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Organically-modified ceramic membranes for solvent tolerant nanofiltration

Organically-modified ceramic membranes for solvent tolerant nanofiltration

Ceramic materials exhibit high thermal, chemical and mechanical stability [1]. As a result, ceramic membranes are suitable for filtration processes under harsh conditions. An interesting and upcoming separation process is nanofiltration (NF), which deals with separations on molecular level, i.e. molecules in the range of 200-1000 g mol‑1. The importance of NF processes and, by extend, of NF membranes lies on the possible recovery of valuable materials, such as transition metal catalysts and synthetic products, reuse of solvent mixtures, reduction of energy consumption for separations involving thermal treatments etc.

NF membranes must have pore sizes of approximately 1 nm or smaller [2]. Inorganic membranes, depending on the material used, show pore sizes larger than the NF limit (ca. 1 nm). On the other hand, hybrid ceramic membranes (ceramic substrates with a covalently-grafted thin polymeric layer, operating as the membrane) have tunable pore size distributions and can be used for NF applications in chemical industry. The preparation of such membranes involves the grafting of polymeric brushes on gamma-alumina (γ-Al2O3) substrates via simple condensation reactions, in solution or in vapor phase (Figure 1). A simple reaction which, depending on the polymer used, can deliver a wide range of membranes with different properties [3,4].

Figure 1: Grafting of phosphonic acid terminated polyethylene glycol on a γ-alumina porous support as an example of an organically-modified ceramic membrane.

This Bachelor assignment is focused on the development and understanding of a new and simple grafting method which would allow for easy integration to industrial levels. In this project, the candidate will benefit of the expertise and equipment of the Inorganic Membranes group to develop and assess the stability as well as the performance of hybrid membranes in different media (acidic, binary solvent mixtures etc.).  A general idea for the structure of the Bachelor assignment is provided below:

  1. Fabrication of polymer-grafted membranes on porous alumina supports. The student will develop a protocol for fabrication of hybrid ceramic membranes which can be used in lab or industrial scale.
  2. Characterize the as-prepared membranes by various techniques including contact-angle, FTIR, cyclohexane permporometry, electron microscopy, HR-MAS NMR, etc…
  3. Study the performance and stability of membranes in water-solvent mixtures. Permeability and solute rejection tests.

Skills which will be developed during the Master assignment:

  • Synthesis and understanding of the chemistry involved for fabrication of grafted NF ceramic membranes
  • Characterization of the as-prepared membranes
  • Evaluation of the membrane performances under NF conditions (a mixture of water, solvent, and solutes)

For more information please contact:

[1] Tsuru, T., Inorganic porous membranes for liquid phase separation. Separation and Purification Methods, 30 (2001) 191-220. [2] Mulder, M., Basic Principles of Membrane technology, Kluwer Academic Publishers, Dordrecht, 2nd Ed., 2004. [3] C.R. Tanardi, R. Catana, M. Barboiu, A. Ayral, I.FJ. Vankelecom, A. Nijmeijer, L. Winnubst. Polyethyleneglycol grafting of y-alumina membranes for solvent resistant nanofiltration, Microporous Mesoporous Mater. 229 (2016) 106–116. [4] C.R. Tanardi, I.F.J. Vankelecom, A.F.M. Pinheiro, K.K.R. Tetala, A. Nijmeijer, L. Winnubst. Solvent permeation behavior of PDMS grafted γ-alumina membranes, J. Memb. Sci. 495 (2015) 216–225.