The surface acidity and reactive activity of beta-FeOOH. mesoporous alumina (MA), beta-FeOOH/MA were investigated in catalytic ozonation of pharmaceutically active compounds (PhACs) aqueous solution. beta-FeOOH/MA showed high efficiency for the degradation and mineralization of ibuprofen and ciprofloxacin. Its surface Lewis acid sites on beta-FeOOH/MA were more greatly enhanced compared with those on MA and beta-FeOOH. In situ attenuated total reflection FTIR (ATR-FTIR) spectroscopy was used to investigate the interaction of D2O and O-3 with the catalysts in aqueous phase under various conditions. The dissociative chemisorptions of D2O occurred at the surface Lewis acid sites of the catalyst. Furthermore, O-3 interacted with the surface hydrogen-bonded -O-D and D2O to initiate reactive oxygen species (ROS). The stronger Lewis acid sites of beta-FeOOH/MA caused the more chemisorbed water enhancing the interaction with ozone, resulting in higher catalytic reactivity. The observations verified that the Lewis acid sites were reactive centers for the catalytic ozonation of PhACs in water. (C) 2010 Elsevier B.V. All rights reserved.