Lignin conversion into high added-value products.

230 p.(eng.) 232 p. (eusk.)El agotamiento de los recursos fósiles y el alto impacto ambiental que supone la no biodegradabilidad que presentan los materiales poliméricos procedentes de estas fuentes han promovido la necesidad urgente de buscar recursos alternativos sostenibles y más respetuosos con el medio ambiente como son los biopolímeros. Entre ellos, la lignina parece ser una candidata prometedora para la fabricación de compuestos como productos químicos y materiales. Sin embargo, este biopolímero está poco explotado, probablemente debido a su comportamiento recalcitrante y a su compleja estructura química, pero su valorización es esencial para que las biorrefinerías sean económicamente competitivas.En este contexto, esta tesis se centró en la revalorización de la lignina para su conversión en compuestos de alto valor añadido como los hidrogeles. Para ello, primeramente se llevó a cabo la optimización de la síntesis de hidrogeles físicos basados en lignina. A continuación, se estudió el efecto de varios parámetros sobre las propiedades finales de los materiales sintetizados y, finalmente, se testó su aplicabilidad en múltiples campos. Los resultados mostraron la importancia de la selección de los componentes así como del procedimiento de síntesis, y destacaron los beneficios que aporta la adición de lignina. Además, estos materiales presentaron resultados prometedores en la adsorción de colorantes y en el suministro de fármacos, y algunos de ellos presentaron también propiedades antifúngicas, haciéndolos útiles en muchos sectores. No obstante, los análisis de biocompatibilidad han evidenciado la necesidad de mejorar algunas características de los hidrogeles para su uso en biomedicina

Influence of lignin modifications on physically crosslinked lignin hydrogels for drug delivery applications

So far, the possibility of synthesizing hydrogels based on multiple biopolymers has been investigated, and among them lignin has proven to be one of the potentials for this purpose due to the multiple advantages it offers. However, because of its high molecular weight, steric hindrance and few reactive sites on its structure, it is sometimes necessary to improve its reactivity though chemical modifications. On the basis of previous results, two chemical modifications were selected in order to enhance almond, walnut and commercial alkaline and organosolv lignins' reactivity: a peroxidation reaction for alkaline ones and a hydroxymethylation for organosolv ones. Both reactions were confirmed by multiple techniques (i.e. FTIR, GPC and TGA). Hydrogels were syn-thesized from these lignins according to previous works. The high lignin waste of the synthesized hydrogels suggested that despite the modification of the lignins, just the highest molecular weight fractions reacted with the matrix polymer. Moreover, the swelling capacity of modified alkaline lignin-based hydrogels was negatively affected, whereas the one for organosolv lignin-based samples improved. The SEM micrographs explained the aforementioned, and the results from the DSC and compression tests were in accordance with them. Self -extracted quercetin loading and release studies suggested that these samples could be used for controlled drug delivery.The authors would like to acknowledge the financial support of the Department of Education of the Basque Government (IT1498-22) . A. Morales would like to thank the University of the Basque Country (Training of Researcher Staff, PIF17/207) . P. Gullón would like to acknowledge the Grants for the recruitment of technical support staff (PTA2019-017850-I) under the Spanish State Plan for Scientific and Technical Research and Innovation 2017-2020. The authors thank SGIker (UPV/EHU/ERDF, EU) for their technical and human support

Impact of the lignin type and source on the characteristics of physical lignin hydrogels

