Abstract

Superabsorbent aerogels are fascinating materials for oil and chemical spillage cleanup. However, the development of an economic and efficient superabsorbent is still highly challenging. In this study, we introduce a novel approach to prepare very low density (0.005 g/cm³), highly porous (>99.6%), economic, reusable, hydrophobic, and magnetic spherical cellulose nanofiber-derived aerogels (i.e., aerobeads) prepared from waste boxboards via a simple freeze-drying procedure. The spherical aerobeads were fabricated easily after dropping a hydrophobized nano-fibrillated cellulose solution containing magnetic Fe₃O₄ nanoparticles into liquid nitrogen. The aerobeads showed outstanding absorption efficiency for several oils and organic solvents (up to 279 g/g with castor oil) and demonstrated excellent selectivity for absorbing oil from an oil/water mixture. Moreover, they were easily collected by an external magnet, indicating excellent recyclability and reusable for at least 10 cycles while still retaining supreme absorption capacity (up to 101 g/g for diesel oil). This study proposes an economic and novel method for the large-scale preparation of spherical superabsorbent aerobeads, making them a promising candidate for the efficient and sustainable cleaning of oil and chemical spills.