ABSTRACT
Oily streams, which are found in various industries, with micron size oil emulsions are separated effectively via membrane filtration technology; however, membrane fouling remains an inevitable drawback, which necessitates comprehensive understanding to properly tackle. The interaction between membrane and oil emulsion is acknowledged to play an important role in determining the fouling phenomenon and commonly analyzed via the well-known Derjaguin–Landau–Verwey–Overbeek (DLVO) model. The additional incorporation of the Lewis acid–base (AB) interaction at shorter separation distances resulted in the extended DLVO (XDLVO) model. Many studies employed DLVO and XDLVO models for quantifying the oil–membrane interactions, which agreed well with fouling trends. These models are mainly used for understanding the oil fouling mechanism and validating of the antifouling property of modified membranes. Although XDLVO is a more comprehensive model, it falls short for comparing fouling tendencies by different oils, because the AB value, which is unrelated to the nonpolar oils, is orders of magnitude greater than the Lifshitz–van der Waals (LW) and electrostatic (EL) components. Therefore, the DLVO model, which neglects the AB component, is better suited for comparing oils. Nonetheless, for comparing oil with other colloids and for validating the antifouling properties of membranes, the significant polarity difference gives clearly distinguishable XDLVO oil–membrane interaction energy values.
