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Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane

Synthesis of a nanoporous alumina membrane (NPAM) by the two-step anodization method and its morphological and chemical surface characterization by analyzing Scanning Electron Microscopy (SEM) micrographs and X-Ray Photoelectron Spectroscopy (XPS) spectra is reported. Influence of electrical and dif...

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Autores principales: Vázquez, María I., Romero, Virgina, Vega, Victor, García, Javier, Prida, Victor M., Hernando, Blanca, Benavente, Juana
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5304769/
https://www.ncbi.nlm.nih.gov/pubmed/28347115
http://dx.doi.org/10.3390/nano5042192
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author Vázquez, María I.
Romero, Virgina
Vega, Victor
García, Javier
Prida, Victor M.
Hernando, Blanca
Benavente, Juana
author_facet Vázquez, María I.
Romero, Virgina
Vega, Victor
García, Javier
Prida, Victor M.
Hernando, Blanca
Benavente, Juana
author_sort Vázquez, María I.
collection PubMed
description Synthesis of a nanoporous alumina membrane (NPAM) by the two-step anodization method and its morphological and chemical surface characterization by analyzing Scanning Electron Microscopy (SEM) micrographs and X-Ray Photoelectron Spectroscopy (XPS) spectra is reported. Influence of electrical and diffusive effects on the NaCl transport across the membrane nanopores is determined from salt diffusion measurements performed with a wide range of NaCl concentrations, which allows the estimation of characteristic electrochemical membrane parameters such as the NaCl diffusion coefficient and the concentration of fixed charges in the membrane, by using an appropriated model and the membrane geometrical parameters (porosity and pore length). These results indicate a reduction of ~70% in the value of the NaCl diffusion coefficient through the membrane pores with respect to solution. The transport number of ions in the membrane pores (Na(+) and Cl(−), respectively) were determined from concentration potential measurements, and the effect of concentration-polarization at the membrane surfaces was also considered by comparing concentration potential values obtained with stirred solutions (550 rpm) and without stirring. From both kinds of results, a value higher than 0.05 M NaCl for the feed solution seems to be necessary to neglect the contribution of electrical interactions in the diffusive transport.
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spelling pubmed-53047692017-03-21 Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane Vázquez, María I. Romero, Virgina Vega, Victor García, Javier Prida, Victor M. Hernando, Blanca Benavente, Juana Nanomaterials (Basel) Article Synthesis of a nanoporous alumina membrane (NPAM) by the two-step anodization method and its morphological and chemical surface characterization by analyzing Scanning Electron Microscopy (SEM) micrographs and X-Ray Photoelectron Spectroscopy (XPS) spectra is reported. Influence of electrical and diffusive effects on the NaCl transport across the membrane nanopores is determined from salt diffusion measurements performed with a wide range of NaCl concentrations, which allows the estimation of characteristic electrochemical membrane parameters such as the NaCl diffusion coefficient and the concentration of fixed charges in the membrane, by using an appropriated model and the membrane geometrical parameters (porosity and pore length). These results indicate a reduction of ~70% in the value of the NaCl diffusion coefficient through the membrane pores with respect to solution. The transport number of ions in the membrane pores (Na(+) and Cl(−), respectively) were determined from concentration potential measurements, and the effect of concentration-polarization at the membrane surfaces was also considered by comparing concentration potential values obtained with stirred solutions (550 rpm) and without stirring. From both kinds of results, a value higher than 0.05 M NaCl for the feed solution seems to be necessary to neglect the contribution of electrical interactions in the diffusive transport. MDPI 2015-12-05 /pmc/articles/PMC5304769/ /pubmed/28347115 http://dx.doi.org/10.3390/nano5042192 Text en © 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Vázquez, María I.
Romero, Virgina
Vega, Victor
García, Javier
Prida, Victor M.
Hernando, Blanca
Benavente, Juana
Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane
title Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane
title_full Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane
title_fullStr Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane
title_full_unstemmed Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane
title_short Morphological, Chemical Surface, and Diffusive Transport Characterizations of a Nanoporous Alumina Membrane
title_sort morphological, chemical surface, and diffusive transport characterizations of a nanoporous alumina membrane
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5304769/
https://www.ncbi.nlm.nih.gov/pubmed/28347115
http://dx.doi.org/10.3390/nano5042192
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