Journal of Membrane Science 218 (2003) 219–233 Preparation of mixed matrix adsorber membranes for protein recovery Maria-Elena Avramescu, M´ ıriam Gironès, Zandrie Borneman, Matthias Wessling ∗ Membrane Technology Group, Faculty of Science and Technology, University of Twente, P.O. Box 217, NL 7500 AE Enschede, The Netherlands Received 2 December 2002; received in revised form 8 April 2003; accepted 14 April 2003 Abstract This paper presents a generic technology allowing the incorporation of functional entities into a porous substrate. Various ion exchange particles were incorporated into an ethylene vinyl alcohol (EVAL) copolymer porous matrix by an immersion phase separation process and a heterogeneous matrix, composed of solid particles surrounded by a polymeric film, was formed. The developed concept is flexible and offers the possibility to easily adjust the geometry, the adsorption capacity, as well as the functionality of the structure. A series of fibers as well as flat membranes bearing an adsorptive function and high protein binding capacities were prepared. The membranes were characterized with respect to their morphology, porosity, permeability and adsorption capacity. High values of the protein adsorption capacity (40–45mg bovine serum albumin (BSA)/ml membrane) were obtained by static adsorption experiments. In a sequential desorption step by changing the pH and/or the ionic strength of the eluent, up to 90% protein recovery can be obtained. Dynamic capacity experiments were performed by flowing the protein solution through a stack of 10 membranes. The protein mass adsorbed per unit of membrane bed was calculated at a breakthrough concentration 10% of the feed concentration. The adsorber membranes can be reused in multiple adsorption/desorption cycles without significant loss of performance. © 2003 Elsevier Science B.V. All rights reserved. Keywords: EVAL; Mixed matrix adsorber membranes; Bovine serum albumin (BSA); Ion exchange particles; Protein recovery 1. Introduction A new method to prepare structures of any geome- try and large variety of functionality will be described in this paper. The motivation to develop a new plat- form technology for protein recovery and separation lies in the shortcomings of classical technologies. We propose to incorporate the functionality by dispersion of particles in a polymeric porous structure, which is formed by phase inversion. A slurry of dissolved poly- mer and particulate material is cast as a flat film or ∗ Corresponding author. Tel.: +31-53-4892951; fax: +31-53-4894611. E-mail address: m.wessling@ct.utwente.nl (M. Wessling). spun into a fiber and then solidified by a phase inver- sion process. The adsorber membranes prepared via this route contain particles tightly held together within a polymeric matrix (25–75% sorbent by weight). The polymer used should not interfere with the activity of the particles. Such adsorber membranes can be pre- pared in different shapes and can be operated either in stack of macroporous flat membranes or as a bundle of solid or hollow fiber membranes. They may also serve as a platform to which an end-user can couple the spe- cific ligate needed. This has been recently pointed out by Klein [1] as one of the significant opportunities in membrane chromatography. A schematic representa- tion of the technology platform is presented in Fig. 1. We named the platform “mixed matrix” in analogy to 0376-7388/03/$ – see front matter © 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0376-7388(03)00178-9