Characterization of UF membranes by liquid–liquid displacement porosimetry J.M. Sanz, a,b R. Peinador, a,b J.I. Calvo, a,b, * A. Hernández, a,b A. Bottino, c G. Capannelli c a Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 – Valladolid, Spain, Real de Burgos, s/n, 47071–Valladolid (Spain Tel. +34 983423758, email: jicalvo@termo.uva.es b Real de Burgos, s/n, 47071 Valladolid, Spain cDipartimento di Chimica e Chimica Industriale, Universitá di Genova, Via Dodecaneso 31, 16141 Genova, Italy Received 30 June 2008; revised 11 January 2009; accepted 09 February 2009 Abstract Several UF membranes with fairly different structure have been characterized by using a liquid–liquid dis- placement porometer, which has been developed under a close collaboration of our laboratories. Three polysulfone membranes from Millipore and three polycarbonate membranes from Nuclepore–Whatman were studied. The results of pore size distributions showed nice reproducibility and accuracy. The technique is also able to accurately evaluate membrane porosity for membranes with simple cylindrical pore-like structure. In addition the possibility to estimate MWCO, by LLDP results, makes the technique very useful for process selection. Finally SEM pictures of the Millipore membranes show that usual porosimetric liquids do not alter membrane structure. Keywords: Ultrafiltration; Membrane characterization; Polymeric membranes; Pore size distributions; Liquid– liquid displacement porosimetry *Corresponding author. Presented at the conference Engineering with Membranes 2008; Membrane Processes: Development, Monitoring and Modelling – From the Nano to the Macro Scale – (EWM 2008), May 25–28, 2008, Vale do Lobo, Algarve, Portugal. 0011-9164/09/$– See front matter © 2009 Elsevier B.V. All rights reserved. doi: 10.1016/j.desal.2009.02.019 1. Introduction Membrane-based separation technologies have found a widespread use in biotechnological, pharmaceutical or food industries. Size exclusion based processes as Microfiltration (MF), Ultra- filtration (UF) or Nanofiltration (NF) offer a range of separations able to recover, concentrate or purify valuable solvents in all these fields. In this frame, membrane characterization is an invaluable tool for both membrane users and manufacturers, helping both to make appropri- ated decisions on which membrane to be chosen for a given separation process. Several character- ization methods can be considered depending on the membrane characteristics and the relevant Desalination 245 (2009) 546–553