In membrane processes, fouling from ongoing deposition of particles is the major issue for membrane failure and thus many researches on fouling characteristics have been conducted. Most of the researches have been performed with monodisperse particle systems to clarify effects of particle size on the deposition and fouling mechanisms. However, particle systems in nature have a wide size distribution with polydispersity. In this study, we used an electrospray-scanning mobility particle sizer method, which is suitable for characterizing the concentration of each component in mixtures. A series of filtration tests for 0.03 µm rated Polyethersulfone membrane against mixtures of different sized polystyrene latex particles was performed. The results showed a significantly enhanced retention efficiency of 60 nm particles in mixtures with larger particles. This was attributed from the larger particles clogging large pores, so 60 nm particles could not penetrate. For the cases of mixtures of 60 + 150 nm and 100 + 150 nm, we found much more pressure drop increases compared to the summation of the pressure drop increase for each monodisperse case. In these mixture cases, smaller particles supposed to have a depth filtration mechanism formed the cake layers due to initially blocked larger pores.
Bibliographical noteFunding Information:
The authors thank the support of members of the Center for Filtration Research: 3M Corporation, A.O. Smith Company, Applied Materials, Inc. BASF Corporation, Boeing Company, Corning Co. China Yancheng Environmental Protection Science and Technology City, Cummins Filtration Inc. Donaldson Company, Inc. Entegris, Inc. Ford Motor Company, Guangxi Wat Yuan Filtration System Co., Ltd, LG Electronics Inc., Mott Corporation, MSP Corporation, Parker Hannifin, Samsung Electronics Co. Ltd., Xinxiang Shengda Filtration Technology Co. Ltd. Shigematsu Works Co. Ltd., TSI Inc. W. L. Gore & Associates, Inc. and the affiliate member National Institute for Occupational Safety and Health (NIOSH).
© 2019 Elsevier B.V.
- Depth filtration
- Electrospray-scanning mobility particle sizer
- Surface filtration