Critical and sustainable fluxes of mixed and flocculated feeds during membrane filtration

Abstract

The disadvantage of microfiltration is that the filtration flux declines with time due to a cake layer of deposit formed or the blockage in the membrane pores. This thesis presents the study of particle deposition on the membrane surface during separating mixed and flocculated feeds using the Direct Observation Through Membrane (DOTM) technique. This study was aimed to find sub-critical strategies and to identify methods to increase sustainable flux for mixed and flocculated feeds. Uniform and mixed latex particles were selected as the mono- and bi-disperse suspensions and flocculated hematite particles were used as the poly-disperse suspensions. The investigation was focused on measuring the critical fluxes of these suspensions under various conditions. The mechanisms of particle deposition of mixed and flocculated feeds were observed using the DOTM. Enhancement in critical flux was found in the presence of larger particles due to the increased back diffusions. The enhancement induced by electro-magnetic field (EMF) was also mentioned in this thesis.