On Pore-size Graded Membrane Networks

Pore-size gradients are often used in the design of membrane filters to increase filter lifetime and ensure fuller use of the initial membrane void volume. In this work, we model pore-size gradients in the setting of a membrane filter with an internal network of interconnected pores, and study the influence on membrane performance measures such as total filtrate throughput and accumulated contaminant concentration at the membrane downstream pore outlets. Within the limitations of our modeling assumptions we find that there is an optimal pore-radius gradient that maximizes filter efficiency independent of maximal pore length (an input parameter that influences membrane geometry), and that membrane pore networks with longer characteristic pore length perform better.