Escuela de Química

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14435

Misión Contribuir con el desarrollo integral de la sociedad costarricense en un marco de solidaridad y armonía con la naturaleza, por medio de su quehacer en investigación, extensión, docencia y producción, lo que permite la generación de conocimiento, la vinculación externa y la formación y actualización de profesionales en Enseñanza de la Química, Química y sus aplicaciones. Visión Es la Escuela de Química con liderazgo por su excelencia académica, innovación, y vocación de servicio en las áreas de Enseñanza de la Química, Química y sus aplicaciones. Goza de prestigio, a partir de una oferta académica (investigación, docencia, extensión y producción) actualizada, flexible y que responde a las necesidades emergentes del desarrollo nacional e internacional.

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Mostrando 1 - 20 de 180

Acerola (Malpighia spp.) Waste: A Sustainable Approach to Nutraceutical, Pharmaceutical, and Energy Applications
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2023) Jose-Roberto, Vega-Baudrit; Camacho Elizondo, Melissa; Batista-Menezes, Diego; Corrales-Ureña, Yendry; Zúñiga, Juan Miguel; Mora Chacón, Arturo; Lecot, Nicole; Castillo Henríquez, Luis; Lopretti, Mary
Abstract. This study reviews the many uses for waste generated from acerola (Malpighia spp.) production, a tropical fruit renowned for its nutrient-rich content. Traditionally considered an environmental burden, this waste is now gaining attention for its sustainable applications in green technology. This review outlines the extraction of valuable bioactive compounds, like polyphenols, carotenoids, and pectin, that can be extracted from the acerola fruit and acerola waste, and it also delves into its potential in materials science, particularly in the creation of pharmaceutical formulations, nanomaterials, composites, biofuels, and energy applications. On the medical front, the paper highlights the promise that acerola waste holds in anti-inflammatory, antihyperglycemic, and anticancer therapies. By outlining challenges and opportunities, the review emphasizes the untapped potential of acerola waste as a resource for high-value products. These findings suggest a paradigm shift, turning what has been considered waste into a sustainable asset, thereby encouraging environmentally responsible practices within the fruit industry.
Adaptación del Método de Descarga de Arco Voltaico para la Síntesis de Nanotubos de Carbono de Pared Simple
(Universidad del País Vasco (España), 2011) Ramirez Amador, Sergio Alberto; Jose-Roberto, Vega-Baudrit
Resumen. Se obtuvieron nanotubos de carbono de pared simple (SWCNT, en inglés) por el método de descarga de arco voltaico. El anterior es un método sencillo, económico y energéticamente eficiente empleado para la síntesis de nanotubos de carbono de alta calidad sin la necesidad de catalizadores. En esta investigación, la metodología fue optimizada variando el amperaje de la fuente de poder, naturaleza y presión del gas de protección. La caracterización de los nanotubos de carbono de pared simple obtenidos fue realizada por análisis microscópicos (SEM, TEM y AFM), térmicos (TGA) y espectroscópicos (FTIR).
Advanced Extraction and Comprehensive Characterization of Sustainable Textile Fibers from Mango (Mangifera indica L.) Waste
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2024) Ferreiro, Omayra; Mallorquín, Rodrigo; Rodas, Jorge; Vargas, Violeta; Flecha, Aida; Jose-Roberto, Vega-Baudrit; Duarte, Shirley; Batista, Diego; RIVALDI CHAVEZ, JUAN DANIEL
Abstract. The global textile sector, pivotal to economic development, significantly contributes to environmental degradation, prompting a shift towards sustainable raw material sources. Embracing circular economy principles, this industry is exploring the valorization of agricultural by-products. This study introduces an innovative approach to repurposing mango waste into valuable textile fibers, a byproduct of the fruit processing industry, predominantly generated during juice and jam production. The focus is on the lignocellulosic constituents of mango waste, specifically the peel, seed, and fibrous material, traditionally considered as refuse. Previous research has predominantly utilized mango peel in pectin extraction for food applications, whereas the potential of seed and fibrous content remains underexplored. This investigation endeavors to transform these fibrous by-products into high-value materials suitable for textile manufacturing. The process involved washing, drying, and comprehensive physicochemical characterization of mango fibers, emphasizing lignin quantification, revealing a composition of 12.2% lignin. An experimental design was employed to elucidate the impact of variables such as liquid-to-solid ratio, reaction duration, and sodium hydroxide concentration on lignin dissolution through alkaline hydrolysis. Optimal conditions—10% NaOH concentration, 30 mL/g liquid-to-solid ratio over six hours—achieved an 83% reduction in lignin content. The resulting fibers exhibited properties akin to conventional natural fibers, including a favorable aspect ratio indicative of their suitability for textile applications. A subsequent softening process using propylene glycol enhanced the fibers’ spinability, producing a durable, textured fabric ideal for eco-conscious fashion applications, including bags, footwear, and accessories. This research demonstrates the feasibility of converting mango waste into a textile-worthy material and underscores the importance of waste revalorization in promoting sustainability within the circular economy framework.
