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[EN] Usually, EIS measurements are performed in 2 steps: a stabilization step followed by an acquisition step. The first is necessary in order to ensure that the impedance is determined when the system has reached its stationary state. In this work, a theoretical framework is proposed for estimating the required stabilization time for EIS measurements. Here, it was applied to the simplest case: the simplified Randles cell. In order to calculate the required stabilization time for performing EIS measurements, a theoretical dynamic model of a Randles cell under galvanostatic sinusoidal perturbation was developed. The proposed model can be used to estimate, from a theoretical point of view, the required stabilization time for performing EIS measurements in a Randles-like system. Even though, this work focuses on the simplest case, the developed theoretical framework can be applied to any system, however complex it may be.

[EN] Silver nanoparticles were electrodeposited into the surface of a macroporous Ni electrode. The developed electrodes were characterized morphologically by confocal laser scanning microscopy and field emission scanning electron microscopy. The activity of the developed electrodes towards the hydrogen evolution reaction was assessed by pseudo-steady-state polarization curves and electrochemical impedance spectroscopy in alkaline solutions at different temperatures. The incorporation of the silver nanoparticles on the surface of the electrode improved the catalytic activity towards the hydrogen evolution reaction due to an improvement in the electrochemically active surface area rather than in the intrinsic catalytic activity.

[EN] Electrodialysis was applied as a tertiary treatment for effluents from a Brazilian sewage treatment plant, and the results are discussed in terms of membrane ageing and process efficiency. Current-voltage analysis and electrodialysis (ED) treatment were performed in a bench cell. The treatment was discontinuously carried out for 930 h within one year. During the experiments, samples were collected for evaluation, and the pH, conductivity and ion concentration were monitored. Thermogravimetric analyses of the membrane were also performed. A reduction in electrical conductivity and the high ion percentage extraction demonstrated the efficiency of the ED treatment, confirming the possibility of using ED as a tertiary treatment for sewage. ED showed 100% effectiveness in terms of meeting the quality standards established by Brazilian legislation on the discharge of effluents. Additionally, important corrosive (Cl-) and encrusting ions (Ca-2 +/- and Mg-2 +/- ) that limit certain industrial uses of water were satisfactorily removed, giving the treated effluent a suitable quality for industrial purposes. The treatment did not suffer harmful fouling effects in terms of ion extraction in the membrane ageing study, indicating the possibility of long-term treatment without requiring cleaning for the membranes; however, this needs to be validated by scaling up the process.

[EN] 6:2 Fluorotelomer sulfonic acid (6:2 FTSA) is used as surfactant and foam stabilizer in the formulation of air firefighting foams (AFFFs). 6:2 FTSA is produced as an alternative to persistent and bioaccumulative long-chain perfluoroalkyl compounds. This study investigates the electrochemical degradation of 6:2 FTSA on a boron-doped diamond (BDD) anode. First, the BDD anode was characterized by cyclic voltammetry, revealing that the direct oxidation of 6:2 FTSA occurred at an anodic potential of 2.72 V versus Ag/AgCl (saturated KCl) electrode. Increasing the scan rate resulted in an increased current intensity of the direct oxidation peak, and this relationship was analyzed using the Randles¿Sevcik equation to calculate the diffusion coefficient of 6:2 FTSA in aqueous media (D = 4.16 × 10¿6 cm2 s¿1 at room temperature). This value is in close agreement to the predicted value obtained by the Wilke¿Chang correlation. In electrolysis experiments under potentiostatic control, increasing the anode potential over 2.72 V greatly enhanced the 6:2 FTSA removal, and the simultaneous formation of short-chain perfluorocarboxylic acids (perfluorohexanoic acid, perfluorpentanoic acid and perfluorobutanoic acid) and fluoride release were observed. Based on these observations, the 6:2 FTSA degradation pathway was predicted to start by the attack of hydroxyl radicals to the non-fluorinated carbons to form a perfluorocarboxylate, followed by a single electron transfer to the anode to yield a reactive radical C6F13COO¿. The latter species decarboxylated and finally combined with hydroxyl radicals to allow defluorination to form shorter-chain perfluorocarboxylic acids.

[EN] he internal resistance of a PEM fuel cell depends on the operation conditions and on the current delivered by the cell. This work's goal is to obtain a semiempirical model able to reproduce the effect of the operation current on the internal resistance of an individual cell of a commercial PEM fuel cell stack; and to perform a statistical analysis in order to study the effect of the operation temperature and the inlet humidities on the parameters of the model. First, the internal resistance of the individual fuel cell operating in different operation conditions was experimentally measured for different DC currents, using the high frequency intercept of the impedance spectra. Then, a semiempirical model based on Springer and co-workers¿ model was proposed. This model is able to successfully reproduce the experimental trends. Subsequently, the curves of resistance versus DC current obtained for different operation conditions were fitted to the semiempirical model, and an analysis of variance (ANOVA) was performed in order to determine which factors have a statistically significant effect on each model parameter. Finally, a response surface method was applied in order to obtain a regression model.

[EN] One of the industrial concerns is to change procedures into sustainable and cleaner processes. In electroplating, researches have been developed to replace toxic materials for safer alternatives. Cyanide salts are toxic compounds used as complexing agents in alkaline baths. This work focused in a cyanide-free copper alkaline bath developed for copper coating onto zinc alloys. Electrodialysis was evaluated to obtain a concentrated solution from a model rinsing water and simultaneously to treat the effluent for further reuse. Membrane properties after electrodialysis were analyzed, before and after cleaning procedures. Deposition tests were performed using electrolytes containing the recycled inputs and the coatings were analyzed. As results, a solution 5 to 6 times more concentrated than the initial one was obtained. The average demineralization was 90% and the percent extraction of ions was higher than 80%. Interactions between the organic acid and the exchange groups may affect membrane properties. Nevertheless, FTIR analyses and the applied cleaning procedures showed that bonds between phosphorus and quaternary amine may be reversible. Both cleaning procedures presented similar performance and partially restored the membrane properties. The concentrate could be added to the copper bath to compensate eventual drag-out losses without affecting the quality of the coatings.

[ES] La conductividad eléctrica es un parámetro importante a controlar en la industria química, ya que es necesario mantenerlo en un rango de valores óptimo en numerosos procesos. Para ello, es necesario tener un sistema de control que mantenga este proceso en unos valores de funcionamiento óptimos y satisfacer los requerimientos de calidad, seguridad y protección del medio ambiente. En este Trabajo de Final de Grado se ha llevado a cabo el estudio dinámico del parámetro de la conductividad en un reactor continuo de tanque agitado y en un reactor de flujo pistón, con objeto de diseñar los controladores convencionales de realimentación apropiados para cada tipo de reactor. Para llevar a cabo dicho estudio se fijó un caudal de entrada de agua al reactor y se fueron aplicando saltos en forma de escalón en el caudal de ácido clorhídrico, realizándose esta experiencia para distintos caudales de agua. También se trabajó con un caudal de agua constante y se aplicaron saltos en escalón en el caudal de ácido clorhídrico cada vez mayor, y cuando se alcanzaba el nuevo estado estacionario, se volvía al estado estacionario inicial. Observando así que el sistema que se analizaba no era un sistema lineal. Se separaron los diferentes saltos y se obtuvieron los parámetros matemáticos de cada salto escalón con objeto de diseñar los distintos controladores para cada salto escalón, utilizando para ello diversos criterios como el ¿criterio de estabilidad de Bode¿ y el criterio basado en ¿la curva de reacción del proceso¿. Una vez diseñados se seleccionaron unas condiciones óptimas de operación y se comprobó la validez del diseño de los controladores para los dos tipos de reactor, observando que para un RCTA el control es efectivo, pero para un el RFP el control no es adecuado, debido al gran valor en su tiempo muerto. Debido al control inefectivo del RFP se propuso como alternativa de mejora el uso de un Predictor de Smith. Para ello, se utilizó la herramienta matemática Simulink de ¿Ma, [EN] The electrical conductivity is a key parameter in the chemical industry, and therefore, it must be controlled in order to keep it in an optimal range of values. The control system must satisfy the requirements of quality, safety and environmental protection. In this Final Grade Report the study of the dinamyc behaviour of this parameter has been carried out in a continuous stirred tank-reactor and in a flow reactor piston, with the aim of designing conventional controllers appropriate feedback for each type of reactor. To carry out this study, a water inlet flow rate was set to the reactor and stepped jumps were applied in the flow of hydrochloric acid, this experience being carried out for different water flow rates. Work was also carried out with a constant flow of water and step jumps were applied to the increasing flow rate of hydrochloric acid, and when the new stationary state was reached, it was returned to the initial stationary state. Noting that the system being analyzed was not a linear system. These stepped jumps were separated and the mathematical parameters of each step jump were obtained in order to design the different controllers for each step jump, using various criteria such as the "Bode stability criterion" and the criterion based on " the reaction curve of the process. " Once designed, optimum operating conditions were selected and the validity of the design of the controllers for the two reactor types was checked, observing that for an CSTR (continuos stirred tank reactor)the control is effective, but for an PFR (plug flow reactor) the control is not adequate, due to the Great value in your downtime. Due to the ineffective control of the PFR, the use of a Smith Predictor was proposed as an alternative to improvement. For this, the mathematical tool Simulink of "Matlab" was used, with which a simulation of the PFR was carried out and it was verified that the system can be controlled effectivel

