Person:
Seoane Rodríguez, Benjamín

First Name

Benjamín

Last Name

Seoane Rodríguez

URI

https://hdl.handle.net/20.500.14352/84030

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Físicas

Area

Física Aplicada

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Now showing 1 - 10 of 16

Water and methanol transport in Nafion membranes with different cationic forms 1. Alkali monovalent cations
(Journal of Power Sources, 2006) Godino Gómez, María Paz; Barragán García, Vicenta María; García Villaluenga, Juan Pedro; Ruiz Bauzá, Carlos; Seoane Rodríguez, Benjamín
The mass flux originated when two methanol-water solutions of different methanol concentration are separated by a Nation 117 membrane in acid (H+) and different alkali metal forms (Li+, Na+, K+, Rb+, Cs+) have been measured, as a function of the methanol concentration difference. From the experimental results, the methanol and water permeabilities have been estimated for the different forms of the membrane. The results show that the cationic form of the membrane strongly influences on the methanol and water permeabilities with respect to the values corresponding to its acid form. Moreover, this influence is different for water and methanol depending on the substituted cation. This strong influence of the cationic form of the membrane on the methanol and water permeabilities could be important in relation to the development of new membranes to decrease the methanol crossover in direct methanol fuel cells.
Study of the activation energy for transport of water and methanol through a Nafion membrane
(Chemical Engineering Journal, 2009) Godino Gómez, María Paz; Barragán García, Vicenta María; García Villaluenga, Juan Pedro; Izquierdo Gil, María Amparo; Seoane Rodríguez, Benjamín; Ruiz Bauzá, Carlos
This study investigates the influence of different operating parameters in the transport of water and methanol through a Nafion membrane when it is used to separatewater fromamethanol–water solution. For this purpose, measurements of mass flux and concentration change have been performed at different values of circulation velocity, concentration of themethanol–water solutions and temperature conditions. From the experimental data, thewater and methanol partial fluxes have been estimated, and itwas found that the water flux is always lower than the methanol flux, but it cannot be neglected. Whereas total and methanol fluxes seem to have predictable and similar behaviors, the water flux seems to be less predictable and it exhibits a very distinct behavior. Methanol and water permeabilities have been calculated, and from these values the activation energy of methanol and water fluxes in the membrane has been estimated. The results have been discussed in terms of the methanol and water solubilities in the membrane.
Fluid flow modeling in a sulfonated cation-exchange membrane
(Journal of Applied Polymer Science, 2009) García Villaluenga, Juan Pedro; Barragán García, Vicenta María; Izquierdo Gil, María Amparo; Godino Gómez, María Paz; Seoane Rodríguez, Benjamín; Ruiz Bauzá, Carlos
Liquid permeation measurements of water, methanol, and 2-propanol were carried out using a commercial cation-exchange membrane Nafion-117 (perfluorinated polyethylene with pendant ether-linked side chains terminated with sulfonated groups). The experimental permeation data are treated and analyzed using the capillary model, leading to the determination of equivalent pore radius of the membrane structure.
Experimental estimation of equilibrium and transport properties of sulfonated cation-exchange membranes with different morphologies
(Journal of Colloid and Interface Science, 2009) Barragán García, Vicenta María; García Villaluenga, Juan Pedro; Godino Gómez, María Paz; Izquierdo Gil, María Amparo; Ruiz Bauzá, Carlos; Seoane Rodríguez, Benjamín
Solvent uptake, hydraulic and electroosmotic permeabilities, true cation transport number, effective fixed charge concentration, and limiting current values have been determined in aqueous LiCl solutions for three commercial cation-exchange membranes with different morphologies and similar electric properties. The differences found in the equilibrium and transport properties of the membranes have been analyzed on the basis of their different structures. The experimental results show that the membrane morphology has an influence on the effect that the presence of an electrolyte has in the solvent uptake and in the liquid permeation. Differences have also been found in the polarization concentration effects, and on the loss of the membrane selectivity with the increase of the electrolyte concentration.
Simultaneous electroosmotic and permeation flows through a Nafion membrane - 1. Aqueous electrolyte solutions
(Journal of Colloid and Interface Science, 2004) Barragán García, Vicenta María; Ruiz Bauzá, Carlos; García Villaluenga, Juan Pedro; Seoane Rodríguez, Benjamín
The volume flow through a Nafion membrane originated by the simultaneous action of an electric potential difference and a pressure difference has been measured using aqueous KCl solutions under different experimental conditions. The behavior has been analyzed when both gradients act in the same and in the opposite sense. The results indicate that the simultaneous action of the pressure and potential differences originates a total flow different from the sum of the electroosmotic and permeation flows due to each force acting separately. The application of irreversible thermodynamics, which includes second-order terms, allowed the determination of the phenomenological coefficients. Moreover, from these values, the equivalent pore radius was estimated on the assumption that the membrane is a porous medium filled with an internal solution.
