Density functional theory study of adsorption of acid red 33 Dye on the single-walled BN nanotubes

In this study interaction of acid red 33 Dye with (4, 4) armchair open-end boron nitride nanotubes (BNNTs) in interaction (with a length of 7 Å) was investigated. The impacts of the estereoelectronic effect associated with donor-acceptor electron delocalizations, dipole-dipole interactions and total steric exchange energies on the structural and electronic properties and reactivity of semiconductors of (4, 4) armchair open-end boron nitride nanotube (BNNT) in interaction with acid red 33 Dye was studied based on the Density Functional Theory (DFT) calculations by using the B3LYP/(6-31G, 6-31G* and 6-31+G*) level of theory in gas phase and water solution. Thermodynamic functional analysis indicate that the relative energies (ΔE), free Gibbs energies (ΔG) and enthalpies (ΔH) are negative for (BNNT - acid red 33 Dye) system but the calculated entropies (ΔS) are Positive, suggesting thermodynamic favourability for covalent attachment of Dye on (4, 4) BNNT and this results confirm the structural stability of the BNNT - acid red 33 Dye in both gas and solvent phases. Delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by NBO (natural bond orbital) analysis. These methods are used as a tool to determine structural characterization BNNTs during the adsorption reactions in the gas phase. In order to investigation of conductivity and electronic properties of (4, 4) open-end boron nitride nanotube (BNNT) in the reaction with acid red 33 Dye, the total electronic energy, dipole moment, orbital energies, charge density, density of state (DOS), energy bond gaps, Adsorption energies (EAd), the global index were calculated. The calculated LUMO-HOMO energy bond gap show that charge density transfer occurs within the molecules and the semi-conductivity of BNNTs could be justified.