Wood Nanofibrillated Cellulose Aerogel for Sustainable Oil–Water Mixture Separation

Oil-water mixture separation is a crucial issue in various industrial and environmental fields. However, most existing methods often come at the expense of sustainability, such as employing separation materials that pose environmental risks, facing limitations in scalability and producing large-sized samples, and suffering from imbalances in separation efficiency and filtration rate. Here, we address this challenge by constructing a lightweight and porous wood nanocellulose aerogel. The unique surface rich in hydroxyl groups, one-dimensional nanostructure, and assembly properties of nanocellulose endow the aerogel with superhydrophilicity and underwater oleophobicity. Driven by gravity, the as-fabricated aerogel achieves oil-water mixture separation with a filtration rate of 8153 L m⁻² h⁻¹. An assembled large-sized aerogel filter realizes continuous and rapid separation of a 40 L soybean oil/water mixture. The aerogel can be recycled via disintegration and reorganization several times and maintain stable oil-water mixture separation performance. Moreover, the aerogel is biodegradable and biofriendly, ensuring that it is a viable material choice for sustainable oil-water mixture separation.