β-Cyclodextrin's orientation onto TiO2 and its paradoxical role in guest's photodegradation.

This work revealed that β-cyclodextrin was attached onto the surface of TiO(2) predominately by its secondary ring side, which caused paradoxical functions of β-cyclodextrin in the photodegradation of the four bisphenols. The equilibrium between the guest adsorbed through β-cyclodextrin onto TiO(2) and the one locked in β-CD in water could also change the role of β-cyclodextrin in the degradation of a certain guest.