Agro-Industrial Avocado (Persea americana) Waste Biorefinery
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2021) Mora-Sandí, Anthony; Ramírez-González, Abigail; Castillo-Henríquez, Luis; Lopretti-Correa, Mary; Jose-Roberto, Vega-Baudrit
Abstract. Significant problems have arisen in the last years, such as climate change, global warming, and hunger. These complications are correlated with the depletion and exploitation of natural resources and environmental contamination. Due to overcrowding, the list of challenges for the next few years is growing. A comprehensive approach was made to the agro-industrial production of Avocado (Persea americana) and the management of all its biomass waste. So, bioprocesses and biorefinery can be used to produce high added-value products. A large number of residues are composed of lignin and cellulose. They have many potentials to be exploited sustainably for chemical and biological conversion; physical, chemical, and natural treatments improve the following operations. There are some applications to many fields such as pharmaceutical, medical, material engineering, and environmental remediation. Possible pathways are mentioned to take advantage of Avocado as biofuels, drugs, bioplastics, and even in the environmental part and emerging technologies such as nanotechnology using bioprocesses and biotech. In conclusion, Avocado and its waste could be transformed into high value-added products in industries above to mitigate global warming and save non-renewable energy.
Agua, naturaleza y seguridad hídrica
(Universidad Nacional, Costa Rica, 2022) Suárez Serrano, Andrea; Alfaro-Chinchilla, Carolina; Bautista-Solís, Pável
Boletín técnico sobre Soluciones Basadas en la Naturaleza (SbN). Los ecosistemas naturales generan importantes servicios ecosistémicos que son utilizados por los ecosistemas naturales y la sociedad. El agua es un recurso estratégico y vital para la vida. En esta obra se revisa el concepto y algunos ejemplos de Soluciones Basadas en la Naturaleza que son importantes para fortalecer la seguridad hídrica de Costa Rica.
Aislamiento y purificación de la enzima lacasa: evaluación de su potencial biodegradador en residuos agrícolas
(Sociedad Mexicana de Biotecnología y Bioingeniería (México), 2020) Valdés, Sandra; Garita, Cristian; Esquivel, Carmenza; Villegas Peñaranda, Luis Roberto
Resumen. A nivel mundial, el inadecuado manejo de los residuos está generando el deterioro acelerado del planeta y, Costa Rica no es la excepción. Con el objetivo de aislar y purificar la enzima lacasa para la evaluación de su potencial degradador de residuos agrícolas, se obtuvieron cultivos axénicos de Ganoderma applanatum y Trichoderma harzianum, en los cuales se determinó la actividad de la enzima lacasa mediante la oxidación del ABTS. El aislamiento de G. applanatum registró la mayor concentración de la enzima, por lo que fue parcialmente purificada mediante electroforesis en gel de poliacrilamida (SDS-PAGE), luego el extracto enzimático fue purificado con filtro Vivaspin de 20 ml y peso molecular 50 kDa. Posteriormente, se llevaron a cabo los tratamientos enzimáticos de los residuos agroindustriales de caña, piña y banano durante 45 días. Los resultados mostraron que la enzima redujo la concentración de lignina en los residuos de banano y caña en lapsos que oscilaron entre 15 y 45 días.
