Three dimensionless parameters influencing the optimal membrane orientation for forward osmosis
Author(s)McGovern, Ronan Killian; Mizerak, Jordan P.; Zubair, Syed M.; Lienhard, John H.
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In many forward osmosis applications, flux is maximised (and capital costs minimised) when the membrane is oriented such that the feed solution faces the support layer (PRO mode). Here, a framework is developed to understand the factors that determine the membrane orientation that maximises flux. In the absence of fouling, a dimensionless form of the water transport equations reveals the importance of three dimensionless groups: the ratio of draw to feed osmotic pressure, the ratio of draw to feed solute diffusivity, and the resistance to water transport of the support layer relative to the active layer. A parametric study of these parameters and an application of the dimensionless equations to three important FO processes reveal that having the draw solution face the support layer (FO mode) can maximise flux in specific instances. Interestingly, this implies that operation in FO mode can both maximise flux and minimise fouling for fertigation applications and the concentration of flowback waters from hydraulic fracturing.
DepartmentMassachusetts Institute of Technology. Abdul Latif Jameel World Water & Food Security Lab; Massachusetts Institute of Technology. Department of Mechanical Engineering
Journal of Membrane Science
McGovern, Ronan K., Jordan P. Mizerak, Syed M. Zubair, and John H. Lienhard V. “Three Dimensionless Parameters Influencing the Optimal Membrane Orientation for Forward Osmosis.” Journal of Membrane Science 458 (May 2014): 104–110.
Author's final manuscript