Hierarchically porous boron nitride nanoribbon for safe and high-performance bisphenol A adsorption

Layered boron nitrides (BNs) are usually viewed as excellent protective coatings and reinforcing materials due to their chemical inertness and high mechanical strength. However, the attention paid to their potential applications in gas sorption, especially in case of hydrogen, has obviously been insufficient. Herein, a novel BN material (i.e., porous microbelts), with the highest specific surface area ever reported for any BN system, up to 1488 m² g⁻¹, is obtained through one-step template-free reaction of a boron acid-melamine precursor with ammonia. Comprehensive high-resolution transmission electron microscopy, X-ray diffraction, and Raman characterizations all confirm that the obtained BN phase is partially disordered, shows an enlarged average spacing between adjacent (0002) layers (d₀₀₀₂ = 0.38 nm, compared to normal 0.33 nm for a bulk layered BN), and belongs to an intermediate state between hexagonal (h-BN) and amorphous (a-BN) phases. By changing the synthesis temperatures, the textures of obtained porous microbelts are adjustable. H₂ sorption evaluations demonstrate that the materials exhibit high and reversible H₂ uptake from 1.6 to 2.3 wt % at 77 K and at a relatively low pressure of 1 MPa.

The porous hexagonal BN with flame retardancy and high stability could serve as the adsorbent for radioactive iodine under harsh spent nuclear fuel reprocessing conditions. Appropriate disposal of radioactive iodine in spent nuclear fuel reprocessing represents an acknowledged challenging topic. Currently, most solid sorbents for radioactive iodine treatment are suffering from the risk of fire and explosion due to the presence of nitrogen oxides in the exhaust stream. Herein, we reported for the first time the use of porous hexagonal boron nitride (porous BN) to capture radioactive iodine and further studied its practicability and iodine-removal performance. A series of tests, such as flammability, acid leaching durability and so on, revealed the excellent thermal stability, acid-resistance, anti-oxidation activity and hydrophobic properties of porous BN. It should be highlighted that porous BN exhibits outstanding flame-retardant ability, which is superior to that of well-studied MOF and POP iodine-removal materials. These merits will enormously reduce the risk of fire and explosion in the exhaust stream and endow this material with great potential in practical radioactive waste reprocessing. Benefiting from the porous properties and Lewis acid–base interaction, porous BN demonstrated 213 wt% adsorption capacity for iodine vapor, which is a considerably high value among inorganic materials. The iodine removal performance of porous BN was further demonstrated by a column test under simulated reprocessing. Combining its superb physicochemical properties with iodine removal capacity, porous BN is thereby a promising iodine sorbent for safe and effective radioactive iodine capture in practical applications.