An in situ approach to entrap ultra-small iron oxide nanoparticles inside hydrophilic electrospun nanofibers with high arsenic adsorption
(Elsevier (Países Bajos), 2023) Torasso, Nicolás; Vergara-Rubio, Alicia; Pereira, Reinaldo; Martinez-Sabando, Javier; Jose-Roberto, Vega-Baudrit; Cerveny, Silvina; Goyanes, Silvia
Abstract. The problem of arsenic contamination in water demands sustainable, scalable, and easy-to-implement solutions. Various nano-adsorbents flourished in the last decade, but their use alone requires additional filtering processes to avoid environmental contamination. This work presents a simple, efficient, green approach to overcome this inconvenience while maximizing adsorption capacity. We show for the first time a novel approach to synthesizing ultra-small nanoparticles (IONPs) within electrospun hydrophilic poly(vinyl alcohol) (PVA) nanofibers, avoiding NPs release into the environment when submerged in water. The in-situ synthesis favor enhanced arsenic adsorption capacity due to the excellent dispersion, tiny size, and surface availability of IONPs, reaching 3.5 mg/g at 10 μg/L. We show that IONPs alter the polymeric matrix properties, such as the glass transition temperature and crystallinity, by preventing the formation of strong hydrogen bond inter/intramolecular interactions of PVA. Insolubility and swelling capacity are essential characteristics of this membrane, which allow solution interchange for arsenic adsorption onto IONPs. Isotherm studies show that the increase from 1 wt% to 3 wt% of IONPs content decreases the active sites for adsorption per mass of IONPs. Still, it does not alter the reusability of the membrane, which reaches at least 3 adsorption cycles with 80 % efficiency. We discuss the adsorption mechanisms and show that phosphate anions partially inhibit As(V) adsorption and that the membranes are also highly capable of removing Cr(VI), independently of the presence of Ni(II).
Análisis de la producción de metano entérico generado vía fermentación ruminal In vitro
(Universidad Nacional (Costa Rica), 2020) Martínez Arroyo, Mariela; Esquivel Hernández, Germain
La generación de CH4 entérico de origen bovino es una problemática que afecta el balance radiativo del planeta, ya que, el potencial de calentamiento global del CH4, debido a la absorción de radiación infrarroja, es 28 veces mayor al del CO2. La concentración de este gas en la atmósfera es favorecida por la fermentación de las pasturas que realizan los animales rumiantes de los sistemas ganaderos y significa una pérdida de la energía asimilable por la alimentación de hasta un 12 %, lo cual implica problemas en su desarrollo, así como una disminución en la calidad de los productos que se obtienen de este. En este estudio se analizaron seis especies de pastos tropicales (kikuyo, ratana, mombaza, toledo, diamantes y estrella africana) para evaluar su emisión de CH4, vía digestión ruminal in vitro. Para ello, se muestrearon las especies en cuatro edades de rebrote: 14, 28, 42 y 56 días, entre abril y mayo del 2018. Las muestras recolectadas se incubaron para una fermentación en frascos provistos de un sensor de presión, el cual registró las variaciones en la presión total del sistema, producto de la generación de gases de la fermentación de cada pasto. La fermentación se llevó a cabo a 39 °C, a un pH de 7,01 y por 24 h, las cuales se determinaron que eran las condiciones óptimas para el análisis. Se obtuvo que el pasto que generó la mayor cantidad de CH4 fue el estrella africana, con un promedio de concentración de 0,360 g/kg, mientras que la especie que emitió menos gas fue el kikuyo, con un promedio de concentración de 0,095 g/kg. Estos pastos tuvieron promedios de generación significativamente distintos (p < 0,05) a las especies restantes. Las emisiones de las otras pasturas estuvieron entre 0,178 g/kg y 0,250 g/kg. La emisión de CH4 del pasto mombaza a los 14 días de edad fue significativamente distinta (p < 0,001) a la generación del gas en las demás edades de rebrote de esta especie, para el grupo 1 (14 días de rebrote) fue en promedio de 0,43 g/kg, mientras que la del grupo 2 (28, 42 y 56 días) fue de 0,182 g/kg. Se identificó una correlación (método de Spearman) significativa (p < 0,05) entre la emisión de CH4 del pasto mombaza a los 28, 42 y 56 días de rebrote, con la fibra detergente neutro (FDN), la proteína y la edad. Además, se modeló la emisión de CH4 de estas edades (28, 42 y 56 días), donde la variable predictiva fue la proteína y el R2 de 0,81. Se concluyó que el factor más determinante en la generación de CH4 fue la composición química del tipo de pasto, la cual no necesariamente va en detrimento con la edad, ya que hay otros elementos asociados como la acumulación de carbohidratos solubles que influyen en la digestión ruminal. Sin embargo, para escoger el mejor forraje para el pastoreo, deben considerarse componentes adicionales a la generación de metano, tales como la productividad por unidad de área, meteorología y el tipo de suelo, así como la calidad nutricional.
