zeta电位与膜电导关系以及具体测定方法.pdfVIP

Journal of Membrane Science 226 (2003) 227–236 Determining the ζ-potential of plane membranes from tangential streaming potential measurements: effect of the membrane body conductance ∗ ¨ P. Fievet , M. Sbaı, A. Szymczyk, A. Vidonne Laboratoire de Chimie des Matériaux et Interfaces, 16 Route de Gray, 25030 Besançon Cedex, France Received 28 April 2003; received in revised form 5 September 2003; accepted 11 September 2003 Abstract The ζ-potential is an important and reliable indicator of the surface charge of membranes and its knowledge is essential for the design and operation of membrane processes. The streaming potential remains the most widely used technique for determining the ζ-potential of membranes. In the case of asymmetric or composite membranes, the ζ-potential is now frequently determined from tangential flow streaming potential measurements. However, the interpretation of data in terms of ζ-potential is usually carried out by doing the implicit assumption of non-conducting substrates. In this paper, we investigate the electrokinetic properties of a ceramic membrane close to the NF range, the porous structure of which affects the streaming potential because streaming and conduction currents involved in the streaming potential process do not flow through identical paths (the streaming current flows only through the slit channel formed by the two membrane samples facing each other whereas a non-negligible part of the conduction current is likely to flow through the membrane pores filled with electrolyte solution). In this case, the so-called Fairbrother and Mastin (F–M) procedure accounting for the surface conductance to correct the Helmholtz–Smoluchowski (H–S) relation is not suitable and l