Easy preparation of wood-base membrane with fouling resistance in complex environments for efficient oil–water emulsion separation

Oily wastewater causes a serious threat to the ecological environment and human health, how to effectively treat oily wastewater is a big concern. In recent years, the treatment of oil–water emulsions has considerably advanced through the development of separation membranes with special wettability, However, these membranes involve problems, such as complex preparation processes and material contamination, so developing an economical and environmentally friendly, high-performance membrane is a significant challenge. In this work, a wood-based membrane was easily prepared by a simple dipping process using aramid nanofibers (ANFs) to modify the surface of wood. Compared to synthetic hydrogel membranes, the wet ANF/wood membrane exhibits higher tensile strength (1.69 ± 0.32 MPa). More importantly, the membrane presents underwater superoleophobic properties and fouling resistance under complex environmental conditions (acid, alkali, seawater, and high temperature) and effectively separates various oil–water emulsions with high separation efficiency (> 99.3%) and flux (> 227 L m⁻² h⁻¹). More excitingly, the membrane retains its original separation properties after 13 cycles of oil–water emulsion separation. Therefore, the inexpensive, environmentally friendly and easily prepared ANF/wood membrane is well tolerated under extreme conditions, presents excellent separation performance and provides a material basis for the treatment of actual oily wastewater.