Assessment of the potential and application of BeO nanocage for removal of ciprofloxacin from water employing density functional theory.

The modern world is facing the issue of emerging pollutants for its sustainable development. We report a detailed study on the abatement of ciprofloxacin (CIP) by BeO nanocage. Five different geometries of BeO nanocage with CIP i.e., Com-A, Com-B, Com-C, Com-D and Com-E are optimized. All the complexes show chemisorption with the highest adsorption energies (E) of - 39.86 kcal/mol for Com-E followed by Com-A, Com-B, Com-C and Com-D without any structural change. The O and F atoms of ciprofloxacin (CIP) interacts strongly with the Be atoms of the nanocage respectively. Charge transfer from the nanocage to CIP reveals strong interaction in all the optimized complexes, with maximum charge transfer of -0.199 e for Com-E with the smallest bond lengths of 1.52 Å and 1.63 Å. The decrease in the bandgap of the optimized geometries witnesses increase in the sensing ability of the adsorbent and demonstrates strong interaction between the adsorbent and adsorbate supporting the adsorption energies. The positive values of H and ∇ρ for all complexes reveals strong interaction of electrostatic nature between CIP and BeO nature which is supported by different tools of DFT. The overall study suggests BeO an efficient, reusable adsorbent for the purification of water from CIP and therefore BeO can be used effectively to eliminate antibiotics from water.