Influences of Various Cyclodextrins on the Photodegradation of Phenol and Bisphenol A under UV Light

Recently, the removal of phenolic compounds has attracted great attention in wastewater treatment. In this work, the influences of various cyclodextrins (CDs) on the photodegradations of phenol and bisphenol A (BPA) under UV light were investigated systematically. The results show that the photodegradation of phenol displays no obvious differences in the presence or absence of CDs. In contrast, BPA photodegradation increases considerably in the presence of β-CD and its derivatives. Moreover, the catalytic effects of BPA differed among α-CD, β-CD, carboxymethyl-β-CD (CM-β-CD), and hydroxypropyl-β-CD (HP-β-CD), following the order β-CD ≈ HP-β-CD > CM-β-CD > α-CD. Specifically, over 99% of the BPA was degraded in the HP-β-CD and β-CD systems within 120 min. Additionally, six main intermediates of BPA in the presence of β-CD were confirmed, and the probable degradation pathway was proposed, which provides a useful platform for the application of CDs in the photodegradation of BPA.