Theoretical study of geometry, stability and interaction in configurations of ampicillin and amoxicillin molecules on the surface of anatase-TiO2 (101)
Abstract
By using density functional theory calculations, we examined the adsorption of ampicillin (AP) and amoxicillin (AX) molecules on anatase-TiO 2 (101) surface (a-TiO 2 ). The periodic slab model and plane wave method were applied in all calculations. Results indicate that these processes are evaluated as chemical adsorptions with associated energies of -31 kcal.mol -1 . Stability of configurations is significantly contributed by Ti‧‧‧O electrostatic interactions and O/N/C-H‧‧‧O hydrogen bonds. Existence and role of surface interactions in complex stabilization are analyzed in detail based on quantum chemical approaches. As a consequence, the adsorption capacity of AP on the a-TiO 2 is slightly stronger than that of AX. Remarkably, the horizontal arrangement along with large surface area occurred favorably in adhesion of these antibiotics on the a-TiO 2 .