Esta tesis de doctorado tuvo como objetivo evaluar la eliminación del antibiótico norfloxacino (NOR) por oxidación electroquímica avanzada (OEA). Se evaluó la influencia de parámetros de operación como la corriente aplicada, la concentración inicial del antibiótico y del electrolito soporte Na_2 SO_4, y el material que compone el ánodo en el proceso de OEA. Además, los diferentes materiales de ánodo se caracterizaron por voltametría cíclica, voltametría de barrido lineal y cronoamperometría. Los resultados mostraron que para electrodos de diamante dopado con boro (Si/DDB) la carga de boro influye en la cantidad de impurezas de carbono-sp2. Cuantas más impurezas de carbono-sp2 mayor es la posibilidad de generar electroquímicamente agentes oxidantes des del electrolito soporte, reduciendo la oxidación de los contaminantes por los radicales hidroxilo (HO^¿), fenómeno que se intensifica para el electrodo de Nb/DDB. Dependiendo de la corriente aplicada, y de la concentración de NOR y Na_2 SO_4, el antibiótico puede ser oxidado por transferencia directa de electrones con las impurezas de carbono-sp2 en la superficie del DDB, por iones persulfato y / o HO^¿. Cuando el reactor opera favoreciendo la generación de HO^¿, la degradación del NOR y la eliminación de la demanda química de oxígeno (DQO) son simultáneas. Por otro lado, en el momento en que el reactor opera favoreciendo la oxidación del NOR por intercambio de electrones con el DDB y por iones persulfato, la degradación del NOR y la reducción de la DQO no son paralelas, conduciendo a la formación de subproductos. Además, esta situación es más acentuada cuando la concentración del Na_2 SO_4 es mayor, actuando como aprisionador de HO^¿ para generar iones persulfato. Pequeñas diferencias en las proporciones de diamante-sp3/sp2-carbono no afectaron significativamente el proceso de OEA. El sustrato soporte de la película de diamante, Si, presentó mejores resultados en la eliminación de DQO que cuando el sustrato es Nb, deb, This doctoral thesis aimed to evaluate the removal of the antibiotic norfloxacin (NOR) by electrochemical advanced oxidation (EAO) process. The influence of operational parameters such as the applied current, the initial concentration of the antibiotic and the supporting electrolyte Na_2 SO_4, and the anode material were evaluated in the EAO process. In addition, the anode materials were characterized by cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The results showed that, for boron doped diamond electrodes (Si/BDD), the boron load influences in the amount of carbon-sp2 impurities. The more carbon-sp2 impurities, higher was the possibility of electrochemically generating oxidizing agents from the supporting electrolyte, reducing the oxidation of the contaminants by hydroxyl radicals (HO^¿). This phenomenon intensifies for the Nb/BDD electrode. Depending on the applied current, and the concentration of NOR and Na_2 SO_4, the antibiotic can be oxidized by direct electron transfer with the carbon-sp2 impurities on the BDD surface and by persulfate ions and / or HO^¿. When the reactor was operated favoring the HO^¿ generation, NOR degradation and the removal of chemical oxygen demand (COD) were simultaneous. On the other hand, when the reactor was operated favoring the NOR oxidation by direct electron transfer and by persulfate ions, NOR degradation and COD reduction are not parallel, leading to the by-products generation. Besides, this situation was pronounced when the Na_2 SO_4 concentration is higher, acting as HO^¿ scavenger to generate persulfate ions. Small differences in the diamond-sp3/sp2-carbon ratio did not significantly affect the EAO process. The substrate of the diamond film Si when compared to Nb showed better COD removal due to the difference in sp3/sp2 ratios. However, the EAO process using Nb had a lower energy consumption of 60% when compared to Si, which may be a technological advantage for industrial application. Significant d, Aquesta tesi de doctorat va tenir com a objectiu avaluar l'eliminació de l'antibiòtic "Norfloxacino" (NOR) per oxidació electroquímica avançada (OEA). Es va avaluar la influència de paràmetres d'operació com el corrent aplicat, la concentració inicial de l'antibiòtic i de l'electròlit suport Na_2 SO_4, així com diferents materials anòdics en el procés d' OEA. A més, els diferents materials d'ànode es van caracteritzar mitjançant les tècniques de voltametria cíclica, voltametria de passada lineal i cronoamperometria. Els resultats van mostrar que per a elèctrodes de diamant dopat amb bor (Si/DDB) la càrrega de bor influeix en la quantitat d'impureses de carboni-sp2. Com més impureses de carboni-sp2 més gran és la possibilitat de generar electroquímicament agents oxidants des de l'electròlit suport, de forma que es redueix l'oxidació dels contaminants pels radicals hidroxil (HO^¿), fenomen que s'intensifica per a l'elèctrode de Nb/DDB. En funció del corrent aplicat i de la concentració de NOR i Na_2 SO_4, l'antibiòtic pot ser oxidat per transferència directa d'electrons amb les impureses de carboni-sp2 en la superfície del DDB, per ions persulfat i / o per radicals HO^¿. Quan el reactor opera amb unes condicions que afavoreixen la generació de HO^¿, la degradació del NOR i l'eliminació de la demanda química d'oxigen (DQO) són simultànies. D'altra banda, quan el reactor opera afavorint l'oxidació del NOR per intercanvi directe d'electrons i per ions persulfat, la degradació d'aquest i la reducció de la DQO no són paral·leles, amb la conseqüent formació de subproductes. A més, aquesta situació és més accentuada quan la concentració del Na_2 SO_4 és major, ja que actua com a segrestador de HO^¿ per generar ions persulfat. Xicotetes diferències en les proporcions de carboni-sp3/sp2 no van afectar significativament el procés d' OEA. El substrat de suport de la pel·lícula de diamant de Si va presentar millors resultats en l'eliminació de NOR que quan el substrat és de Nb, a

Los dos baños de cobre más utilizados comercialmente son el baño ácido a base de sulfato y el baño alcalino a base de cianuro. Los baños alcalinos son utilizados principalmente para producir recubrimientos en piezas con geometría compleja y para evitar la deposición galvánica cuando se deposita un metal en un sustrato menos noble. Debido a la toxicidad de los compuestos de cianuro, se han desarrollado baños alternativos usando diferentes agentes complejantes. El punto de partida de la presente investigación es un baño primario sin cianuros para deposición de cobre en sustratos de Zamak desarrollado en el Instituto de Investigaciones Tecnológicas del Estado de Sao Paulo / Brasil. La sustitución de materias primas como el cianuro debe ser económicamente ventajosa y técnicamente viable. De esta manera, la investigación presentada pretendió proponer una alternativa para el tratamiento de residuos líquidos del baño ya mencionado con la finalidad de recuperar de manera simultánea el agua y las materias primas en un sistema cerrado. Se ha estudiado el proceso de separación por membranas de intercambio iónico, la electrodiálisis, usando un sistema en escala de laboratorio y una disolución sintética que simulaba las aguas residuales del baño a base de HEDP. Se ha evaluado la viabilidad del sistema por medio del análisis de los parámetros de operación, como la extracción de iones, la tasa de desmineralización, el porcentaje de concentración, la eficiencia de la intensidad calculada para cada especie y el consumo medio de energía. Debido a que el ácido HEDP es un agente quelante, se ha evaluado el transporte de los quelatos Cu(II) HEDP a través de membranas de intercambio de aniones por medio de métodos electroquímicos. Se han construido curvas cronopotenciométricas y curvas intensidad-potencial para diferentes disoluciones sintéticas que contenían los mismos compuestos que el baño original. Se ha establecido la relación entre la presencia de los quelatos en las disoluciones y, The two most common commercial copper baths are the acid sulfate copper bath and the alkaline cyanide copper bath. Alkaline copper baths are mostly used to coat parts with complex geometry and to avoid galvanic deposition when depositing a metal on a less noble substrate. Because of the toxicity of cyanide compounds, alternative baths have been developed using different complexing agents. The starting point of the present study is a cyanide free strike bath developed for copper plating on Zamak substrates developed by the Institute for Technological Research of the State of São Paulo/ Brazil. The replacement of a raw material such as cyanide must be economically advantageous and technically feasible. Therefore, this study intended to propose an alternative to the treatment of liquid wastes from the mentioned bath, aiming at simultaneous water reclamation and chemicals recovery in a closed system. The electrodialysis membrane separation process was studied, using a laboratory-scale system operating with a synthetic solution simulating the rinsing waters from the HEDP-based bath. The feasibility of the technique was evaluated by analyzing operational parameters such as ion extraction, demineralization rate, concentration rate, current efficiency for each anionic specie and average energy consumption. Because HEDP is a chelating agent, the transport of Cu(II) HEDP chelates through anion exchange membranes was also evaluated by means of electrochemical methods. Chronopotentiometric and current-voltage curves were constructed for different model solutions containing the same compounds as the original bath. A relation between the presence of chelates in the solutions and the fixed ion exchange group could be established. Lastly, deposition tests were performed using electrolytes containing the recycled inputs and the characteristics of the coatings were analyzed. The results showed that an electrodialysis stack using strongly basic anion exchange membranes was suitable to, Els dos banys de coure més utilitzats comercialment són el bany àcid a base de sulfat i el bany alcalí a base de cianur. Els banys alcalins són utilitzats principalment per a produir recobriments en peces amb geometria complexa i per a evitar la deposició galvànica quan es deposita un metall en un substrat menys noble. A causa de la toxicitat dels compostos de cianur, s'han desenrotllat banys alternatius usant diferents agents complexants. El punt de partida de la present investigació és un bany primari sense cianurs per a deposició de coure en substrats de Zamak desenrotllat en l'Institut d'Investigacions Tecnològiques de l'Estat de Sao Paulo / Brasil. La substitució de matèries primeres com el cianur ha de ser econòmicament avantatjosa i tècnicament viable. D'aquesta manera, la investigació presentada va pretendre proposar una alternativa per al tractament de residus líquids del bany ja mencionat amb la finalitat de recuperar de manera simultània l'aigua i les matèries primeres en un sistema tancat. S'ha estudiat el procés de separació per membranes d'intercanvi iònic, electrodiàlisi, usant un sistema en escala de laboratori i una dissolució sintètica que simulava les aigües residuals del bany a base d'HEDP. S'ha avaluat la viabilitat del sistema per mitjà de l'anàlisi dels paràmetres d'operació, com l'extracció d'ions, la taxa de desmineralització, el percentatge de concentració, l'eficiència de la intensitat calculada per a cada espècie i el consum mitjà d'energia. Pel fet que l'àcid HEDP és un agent quelant, s'ha avaluat el transport dels quelats Cu (II)-HEDP a través de membranes d'intercanvi d'anions per mitjà de mètodes electroquímics. S'han construït corbes cronopotenciomètriques i corbes intensitat-potencial per a diferents dissolucions sintètiques que contenien els mateixos compostos que el bany original. S'ha establit la relació entre la presència dels quelats en les dissolucions i els grups fixos d'intercanvi d'anions. Finalment, s'han realitzat les pro

