Caracterización estructural y superficial de membranas microporosas

El objetivo fundamental de este trabajo es el estudio y conocimiento de distintas técnicas de caracterización estructural y superficial, es decir, técnicas aplicables a la determinación de la estructura de la membrana así como el estudio de su superficie. Buscando una caracterización lo más amplia posible se han recopilado y empleado diferentes métodos y técnicas. En la parte de aplicación de dichas técnicas se han estudiado determinados casos concretos de membranas, intentando abarcar el mayor número de tipos diferentes de estos filtros. La utilización de un amplio rango de técnicas de caracterización, así como su aplicación a tipos de membranas, en principio muy diversas, nos va a permitir conocer y analizar las potencialidades de cada una de las técnicas, dándonos al mismo tiempo un conocimiento lo más preciso posible sobre los filtros analizados.Departamento de Física Aplicad

Enseñas: Material didáctico para el desarrollo del bilingüismo en niñas y niños con discapacidad auditiva

145 Páginas.“Enseñas” es un material didáctico que busca potencializar los procesos de enseñanza y aprendizaje de la segunda lengua (castellano escrito) de estudiantes con discapacidad auditiva bajo un enfoque bilingüe, éste consta de un tapete con 15 casillas de diferentes colores; contiene 40 tarjetas, cada una presenta una imagen, la palabra de la imagen, su respectivo deletreo en el alfabeto de Lengua de Señas Colombiana, en el reverso de la tarjeta se encuentra una fotografía con la seña correspondiente a la imagen. El juego trae una ruleta que indica a los niños cuántos pasos deben dar en el tapete de 1 a 6 y por el otro lado les indica qué acción deben hacer (deletrear, escribir o hacer la seña), por último, contiene un tablero de acrílico pequeño donde los niños pueden escribir la palabra que han seleccionado. El presente trabajo muestra un rastreo teórico sobre algunos conceptos como modelo bilingüe en personas sordas, discapacidad auditiva y las dificultades que presentan estos estudiantes en el ámbito educativo; De igual manera se da a conocer el proceso mediante el cual se creó el material didáctico, se implementó y se evaluó; el material didáctico diseñado y elaborado incluye una guía para el docente, la cual contiene algunas ideas y actividades que optimizan el uso del material. Así mismo, se presenta el modelo pedagógico en el que se fundamentó: El constructivismo, puesto que a través de este modelo el estudiante con discapacidad auditiva al enfrentarse al material siente cierta independencia al momento de aprender y construye su propio aprendizaje viendo al docente como un guía en el proceso. Por último, se presentan los resultados obtenidos y su posterior análisis en cada uno de los instrumentos de recolección de información, siendo ésta una investigación de tipo mixto

Alcohol reduction in red and white wines bynanofiltration of musts before fermentation

Producción CientíficaOne of the consequences of global warming is the early ripening of grapes which promotes a sugar content increase. Fermentation of their must leads to wines with an alcoholic degree higher than desired. The scope of this study is to select a nanofiltration (NF) technique to reduce the alcohol content of wines approximately 2 degrees by controlling the sugar content of grape must before its fermentation. For this purpose the performance of single-stage and two-stage NF processes using a spiral wound membrane unit were compared for white must (Spanish Verdejo) while for red must (Spanish Garnacha) a two-stage procedure was tested. During the singlestage NF intermittent backflush due to the osmotic pressure effect was tested. Results showed that backflushing had an undesirable effect because it increased the flux decay by disturbing the cake stabilization on the membrane. The corresponding wines obtained by adequate mixing of permeated and retained or control musts showed a 1 to 2 degrees alcohol reduction. Sensory evaluation and principal component analysis (PCA) revealed that there were no significant differences between the control and the filtered wines. Among the processes studied, the best NF technique was the two-stage process without backflush.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA248U13

Recent advances in membrane-based biogas and biohydrogen upgrading

Producción CientíficaBiogas and biohydrogen, due to their renewable nature and zero carbon footprint, are considered two of the gaseous biofuels that will replace conventional fossil fuels. Biogas from anaerobic digestion must be purified and converted into high-quality biomethane prior to use as a vehicle fuel or injection into natural gas networks. Likewise, the enrichment of biohydrogen from dark fermentation requires the removal of CO2, which is the main pollutant of this new gaseous biofuel. Currently, the removal of CO2 from both biogas and biohydrogen is carried out by means of physical/chemical technologies, which exhibit high operating costs and corrosion problems. Biological technologies for CO2 removal from biogas, such as photosynthetic enrichment and hydrogenotrophic enrichment, are still in an experimental development phase. In this context, membrane separation has emerged as the only physical/chemical technology with the potential to improve the performance of CO2 separation from both biogas and biohydrogen, and to reduce investment and operating costs, as a result of the recent advances in the field of nanotechnology and materials science. This review will focus on the fundamentals, potential and limitations of CO2 and H2 membrane separation technologies. The latest advances on membrane materials for biogas and biohydrogen purification will be systematically reviewed.Ministerio de Ciencia e Innovación/Agencia Estatal de Investigación (AEI)/10.13039/501100011033 - (projects PID2019- 109403RB-C21)Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (grant CLU2017-09, UIC082, CL-EI-2021-07 and UIC 315

A systematic study of ammonia recovery from anaerobic digestate using membrane-based separation

