PERSONAL DE APOYO
DIAZ Dario Ramon
artículos
Título:
Impedance spectroscopy and membrane potential analysis of microfiltration membranes. The influence of surface fractality
Autor/es:
DARÍO RAMÓN DÍAZ ; FRANCISCO JAVIER CARMONA ; LAURA PALACIO; NELIO ARIEL OCHOA; ANTONIO HERNANDEZ; PEDRO PRADANOS
Revista:
CHEMICAL ENGINEERING SCIENCE
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2018 p. 27 - 38
ISSN:
0009-2509
Resumen:
In this work, the proper charge density of a microfiltration membrane has been determined by using twodifferent methods. Firstly, the ionic transport of a KCl solution has been investigated by simultaneousmeasurements of saline flux and membrane potential (MP) resulting from a concentration gradientthrough the membrane. A simple model, including all the relevant contributions to the global electricalpotential drop, allowed a calculation of transport numbers and membrane charge density.The response of ions inside the membrane to an oscillating electrical potential has been analyzed byimpedance spectroscopy (or electrical impedance spectroscopy EIS). A quite simple experimental EISdesign allowed, by taking into account MP measurements too, an easy assignation of an equivalent circuit.After a careful analysis of EIS results, it was possible to evaluate the electrical conductivity insidethe pores and the charge density. Both were found to be quite similar to the values obtained from MPalone. This agreement of EIS results with the MP ones, that are much simpler to deal with, confirmsthe accuracy of EIS to study the electrical properties of microfiltration membranes.The influence of electrode roughness and, in our EIS cell, the membrane roughness, on the constantphase element (CPE) of the equivalent circuit has been proved. Within this frame, the roughness fractaldimension of the membrane surface could be determined from EIS measurements. It resulted in fairagreement with the atomic force microscopy (AFM) determination.