Effect of hydrothermal pretreatment for fermentable sugars production using brown macroalgae as raw material

Energy high demands and concerns about global climate changes have led to the resurgence of biofuels as bioethanol. The conversion of biomass (macroalgae) into high added-value chemicals (pigments, food supplements, polymers, surfactants and fertilizer) and bioenergy renewable products as bioethanol is essential in order to sustain our present and future. The polysaccharides conversion from macroalgae to fermentable sugars and fuel ethanol production is still to be studied. For that reason, the aim of this work was to evaluate the production of fermentable sugars from brown macroalgae using hydrothermal pretreatment that it is considered an environmentally friendly process. The hydrothermal pretreatment was evaluated in different conditions of time and temperature. The best operating condition for the production of fermentable sugars was at 200 ºC for 30 min, obtaining 0.41 g of total sugars/ g of macroalgae, dry basis. The hydrothermal process proved to be a promising pretreatment to produce fermentable sugars

Glycine-betaine-derived ionic liquids: Synthesis, characterization and ecotoxicological evaluation

Ionic Liquids (ILs) are generically regarded as environmentally "harmless" and thus, assumed as "non-toxic". However, due to the endless design possibilities, their ecotoxicological profile is still poorly known. An accurate knowledge on the toxicity of a substance is required, under the scope of environmental regulation worldwide, before their application and commercialization. Knowledge on the relationship between the chemical structure and toxic effects is essential for the future design of more biocompatible solvents. Focusing on the use of ILs as base lubricants, lubricant additives, or even as potential working fluids for absorption heat pumps, the knowledge on its environmental impact is of great importance, due to the possibility of spills. In this specific context, four analogues of glycine-betaine-based ILs (AGB-ILs) and four glycine-betaine based ILs (GB-ILs) were synthesized and characterized. Their ecotoxicity was assessed using representatives of two trophic levels in aquatic ecosystems, the bacteria Allivibrio fischeri (commonly used as a screening test organism) and the microalgae Raphidocelis subcapitata (as an alternative test organism that has been proven very sensitive to several IL families). The microalgae were more sensitive than the bacteria, hence, following a precautionary principle, we recommend considering the toxicity towards microalgae as an indicator in future studies regarding the focused ILs. Although four of the studied ILs were derived from a natural amino acid, all were considered hazardous for the aquatic environment, disproving the primary theory that all ILs derived from natural compounds are benign. Furthermore, the modification in the structure of anion and the cation can lead to the increase of toxicity.publishe

Synthesis, microstructure and volumetry of novel metal thiocyanate ionic liquids with [BMIM] cation

We present a new family of ionic liquids (ILs) with a common cation, 1-butyl-3-methyl imidazolium, the popular [BMIM]+ (also written C4C1Im+) and a variety of anionic complexes (also called adducts) based in thiocyanate (SCN)?: one blank compound, BMIM(SCN), and ten doped with metals having different oxidation states: Al+3, Mn+2, Fe+3, Cr+3, Ni+2, Hg+2, Zn+2, Co+2, Cd+2 and Cu+, forming, respectively, [BMIM]3[Al(SCN)6], [BMIM]4 Mn(SCN)6, [BMIM]3 Fe(SCN)6, [BMIM]3 Cr(SCN)6, [BMIM]4 Ni(SCN)6, [BMIM]2 Hg(SCN)4, [BMIM]2 Zn(SCN)4, [BMIM]2 Co(SCN)4, [BMIM]2 Cd(SCN)4 and [BMIM]3 Cu(SCN)4. All of them were synthesized by us, except the blank IL and the Co thiocyanate, which are commercial. Obtained products have been characterized by NMR, and also by electrospray ionization, MS-ES, which allows the determination of the new ILs purities. Then, compounds have been analyzed using FT-IR and Raman spectroscopy. In addition, magnetic susceptibility and refractive index measurements were performed in some of the compounds studied, as well as thermal characterization using DSC and TGA. Finally, experimental measurements of density on all those ILs have been performed, and for some of the samples in a broad temperature range (about 100 K). In spite of being very similar compounds from the chemical point of view, they present quite different physical properties, including optical, thermal and magnetic ones? Also, they show different oxidation states (one with +1, six with +2 and other three with +3). We guess that this family of ILs will have interesting applications, mainly for photonic devices

Is the Impact of Ethylammonium Nitrate on Soil Basal Respiration Modified by Addition of Aluminium Salt to Improve the Performance in Electrochemical Applications?