Consulta en la Biblioteca ETSI Industriales (Riunet), [ES] El propósito de este Proyecto Final de Carrera es analizar la influencia que tiene el catión presente en una disolución sobre las propiedades electroquímicas de una membrana catiónica de Nafion®117. Se caracterizará dicha membrana mediante las técnicas electroquímicas de voltametría de barrido lineal (LSV) y la de espectroscopia de impedancias electroquímicas (EIS). A partir de los resultados de la voltametría de barrido lineal se evaluará la influencia de la naturaleza del catión (Na⁺, Ni²⁺ y Cr3+) y de su concentración sobre la resistencia de la membrana y la intensidad límite. En cuanto a la espectroscopia de impedancias, a partir de ésta se evaluará cualitativamente la influencia del nivel de polarización y la naturaleza del catión sobre la forma de los espectros de impedancias. Este Proyecto se ha realizado de forma íntegra en el Departamento De Ingeniería Química Y Nuclear de la Universitat Politècnica de València, en el cual una de las ramas de investigación dentro de la electroquímica es el estudio de las membranas de intercambio iónico y sus propiedades. De este modo podrán ser de utilidad en diversas aplicaciones a nivel industrial. Además, con este trabajo también se persigue aportar resultados de interés dentro de este campo de investigación.

[EN] Electrochemical impedance spectroscopy (EIS) has been widely used in the fuel cell field since it allows deconvolving the different physic-chemical processes that affect the fuel cell performance. Typically, EIS spectra are modelled using electric equivalent circuits. In this work, EIS spectra of an individual cell of a commercial PEM fuel cell stack were obtained experimentally. The goal was to obtain a mechanistic electric equivalent circuit in order to model the experimental EIS spectra. A mechanistic electric equivalent circuit is a semiempirical modelling technique which is based on obtaining an equivalent circuit that does not only correctly fit the experimental spectra, but which elements have a mechanistic physical meaning. In order to obtain the aforementioned electric equivalent circuit, 12 different models with defined physical meanings were proposed. These equivalent circuits were fitted to the obtained EIS spectra. A 2 step selection process was performed. In the first step, a group of 4 circuits were preselected out of the initial list of 12, based on general fitting indicators as the determination coefficient and the fitted parameter uncertainty. In the second step, one of the 4 preselected circuits was selected on account of the consistency of the fitted parameter values with the physical meaning of each parameter.

[EN] Ohm's generalized law defines the concept of impedance. This law, and thus the definition itself, are only valid if the system fulfills the linearity condition. However, electrochemical systems are typically highly nonlinear. Consequently, the linearity condition can only be achieved in these systems if a low perturbation amplitude is used for performing EIS measurements. Nevertheless, the use of low amplitude perturbations leads to low signal-to-noise ratios, which result in high measurement errors. The concept of optimum amplitude arises from this tradeoff: the perturbation has to have an amplitude big enough in order to minimize the measurement errors (i.e. maximize the SNR), but at the same time, the perturbation has to have an amplitude small enough to avoid the generation of significant nonlinear effects that would distort the measured EIS spectra. In a previous work, a linearity assessment quantitative method based on the total harmonic distortion parameter was developed. In this work, the aforementioned THD method was applied for the perturbation amplitude selection for EIS measurements in a highly nonlinear model system: the cathodic electrode of an alkaline water electrolyzer. The THD method successfully obtained the optimum amplitudes both, for a constant amplitude strategy and for a frequency dependent strategy. The THD method also allowed to obtain the noise structure and to quantify the nonlinear effects. This method is slightly superior to the U-P method, a method based on the harmonic analysis of the output signal that was developed in earlier works. (C) 2018 The Electrochemical Society.

[EN] The properties of the ceramic electrodes make them interesting for electrochemical advanced oxidation processes (EAOPs), destined to the elimination of emergent or refractory contaminants, as an alternative to boron doped-diamond (BDD) electrodes. For this purpose, new ceramic electrodes based on Sb-doped SnO2 have been developed. Sb-doped tin oxide electrodes have been obtained through mechanical mixing of raw materials and sintering of dry-pressed specimens. Different sintering temperatures (1050 degrees C to 1250 degrees C) were considered. The electrochemical behavior of the resulting electrodes has been compared to that exhibited by Pt and BDDs electrodes. The oxygen discharge potential (E-02) for the ceramic electrodes decreases as the sintering temperature increases, being these values higher than that observed for the Pt electrode and smaller than that for the BDD electrode. This result in a highest rate of COD removal for the electrode sintered at 1050 degrees C comparing with the rest of ceramic electrodes under potentiostatic operation. On the other hand, in galvanostatic mode, the performance of the different ceramic electrodes in terms of the degradation of Norfloxacin, used as tested antibiotic, was similar. Comparing the behavior of the ceramic electrode sintered at 1250 degrees C and that of the BDD electrode at an applied potential of 3 V, it is inferred that although both present similar values in terms of the degradation of Norfloxacin, the rate of removal of the chemical oxygen demand is higher in the case of the BDD.

[ES] El sistema energético mundial está basado en los combustibles fósiles, y éstos conllevan graves problemas de contaminación además de ser fuentes de energía no renovables. Una de las nuevas alternativas energéticas es el hidrógeno. El hidrógeno es un vector energético idóneo para convertirse en el combustible del futuro. Con la creación de un sistema energético basado en el hidrógeno denominado “Economía del hidrógeno” se conseguiría energía de forma limpia y renovable. La electrólisis alcalina del agua es una tecnología sencilla y es una forma fácil de obtener hidrógeno de manera limpia y renovable. Sin embargo, debido a su baja eficiencia y su alto coste no se utiliza masivamente a nivel industrial. Uno de los aspectos negativos es el alto sobrepotencial necesario para que se produzca la reacción de evolución de hidrógeno en el cátodo de la celda de electrólisis. Este sobrepotencial depende del material del electrodo, y aunque se utilizan metales nobles con alta conductividad como el platino, éstos tienen un coste muy elevado y ello no permite la implantación a gran escala. En este contexto, el presente Trabajo de Fin de Grado pretende contribuir a la mejora de la eficiencia energética de la celda electroquímica reduciendo el sobrepotencial de cátodo a partir de la electrodeposición de nanopartículas de paladio sobre electrodos de níquel para mejorar la actividad catalítica y disminuir la energía de activación de la reacción de producción de hidrógeno. Con este fin, se han caracterizado 3 electrodos, antes y después de la deposicón de paladio, para ver el efecto de éste en el sistema. Por una parte, se ha caracterizado la superficie de los electrodos mediante las técnicas de microscopía láser confocal y la microscopía de barrido de emisión de campo, FESEM con acoplamiento de microanálisis EDX para analizar su composición. Por otra parte, los electrodos se han caracterizado electroquímicamente mediante la obtención de curvas de polarización de estado estacionar, [EN] The global energy system is based on fossil fuels, and these entail serious problems of pollution, in addition to being sources of non-renewable energy. One of the new energy alternatives is hydrogen. Hydrogen is an energy carrier suitable to become the fuel of the future. With the creation of an energy system based on so-called “Hydrogen economy” would get power clean and renewable. Alkaline electrolysis of water is a simple technology and is an easy way of obtaining hydrogen from clean and renewable way. However, due to their low efficiency and high cost not used massively at the industry level. One of the negative aspects in the necessary high overpotential for hydrogen evolution reaction at the cathode for the electrolysis cell. This overpotential depends on the electrode material, and though noble metals with high conductivity such as Platinium are used, these have high cost and this does not allow implementation on a large scale. In this context, the present end of degree work aims to contribute to the improvement of the energy efficiency of the electrochemical cell by reducing the overpotential of the cathode electrodeposition of Palladium deposit upon nickel electrodes to enhance the catalytic activity and decrease the activation energy of the reaction of hydrogen production. To this end, 3 electrodes has been characterized before and after the deposition of Palladium, to see their effect in the system. One the one hand, the surface of the electrodes was characterized by confocal laser microscopy techniques and field emission scanning microscopy, FESEM with EDX microanalysis coupling to analyse its composition. On the other hand, the electrodes have been characterized electrochemically by obtaining steady-state polarization curves and by electrochemically impedance spectroscopy (EIS), to obtain the kinetic parameters of the reaction and to be able to calculate if the process is really improved with the addition of Pd on the nickel electrodes. When analy, [CA] El sistema energètic mundial està basat en els combustibles fòssils, i estos comporten greus problemas de contaminación a més de ser fonts d’energia no renovables. Una de les noves alternatives energètiques és l’hidrogen. L’hidrogen és un vector energètic idoni per a convertir-se en el combustible del futur. Amb la creació d’un sistema energètic basat en l’hidrogen denominat “Economia de l’hidrogen” s’aconseguirà energia de forma neta i renovable. L’electròlisi alcalina de l’aigua és una tecnologia senzilla i és una forma fàcil d’obtindre hidrogen de manera neta i renovable. No obstant això, a causa de la seua baixa eficiència i el seu alt cost no s’utilitza massivament a nivel industrial. Un dels aspectos negatius és l’alt sobrepotencial necessari perquè es produïsca la reacció d’evolució d’hidrogen en el càtode de la cel·la d’electròlisi. Aquest sobrepotencial depén del material de l’electrode, i encara que s’utilitzen metalls nobles amb alta conductivitat com el platí, aquests tenen un cost molt elevat y això no permet la implantació a gran escala. En aquest context, el present Treball de Fi de Grau pretén contribuir a la millora de l’eficiència energètica de la cel·la electroquímica reduint el sobrepotencial de càtode a partir de l’electrodeposició de nanopartícules de pal·ladi sobre electrodes de níquel per a millorar l’activitat catalítica i disminuir l’energia d’activació de la reacción de producció d’hidrogen. Amb aquest fi, s’han caracteritzat 3 electrodes, abans i després de la depoició de pal·ladi per a veure l’efecte d’aquest en el sistema. D’una banda, s’ha caracteritzat la superfície dels electrodes per mitjà de les tècniques de microscopia làser confocal i la microscopia d’agranat d’emissió de camp, FESEM amb adaptament de microanàlisi EDX per a analitzar la seua composició. D’altra banda, els electrodes s’han caracteritzat electroquímicament per mitjà de l’obtenció de curves de polarització en estat estacionair i per espectroscopia de impedància