[EN] Multiple natural polymers have been investigated for the synthesis of hydrogels to the present date, but lignin has demonstrated to be a promising one for this purpose for the multiple advantages it offers. Lignin can be isolated from lignocellulosic material such as nut shells, which are usually undervalued wastes, and would be a great step forward on circular economy. Thus, in the present work, lignin was extracted from almond and walnut shells following a single-step (delignification) and double-step (autohydrolysis and delignification) biorefinery scheme. After the chemical composition and structures of these lignins were determined, hydrogels were synthesized combining them with poly (vinyl alcohol) by the means of freeze-thawing cycles so as to study the influence of the different lignins on their final properties. Additionally, the last thawing cycle of the synthesis process was lengthened in order to confirm previous assumptions about its effect on the characteristics of the synthesized materials. The obtained results showed significant variation between the 8 lignin samples, especially in their purity, molecular weights and total phenolic contents. The variation on the lignins leaded to several hydrogel morphologies, which directly affected their properties, primarily their swelling capacity, glass transition temperatures and compression strengths. It was also demonstrated the great effect that the duration of the last thawing had on the morphology and, hence, on the characteristics of the obtained materials. The synthesized samples were successfully employed as dye adsorbents and the evaluation of their antifungal activity showed positive results in some of the samples, which could be applied for food packaging.The authors would like to acknowledge the financial support of the Department of Education of the Basque Government (IT1008-16). A. Morales would like to thank the University of the Basque Country (Training of Researcher Staff, PIF17/207). P. Gull ' on would like to acknowledge the Grants for the recruitment of technical support staff (PTA2019-017850-I) under the State Plan for Scientific and Technical Research and Innovation 2017-2020. The authors thank SGIker (UPV/EHU/ERDF, EU) for their technical and human support

Integral valorisation of walnut shells based on a three-step sequential delignification

[EN] Walnut kernels represent no more than 50-60% of the total weight of the fruit, so the sum of walnut shells generated every year is immense. Nonetheless, these shells could be further valorised for the extraction of their main constituents following a biorefinery scheme. Hence, the objective of this work was an integral valorisation of walnut shells, which involved a sequential organosolv delignification (200 ?, 90 min, 70/30 v/v EtOH/H2O, LSR 6:1) and several posterior non-isothermal hydrothermal treatments (180, 195 and 210 ?, LSR 8:1). Moreover, the spent solids after the aforementioned treatments were evaluated as possible sources of cellulose nanocrystals. The results showed that the sequential organosolv delignifications presented relative lignin yields up to 60%, which leaded to lignins that just differed on their molecular weight distributions. The hydrothermal treatments were efficient for the removal of still present hemicelluloses (14.7-71.8%), and permitted a successful cellulose nanocrystal obtaining whereas the spent solid from the delignification stages did not. Thus, this study presented an innovative strategy for the integral valorisation of walnut shells.The authors would like to thank the Department of Education of the Basque Government (IT1008-16) for the financial support. A. Morales would like to thank the University of the Basque Country (Training of Researcher Staff, PIF17/207). The authors would like to thank SGIker for the provided technical and human support (UPV/EHU/ERDF, EU)

The meaning and evolution of the term "coeducation" with the turn of the century: the case of the schools of Vitoria-Gasteiz

El término coeducación se suele utilizar cuando se habla de perspectiva de género o feminista en educación o al situar este tema en la escuela. Sin embargo, parece que en ciertos ámbitos la coeducación es un tema del pasado, algo que ya se ha superado en educación. Por esta razón cuando se habla de ello hay personas que cuestiona la necesidad de tratar estos temas como parte del currículum, ya que creen que es solo la familia la que debe transmitir este tipo de valores, y sin embargo, hoy en día aún no se ha logrado llegar a una escuela coeducativa. Este estudio pretende comprender cómo se entiende el término coeducación y cuál ha sido su evolución. La presente investigación relata un estudio diagnóstico centrado en 30 centros escolares de Vitoria-Gasteiz, en el que a través de cuestionarios a profesorado y grupos de discusión con familias, profesorado y alumnado. Se trata de un estudio de caso que recoge diferentes concepciones sobre la coeducación en los centros de la ciudad. Los resultados aportados constatan que es necesaria una actualización conceptual, ya que este término sigue asociado a la escuela mixta y a un concepto de igualdad basado en un sistema binario, y no se relaciona con otras opciones más recientes relacionadas con la feminización del conocimiento, la revisión de la masculinidad o la visibilización y la valoración de la diversidadAs we speak about gender perspective or feminism in education or at the school, people use the coeducation concept. In some areas it seems like coeducation was an ancient subject, an acquired matter in education. For this reason when it comes to talking about it there are people who question the need to treat these issues as part of the curriculum, since they believe that it is only the family that should transmit this type of values, and yet today they still do not have managed to reach a coeducational school. However, we have not reached a coeducative school yet. That is why this research pretends to know how this concept is understand and which has been its evolution. In the present article the reader will find a diagnosis made in 30 schools in Vitoria-Gasteiz. In those schools has been done focus groups with families, teachers and students, and we have found different ways of looking to this term, coeducation. It is a case study that gathers different conceptions about coeducation in the city. We have concluded that an update is needed for this concept, since it is still related to the mixed school (girls and boys studying together), and to the idea of equality based on a binary social system. Thus, it is not related to more recent ideas, as the feminization of knowledge, the revision of the hegemonic masculinity, or the visibilization and valuation of the diversit

