Bulk and surface characterization of composite UF membranes atomic force microscopy, gas adsorption-desorption and liquid displacement techniques

J. I. Calvo, P. Prádanos, A. Hernández, W. Richard Bowen, Nidal Hilal, Robert W. Lovitt, Peter M. Williams

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

In this work, the pore size distributions referred to volume, surface and number of bulk pores, along with the internal surface area and the size parameters of surface pores are determined for two polyethersulphonic microporous composite membranes of nominal MWCO of 4000 and 30,000 Da. The microporous support pore size distribution has also been obtained. These goals have been achieved using several characterization techniques: atomic force microscopy (AFM), N2 adsorption-desorption at 77 K and a liquid displacement technique. A computerized analysis of the AFM micrographs allowed determination of the pore size distribution of surface pores at different magnifications. Also, surface roughness can be obtained. Adsorption isotherms, combined with the BET theory for multilayer adsorption, allowed determination of the internal surface area of the membrane, while the volume, surface and pore number distributions were calculated from the Kelvin equation, both in the desorption process to obtain the so-called mesopore distribution. Further analysis, by extending the pore size analysis to pores where the Kelvin equation is not valid, allowed determination of the micropore distribution. Finally, the membrane support has been detached and analyzed by a modified bubble point or liquid displacement technique. Analysis and comparison of all results show that several pore populations (including micro- and mesopores) are present in the membrane with considerable differences between surface pores and bulk pores, the latter being those which should determine permeation. Two further meso- and macropore populations could be assigned to the membrane-support transition or the support itself.

Original languageEnglish
Pages (from-to)7-21
Number of pages15
JournalJournal of Membrane Science
Volume128
Issue number1
DOIs
Publication statusPublished - 28 May 1997
Externally publishedYes

Fingerprint

Gas adsorption
Atomic Force Microscopy
Composite membranes
Adsorption
Atomic force microscopy
Desorption
Gases
desorption
atomic force microscopy
membranes
porosity
adsorption
composite materials
Membranes
Liquids
liquids
Pore size
gases
Population
Bubbles (in fluids)

Keywords

  • Atomic force microscopy
  • Composite ultrafiltration membrane
  • Gas adsorption-desorption
  • Macro-, meso- and micropores
  • Pore size distribution

ASJC Scopus subject areas

  • Filtration and Separation
  • Polymers and Plastics

Cite this

Bulk and surface characterization of composite UF membranes atomic force microscopy, gas adsorption-desorption and liquid displacement techniques. / Calvo, J. I.; Prádanos, P.; Hernández, A.; Bowen, W. Richard; Hilal, Nidal; Lovitt, Robert W.; Williams, Peter M.

In: Journal of Membrane Science, Vol. 128, No. 1, 28.05.1997, p. 7-21.

Research output: Contribution to journalArticle

Calvo, J. I. ; Prádanos, P. ; Hernández, A. ; Bowen, W. Richard ; Hilal, Nidal ; Lovitt, Robert W. ; Williams, Peter M. / Bulk and surface characterization of composite UF membranes atomic force microscopy, gas adsorption-desorption and liquid displacement techniques. In: Journal of Membrane Science. 1997 ; Vol. 128, No. 1. pp. 7-21.
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