The effective flux through a thin-film composite membrane
1 Mathematical Institute, University of Oxford - OX2 6GG Oxford, UK
2 Department of Civil & Environmental Engineering, Technion - Israel Institute of Technology Haifa 32000, Israel
Received: 23 March 2015
Accepted: 15 May 2015
Composite membrane structures, used extensively in separation processes, comprise an ultra-thin selective polymer film cast over a porous support, whose pores partially obstruct transport out of the top film. Here, we model the composite as a finite thickness slab with a periodic array of circular absorbing patches in an otherwise reflective surface and study the effective transport properties of the composite. We obtain an analytical approximation for the effective diffusive flux as a function of the geometrical parameters, namely the film thickness, the support porosity and the pore size. We find a good agreement with full numerical solutions, and that a good effective rate is achievable with a relatively small number of pores.
PACS: 02.30.Mv – Approximations and expansions / 66.30.J- – Diffusion of impurities / 82.45.Mp – Thin layers, films, monolayers, membranes
© EPLA, 2015