Aplicación de la microextracción en fase sólida y de la cromatografía de gases - Fid para la evaluación de la concentración del éter metil terc-butílico (MTBE) en agua de lluvia y subterránea
(Universidad Nacional (Costa Rica), 2009) Vega Guzmán, Ilena; Valdés González, Juan
Se implementó el análisis del éter metil terc-butílico (MTBE) en agua de lluvia y en agua subterránea, utilizando la microextracción en fase sólida por espacio de cabeza (SPME/HS). La determinación analítica se realizó empleando cromatografía de gases con un detector de ionización de llama (FID). Para la extracción del MTBE se utilizaron fibras de 65-pm, con una fase estacionaria de polidimetilsiloxano - djvinilbenceno (PDMS/DVB). En la etapa de extracción se optimizaron la temperatura, el tiempo de extracción y la fuerza iónica, utilizando una disolución de cloruro de sodio, mediante el diseño estadístico de variación en un solo factor. Se obtuvo la mayor extracción del MTBE a 26,00 ± 0,01 0C, 8,000 ± 0,005 min y a una concentración de cloruro de sodio de 300,0 ± 0,4 g/L. En la etapa de desorción se optimizaron la temperatura, el tiempo de desorción y la profundidad de inserción de la fibra en el inyector, obteniéndose la mayor desorción a 250 ± 10C, 2,000 ± 0,001 min y 3,8 ± o,lcm. Se determinaron la linealidad, ja reproducibilidad, la repetibilidad, la precisión, el límite de detección (0,3 pg/L) y el límite de cuantificación (0,6 pg/L) del método de análisis. El coeficiente de correlación fue de 0,9991, el porcentaje de recuperación de 100 ± 1 % y el porcentaje del desvío relativo fue de 5,3 ± 0,1 0/0. Además, se verificó la linealidad y homocesdasticidad, en un ámbito de O a 160 ± 0,3 pg/L MTBE, del método con las pruebas estadísticas y Cochran, con la cual se demostró que el método de análisis es válido desde el punto de vista analítico. El método de análisis se aplicó a muestras de agua de lluvia recolectadas durante siete días en Pavas, San José y a aguas subterráneas del pozo AB-1089, ubicado en Barreal de Heredia. Las concentraciones promedias del MTBE, durante el muestreo de agua de lluvia en Pavas, se encontraron por debajo del límite de cuantificación del método (0,6 ug/L MTBE). En el caso de las aguas subterráneas, las concentraciones promedio de MTBE en el piezómetro 1, del pozo AB- 1089, fue de 3,7 ± 0,3 pg/L MTBE, el cual no sobrepasó la normativa establecida para aguas subterráneas por la UE (10 pg/L MTBE) y la EPA (40 pg/L MTBE). Las concentraciones oscilaron entre 0,6 y 9,4 ± 0,3 pg/L MTBE. El valor máximo encontrado estuvo muy cerca del límite establecido por la Unión Europea, aunque el promedio de 3,7 ± 0,3 pg/L MTBE está 2,7 veces debajo de la norma.
