Stability and Filtration Characteristics of Surface-Modified Membranes of Alumina

Abstract

Surface modified alumina membranes were examined in terms of stability in water and filtration characteristics to apply the membranes for membrane bioreactors. Surface modifications were carried out by the treatment of octadecyldimethylchlorosilane (ODS), γ-aminopropyltriethoxysilane (γ-APS) and 1, 3-propane sultone (PS) to control the zeta potential and surface free energy. The introduced functional groups from the treatment of silane coupling agents such as ODS and γ-APS were stable in water. While sulfo groups from PS were hydrolyzed and reduced to 1/3 under reflux for 20 hours, it were stable enough at room temperature for 8 hours enough to operate a short time filtration examinations. The relationship between zeta potential and restration of membrane permeability by backflush was predicted from DLVO theory. Low zeta potential for membrane predicts better permeation characteristics. It is confirmed that surface modification to control the zeta potential for negative improves the clogging characteristics of membrane.