[EN] Electrodialysis is utilized for the deionization of saline streams, usually formed by strong electrolytes. Recently, interest in new applications involving the transport of weak electrolytes through ion-exchangemembranes has increased. Clear examples of such applications are the recovery of valuable metal ions from industrial effluents, such as electronic wastes or mining industries. Weak electrolytes give rise to a variety of ions with different valence, charge sign and transport properties. Moreover, development of concentration polarization under the application of an electric field promotes changes in the chemical equilibrium, thus making more complex understanding of mass transfer phenomena in such systems. This investigation presents a set of experiments conducted with salts of multivalent metals with the aim to provide better understanding on the involved mass transfer phenomena. Chronopotentiometric experiments and current-voltage characteristics confirm that shifts in chemical equilibria can take place simultaneous to the activation of overlimiting mass transfer mechanisms, that is, electroconvection and water dissociation. Electroconvection has been proven to affect the type of precipitates formed at the membrane surface thus suppressing the simultaneous dissociation of water. For some electrolytes, shifts in the chemical equilibria forced by an imposed electric field generate new charge carriers at specific current regimes, thus reducing the system resistance.

[EN] The roles of the anode material, boron-doped diamond (BDD), with different boron (B) and substrate Silicon (Si) or Niobium (Nb) content, and one dimensionally stable anode (DSA (R)), were evaluated in the oxidation of norfloxacin (NOR) by electrochemical advanced oxidation process (EAOP). The effect of other components in real wastewater on the performance of EAOP was also studied. The anode materials were characterized by cyclic voltammetry, regarding diamond quality, electro-generation of oxidants and NOR oxidation mechanism (direct and/or indirect). The results showed that the anode material influences on the NOR oxidation pathway, due to distinct characteristics of the substrate and the coating. Apparently, low difference in diamond-sp(3)/sp(2)-carbon ratio (Si/BDD100 x Si/BDD2500) does not leads to significant differences in the EAOP. On the other hand, the variation in the sp(3)/sp(2) ratio seems to be higher when Si/BDD2500 and Nb/BDD2500 are compared, which would explain the best current efficiency result for Si substrate. However, the Nb substrate presented a similar current efficiency and a 60% lower energy consumption. Dissolved organic matter (DOM) present in the real wastewater affect the EAOP-Nb/BDD due to HO center dot and persulfate ions scavenged. However, when supporting electrolyte was added to a real wastewater spiked with NOR, the NOR decay reaches similar values found to the synthetic one. Due to the energy saving and mechanical properties, Nb substrate presents some technological advantages in relation to Si, which can facilitate the application to industrial levels. (C) 2018 Published by Elsevier Ltd.

[ES] El óxido de estano¿ es un material ampliamente estudiado dada su gran variedad de aplicaciones. Sin embargo, debido a que sinteriza sin densificar, su procesado requiere la incorporación de promotores de la sinterización. Se ha estudiado el comportamiento de 3 mezclas a base de óxido de estano¿ que contenían óxido de bismuto como promotor de la sinterización, en proporciones 1-2%mol. A través de un diseno¿ factorial de experimentos 2 3 , se han evaluado los efectos de los parámetros del tratamiento térmico (velocidad de calentamiento, temperatura máxima y tiempo de permanencia) sobre la densificación. La combinación de una adecuada proporción de Bi2O3 (alrededor del 1,5%), una velocidad de calentamiento rápida (15 ¿C·min¿1 ) y una temperatura de sinterización elevada (1.300 ¿C), permite alcanzar una densificación del 45%. Sin embargo, el tiempo de permanencia no ejerce un efecto significativo. Se propone una interpretación de los efectos significativos sobre la densificación, basada en el comportamiento termodinámico de los compuestos que contienen Bi y en los mecanismos de transporte de materia., [EN] Tin oxide has been extensively studied due to its wide variety of applications. However, its poor sinter ability requires the use of sintering aids for its processing. The sintering behaviour of three different SnO2-based powder mixtures, containing Bi2O3 in amounts between 1 and 2 mol%, has been analyzed. The effects of thermal treatment parameters (heating rate, maximum temperature and soaking time) on the densification were obtained by a factorial experimental design 2(3). Bi2O3 adequate proportion (around 1.5%) combined with a fast heating (15 degrees C min(-1)) and a high maximum temperature (1300 degrees C), allows reaching densifications around 45%. However, soaking time has no significant effect over densification. An interpretation of the significant effects has been proposed based on thermodynamic behaviour of Bi-containing compounds and the mass transport mechanisms. (C) 2017 SECV. Published by Elsevier Espana, S.L.U.

[EN] The high volume of sales and the high degree of obsolescence of mobile phones, together with the reduction of the natural reserves of the metals used in the composition of their printed circuit boards (PCBs), makes the recycling of these devices economically and environmentally attractive. Moreover, the search for the reduction of toxicity levels inherent to the gold leaching processes with alternatives to cyanide, such as thiosulfate is a priority. Thus, it is necessary to search for efficient alternatives for the recovery of gold from solutions containing thiosulfate, in the presence of copper, used in the leaching of PCBs of mobile phones. One of these alternatives could be the electrochemical recovery of the metals present in solution. Thus, this study aimed to verify some variables involved in the process of recovery of gold and copper and to determine the electrochemical yield obtained for these solutions. Initially, cyclic scanning voltammetry with a rotating disk electrode (RDE) was performed to verify the electrochemical behavior of gold and copper in solution. Then, electrowinning tests were used to determine the recovery rates of these metals and to calculate the yield obtained in the process. The results showed that this electrochemical reaction is mass transport controlled, which allowed the calculation of the diffusion coefficients of the metal in solution. In real solutions, the gold fraction recovered reached a 94%, and the copper fraction recovered was 95%, applying electrode potential values of -500 mV(Ag/AgCl) and -700 mV(Ag/AgCl), respectively. The current efficiency for the gold electrowinning achieved in the experiments was lower than 3%. (c) 2017 Elsevier Ltd. All rights reserved.

[EN] Cleaner production is an industrial preventive strategy created to promote benefits for the environment and for human beings. Its basic principle lies in using natural energy resources in an efficient way and yet in reducing risks and impacts on the environment and on human beings throughout the life cycle of a product. Electrodialysis is a membrane separation process which uses an electrical potential difference as a driving force to promote ionic separation in aqueous solutions. The technique was initially developed for the production of drinking water from brackish water. However, the use of electrodialysis in the treatment of industrial wastewaters is becoming more attractive, due to its characteristics. The technique is considered a clean process, since it allows the reuse of water and the recovery of substances. In this work, the advancement of electrodialysis applied to cleaner production in electroplating industry will be discussed. The aim of this work is to present electrodialysis as a technology which can fulfill the requirements of cleaner production concepts in the electroplating industry. The research was performed starting from a predefined question: "how is electrodialysis becoming a cleaner production strategy in the electroplating industry?". The research was divided in two main themes. The first search was related to the most important cleaner production practices applied for the plating industry. The second search was associated with the electrodialysis application in the electroplating industry. The results obtained from the collected publications were compared in order to propose an answer to the research question. The results showed that almost a half of the published articles evaluated the improvement of the wastewater treatment as a cleaner production strategy to be applied in plating industries. In addition, the wastewater treatment was the most cited application of electrodialysis in the plating industry, especially for copper, nickel

[EN] The transport properties of copper chelates across an anion-exchange membrane were investigated by means of chronopotentiometry. Several solutions containing etidronic acid, copper sulfate and potassium chloride were evaluated. Tests were accomplished in a three-compartment reactor using a heterogeneous membrane containing quaternary ammonium functional groups. Results showed a strong relation between the amount of chelated anions and the limiting current density, the electrical resistance and the concentration polarization. An increase in the anionic equivalent charge of the solutions modified the three regions of the current-voltage curves. The acid medium was found to be less favorable because of the possibility of the formation of non-charged species in overlimiting regions. The presence of chloride anions increased the limiting current density, especially when the chloride concentration exceeded the etidronic acid concentration.