Aplicación de un método para evaluar el impacto ambiental de proyectos de construcción de edificaciones universitarias
(2016) mora barrantes, jose carlos; Molina-León, Oscar Mario; Sibaja, José
La evaluación de impacto ambiental consiste en la identificación y valoración de los impactos potenciales de proyectos respecto a los componentes físicos, químicos y biológicos, culturales, económicos y sociales, con el fin de que mediante la planificación y la correcta toma de decisiones se desarrollen aquellas actuaciones más compatibles con el medio ambiente. El objetivo principal es asegurar que las consideraciones ambientales sean explícitamente expresadas e incluidas en el proceso de toma de decisiones y anticipar y evitar, minimizar y compensar los efectos negativos sobre el medio ambiente. Al proceso de evaluación ambiental de un proyecto se le pueden aplicar diferentes técnicas metodológicas, algunas generales, otras de carácter más específico. En Costa Rica la metodología más común es la elaborada por la Secretaría Técnica Ambiental (SETENA, 2016A). Con el fin de valorar el impacto ambiental de los proyectos de construcción en una universidad, se aplicó el formulario ambiental del SETENA, identificándose la magnitud de los factores, componentes y subcomponentes ambientales significativos de cada uno de ellos (SETENA, 2016B). La investigación permitió obtener y analizar los valores de significancia del impacto ambiental de los proyectos en función de: la cantidad de aspectos ambientales, la aplicación de reglamentos específicos, la ubicación geográfica del proyecto y el uso guías ambientales. Se identificaron los proyectos con mayor o menor cantidad de subcomponentes ambientales significativos, metros cuadrados de construcción, y valores de impacto ambiental preeliminar, ponderado y final. Se analizó la relación existente entre la cantidad de aspectos ambientales significativos de cada proyecto y su influencia en el valor final de significancia ambiental.
Application of a Sulfur Removal Hydrometallurgical Process in a Lead-Acid Battery Recycling Plant in Costa Rica
(Scientific Research Publishing Inc., 2017) Navarro-Monge, Marta; Esquivel-Hernández, Germain; Sibaja, José; mora barrantes, jose carlos; Sanchez-Murillo, Ricardo; Valdés-González, Juan; Bolaños-Ulloa, Pablo
This study presents the implementation of a desulphurization process for lead recycling under different chemical and physical conditions using pyro-metallurgical processes. Desulphurization was done using a hydrometallurgical process using sodium carbonate as a desulphurization agent and different lead bearing loads compositions. Waste characterization included: SO2 concentrations in the stack emissions, total lead content in the furnace ash, the total lead content in the slag, and the toxicity characteristic leaching procedure (TCLP). A significant reduction in SO2 emissions was achieved (~55% reduc tion) where mean SO2 concentrations changed from 2193 ± 135 ppm to 1006 ± 62 ppm after the implementation of the modified processes. The desulfurized lead paste (i.e. the metallic fraction lead of the battery) of the modified process exhibited an improvement in the concentration of the lead in the TCLP test, with an average value of 1.5 ppm which is below US EPA limit of 5 ppm. The traditional process TCLP mean value for the TCLP was 54.2 ppm. The total lead content in the bag house ashes shows not significant variations, when comparing the desulphurization (67.6% m/m) and non-desulphurizationvprocess (64.9% m/m). The total lead mean content in the slag was higher in the desulphurization process (2.49% m/m) than the traditional process (1.91% m/m). Overall, the implementation of a new esulphurization method would potentially increase the operation costs in 10.3%. At the light of these results, a combination of hydrometallurgical and pyro-metallurgical processes in the recycling of lead-acid batteries can be used to reduce the environmental im pact of these industries but would increase the operational costs of small lead recyclers.
