Facile and Green Route to Fabricate Bacterial Cellulose Membrane with Superwettability for Oil–Water Separation

Abstract The separation of oil–water mixtures by membranes with hydrophilicity and underwater superoleophobicity is an effective method. However, the fabrication of these oil–water separation membranes usually needs a complex chemical treatment process. In this study, a facile and green method to fabricate bacterial cellulose membranes (BCMs) with superwettability through one‐step filtration process without any further tedious and costly chemical modification for efficient oil–water separation is proposed. Owing to the ultrafine (20–80 nm in diameter) nanofiber structure and intrinsic hydrophilicity of bacterial cellulose (BC), BCMs with a 3D web‐like structure show superhydrophilicity in air (water contact angles about 0°) and underwater superoleophobicity (oils contact angles >150°). During the oil–water separation process, water permeates through BCMs quickly while oils remain at the BCMs' upper side. Furthermore, all separation processes present high separation efficiency (>99.7%) and high fluxes. In addition, two different models are proposed to describe the formation and microstructure of BCMs and how it affect the separation process. Thus, this work provides a facile and environment benign route for obtaining excellent separation membranes for oil‐polluted‐water treatment.