Emerging contaminants are compounds that are found in the environment at very low concentrations and which are not yet subjected to environmental regulations. Most of these contaminants are highly resistant, in some cases refractory organic compounds that can not be easily removed by conventional physical, chemical or biological methods. An alternative is to use advanced electrochemical oxidation processes in which Boron doped diamond electrodes (BDD) are used. These electrodes have a very wide electrochemical window because they present very high overpotentials for the oxygen evolution reaction. For this reason, when high overpotentials are applied to these electrodes, ·OH radicals are generated on the electrode surface. ·OH radical is a strong oxidizing agent that can react with organic matter, which can undergo complete oxidation to CO2. In this TFM an electrochemical reactor provided with several BDD electrodes in bipolar configuration for the elimination of the antibiotic norfloxacin is used. The effect of the applied current density, the supporting electrolyte concentration and the inversion time of the electrodes polarity on the operation of the electrochemical reactor is studied, Los contaminantes emergentes son compuestos que se encuentran en el medio ambiente en concentraciones muy bajas y que todavía no están sometidos a regulación medioambiental. Muchos de estos contaminantes son compuestos orgánicos muy resistentes, en algunos casos refractarios que difícilmente se pueden eliminar mediante métodos físicos, químicos o biológicos convencionales. Una alternativa es utilizar procesos electroquímicos de oxidación avanzada en los que se utilizan electrodos de diamante dopados con Boro (BDD). Estos electrodos tienen la particularidad de que su ventana electroquímica es muy amplia debido a que presentan un sobrepotencial muy elevado para la reacción de oxidación del agua para obtener oxígeno. Esto hace que cuando los electrodos se someten a sobrepotenciales lo suficientemente elevados, es posible la generación del radical ·OH que es un oxidante poderoso. Estos radicales pueden reaccionar con la materia orgánica degradándola completamente a CO2. En este TFM se utiliza un reactor eletroquímico provisto de varios electrodos BDD en configuración bipolar para la eliminación del antibiótico norfloxacino. Se estudia el efecto de la densidad de corriente aplicada, de la concentración de electrolito soporte y del tiempo de inversión de la polaridad de los electrodos sobre el funcionamiento del reactor

The concept of Hydrogen Economy, coined in the second half of the twentieth century, has gained strength as a solution to the problems derived from the consumption of fossil fuels. The main idea of the Hydrogen Economy is the use of hydrogen as an energy vector. Fuel cells play a leading role in this economy, since today, fuel cells are the most attractive hydrogen final conversion technology. This technology, invented more than 150 years ago, is well established nowadays. However, there is still research to be done in the fuel cell field, in order to make them economically profitable in comparison to the competing technologies. One of the research lines that have attracted a great attention in recent years, is the development of diagnosis and control tools for fuel cells. This Thesis is framed in this research line. This work's main goal is to obtain a semiempirical model of an individual cell of a commercial 300W PEM fuel cell stack. The developed model is meant to be used in diagnosis and control systems. In order to fulfill this goal, a steady state model and a dynamic model were developed. On the one hand, the developed steady state model consists in a semiempirical steady state model coupled with an open circuit loss model, obtained from the open circuit loss experimental characterization. On the other hand, the proposed dynamic model consists in an electric equivalent circuit with a mechanistic meaning, coupled with an empirical model to represent the evolution of the equivalent circuit parameters with the operation current. Since the dynamic model was built using electrochemical impedance spectroscopy (EIS) spectra, two experimental EIS spectra validation methods were developed in this work. Moreover, the EIS measurement was optimized in order to minimize the experimental error related to EIS measurements. Both, the measurement parameters and the perturbation amplitude, were optimized in this work. Finally, a statistical study was performed in order to deter, El concepto de Economía del Hidrógeno, acuñado en la segunda mitad del siglo XX, ha ido cobrando fuerza como solución a los problemas derivados del consumo de combustibles fósiles. La idea central de la Economía del Hidrógeno es el empleo del hidrógeno como vector energético. Las pilas de combustible tienen un papel protagonista en dicha Economía, siendo la tecnología de conversión final de hidrógeno más atractiva en la actualidad. Esta tecnología, inventada hace más de 150 años, está bien establecida actualmente. Sin embargo, aún quedan líneas de investigación abiertas en el campo de las pilas de combustible, para conseguir que sean rentables frente a las tecnologías competidoras. Una de dichas líneas de investigación es la problemática de su diagnóstico y control. Y es precisamente en esta línea de investigación donde se enmarca la presente Tesis. El objetivo central es la elaboración de un modelo semiempírico de una monocelda individual de un stack comercial de tipo PEM de 300 W. La finalidad del modelo desarrollado es su empleo en sistemas de diagnóstico y control. Para conseguir dicho objetivo se elaboró tanto un modelo estacionario del sistema, como uno dinámico. Por una parte, el modelo estacionario corresponde con un modelo semiempírico estacionario acoplado con un modelo de pérdidas de circuito abierto, este último desarrollado a partir de la caracterización experimental de dichas pérdidas. Por otra parte, el modelo dinámico propuesto corresponde con un circuito eléctrico equivalente con sentido mecanístico, dotado de un modelo empírico para representar la evolución de los parámetros del circuito equivalente con la corriente de operación. Puesto que dicho modelo se construyó empleando la técnica de espectroscopia de impedancias electroquímicas, se decidió desarrollar métodos de validación de espectros de impedancias electroquímicas obtenidos experimentalmente; y se optimizó el método de medida de los espectros, tanto los parámetros de medida como la amplitu, El concepte d'Economia de l'Hidrogen, encunyat en la segona mitat del segle XX, ha anat cobrant força com a solució als problemes derivats del consum de combustibles fòssils. La idea central de l'Economia de l'Hidrogen és la utilització de l'hidrogen com a vector energètic. Les piles de combustible tenen un paper protagonista en dita Economia, sent la tecnologia de conversió final d'hidrogen més atractiva en l'actualitat. Esta tecnologia, inventada fa més de 150 anys, està ben establida actualment. No obstant això, encara queden línies d'investigació obertes en el camp de les piles de combustible, per a aconseguir que sigan rendibles enfront de les tecnologies competidores. Una de dites línies d'investigació és la problemàtica del seu diagnòstic i control. I és precisament en esta línia d'investigació on s'emmarca la present Tesi. L'objectiu central és l'elaboració d'un model semiempíric d'una monocel·la individual d'un stack comercial de tipus PEM de 300 W. La finalitat d'aquest model és la seua utilització en sistemes de diagnòstic i control. Per a aconseguir dit objectiu es va elaborar tant un model estacionari del sistema, com un dinàmic. D'una banda, el model estacionari desenrotllat correspon amb un model semiempíric estacionari acoplat amb un model de pèrdues de circuit obert, desenrotllat a partir de la caracterització experimental de dites pèrdues. D'altra banda, el model dinàmic proposat correspon amb un circuit elèctric equivalent amb sentit mecanístic, dotat d'un model empíric per a representar l'evolució dels paràmetres del circuit equivalent amb el corrent d'operació. Ja que dit model es va construir emprant la tècnica d'espectroscòpia d'impedàncies electroquímiques, es va decidir desenrotllar mètodes de validació que permeten validar els espectres d'impedàncies electroquímiques obtinguts experimentalment; i es va optimitzar el mètode de mesura dels espectres, tant els paràmetres de mesura com l'amplitud de la pertorbació. Finalment, es va realitzar un

In this TFM is proposed an advanced electrochemical oxidation process for the removal of, propanolol, which can be considered an emerging contaminant. Emerging contaminants are compounds that are in low concentration in the environment and are not yet subject to environmental regulation; they are difficult to remove, and it is necessary to operate the electrochemical reactor at very high oxidation potentials. For this reason, it is necessary to use very stable electrodes, as the Boron dopped diamond electrodes (BDD), that allow to reach such high oxidation overpotentials. These electrodes have a very wide electrochemical window because they present very high overpotentials for the oxygen evolution reaction. For this reason, when high overpotentials are applied to these electrodes, ·OH radicals are generated on the electrode surface. ·OH radical is a strong oxidizing agent that can react with organic matter, which can undergo complete oxidation to CO2. In this TFM the effect of the applied current density and the supporting electrolyte concentration on the oxidation of propanolol is studied, En este TFM se propone un proceso electroquímico de oxidación avanzada para la eliminación de un medicamento, el propanolol, que puede considerarse un contaminante emergente. Los contaminantes emergentes son compuestos que se encuentran en baja concentración en el medio ambiente y que todavía no están regulados; son difíciles de degradar, y es necesario operar el reactor electroquímico a potenciales de oxidación muy elevados. Para ello es necesario utilizar electrodos muy estables y que permitan alcanzar dichos potenciales como son los electrodos de diamante dopado con Boro (BDD). Estos electrodos tienen la particularidad de que su ventana electroquímica es muy amplia debido a que presentan un sobrepotencial muy elevado para la reacción de oxidación del agua para obtener oxígeno. Esto hace que cuando los electrodos se someten a sobrepotenciales lo suficientemente elevados, es posible la generación del radical ·OH que es un oxidante poderoso. Estos radicales pueden reaccionar con la materia orgánica degradándola completamente a CO2. En este TFM se estudia el efecto de la densidad de corriente aplicada y de la concentración de electrolito soporte sobre la oxidación del propanolol