Producción CientíficaAmmonia recovery from synthetic and real anaerobic digestates was accomplished using hydrophobic flat sheet membranes operated with H2SO4 solutions to convert ammonia into ammonium sulphate. The influence of the membrane material, flow rate (0.007, 0.015, 0.030 and 0.045 m3 h−1) and pH (7.6, 8.9, 10 and 11) of the digestate on ammonia recovery was investigated. The process was carried out with a flat sheet configuration at a temperature of 35 °C and with a 1 M, or 0.005 M, H2SO4 solution on the other side of the membrane. Polytetrafluoroethylene membranes with a nominal pore radius of 0.22 µm provided ammonia recoveries from synthetic and real digestates of 84.6% ± 1.0% and 71.6% ± 0.3%, respectively, for a membrane area of 8.6 × 10−4 m2 and a reservoir volume of 0.5 L, in 3.5 h with a 1 M H2SO4 solution and a recirculation flow on the feed side of the membrane of 0.030 m3 h−1. NH3 recovery followed first order kinetics and was faster at higher pHs of the H2SO4 solution and recirculation flow rate on the membrane feed side. Fouling resulted in changes in membrane surface morphology and pore size, which were confirmed by Atomic Force Microscopy and Air Displacement Porometry.Junta de Castilla y León - FEDER (VA088G19, CLU 2017-09 y UIC 071)Ministerio de Ciencia e Innovación (proyecto: PID2019-109403RB-C21/AEI/10.13039/501100011033

Fouling study of nanofiltration membranes for sugar control in grape must: Analysis of resistances and the role of osmotic pressure

Producción CientíficaThree membranes are analyzed attending to their retention, flux and fouling when used to nanofiltrate sugars in red grape musts. With high molecular weight compounds, fouling develops from initial pore blocking to final cake deposition. A decrease of resistance appears due to a decrease of the effective transmembrane pressure and cake compaction. The final effective pore size corresponds to that of the compacted cake. Attending to flux decay and sugar retention, two membranes, HL and SR3, are appropriate to reduce the content of sugar of red must. Specifically SR3 shows the best passage of sugar and less foulingJunta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Fabrication and characterization of polyethersulfone nanocomposite membranes for the removal of endocrine disrupting micropollutants from wastewater. Mechanisms and performance

Producción CientíficaThe addition of carbon nanotubes to improves the removal and adsorption of endocrine disrupting micropollutants (bisphenol A and nonylphenol). Increasing the SWCNT (single walled carbon nanotubes) content increases removal and diminishes reversible and irreversible fouling. The isoelectric point of the SWCNT containing membranes decreases when the content of nanotubes increases with more negative charges at alkaline pH. Because, the nanotube loaded membranes are also less hydrophilic and bisphenol and nonylphenol are hydrophobous, adsorption plays a key role in the removal of micropollutants. An increase in the transmembrane applied pressure decreases the removal and more steeply for the membranes containing more SWCNT. Higher porosities, leading to higher water permeabilities, are also obtained for more loaded membranes. Too high SWCNT contents lead to a saturation and decrease of removal probably because high porosities lead to a decrease in adsorption due to both a decrease in the available surface and a sweeping action of convection through the membrane.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Comparative study of red grape mustnanofiltration: Laboratory and pilot plant scales

Producción CientíficaA consequence of global warming is the early ripening of grapes which promotes, among others, a higher fermentablesugar (glucose and fructose) content. This leads to wines with an alcoholic degree higher than desired.In this work, the main differences between red grape must nanofiltration at laboratory and pilot plant scale werestudied in order to perform the scale-up of a nanofiltration process to reduce the sugar content. For this, previousresults of the nanofiltration of commercial red must using the SR3 membrane in a flat sheet crossflow module werecompared with those obtained for the filtration of natural red must using the same membrane in a spiral woundmodule at two different applied pressures.The aim of this publication is to analyze the main differences between red grape must nanofiltration at laboratoryand at pilot plant scale.Results: showed that the flow destabilization and eddy promotion caused by spacers in the spiral wound modulemitigate the rate at which the cake thickens and compacts on the membrane surface. This causes a less sharp fluxdecrease, less variable sugars rejection and osmotic pressure difference. Moreover, higher applied pressure promotesa higher membrane fouling and osmotic pressure that worsen the flux decayJunta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA248U13

Side-stream membrane-based NH3 extraction to improve the anaerobic digestion of poultry manure

Producción CientíficaThe influence of membrane-based ammonia extraction on poultry manure (PM) wastewater treatment was assessed in a 3 L continuous stirred tank reactor (CSTR). The anaerobic digester operated for 91 days at a hydraulic retention time of 15 days and 37 °C. The flat sheet polytetrafluoroethylene (PTFE) membrane module was interconnected to the CSTR and operated at a recirculation flow rate of 0.25 L min−1. The membrane-based ammonia extraction mediated a decrease of total ammonia nitrogen of 64.5 % and of total nitrogen of 53.4 %, which induced an increase in the methane yields from 360 ± 70 up to 574 ± 5 N mL CH4 g VS fed−1. Similarly, chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies increased from 59 % ± 2 % and 57 % ± 3 % up to 79.1 % ± 0.8 % and 65.8 % ± 0.2 %, respectively. This work targeted the enhancement of the performance of full-scale anaerobic digestion plants via reduction of NH3 concentration with a membrane-based extraction unit.Junta de Castilla y León - FEDER (VA088G19, CL-EI-2021-07, UIC 315 y UIC 082)Ministerio de Ciencia e Innovación - AEI (PID2019-109403RB-C21