On the methanol-water electroosmotic transport in a Nafion membrane
(Journal of Membrane Science, 2004) Barragán García, Vicenta María; Ruiz Bauzá, Carlos; García Villaluenga, Juan Pedro; Seoane Rodríguez, Benjamín
Electroosmosis experiments through a Nafion membrane have been performed using methanol–water KCl solutions in different experimental situations. The influence on the electroosmotic transport of the percentage of methanol on solvent at different electrolyte concentrations has been studied. The experimental results show that the presence of methanol on the solutions affects strongly to the electroosmotic flow. From the current–voltage curves determined for this membrane system, the limiting currents were obtained at different volume percentages of methanol. The values obtained decrease with increasing the percentage of methanol and a minimum value seems to be reached at certain percentage of alcohol.
Salt diffusion through cation-exchange membranes in alcohol-water solutions
(Separation and Purification Technology, 2009) Izquierdo Gil, María Amparo; Barragán García, Vicenta María; Godino Gómez, María Paz; García Villaluenga, Juan Pedro; Ruiz Bauzá, Carlos; Seoane Rodríguez, Benjamín
The salt flow through several commercial cation-exchange membranes separating two NaCl alcohol-water solutions with the same alcohol concentration, but different NaCl concentration was investigated. Homogeneous (Nafion-115) and heterogeneous (MK-40 and CR65-AZL-412) membranes were used in this work. The integral permeability coefficient was determined from the temporal evolution of the concentration in the dilute solution. The results showed that the integral permeability coefficient depends on both the solution alcohol concentration and the type of alcohol. It is observed that this dependence is function of the membrane structure. In general, for the heterogeneous membranes, the integral permeability coefficient is less sensible to alcohol concentration than for the homogeneous membrane at low and intermediate values of the alcohol percentage in the solutions.
Swelling and electro-osmotic properties of cation-exchange membranes with different structures in methanol-water media
(Journal of Power Sources, 2008) Barragán García, Vicenta María; García Villaluenga, Juan Pedro; Godino Gómez, María Paz; Izquierdo Gil, María Amparo; Ruiz Bauzá, Carlos; Seoane Rodríguez, Benjamín
Electro-osmosis experiments through three cation-exchange membranes with different morphology and similar electric properties have been performed using methanol-water solutions under different experimental conditions. The influence on the electro-osmotic transport of the percentage of methanol on solvent with two different electrolytes, NaCl and LiCl, has been studied. The experimental results show that the presence of methanol in the solutions affects strongly the electro-osmotic flow, and this influence is different depending on the membrane morphology. Correlations among electro-osmotic permeability, swelling behavior, and cell resistance are studied for these membrane systems at different percentages of methanol in solvent.
Simultaneous electroosmotic and permeation flows through a Nafion membrane - 2. Methanol-water electrolyte solutions
(Journal of Colloid and Interface Science, 2005) Barragán García, Vicenta María; Ruiz Bauzá, Carlos; García Villaluenga, Juan Pedro; Seoane Rodríguez, Benjamín
The volume flow of methanol-water potassium chloride solutions through a Nation membrane originated by the simultaneous action of electric potential and pressure gradients has been measured at different percentage, of methanol. Measurement were conducted when both gradients act in the same and in the opposite directions under different experimental conditions. The result, indicate that the simultaneous action of the pressure and potential differences originates a total flow different from the sum of the individual electroosmotic and permeation flows due to each force acting separately. The application of the irreversible thermodynamics theory, which includes second-order terms, allowed the study of the influence of the composition of the solutions on the determination of the different phenomenological coefficients.
Sorption and permeation of solutions of chloride salts, water and methanol in a Nafion membrane
(Electrochimica Acta, 2006) García Villaluenga, Juan Pedro; Barragán García, Vicenta María; Seoane Rodríguez, Benjamín; Ruiz Bauzá, Carlos
The sorption of water-methanol mixtures containing a dissolved chloride salt in a Nafion 117 membrane, and their transport through the membrane under the driving force of a pressure gradient, have been studied. Both type of experiments was performed by using five different salts: lithium chloride, sodium chloride, cesium chloride, magnesium chloride and calcium chloride. It was observed that both the permeation flow through the membrane and the membrane swelling increase significantly with the methanol content of the solutions. These facts are attributed to the increase in wet membrane porosity, which brings about the increase of the mobility of solvents in the membrane, besides the increase of the mobility of the polymer pendant chains. In contrast, the influence of the type of electrolyte on the membrane porosity and permeability is not very important, with the exception of the CsCl solutions, which is probably due to the small hydration ability of the Cs+ ion.