[EN] In this work, the pH effect on the zinc electrowinning present in the spent pickling baths (SPBs) is analysed with the aim of decreasing the energetic cost of the process. Specifically, the effect of increasing the initial pH with and without its control during the whole electrolysis experiment is studied on synthetic solutions with concentration values similar to those present in the spent pickling baths. Finally, real SPBs are treated under pH control and the results obtained are also compared with those acquired with the direct electrolysis of these SPBs in a membrane reactor. The modification of the initial pH on synthetic solutions shows an increase in zinc deposition rate as the initial pH is risen. However, the zinc redissolution phenomenon is present during the whole experiment. On the other hand, when the pH is controlled, the results obtained are much better as zinc redissolution is prevented and the hydrogen evolution reaction rate is decreased. Comparing the behaviour between the reactor under pH control and that in the presence of an anion exchange membrane, reflects zinc conversion values slightly higher for the membrane reactor due to the zinc precipitation occurring in the reactor under pH control, which is higher as the pH rises. However, the specific energy consumption is considerably higher in the membrane reactor mainly due to the ohmic drop introduced by the membrane. (C) 2016 Elsevier B.V. All rights reserved.

This is the peer reviewed version of the following article: Mora-Gómez, Julia, García Gabaldón, Montserrat, Martí Calatayud, Manuel César, Mestre, Sergio, Pérez-Herranz, Valentín. (2017). Anion transport through ceramic electrodialysis membranes made with hydrated cerium dioxide.Journal of the American Ceramic Society, 100, 9, 4180-4189. DOI: 10.1111/jace.14978, which has been published in final form at http://doi.org/10.1111/jace.14978. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving, [EN] In this research, low-cost ceramic anion-exchange membranes have been developed from porous supports manufactured, using a chamotte as a pore former. An inorganic anion-exchanger (hydrated cerium dioxide) has been deposited into the support and fixed by thermal treatment. The effects of some process variables (such as the temperature of the thermal treatment or the pH of the electrolyte) on the properties of the anion-exchange membranes have been investigated. The electrochemical performance of the resulting membranes has been compared to that exhibited by ceramic anion-exchange membranes based on another anion exchanger (hydrated zirconium dioxide) deposited into alumina-kaolin supports. The temperature of the thermal treatment applied to fix the hydrated cerium dioxide (HCeD) does not affect the structure nor the electrochemical properties of the membranes. The porosity of the supports obtained, using a chamotte as the pore former was lower than that of the alumina-kaolin ones, which led to a lower deposition of hydrated cerium dioxide than that obtained for hydrated zirconium dioxide (HZrD) in alumina-kaolin supports. The higher porosity registered for the HZrD-based membrane also implies higher membrane conductivities. The selective transport of anions through the membranes was enhanced by increasing the number of infiltrating steps, as confirmed from current to voltage curves. However, this behavior was only apparent at acidic or neutral pH, thus confirming the amphoteric character of the anion-exchanger. Comparing the parameter (equivalents of ion exchanger per gram of deposited oxide), it is concluded that the porosity of the ceramic supports, consequence of their distinct microstructure, is the main parameter responsible for the difference in the ion-exchange capacity obtained for HZrD and HCeD membranes. Consequently, the CeO2 particles used in this work are also good candidates to impart ion-exchange properties to microporous ceramic supports.

[EN] The impedance concept is defined by Ohm's generalized law. Ohm's law requires the fulfilment of 3 conditions in order to be valid: causality, linearity and stability. In general, electrochemical systems are highly nonlinear systems; and therefore, in order to achieve linearity low amplitude perturbations have to be used during EIS measurements. However, small amplitude perturbations lead to low signal-to-noise ratios. Consequently, the quality of an EIS measurement is determined by a trade-off: the perturbation amplitude should be big enough in order to obtain a good signal-to-noise ratio; and at the same time, it should be small enough in order to avoid significant nonlinear effects. The optimum perturbation amplitude corresponds with the maximum perturbation amplitude that ensures a pseudo linear response of the system. In this work, a method for experimentally determining the optimum perturbation amplitude for performing EIS measurements of a given system is presented. The presented method is based on the harmonic analysis of the output signals; and in this work, it was applied to a highly nonlinear system: the cathodic electrode of an alkaline water electrolyser. The presented method allows optimising the perturbation amplitude in both, constant amplitude and frequency dependant amplitude strategies. (c) 2017 The Electrochemical Society. All rights reserved.

[EN] The increasing demand for clean industrial processes has intensified the use of electrodialysis (ED) in the treatment of metal containing effluents from plating processes. Nickel rinsewater is a multicomponent solution that can be treated by ED in order to recover chemicals and reuse water. The investigation of the different phenomena involved in the transport of anions through anion-exchange membranes in this wastewater has been performed in different synthetic solutions by chronopotentiometry. Parameters like the limiting current density (i(lim)), the plateau length (Delta U-m), the resistance of the ohmic region (R-ohm) and the resistance of the overlimiting region (R-3) were also determined. Even though an anion exchange membrane (AEM), the limiting current density was affected by the proton leakage phenomena, indicated that the proton H+ has a greater effect than the other co-ions (Ni2+, Mg2+ and Na+). Ohmic resistances were reduced and plateau lengths were increased in the presence of protons. For salts solutions (without acid) the highest diffusion coefficients and lowest co-ion hydrated radii gave the highest plateau lengths and i(lim), but the lowest R-ohm.

[ES] Los contaminantes emergentes son compuestos de los que se tiene poca información y se desconoce su impacto sobre el medioambiente, siendo muy difíciles de eliminar utilizando métodos convencionales. Por este motivo, el objetivo del presente Trabajo Fin de Grado es la caracterización y modelización de un reactor electroquímico provisto de un ánodo de diamante dopado con boro aplicado a la eliminación de un fármaco catalogado como contaminante emergente. Para su caracterización, se han obtenido los coeficientes de transferencia de materia así como los parámetros de funcionamiento del reactor. Los coeficientes de transferencia de materia se han calculado a través del método de las densidades de corriente límite y, una vez analizados, se han ajustado a una correlación. Por otro lado, se han realizado experiencias de eliminación utilizando una disolución de 32 mg/L de norfloxacino, fármaco catalogado como contaminante emergente. La disolución se ha recirculado con un caudal de 30 L/h y al reactor se le ha aplicado una corriente fija y diferente para cada experiencia. De esta forma, se han podido obtener los principales parámetros de funcionamiento del reactor como son la conversión, rendimiento específico, rendimiento farádico y el consumo específico. Los resultados obtenidos, apuntan a que aplicando la mayor de las intensidades, 2 A, tanto la conversión (92%) como la velocidad de reacción (0,008 g/Lh) son las más elevadas. Sin embargo, al aplicar una intensidad de 2 A, el rendimiento farádico es el más bajo obtenido (0,6%) y el consumo específico (3,96x104 kWh/kg) es el más alto de los obtenidos., [EN] Emerging contaminants are compounds about which there is little information and consequently their impact on the environment is not well known. Furthermore, they are very difficult to eliminate by conventional methods. The goal of this Final Thesis Project is the characterization and modeling of an electrochemical reactor provided with a boron doped diamond anode applied to the elimination of norfloxacin, a drug classified as an emerging contaminant. To characterize the reactor, the coefficients of mass transfer were determined as well as the following main operating parameters; conversion, specific performance, faradaic yield and specific consumption. The mass transfer coefficients were calculated by the method of current density limitation and once analyzed, they were adjusted to a correlation. In order to determine the main operating parameters for the reactor, each trial consisted of applying a discrete current to a norfloxacin solution of 32 mg/L recirculated at 30L/h. At the maximum current of 2 A, both conversion (92%) and reaction rate (0.008 g / Lh) were highest. However, at this current, the faradic yield (0.6%) was lowest while the specific consumption (3,96x104 kWh / kg), was highest.

Electrochemical Impedance Spectroscopy (EIS) is a very powerful tool to study the behaviour of electrochemical systems. Three conditions must be fulfilled during EIS measurements: causality, linearity, and stability. If any of these conditions is not achieved, then the conclusions obtained from the analysis of the measured spectra may be biased, or even misguided. For this reason, the verification of the compliance of these conditions is critical before accepting any analysis performed on an experimental spectrum. In a previous work, an experimental spectrum quantitative validation technique based on Kramers-Kronig relations was presented. The validation method consists in a Kramers-Kronig (KK) validation test, by equivalent electrical circuit fitting, coupled with a Montecarlo error propagation method. The validation technique builds a consistency region for a given confidence level that allows to discriminate between the individual points of the EIS spectrum that are consistent with the four fundamental hypotheses, and the inconsistent ones. The aim of this work is to validate experimentally if the quantitative validation technique is able to detect nonlinearities. In order to achieve this goal, the EIS spectrum of a markedly nonlinear system was measured experimentally using different perturbation amplitudes. The validation technique was applied to each one of the measured spectra. The method successfully managed to identify large nonlinearities; but did not detect slight ones.

