Synthesis and characterization of hexagonal BN-based aerogels for absorbing oils

Abstract Porous oil absorbents have been extensively studied in recent years. Boron nitride (BN) is an ideal inorganic material to withstand severe absorption conditions due to its excellent inertness and high-temperature resistance. A large challenge of BN aerogels is their high preparation costs due to requiring high temperatures and dangerous atmospheres. A facial synthesis of h-BN-based aerogels by the cast-freezing method is reported here, which has the advantages of producing a light and recyclable material (~0.035 g/ml) at a low cost and with low energy consumption. In this work, carboxymethylcellulose (CMC) is used as the compounder to interact with BN and form an aerogel that has controllable porosity (38–86 μm) and hydrophobicity (~140°). The porous structure, components, and reaction mechanisms are analyzed by SEM, XRD, mercury porosimetry, etc.. The pore distributions can be controlled by the concentrations of CMC and crosslinking agents. The intercalation effect on BN is carried out by CMC, which increases the specific surface area. Finally, the oil absorption performances are measured. The oil absorption capacity is up to 31.55 g/g (~97% ml/ml) because of the high specific surface area of the prepared material; additionally, the capacity of this material shows no obvious decrease after 6 cycles. Therefore, h-BN-based aerogels are expected to be applied in the oil absorption field and have the potential to be applied in the biochemical and nuclear fields.