Integral Valorization of Posidonia oceanica Balls: An Abundant and Potential Biomass

Posidonia oceanica balls (POB), a kind of seagrass, are a significant environmental issue since they are annually discharged onto beaches. Their current usefulness limits interest in their management and enhances the environmental problem. Therefore, in this research, the potential of this lignocellulosic biomass was studied from a holistic biorefinery point of view. To this end, an in-depth study was carried out to select the best pathway for the integral valorization of POBs. First, an autohydrolysis process was studied for the recovery of oligosaccharides. Then, a delignification stage was applied, where, in addition to studying different delignification methods, the influence of the autohydrolysis pre-treatment was also investigated. Finally, cellulose nanofibers (CNFs) were obtained through a chemo-mechanical treatment. The results showed that autohydrolysis not only improved the delignification process and its products, but also allowed the hemicelluloses to be valorized. Acetoformosolv delignification proved to be the most successful in terms of lignin and cellulose properties. However, alkaline delignification was able to extract the highest amount of lignin with low purity. CNFs were also successfully produced from bleached solids. Therefore, the potential of POB as a feedstock for a biorefinery was confirmed, and the pathway should be chosen according to the requirements of the desired end products.This research was funded by the Ministry of Higher Education and Scientific Research of Tunisia and Gobierno Vasco/Eusko Jaurlaritza grant number IT-1498-22

Cross-Linked Carboxymethylcellulose Adsorbtion Membranes from Ziziphus lotus for the Removal of Organic Dye Pollutants

The goal of this study is to assess Ziziphus lotus’s potential for producing carboxymethylcellulose adsorption membranes with the ability to adsorb methyl green from wastewaters by the revalorization of its cellulosic fraction. The cellulose from this feedstock was extracted by an alkaline process and TAPPI standard technique T 203 cm-99 and afterwards they were carboxymethylated. The obtained carboxymethylcelluloses were deeply characterized, being observed that the carboxymethylcellulose produced from the alkaline cellulose presented the higher solubility due to its lower crystallinity degree (53.31 vs. 59.4%) and its higher substitution degree (0.85 vs. 0.74). This carboxymethylcellulose was cross-linked with citric acid in an aqueous treatment in order to form an adsorption membrane. The citric acid provided rigidity to the membrane and although it was hydrophilic it was not soluble in water. By evaluating the potential of the produced membrane for the removal of pollutant dyes from wastewater, it was observed that the adsorption membrane prepared from the carboxymethylcellulose’s produced from the Ziziphus lotus was able to remove 99% of the dye, methyl green, present in the wastewater. Thus, this work demonstrates the potential of the Ziziphus lotus for the production of a novel and cost-effective carboxymethylcellulose adsorption membrane with high capacity to treat wastewaters.This research was funded by Ministry of Higher Education and Scientific Research of Tunisia, I. Dávila would like to thank the University of the Basque Country (UPV/EHU) for their financial support (Grant reference DOCREC19/47)

Effect of Heat Treatment on the Microstructure and Hardness of Ni-Based Alloy 718 in a Variable Thickness Geometry Deposited by Powder Fed Directed Energy Deposition

