Analysis of Permeance vs. Support Porosity for Thin Film Composite Membranes

I.H. Karampelas, L. Zhu, W. Jia, M. Yavari, H. Lin, E.P. Furlani
University at Buffalo, SUNY,
United States

Keywords: thin film composite membranes, membrane permeance, support porosity, mass transport analysis


Membranes are an important technology for industrial gas separation and seawater desalination and emerging applications such as CO2 capture. The key to the steady growth of membrane applications is high performance thin film composite (TFC) membranes comprised of a thin selective layer (∼100 nm or less) on a porous support that provides mechanical strength. As the selective layer becomes thinner to increase gas permeance and thus reduce the capital cost, the support surface morphology restricts the concentration profile of the penetrant in the selective layer. This geometric restriction of membrane permeance has been demonstrated using computational simulations. However, there are no rigorous experimental results to verify the modeling results. In this presentation we compare the measured and predicted permeance for two-layer model TFC membranes that are respectively comprised of track-etched polycarbonate (PC) nanofiltration membranes and industrial polyethersulfone (PES) ultrafiltration membranes as porous supports, and perfluorinated glassy polymers, Teflon AF1600 and Hyflon AD 80, with excellent film formation and good stability as the selective layer materials. We discuss the fabrication and characterization of the membranes and show that the measured membrane permeance is consistent with predictions obtained using a three-dimensional (3D) computational mass transport model that predicts the steady-state penetrant concentration in the selective layer. [1] Zhu, Lingxiang, Weiguang Jia, Moon Kattula, Koushik Ponnuru, Edward P. Furlani, and Haiqing Lin. "Effect of porous supports on the permeance of thin film composite membranes: Part I. Track-etched polycarbonate supports." J. Membr. Sci., In press (2015). [2] J. G. Wijmans and P. J. Hao, Influence of the porous support on diffusion in composite membranes, J. Membr. Sci., 494 (2015) 78-85.