Effects of crossflow filtration cell configuration on membrane separation performance and fouling behaviour

Abstract

Configurations of crossflow filtration cells are important to determine membrane separation performance in laboratory studies. We systematically investigated the effects of crossflow filtration cell designs, including sealing approaches and back support configurations, on the determination of membrane water flux, salts rejection, and fouling behaviour. In particular, the definition of effective filtration area in the O-ring sealed cell could lead to an overestimated (defined as flow channel area) or underestimated (defined as O-ring enclosed area) membrane water flux compared to the benchmark data acquired from a silicone gasket sealed cell. In addition, it was found that the highly porous back support could yield higher water flux and salt rejection as well as better antifouling performance than that of the perforated plate support. The porous back support could significantly reduce the total resistance to water permeation thanks to the minimized average path length and increased hydraulic conductance for water transport. Moreover, the porous back support enabled better control of concentration polarization as it avoided local flux ‘hot spots’ that would occur above local perforations, and thus benefits membrane rejections. These findings provide important insights into the design of crossflow filtration cells for a more reliable and representative determination of membrane separation performance.