Chromate ions chemisorption over the exterior surface of pristine boron nitride (B12N12) nanocage: A computational study

In present study, we for the first time investigated boron nitride (B12N12) nanocage as adsorbent material for removal of chromate species Cr(VI) from water using density functional theory simulations. The geometry optimization reveals that Cr(VI) strongly interact with the surface of B12N12 nanocage. The bonding analysis shows that Cr(VI) species make strong intermolecular hydrogen bonds and chemical bonds with the exterior surface of B12N12 nanocage. This stronger interaction leads to larger adsorption energies for different complexes ranging from-27.17 to-168.96 kcal/mol. Moreover, the computed thermodynamic values i.e. Delta H and Delta G are negative (ranging from-55.54 to-156.42 kcal/mol and from-47.31 to-151.21 kcal/mol, respectively) which reflects their feasible and spontaneous adsorption. Furthermore, a large amount of charge transfer between Cr (VI) and B12N12 nanocage, resulting strong electrostatic interactions. The HOMO-LUMO gap is strongly reduced after the adsorption of chromate ions on the B12N12 nanocage surface indicating a strong sensitivity of adsorbent. The AIM, RDG and NCI analyses evince the existence of stronger intermolecular hydrogen and chemical bond between the B12N12 surface and chromate ions. The outcomes of the present study demonstrate that the B12N12 nanocage could be used as an efficient adsorbent for purification of water from toxic pollutants.