Ar (“TiO2 Fibres B” sample). Moreover, these materials have been compared with individualised TiO2 nanoparticles prepared by a sol-gel procedure. CO and H2 are detected as major products with all photocatalysts, with lower amounts of CH4 and CH3OH. The TiO2 nanofibres exhibit better results than the sol-gel photocatalyst, behaviour that may be ascribed to an improved nanocrystals connection, which favours a fast charge transport along the grain boundaries, as measured by electrochemical impedance spectroscopy (EIS). The highest CO2 reduction activity is achieved with the TiO2 Fibres B catalyst, which gives rise to ca. 4 and 2.5 times higher H2 and CO production, respectively, than the TiO2 Fibres-A one. This sample is composed of a mixture of anatase and rutile crystalline phases (80:20), leading to a decrease in the electron-hole recombination rate observed by photoluminescence (PL) measurements. URI: http://hdl.handle.net/11034/83 Ficheros en el ítem: 1
1. ELSEVIER_JCO_in press.pdf (2.609Mb) -
Alvira, Pablo; Moreno, David; Ibarra, David; Saez, Felicia; Ballesteros, Mercedes (December 12, 2013)[+][-]
Resumen: Operating the saccharification and fermentation processes at high substrate loadings is a key factor for making ethanol production from lignocellulosic biomass economically profitable. However, increasing the substrate loading presents some disadvantages, among them larger generation of inhibitors, which negatively affect fermentation performance. In this study, laccase enzymatic treatment was evaluated as a method to reduce these inhibitory effects. The laccase efficiency was analyzed in a presaccharification and simultaneous saccharification and fermentation process (PSSF) at different high substrate loadings. Water insoluble fraction (WIS) from steam-exploded wheat straw was used as substrate and Saccharomyces cerevisiae as fermenting organism. Laccase supplementation reduced strongly the phenolics content in the media, without affecting weak acids and furan derivates. It resulted in an improved yeast performance during simultaneous saccharification and fermentation process, increasing significantly ethanol productivity. URI: http://hdl.handle.net/11034/71 Ficheros en el ítem: 1
Paper Biotechnolgy Progress 2012.pdf (1.494Mb) -
Duque, Aleta; Manzanares, Paloma; Ballesteros, Ignacio; Negro, Maria José; Oliva, Jose Miguel; Saez, Felicia; Ballesteros, Mercedes (December 12, 2013)[+][-]
Resumen: In this work, an integrated one-step alkaline-extrusion process was tested as pretreatment for sugar production from barley straw (BS) biomass. The influence of extrusion 10 temperature (T) and the ratio NaOH/BS dry matter (w/w) into the extruder on pretreatment effectiveness was investigated in a twin-screw extruder at bench scale . A 23 factorial response surface design of experiments was used to analyze the effect of process conditions [T: 50- 100ºC; NaOH/BS ratio: 2.5-7.5% (w/w)] on composition and enzymatic digestibility of pretreated substrate. The optimization of these process variables for a maximum glucan to 15 glucose conversion was determined to be at 6% NaOH/DM and 68ºC. At these conditions, glucan yield reached close to 90% of theoretical, while xylan conversion was 71 % of theoretical. These values are 5 and 9 times higher than that of the untreated material, which supports the great potential of this one-step combined pre-treatment technology for sugar production from lignocellulosic substrates URI: http://hdl.handle.net/11034/72 Ficheros en el ítem: 1
Paper Process Biochemistry 2013.pdf (130.4Kb)
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