Feature addition to existing parts is a trending application for Directed Energy Deposition (DED) and can be used to add complex geometry features to basic forged geometries with the aim to reduce and simplify the number of processing steps as machining and assembling. However, the mechanical properties of as-deposited Inconel 718 fabricated by Powder-fed Directed Energy Deposition (Powder-fed DED) are far lower than the relevant specifications, making it necessary to apply different heat treatment with the purpose of improving deposited material performance. In addition, the effects of heat treatments in both variable thickness deposited geometry and forge substrate have not been studied. In this study, the effect of heat treatment within the Aerospace Materials Specifications (AMS) for cast and wrought Inconel 718 on the microstructure and hardness of both the Ni-Based Alloy 718 deposited geometry and substrate are analyzed in different parts of the geometry. The microstructure of all samples (as-deposited and heat-treated) is analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS), confirming the formation of aluminum oxides and titanium nitrides and carbonitrides in the deposited structure.This research was funded by the vice-counsel of technology, innovation and competitiveness of the Basque Government (Eusko Jaurlaritza) under the ELKARTEK Program, QUALYFAM and EDISON projects, grant number KK-2020/00042 and KK-2022/00070, respectively

Bertso-eskolak: alderdi sozio-emozionalaren garrantzia ahalduntze prozesuan

The teaching of bertsolaritza focused on acquisition of the technique and traditionally bertsolaritza has been an activity of men (Larrañaga 2013: 41). However, there have been changes in society, which have influenced the system of bertsolaritza and teach methods. In this work we wanted to know what kind of methodology current women bertsolaris and teachers use in verse schools and formal education and how they manage the Socio-emotional aspect and the empowerment process, focusing on their discourses and practices. To this end, 10 in-depth interviews and 16 observations were made. Among the results it can be seen the development of emotional intelligence, both personal and group; the gender perspective has been embedded in both formal and non-formal education, and teachers are trying to empower all students to become active agents.Hasierako bertsolaritzaren irakaskuntza teknikaren jabekuntzan zentratzen zen eta tradizionalki bertsolaritza gizonen jarduera izan da (Larrañaga 2013: 41). Mende aldaketarekin batera ordea, gizartean aldaketak egon dira, eta aldaketa horiek bertsolaritzaren sisteman eta ikaskuntzan isla eta eragina izan dituzte. Lan honetan egungo emakume bertsolari eta irakasleek bertso-eskoletan eta hezkuntza arautuan zer-nolako metodologia erabiltzen duten eta alderdi sozio-emozionala eta ahalduntze prozesua zelan kudeatzen dituzten ezagutu nahi izan dugu, euren diskurtso eta praktikei arreta jarriz. Horretarako 10 elkarrizketa sakon eta 16 behaketa egin dira. Emaitzen artean ikus daiteke adimen emozionalaren lanketa egiten dela, bai pertsonala bai taldekoa; genero perspektiba esparru formal eta ez formaletan txertatu dela, eta irakasleak ikasle guztiak ahalduntzen saiatzen direla, ikasleak bide horretan agente aktibo bihurtze aldera

Life Cycle Assessment of various biorefinery approaches for the valorisation of almond shells

In the near future, sustainable and efficient biorefineries would be essential for the production of commodity chemicals and high-added value compounds. Therefore, in this work, six scenarios differing on the delignification steps and cellulose conversion routes were assessed via Life Cycle Assessment methodology in order to study the environmental impacts derived from the conversion of an abundant agricultural residue (almond shells) into high added-value products and select the most suitable one for large-scale valorisation. The assessments were conducted employing experimental results and processing them by SimaPro software. The main conclusion achieved suggested that the enzymatic hydrolysis of the solid from any delignification step entailed the highest environmental impacts and had the highest relative contribution in all the studied impact categories with a maximum of 74%, which was ascribed to Scenario 5. It was also concluded that the organosolv delignification process affected overall more negatively than the alkaline treatment having bigger impacts especially in abiotic depletion (ADP) and photochemical oxidation (POP) categories. Finally, it can be stated that the best route for valorising the almond shell in a biorefinery facility is composed of autohydrolysis (common for every scenario), alkaline delignification, bleaching and acid hydrolysis steps for the obtaining of oligosaccharides, lignin and nanocrystals as products.Authors want to acknowledge the University of the Basque Country UPV/EHU, as well as the Spanish Ministry of Science and Innovation (CTQ2016-78689-R) for supporting financially this research. L.S. and R.F. would like to acknowledge the Departmentof Economic Development and Infrastructures of the Basque Government (scholarship of young researchers training) . A.M. and I.D, would like to thank the University of the Basque Country (Training of Researcher Staff, PIF17/207 and grant reference DOCREC19/47, respectively)