[EN] The current energy system, based basically on the use of fossil fuels is a non-sustainable system and the research for new energy alternatives is necessary. Hydrogen is an ideal energy carrier to become the future fuel, creating a new energy system called "Hydrogen Economy". To achieve this aim a method for producing hydrogen in a clean and renewable way is necessary. Alkaline water electrolysis is a simple and proven technology for hydrogen production in a clean and renewable way. However, its low efficiency is a major disadvantage for its widespread use. One of the aspects which causes this low efficiency is the overpotential required for the hydrogen evolution reaction (HER) at the cathode of an electrolysis cell. This overpotential depends on the electrode material, and although there are materials with high catalytic activity for HER, these are based on the use of noble materials such as platinum, whose high cost and scarcity restrain their use on a large scale. In this context, this Doctoral Thesis aims to contribute to the energy efficiency improvement and the cost reduction of alkaline water electrolysis, as a means of hydrogen production, through the development of cathode materials based on nickel, a material more economic and available than the noble metals. With nickel as base material, increasing the catalytic activity of an electrode can be performed basically in two ways: by alloying nickel with other materials in order to obtain a synergistic effect between their catalytic properties or by using electrodes with a high surface area (porous electrodes). In order to combine both strategies to obtain electrode materials more active towards the HER than those commonly employed in industrial alkaline electrolysis, in this Doctoral Thesis, porous electrodes based on nickel and nickel alloys with cobalt and molybdenum have been developed by using two different techniques of high current density electrodeposition. With the first one, macroporous electrod, [ES] El sistema energético actual, basado fundamentalmente en la utilización de combustibles fósiles, es un sistema no sostenible y se hace necesaria la búsqueda de nuevas alternativas energéticas. El hidrógeno es un vector energético idóneo para convertirse en el combustible del futuro, creando un nuevo sistema energético denominado "Economía del Hidrógeno". Para alcanzar este objetivo es necesario disponer de un método para la obtención de hidrógeno de forma limpia y renovable. La electrólisis alcalina del agua es una tecnología sencilla y probada para la producción de hidrógeno de forma limpia y renovable. Sin embargo, su baja eficiencia es una de las principales desventajas para su uso extendido a nivel industrial. Uno de los aspectos causantes de esta baja eficiencia es el sobrepotencial necesario para que se produzca la reacción de evolución de hidrógeno (REH) en el cátodo de la celda de electrólisis. Este sobrepotencial depende del material de electrodo, y aunque existen materiales con una elevada actividad catalítica para la REH, estos están basados en el uso de materiales nobles como el platino, cuyo elevado coste y escasez restringen su uso a gran escala. En este contexto, la presente Tesis Doctoral pretende contribuir a la mejora de la eficiencia energética y el abaratamiento de costes de la electrólisis alcalina del agua, como vía para la producción de hidrógeno, mediante el desarrollo de materiales de cátodo basados en níquel, material más económico y disponible que los metales nobles. Con el níquel como material base, el aumento de la actividad catalítica de un electrodo se puede realizar por dos vías: mediante la aleación de níquel con otros materiales con los que se produzca un efecto sinérgico entre sus propiedades catalíticas o mediante el uso de electrodos con una elevada superficie específica (electrodos porosos). Con la finalidad de combinar ambas estrategias, en esta Tesis Doctoral se han desarrollado electrodos porosos basados en níquel y alea, [CA] El sistema energètic actual, basat fonamentalment en la utilització de combustibles fòssils és un sistema no sostenible i es fa necessària la recerca de noves alternatives energètiques. L'hidrogen és un vector energètic idoni per esdevenir el combustible del futur, amb el que es crearà un nou sistema energètic denominat "Economia de l'Hidrogen". Per assolir aquest objectiu és necessari disposar d'un mètode per a l'obtenció d'hidrogen de forma neta i renovable. L'electròlisi alcalina de l'aigua és una tecnologia senzilla i provada per a la producció d'hidrogen de forma neta i renovable. No obstant això, la seua baixa eficiència és un dels principals desavantatges per al seu ús a nivell industrial. Un dels aspectes causants d'aquesta baixa eficiència és el sobrepotencial necessari perquè es produïsca la reacció d'evolució de l'hidrogen (REH) al càtode de la cel·la d'electròlisi. Aquest sobrepotencial depèn del material d'elèctrode, i encara que existeixen materials amb una elevada activitat catalítica per a la REH, aquests estan basats en l'ús de materials nobles com el platí, el cost i l'escassesa del qual restringeixen el seu ús a gran escala. En aquest context, la present Tesi Doctoral pretén contribuir a la millora de la eficiència energètica i l'abaratiment de costos de l'electròlisi alcalina de l'aigua, com a via per a la producció d'hidrogen, mitjançant el desenvolupament de materials de càtode basats en níquel, material més econòmic i disponible que els metalls nobles. Amb el níquel com a material base, l'augment de l'activitat catalítica d'un elèctrode es pot realitzar per dos vies: mitjançant l'aliatge de níquel amb altres materials amb els que es produeix un efecte sinèrgic entre les seues propietats catalítiques o per mitjà de l'ús d'elèctrodes amb una elevada superfície específica (elèctrodes porosos). Amb la finalitat de combinar ambdues estratègies, en aquesta Tesi Doctoral s'han desenvolupat elèctrodes porosos basats en níquel i aliatges de níquel

[EN] The precious metals natural sources, including gold, have decreased around the world each year. At the same time, the demand for these metals have increased, especially for the use in the electrical and electronics products industry. The recovery of metals from these scraps could be one way to mitigate this problem, since consumption and disposal have considerably increased every year. Therefore, this study aims to evaluate alternative leaching agents for the gold extraction present in the printed circuit boards (PCB's) of cell phones, and subsequent recovery by electrometallurgical process. Entire PCB's obtained from obsolete or defective cell phones were used. Thus, a commercial stripping (cyanide-based) and alternative leaching agents (sodium and ammonium thiosulfate) were tested under different conditions of concentration, time, pH and temperature. The solutions were analyzed by atomic absorption. The amount of gold contained in the PCB's was measured, by a preliminary test, in which, samples were leached with aqua regia for a complete extraction of the metal and further comparison with the commercial stripping and alternative leaching agents. The electrometallurgical stage began with the cyclic voltammetry experiments to determine the gold and copper electrowinning potential. After that, electrowinning tests using different electrode potentials to determine the recovery rates of these metals were performed. The results obtained in the leaching tests show that with the commercial stripping, it was possible to extract 88% of the gold present in the PCB of cell phones. With sodium thiosulfate, it was possible to extract 70% of the gold contained in the PCB, using 0.12M of sodium thiosulfate, 0.2M of ammonium and 20mM of copper sulphate. With ammonium thiosulfate, it was possible to extract 75% of the gold, using 0.12M of ammonium thiosulfate, 0.2M of ammonium and 20mM of copper sulfate. Regarding the recovery of metals in solution, the results of cyclic volta, [ES] Cada año las reservas naturales de metales preciosos, entre ellos el oro, van disminuyendo en todo el mundo. Paralelamente, la demanda de estos metales va en aumento, especialmente para su utilización en la industria de productos eléctricos y electrónicos. Una forma de atenuar este problema podría ser la recuperación de los metales contenidos en las chatarras de estos productos, cuyo consumo y desechos aumentan considerablemente cada año. Por tanto, este trabajo tiene por objetivo evaluar agentes lixiviantes alternativos para la extracción del oro contenido en las placas de circuito impreso (PCI) de teléfonos móviles y su posterior recuperación por vía electrometalúrgica. Se utilizaron PCI's enteras obtenidas de aparatos de teléfonos móviles obsoletos o defectuosos. En los ensayos de lixiviación se probaron, además de un agente extractor comercial (a base de cianuro), los agentes lixiviantes alternativos tiosulfato sódico y tiosulfato amónico en medio amoniacal, a distintas concentraciones, pH, tiempos y temperaturas. Las disoluciones obtenidas se analizaron por absorción atómica. La cantidad de oro contenido en las placas se midió a través de un ensayo previo donde las muestras fueron lixiviadas con agua regia para una extracción completa del metal y la posterior comparación con el agente extractor comercial y los lixiviantes alternativos. La etapa electrometalúrgica se inició con los ensayos de voltametría cíclica para determinar los potenciales de electrodeposición de oro y de cobre y a continuación se realizaron ensayos de eletrodeposición utilizando diferentes potenciales de electrodo para determinar las velocidades de recuperación de estos metales. Los resultados obtenidos en los ensayos de lixiviación muestran que el agente extractor comercial fue capaz de extraer el 88% del oro contenido en las PCI de los teléfonos móviles. Con la utilización de tiosulfato sódico fue posible extraer el 70% del oro contenido en las PCI's, utilizando disoluciones de compo, [CA] Cada any les reserves naturals de metalls preciosos, entre ells l'or, van disminuint en tot el món. Paral¿lelament, la demanda d'estos metalls va en augment, especialment per a la seua utilització en la indústria de productes elèctrics i electrònics. Una forma d'atenuar aquest problema podria ser la recuperació dels metalls continguts en les ferralles d'aquestos productes, el consum i rebutjos dels quals augmenten considerablement cada any. Per tant, aquest treball té per objectiu avaluar agents lixiviants alternatius per a l'extracció de l'or contingut en les plaques de circuit imprés (PCI) de telèfons mòbils i la seua posterior recuperació per via electrometal¿lúrgica. Es van utilitzar PCI's senceres obtingudes d'aparells de telèfons mòbils obsolets o defectuosos. En els assajos de lixiviació es van provar, a més d'un agent extractor comercial (a base de cianur) , els agents lixiviants alternatius tiosulfat sòdic i tiosulfat d'amoni al medi amoniacal, a distintes concentracions, pH, temps i temperatures. Les dissolucions obtingudes es van analitzar per absorció atòmica. La quantitat d'or contingut en les plaques es va mesurar a través d'un assaig previ on les mostres van ser lixiviades amb aigua règia per a una extracció completa del metall i la posterior comparació amb l'agent extractor comercial i els lixiviants alternatius. L'etapa electrometal¿lúrgica es va iniciar amb els assajos de voltametria cíclica per a determinar els potencials d'electrodeposició d'or i de coure i a continuació es van realitzar assajos d'eletrodeposició utilitzant diferents potencials d'elèctrode per a determinar les velocitats de recuperació d'aquests metalls. Els resultats obtinguts en els assajos de lixiviació mostren que l'agent extractor comercial va ser capaç d'extraure el 88% de l'or contingut en les PCI dels telèfons mòbils. Amb la utilització de tiosulfat sòdic va ser possible extraure el 70% de l'or contingut en les PCI's, utilitzant dissolucions de composició 0,12M de ti

