Effect of fluorosurfactant on alumina membrane for oil and water separation

Abstract

In this study, the surfactant sodium perfluorooctanoate with alumina composite was synthesized via a sol–gel method. The effects of perfluorooctanoic (PFO) acid as an anionic surfactant on the morphological structures, amorphous crystalline, and the functional elements using field emission scanning microscope (FESEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and Fourier transform infrared (FTIR) were evaluated after grafting on kaolin-based hollow fibre membrane through a dip-coating process. The post-heat treatment on the coated surface was investigated. The performance was examined for oil rejection and contact angle test. The results reveal intercalation of PFO on the alumina in the form of film-like top layer, and the oil rejection was attained at 98% and water flux of 21.62 L/m2.h was also obtained after heat treatment. The heat treatment significantly did not alter the surface structure, while the fluorine atoms in the PFO decreased with an increase in temperature from 40 °C to 60 °C. The PFO largely influence the oleophobicity of the membrane. Thus, post thermal treatment of the coated surface influences the properties and performance of the membrane. Fluorosurfactant plays a significant role in simultaneously acting as interfacial surface material and improving the dispersion of alumina particles on the alumina composite membrane.