Application of Poly-L-Lysine for Tailoring Graphene Oxide Mediated Contact Formation between Lithium Titanium Oxide LTO Surfaces for Batteries
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2022) Borge-Durán, Ignacio; Grinberg, Ilya; Jose-Roberto, Vega-Baudrit; Nguyen, Minh Tri; Pereira-Pinheiro, Marta; Thiel, Karsten; Noeske, Paul-Ludwig Michael; Rischka, Klaus; Corrales, Yendry
Abstract. When producing stable electrodes, polymeric binders are highly functional materials that are effective in dispersing lithium-based oxides such as Li4Ti5O12 (LTO) and carbon-based materials and establishing the conductivity of the multiphase composites. Nowadays, binders such as polyvinylidene fluoride (PVDF) are used, requiring dedicated recycling strategies due to their low biodegradability and use of toxic solvents to dissolve it. Better structuring of the carbon layers and a low amount of binder could reduce the number of inactive materials in the electrode. In this study, we use computational and experimental methods to explore the use of the poly amino acid poly-L-lysine (PLL) as a novel biodegradable binder that is placed directly between nanostructured LTO and reduced graphene oxide. Density functional theory (DFT) calculations allowed us to determine that the (111) surface is the most stable LTO surface exposed to lysine. We performed Kubo–Greenwood electrical conductivity (KGEC) calculations to determine the electrical conductivity values for the hybrid LTO–lysine–rGO system. We found that the presence of the lysine-based binder at the interface increased the conductivity of the interface by four-fold relative to LTO–rGO in a lysine monolayer configuration, while two-stack lysine molecules resulted in 0.3-fold (in the plane orientation) and 0.26-fold (out of plane orientation) increases. These outcomes suggest that monolayers of lysine would specifically favor the conductivity. Experimentally, the assembly of graphene oxide on poly-L-lysine-TiO2 with sputter-deposited titania as a smooth and hydrophilic model substrate was investigated using a layer-by-layer (LBL) approach to realize the required composite morphology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM) were used to characterize the formed layers. Our experimental results show that thin layers of rGO were assembled on the TiO2 using PLL. Furthermore, the PLL adsorbates decrease the work function difference between the rGO- and the non-rGO-coated surface and increased the specific discharge capacity of the LTO–rGO composite material. Further experimental studies are necessary to determine the influence of the PLL for aspects such as the solid electrolyte interface, dendrite formation, and crack formation.
Artes visuales aplicadas a la enseñanza de las ciencias: De cómo la práctica artística puede orientarse hacia una enseñanza científica diversificada
(Universidad Nacional (Costa Rica), 2019) Morales-Víquez, José Pablo; Piedra-Marin, Gilberto; ESQUIVEL ALFARO, MARIANELLY
Resumen. El presente trabajo describe brevemente algunas de las actividades que se han realizado en el marco de una investigación entre artes visuales y química, cuyo proceso ha servido para identificar prácticas que se consideran relevantes e innovadoras, con potencial para su aplicación pedagógica. El objetivo de la investigación radica en identificar en estas prácticas interdisciplinarias aquellas potenciales aplicaciones para la enseñanza de las ciencias. La metodología aplicada ha sido empírico-sistemática, donde a partir de la exploración se han sistematizado los procesos pertinentes para el ejercicio didáctico de contenidos específicos, y que a través de lo visual se exploran contenidos propios de la disciplina científica. Entre los principales hallazgos se encontró el uso de reacciones químicas desde la óptica artística, cuyo aporte tanto desde lo visual como pragmático recae en una nueva forma de explorar contenidos científicos, contribuyendo así a una enseñanza interactiva y diversificada que busca huir del hermetismo convencional.
