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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...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2015
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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. |
format | Online Article Text |
id | pubmed-5304769 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
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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