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

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 degrees) and underwater superoleophobicity (oils contact angles >150 degrees). 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.