Bayesian estimates of the mean recharge elevations of water sources in the Central America region using stable water isotopes
(Elsevier, 2020) Avellano, L. Nicole; Good, Stephen; Sanchez-Murillo, Ricardo; Jarvis, Todd; NOONE, DAVID; Finkenbiner, Catherine
Abstract. Study region: Central America. Study focus: Knowledge of the mean recharge elevation (MRE) of water resources is important where water resources are vulnerable. The purpose of this study was to develop and apply a Bayesian approach which incorporates isotopic uncertainties and evaporative effects on isotopic compositions to determine the MRE of 680 surface water sources from Central America. Differences were assessed between results from our approach and those from other isotope-based methods that do not account for these factors. New hydrological insights for the region: Different MRE patterns were identified for Pacific and Caribbean basins, which were characterized by distinct isotopic signatures: 1) the Pacific slope had recharge occurring at higher elevations relative to the source mean catchment elevation (MCE) and 2) the Caribbean slope had recharge largely occurring at elevations lower than the MCE. These relationships were quantified: MREP = 1.072 (MCE) + 45.65 (Pacific: r2 = 0.93, error = 144 m); MREC = 0.9493 (MCE) – 28.24 (Caribbean: r2 = 0.83, error = 190 m). The MRE, surface water site elevation (SWSE), and MRE-SWSE differences were generally greater on the Pacific slope, which hosts most of the region’s population. Bayesian MRE estimates were on average lower than MREs obtained using other methods and may better approximate the actual (recharge-weighed) MRE, suggesting that the inclusion of isotopic uncertainties, evaporative corrections, and recharge likelihoods all positively effect MRE estimations.
Bio Refinery of Oily Wastes
(Juniper Publishers (Estados Unidos), 2018) Rojas Alfaro, Juan José; Fernández Araya, Luis Marcial; Redondo, Carlos; Jose-Roberto, Vega-Baudrit
Abstract. Many attempts have been made in order to establish a concept for biorefinery. The simplest way to do so is in an analogous way to the current oil refinery, where multiple fuels and products are manufactured from fossil source, but in the biorefinery scenario, biomass is converted into a range of biochemicals, materials and energy products in an industrial process.
Bio-inspired membranes for adsorption of arsenic via immobilized L-Cysteine in highly hydrophilic electrospun nanofibers
(Elsevier (Países Bajos), 2022) Picón, David; Torasso, Nicolás; Jose-Roberto, Vega-Baudrit; Cerveny, Silvina; Goyanes, Silvia
Abstract. Arsenic is a concern for its ubiquity in the environment and its accumulative and toxic properties. Water is often contaminated with this chemical, so developing simple, scalable, and green water treatment technologies is urgently needed. We show here that the ability of the L-Cysteine biomolecule to form complexes with arsenic inspires its use as a natural bio-inspired sorbent to develop advanced functional materials. We establish for the first time a way to chemically anchor L-Cysteine (L-Cys) inside highly hydrophilic nanofibers to create a membrane capable of lowering As(V) concentration below the WHO limit of 10 μg/L. A homogeneous precursor mixture of an aqueous solution of PVA and L- Cys (5 wt% and 10 wt% of L-Cys with respect to PVA) was electrospun to obtain a fibrous membrane. Successful immobilization of L-Cys within PVA nanofibers is achieved during heat treatment at 190 °C. It occurs through esterification reactions between the hydroxyl group on the PVA chain and the carboxylic acid on L-Cys. Arsenic sorption (as As (V)) was assessed by batch experiments in aqueous media and at a controlled pH range. The maximum removal efficiency was achieved at pH 7, supporting the formation of thiolate complexes as the primary mechanism for arsenic sorption. We show that L-Cys confinement makes arsenic diffusion inside the nanofibers a rate-limiting process in adsorption kinetics, following the pseudo first order equation. Overall, this work lishes a novel arsenic remediation strategy and encourages the research of nature-mimicking adsorbents and biodegradable polymers to develop functional materials in water remediation.
