Photocatalytic degradation of bilirubin on hydroxyapatite-modified nanocrystalline titania coatings

Quartz crystal microbalance (QCM) technique was employed to in Situ investigate the adsorption and degradation behavior of bilirubin on hydroxyapatite(HAP)-modified titania coatings. The obtained results revealed that the adsorption and photocatalytic degradation of bilirubin related closely to the amount of HAP deposited on titania coatings, and the most degradation efficiency Of bilirubin was found when the percentage of HAP was 0.7 wt%. In terms of the in situ frequency shifts, the degradation-rate constants (K) of bilirubin adsorbed on various titania coatings were estimated, and the K value was (1.18 +/- 0.12) x 10(-3) s(-1) at 0.7 wt%. (C) 2008 Elsevier B.V. All rights reserved.