Adsorption behaviour of hexagonal boron nitride nanosheets towards cationic, anionic and neutral dyes: Insights from first principle studies

In this study, adsorption of methylene blue (MB, cationic), methyl orange (MO, anionic) and neutral red (NR, neutral) dyes on hexagonal boron nitride nanosheets (hBNNs) were investigated using the first principle density functional theory calculations. The electrostatic potential maps were used to inspect the charge accumulation, which revealed an increase in the charge accumulation after the adsorption. The charge accumulation was maximum in the case of the MO-hBNNs complex. The electronic properties of the dye molecules and the dyehBNNs complexes were investigated using the density of states plots. The HOMO-LUMO energy of the complexes was also obtained to study the electronic properties of the dyes before and after the adsorption on the hBNNs. The adsorption energies were calculated to test the feasibility of the adsorption of the dyes on the hBNNs. The adsorption energies for MB and NR dye molecules adsorbed on hBNNs were comparable:-117 kJ mol(-1) and-153 kJ mol(-1), respectively. The adsorption energy for MO was twice that of the other two dyes (-296 kJ mol(-1)). The plausible mechanism of the adsorbent-dye interactions was investigated based on which the physical nature of the interaction was confirmed. The study showed that hBNNs adsorbed the MO dye (anionic) most effectively among the three model dyes.

Automated summary

In this study, the adsorption behavior of different dyes on hexagonal boron nitride nanosheets was investigated using density functional theory calculations. The study examined the charge accumulation and electronic properties of the dye molecules and their complexes with the nanosheets. The adsorption energies were calculated to determine the feasibility of dye adsorption. The study found that the nanosheets showed the highest adsorption effectiveness for the anionic dye.