Insights into adsorptive interactions between antibiotic molecules and rutile-TiO2 (110) surface

Intermolecular interactions between antibiotic molecules, ampicillin (AP), amoxicillin (AX) and tetracycline (TC), and rutile-TiO2 (110) surface (r-TiO2) were thoroughly investigated using density functional theory calculations in solid state. The popular rutile-TiO2 is considered as a material for treatment of antibiotic molecules present in waste water. Calculated results revealed that in these adsorbate-adsorbent systems, significant contributions of TiO2 electrostatic interactions and important addition of O/N-H center dot center dot center dot O hydrogen bonds occur in stabilization of configurations of the most favored structures. Existence and role of adsorptive interactions are clarified by the atom-in-molecule theory, density of states and electron density transfer analyses. Adsorption of antibiotic molecules onto the r-TiO2 surface is characterized as chemisorption processes. Furthermore, the most stable configurations tend to be formed preferably in horizontal arrangement of molecules onto the material surface. The adhesive capacity of these AP, AX and TC antibiotic molecules on r-TiO2 surface is large and quantitatively evaluated.

Automated summary

Density functional theory calculations were used to investigate the intermolecular interactions between antibiotic molecules and the rutile-TiO2 surface, revealing that electrostatic interactions of TiO2 and hydrogen bonds play crucial roles in stabilizing the most favored structures. The existence and role of adsorptive interactions were clarified through atom-in-molecule theory, density of states, and electron density transfer analyses. The adsorption of antibiotic molecules on the r-TiO2 surface was characterized as chemisorption processes, with the most stable configurations forming in a horizontal arrangement.