title: Rapid separation of oil particles from low-concentrated O/W emulsions in the presence of anionic surfactants using fibrous slag.
abstract: Rapid removal of low-concentrated oil from stable O/W emulsions has been one of the most difficult techniques, and an effective method has not yet been established so far. Our novel technique using surface characteristics, the application of a heterocoagulation phenomenon, is a good alternative for separating colloidal particles. In this research, the rapid separation of n-decane oil droplets in the presence of sodium dodecyl sulfate (SDS) by a column bed packed with fibrous ferro-nickel slag (FS) was investigated. Separation of emulsified n-decane droplets was examined at SDS concentrations ranging from 0 to 1.0x10(-4) M, and the results were discussed in terms of electric interfacial interaction of both an n-decane droplet and a collector medium. When the SDS concentration was 3.0x10(-5) M or lower, n-decane droplets were efficiently collected by FS, and the coalescence between approaching and already-deposited oil particles promoted the oil collection. When the SDS concentration was higher than 3.0x10(-5) M, however, the n-decane collection ratio monotonically decreased with time, indicating that n-decane droplets attached to the FS surface. These experimental findings were in qualitative agreement with the DLVO theory and suggested that separation using surface characteristics is a promising method for the recovery of stable emulsified oil droplets.
authors.affiliation: Materials Lab, Technology Research Center, Ebara Research Co., Ltd. Honfujisawa 4-2-1, Fujisawashi, Kanagawa, 251-8502, Japan. itoh21142@erc.ebara.co.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasaki