Review on the Aerogel-Type Oil Sorbents Derived from Nanocellulose

Because of the severe risk of oil pollution and increasing concerns about the sustainability of sorbent materials, there are considerable interests across the world to develop cost-effective, reusable, and environmentally friendly oil sorbents derived from renewable resources. Nanocellulose is a new family of promising cellulosic materials with a cellulose fibril width in the order of nanometer range (i.e., 2–100 nm). As a class of newly developed cellulose aerogels, nanocellulose-derived ones combine intriguing interconnected three-dimensional porous characteristics of aerogel-type materials such as high porosity, large surface area, and low density with fascinating advantages related to naturally occurring nanocellulose: impressive mechanical properties, abundant sources, natural renewability, excellent biodegradability, and ease to surface modification. Therefore, nanocellulose-based aerogels are very ideal "green" oil sorbents after either appropriate hydrophobic modifications or carbonization. This present review summarizes the state-of-the-art in the aerogel-type oil sorbents derived from nanocellulose, including hydrophobized nanofibrillated cellulose (NFC)-based aerogels, hydrophobized bacterial cellulose (BC)-based ones, and the carbon ones prepared through the pyrolysis NFC or BC aerogels. Their respective preparation methods, structure, and oil-absorption performance are summarized. And the existing problems in the current research and the future development perspectives are also presented.