Effect of Porosity and Concentration Polarization on Electrolyte Diffusive Transport Parameters through Ceramic Membranes with Similar Nanopore Size.
Diffusive transport through nanoporous alumina membranes (NPAMs) produced by the two-step anodization method, with similar pore size but different porosity, is studied by analyzing membrane potential measured with NaCl solutions at different concentrations. Donnan exclusion of co-ions at the solution/membrane interface seem to exert a certain control on the diffusive transport of ions through NPAMs with low porosity, which might be reduced by coating the membrane surface with appropriated materials, as it is the case of SiO₂. Our results also show the effect of concentration polarization at the membrane surface on ionic transport numbers (or diffusion coefficients) for low-porosity and high electrolyte affinity membranes, which could mask values of those characteristic electrochemical parameters.
Applied Physics Department I, Faculty of Sciences, University of Malaga, E-29071 Málaga, Spain. virgirom@uma.es.
Virginia
V
Romero
Physics Department, Faculty of Sciences, University of Oviedo, E-33007 Oviedo, Spain. vegavictor@uniovi.es.
Victor
V
Vega
Physics Department, Faculty of Sciences, University of Oviedo, E-33007 Oviedo, Spain. garciaferjavier.uo@uniovi.es.
Javier
J
García
Physics Department, Faculty of Sciences, University of Oviedo, E-33007 Oviedo, Spain. vmpp@uniovi.es.
Victor M
VM
Prida
Physics Department, Faculty of Sciences, University of Oviedo, E-33007 Oviedo, Spain. grande@uniovi.es.
Blanca
B
Hernando
Applied Physics Department I, Faculty of Sciences, University of Malaga, E-29071 Málaga, Spain. j_benavente@uma.es.
Juana
J
Benavente
atomic layer deposition (ALD) surface coating; concentration polarization; membrane potentials; nanoporous alumina membranes (NPAMs)