Electrochemical Impedance Spectroscopy (EIS) is an electrochemical measurement technique that has been applied to a broad range of applications. Three conditions must be fulfilled in order to obtain valid EIS measurements: causality, linearity and stationarity. The non fulfilment of any of these conditions may lead to distorted and biased EIS spectra. Consequently, the verification of the four fundamental conditions is mandatory before accepting any results extracted from an EIS spectrum. In this work, a harmonic analysis based method for linearity assessment and noise quantification in EIS measurements is presented, and validated both from an experimental point of view and from a theoretical point of view, for Tafelian systems. It was shown that the presented method was able to quantitatively assess the nonlinearity of the system; and to quantify and characterize the noise. Moreover, the presented method is able to determine the threshold frequency of the system above which the system does not present significant nonlinear effects even for very large perturbation amplitudes.

Proyecto Confidencial (Riunet)

[ES] La situación energética en la actualidad es insostenible puesto que la mayoría de las energías provienen de combustibles fósiles, siendo estos una fuente de energía finita y contaminante para el medio ambiente. Por consiguiente, ha sido necesario el desarrollo de energías limpias y renovables. Un ejemplo de ello ha sido el desarrollo de pilas de combustible de hidrógeno que permiten obtener energía de manera limpia y eficiente, estas consumen hidrógeno y oxígeno para generar electricidad, agua y calor. En este trabajo de fin de grado, a partir de ahora TFG, se ha planteado un modelo matemático sobre el comportamiento estacionario de una pila de combustible de membrana polimérica de intercambio de protones. La curva de polarización permite caracterizar el funcionamiento de la pila y se puede utilizar a efectos de diseño, diagnóstico y control, por lo tanto es muy interesante tener una ecuación que permita determinar la curva de polarización. La curva de polarización suele empezar con el potencial de circuito abierto, luego la corriente va aumentando mientras que el potencial disminuye, debido a las pérdidas por activación, a la resistencia de la membrana y a las pérdidas asociadas a la resistencia a la transferencia de materia, por esta razón, la curva de polarización se divide en tres zonas. En este TFG se han estudiado las ecuaciones que definen el potencial ideal y las tres zonas por separado. Una vez obtenido el modelo para cada una de las partes se ha analizado el efecto en la curva de polarización de las condiciones de operación como la presión, la temperatura y la humedad de las corrientes de entrada. A modo de conclusión, se ha observado que un aumento de la temperatura o de la presión influye de manera positiva en prácticamente toda la curva de polarización, a excepción del incremento de la temperatura para las pérdidas asociadas a la resistencia a la transferencia de materia. Por otro lado, un aumento de la humedad de los gases hará que el contenido de, [CA] La situació energètica actual no es pot sostindre perquè la major part de les energies vénen de combustibles fòssils i aquests són una font d´energia finita i contaminant per al medi ambient. Per tant, ha sigut necessari el desenvolupament d´energies netes i renovables. Un eixemple d`açò ha sigut el desenvolupament de piles de combustible de hidrogen, amb les que es pot obtindre energia neta i eficient. El seu funcionament es basa en el consum d’hidrogen i oxigen per a obtindre electricitat, aigua i calor. En aquest treball de fi de grau, a partir d´ara TFG, s’ha plantejat un model matemàtic sobre el comportament estacionari d´una pila de combustible de membrana polimèrica d’intercanvi de protons. La corba de polarització permiteix caracteritzar el funcionament de la pila i es pot utilizar a efectes de disseny, diagnòstic i control. Per tant, és molt interessant tindre una equació que permet determinar la corba de polarització. La corba de polarització sol començar amb el potencial de circuit obert. Després, el corrent va aumentant al mateix temps que el potencial va disminuint, degut a les pèrdues per activació, a la resistència de la membrana i a les pèrdues associades a la resistència a la transferència de matèria. Per això, la corba de polarització es divideix en tres parts. En aquest TFG s’han estudiat les ecuacions que defineixen el potencial ideal i les tres parts per separat. Una vegada obtingut el model per a cadascuna de les parts, s’ ha analitzat el efecte en la corba de polarització de les condicions d’operació, com la pressió, la temperatura i la humitat de les corrents d´entrada. Com a conclusió, s’ha observat que un aument de la temperatura o de la pressió influeix de manera positiva en pràcticament tota la corba de polarització, excepte del increment de la temperatura per a les pèrdues associades a la resistència a la transferència de matèria. Per altra banda, un aument de la humitat dels gasos farà que el contingut d’aigua de la membrana aument, [EN] Nowadays the energetic situation is untenable because most of energies are provided from fossil fuels which are endless power sources with harmful effects for the environment. That is the reason why it has been essential to develop clean and renewable energies. An excellent example which shows that need is the growth of hydrogen fuel cells. By the use of these cells, we obtain energy by a clean and efficient way. In this Bachelor’s thesis a mathematical model about the steady state of a proton exchange membrane has been posed. The polarization curve defines the cell’s mechanism and can be used in order to determine the design, diagnostic and control. Hence, it is really engaging to have an equation establishing the polarization curve. The polarization curve is often begun with the open circuit potential. Then the current rises while the power decreases because of the activation losses, the membrane resistance, and the concentration polarization losses. Therefore, the polarization curve is divided in three zones. This Bachelor’s thesis has studied equations defining the theoretical fuel cell potential and the three zones separately. Once the model of each zone is obtained, we have analized the effect of the humidity gases on the polarization curve. All in all, we have realized that an increase of the temperature or pressure affects positively the polarization curve. However, there is an exception of this increase related to the mass transfer resistance. Furthermore, the humidity gases increase will make the water content of the membrane rise, thus, the ohmic losses will decrease.

In this work, the effectiveness of electric fields to clean two ZrO2 TiO2 ultrafiltration (UF) membranes fouled with three types of whey model solutions was investigated. Membranes tested had different molecular weight cut-offs (MWCOs) (15 and 50 kDa). Whey model solutions consisted of aqueous solutions of bovine serum albumin (BSA) at 10 g/L, a mixture of BSA (10 g/L) and CaCl2 (1.65 g/L) and whey protein concentrate (WPC) (total protein content 45%) solutions at different concentrations (22.2, 33.3 and 150.0 g/L). The hydraulic cleaning efficiency (HCE) achieved by means of the application of the electric fields was evaluated as a function of the membrane MWCO and the operating conditions of the cleaning technique (applied potential, temperature of the cleaning solution and concentration of NaCl). The results demonstrated that the presence of NaCl favoured the removal of protein deposits on the membrane layer. On the other hand, the higher the temperature of the cleaning solution and the applied potential were, the higher HCE was achieved. Regarding the membrane MWCO, the permselective properties of the 15 kDa membrane were completely recovered after the cleaning procedure by electric field for all the feed fouling solutions tested, whereas this technique could not completely remove the protein deposits on the 50 kDa membrane when BSA solutions were used as feed.

[ES] El hidrógeno utilizado como vector energético tiene potencial para ser la solución al problema energético actual. El principal inconveniente para la producción de hidrógeno a gran escala son los elevados costes de montaje y de operación, por lo que se hace necesario realizar la optimización de las variables electroquímicas en un reactor comercial para la producción de hidrógeno con el fin de poder minimizar los costes de material y de operación. Para ello en este Trabajo Fin de Grado se va a realizar un análisis de diferentes tipos de electrodos, tanto cátodos como ánodos para minimizar las sobretensiones asociadas, un estudio de diferentes membranas aplicables para que tengan la menor resistencia posible y se van a analizar las mejores condiciones para que la resistencia del electrolito sea la menor posible, teniendo en cuenta el efecto producido por las burbujas de hidrógeno y oxígeno generadas. Todo esto permitirá calcular el potencial de celda total en función de la densidad de corriente y comparar los resultados con los electrolizadores utilizados comercialmente y comparar las eficiencias obtenidas con los valores obtenidos de producciones comerciales., [EN] Hydrogen as an energy vector has the potential to be the solution to the energy problem. The main drawback for hydrogen production on a large scale are the high costs of installation and operation, so it becomes necessary to optimize the electrochemical variables in a commercial reactor for the production of hydrogen in order to minimize the material costs and operating. In this Final Project will be performed an analysis of different types of electrodes, both cathodes and anodes to minimize the associated surge, a study of different membranes applicable to have the least possible resistance and analyse the best conditions for electrolyte resistance as low as possible, taking into account the effect produced by bubbles of hydrogen and oxygen generated. All this will allow estimate the total potential cell based on the current density and compare the results with electrolysers used commercially and compare the efficiencies obtained with the values obtained from commercial productions.