Project title: Flow of fluids through porous media with application to membranes: from the molecular to the continuum scale.
Supervisors: Omar Matar, Erich Müller
Nanoporous materials have been the subject of extensive research in recent years. This includes carbon nanotubes (CNTs) or porous graphene sheets used for water desalination or gas separation.[1,2] Finding more efficient and cheaper methods of separating solutes from a solution can make these separation mechanisms more economically viable and accessible which makes it an important area of research. During my PhD project I aim to analyse non-continuum effects in fluid transport through nanopores and how they can be exploited to improve rejection mechanisms.
Continuum-scale fluid flow through simple channels, such as cylindrical pipes, is well described by the Hagen-Poisieulle equation. This continuum description, however, breaks down for channels with small diameters. This is as there are fluid-wall effects on the molecular scale. As the diameter approaches molecular sizes, these effects will start to significantly effect flow behaviour. Several adaptations to the Hagen-Poisieulle equation have been proposed, ranging from explicitly including a slip length to introducing a different viscosity near the wall [4,5].
In my research project I aim to analyse the applicability of porous media for various rejection processes. The value of my research will be in isolating contributing factors to solute rejection, such as fluid-pore interactions, size effects and properties of fluids under confinement. My calculations will be performed in order to assist the understanding of experimental results, which show slightly counter-intuitive behaviour of rejection in porous media.
 R. R. Nair et al., Science 335, pp. 1–3 (2012).
 A. T. Nasrabadi and M. Foroutan, Desalination (277), pp. 236–243 (2011).
 M. E. Suk and N. R. Aluru, RSC Advances 3, p. 9365 (2013).
 T. G. Myers. Microfluid Nanofluid 10. pp. 1141-45 (2011).
 F. Calabro et al., Applied Mathematics Letters 26, pp. 991-4 (2013).