Condensation-assembly synthesis of three-dimensionally porous boron nitride for effective oil removal

A template-free pyrolysis route has been developed using condensation-assembly precursors made of trimethoxyboroxane (TMB) and melamine (M) to cater the requirements of an industrial real-world environment. The precursors contain abundant B–N bonds and exhibit a high level of interconnectivity, resulting in 3D-PBN with enhanced mechanical properties and the ability to be easily customized in terms of shape. Moreover, 3D-PBN demonstrates rapid adsorption kinetics and excellent reusability, efficiently removing up to 270% of its own weight of fuel within 30 s and being readily regenerated through simple calcination. Even after undergoing 50 cycles, the mechanical properties remain at a remarkable 80%, while the adsorption performance exceed 95%. Furthermore, a comprehensive analysis of thermal behavior from precursor to 3D-PBN has been conducted, leading to the proposal of a molecular-scale evolution process comprising four major steps. This understanding enables us to control the phase reaction and regulate the composition of the products, which is crucial for determining the characteristics of the final product. Three-dimensionally porous boron nitride is prepared by pyrolysis of the preformed condensation-assembly melamine-trimethoxyboroxine precursor, and exhibit an efficient oil clearance capacity. [Display omitted] •Generation of C–N–B–O basic unit interconnected precursors by condensation assembly.•Three-dimensional porous boron nitride (3D-PBN) with excellent overall performance.•Revealing the complete reaction process on a molecular scale.•3D-PBN maintains high efficiency after 50 cycles of oil removal.