10 páginas, 5 tablas, 1 figuraInterest in the possible use of EAN in electronic devices has increased in recent years. EAN can be used directly as an electrolyte, but its application could potentially be optimized by mixing with a metal salt such as Al(NO3)3. Although ionic liquids (ILs) have been considered to cause little harm because they are non-volatile, they can have toxic effects on the terrestrial environment. In this study, the impact on soil basal respiration of EAN alone, a mixture of EAN and Al(NO3)3, and Al(NO3)3 alone was investigated using two soils with different organic matter contents. The Al(NO3)3 did not affect soil respiration in either soil, while EAN, either alone or mixed with Al(NO3)3 affected both soils.This research was financially supported by the Spanish MICINN through project CGL2015-66857-C2-1-R co-financed by the ERDF, and by the Xunta de Galicia through the RCG project IN607A 2017/06, the Contrato-Programa IIAG-Xunta 2021-2022, and the Galician Network project ED431D 2017/06. J. J. Parajó wishes to thank the I2C postdoctoral program of the Xunta de Galicia for support in funding the study. E. Priano is grateful for funding support from the Enhancing Mobility Between Latin-American and Caribbean Countries and Europe Program (Argentina-España, 2018)Peer reviewe

Is the Impact of Ethylammonium Nitrate on Soil Basal Respiration Modified by Addition of Aluminium Salt to Improve the Performance in Electrochemical Applications?

Interest in the possible use of EAN in electronic devices has increased in recent years. EAN can be used directly as an electrolyte, but its application could potentially be optimized by mixing with a metal salt such as Al(NO3)3. Although ionic liquids (ILs) have been considered to cause little harm because they are non-volatile, they can have toxic effects on the terrestrial environment. In this study, the impact on soil basal respiration of EAN alone, a mixture of EAN and Al(NO3)3, and Al(NO3)3 alone was investigated using two soils with different organic matter contents. The Al(NO3)3 did not affect soil respiration in either soil, while EAN, either alone or mixed with Al(NO3)3 affected both soils

Mixtures of ethylammonium nitrate and ethylene carbonate: Bulk and interfacial analysis

The structure and dynamics of binary mixtures of a protic ionic liquid (ethylammonium nitrate) and ethylene carbonate are studied by means of atomistic molecular dynamics simulations and experimental measurements both in bulk and at the electrochemical interface. The solubility limit was experimentally found at 0.6 carbonate molar fraction. Likewise, density and conductivity experimental data are compared with computational results. Also, distribution and correlation functions obtained from bulk simulations are analyzed in the miscible range to clarify the role of the carbonate in the coordination and diffusion of ionic species. Understanding the evolution of the hydrogen bond network is of particular importance since its strength is detected as the most relevant feature in the structural organization of the mixture. Regarding the effects of the presence of an interface, the orientations of the molecules and the density and charge profiles are calculated both in the absence and in the presence of an electric field. This analysis reveals the tendency of the carbonate to displace the ionic liquid from the near-wall region when concentration is increasedhe financial support of the Spanish Ministry of Science and Innovation (PID2021-126148NA-I00 funded by MCIN/AEI/10.13039/501100011033/FEDER, UE) is gratefully acknowledged. Moreover, this work was funded by the Xunta de Galicia (ED431E 2018/08 and GRC ED431C 2020/10). All these research projects were partially supported by FEDER. Authors acknowledge P. Rojo-Garea (iMATUS, University of Santiago de Compostela) for the technical support in conductivity experimental measurements. A.R.P. thanks the Spanish Ministry of Education for his FPU grant. M.O.L. wishes to thank the Xunta the Galicia for his “Axudas de apoio á etapa predoutoral” grant. T. M. M. acknowledges her contract funded by the pilot program of the USC for the recruitment of distinguished research personnel—call 2021 under the agreement between the USC and the Santander Bank for 2021–2024. H.M.C. thanks the USC for his “Convocatoria de Recualificación do Sistema Universitario Español-Margarita Salas” postdoctoral grant under the “Plan de Recuperación Transformación” program funded by the Spanish Ministry of Universities with European Union's NextGenerationEU funds. P.V. thanks the Spanish Ministry of Education for his FPI grant. J.J.P. thanks I2C postdoctoral Program of Xunta de Galicia. R.L.C. acknowledges his Predoctoral Contract under the framework of the project PID2021-126148NA-I00 funded by MCIN/AEI/10.13039/501100011033/FEDER, UE. Facilities provided by the Galician Supercomputing Centre (CESGA) are also acknowledgedS