A novel and simple fabrication method for a biomimetic-inspired lath-structured ceramic microfiltration membrane for the treatment of oil-in-water emulsions

Ceramic membranes have been widely explored as competent alternatives to traditional polymeric membranes for treating oily wastewater. Despite the exceptionally high rejection rate (>90 %) of oil–water (O/W) emulsions, membrane fouling is an inevitable phenomenon that limits the separation efficiency of ceramic membranes. Biomimetic technology, known as the lotus effect, has attracted attention as a groundbreaking method for reducing membrane fouling. However, it is difficult to control the nanostructured surfaces of ceramics, while polymer fabrication is facile. In this study, we developed a novel and simple method to fabricate an α-alumina (Al2O3) microfiltration (MF) membrane with a Nepenthes pitcher plant-like microstructure. The surface roughness of the biomimetic membrane was 286 nm, which was approximately twice that of a normal ceramic membrane. Accordingly, the oil contact angle increased from 88.84 to 128.51°. The novel biomimetic membrane showed high efficiency with an emulsion permeability of 44.1 LMH/bar, a flux recovery of 90.91 %, and an oil rejection rate of 99 %.