Bio-Inspired Proanthocyanidins from Blueberries’ Surface Coating Prevents Red Blood Cell Agglutination on Urinary Silicon-Based Catheters
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2022) Orozco-Fernández, Viviana; Gómez-Solano, Sofía; Calderón, Jennifer; Jose-Roberto, Vega-Baudrit; Rischka, Klaus; Corrales, Yendry
Abstract. Thrombosis can cause the occlusion of implantable medical devices, leading to the rejection of the device and subsequent mortality. Thrombosis is primarily induced by red blood aggregation and coagulation. The administration of anticoagulant drugs is generally used as a treatment to avoid these processes. Adverse effects such as bleeding in the event of an anticoagulant overdose, osteoporosis associated with prolonged use, hypersensitivity, and hives have been reported. New strategies such as biomolecule surface functionalization have recently been studied to overcome these problems. In this study, we report a novel coating composed of polydopamine (PDA) and proanthocyanidins (PACs) from blueberry extract to avoid red blood aggregation in short-term use medical devices such as silicone catheters. We showed that PDA formed stable films on silicone surfaces and PACs could be immobilized on PDA layers using laccase as a catalyst. The PDA–PACs films decreased surface hydrophilicity, increased surface roughness, and decreased plasma protein adsorption. The films were stable in phosphate buffer saline (PBS) and cell culture media. Furthermore, red blood cell adsorption and aggregation decreased. These effects are attributed to changes in the membrane fluidity that influences adhesion, the steric hindrance of the layers, and the low adsorption of plasma proteins on the PAC layer.
Biodegradable plastics in aquatic ecosystems: latest findings, research gaps, and recommendations
(IOP Publishing (Reino Unido), 2022) Ribba, Laura; Lopretti, Mary; Montes de Oca-Vásquez, Gabriela; Batista, Diego; Goyanes, Silvia; Jose-Roberto, Vega-Baudrit
Abstract. The negative impact of plastic accumulation in aquatic ecosystems is a known and undeniable problem. However, while many of the scientific community’s countermeasures against such accumulation target the effects of the most common commodity plastics, the consequences of so-called ‘biodegradable’ plastics in those ecosystems are seldom discussed. After all, though their alleged biodegradability sustains the widespread belief that they are harmless to the environment, because a material’s fate determines its classification as biodegradable or not, many plastics classified as biodegradable do not in fact meet the required norms and standards of biodegradability in aquatic ecosystems. Furthermore, during the past five years, the scientific community has shown that the degradation of such plastics can generate bio-microplastics that have effects similar to or worse than those of conventional microplastics (MPs). Against that background, this review details the latest findings regarding how biodegradable plastics can influence aquatic ecosystems and thus cause adverse health effects in living organisms and/or act as vectors of chemical pollutants. Beyond that, it identifies the key aspects of such trends to be investigated in greater depth, including the need to consider a wider variety of biodegradable plastics and to develop systematic methods that allow quantifying and identifying the remains of those pollutants in living species. Other aspects worth considering include the arrival and mobilisation dynamics of MPs in oceans. The ways in which small animals fed by filtering (e.g. red crabs and other zooplankton organisms) move MPs through the water column and into food webs also merit attention, for those MPs are ingested by numerous species at different trophic levels, at which point bioaccumulation in tissues has to be considered as a factor of toxicity. This review closes with a series of recommendations and perspectives for future studies on biodegradable plastics in aquatic ecosystems.
Biopolymer Development from Acerola (Malpighia spp.) Waste: A Sustainable Approach to Nutraceutical, Pharmaceutical Applications and Environmental Preservation
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2023) Jose-Roberto, Vega-Baudrit; Camacho Elizondo, Melissa; Batista Menezes, Diego; Corrales, Yendry; Zúñiga, Juan Miguel; Mora Chacón, Arturo; Lecot, Nicole; Castillo Henríquez, Luis; Lopretti, Mary
Abstract. Acerola (Malpighia spp.) is a tropical plant genus of shrubs and trees whose fruit is rich in nutrients and bioactive compounds. However, its production generates significant waste that could pose an environmental issue. This review aims to summarize recent research on the potential uses of acerola wastes, including the extraction of bioactive compounds such as polyphenols, carotenoids, and pectins, as well as the development of materials such as nanomaterials, chitosan, and biofuels. Additionally, the paper discusses the potential medical applications of acerola wastes, such as wound healing, antioxidant, and anticancer effects. Finally, the paper explores the challenges and opportunities of using acerola waste as a sustainable source of raw materials and energy. The findings suggest that acerola waste could be a valuable resource for developing highvalue products and promoting sustainable production practices in the fruit industry.

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