Insights into Interactions of Propranolol with Nano TiO2

Beta blockers in the environment are acknowledged to cause health risk towards humans. Insights from molecular-level mechanisms of propranolol adsorption can further our understanding of the fate and transport of beta blockers in the environment. The motivation of our study is to explore the dynamic adsorption process of propranolol at the TiO2/aqueous interface on the molecular scale. Complementary techniques including macroscopic adsorption experiments, UV analysis, surface enhanced Raman scattering (SERS), flow-cell ATR-FTIR measurement, XPS, and quantum chemical calculations were used to study the interaction between propranolol and TiO2. The results show that propranolol adsorption on TiO2 increased from 0.3 to 2.3 mu mol/g in the pH range 5 to 9. The ATR-FTIR and XPS analysis indicated that the hydroxyl and amino groups of propranolol strongly interacted with the TiO2 surface. The DFT calculations suggested the molecular structure of surface complexes with hydrogen bonding and the charge transfer from propranolol to TiO2 surface upon adsorption. The TiO2 doped nanomaterial shows high performance SERS ability together with photocatalytic property towards propranolol.