Photo-degradation of curcumin in the presence of TiO2 nanoparticles: Fundamentals and application

Photo-degradation of curcumin in the presence of TiO2 nanoparticles has been Studied in water-methanol and water-aceronitrile mixed solvents. curcumin was found to form charge transfer(CT)complexes with TiO2 nanoparticles. The binding constant of the CT complexes has been determined. Curcumin was found to undergo photo-degradation under UV-vis and only visible light irradiations. Photo-degradation was investigated in the presence of external electron quenchers like methyl violegen and dissolved oxygen and hole quenchers like iodide ions in a de-aerated condition. The presence of oxygen was found to enhance the photo-degradation processes. The photo-degradation was found to be completely quenched in the presence of iodide ions in both the solvent mixtures in a de-aerated condition. A reaction pathway for the photo-degradation of curcumin in the presence of TiO2 nanoparticles has been proposed. This Study has been Successfully applied to remove the yellow turmeric stain from cotton fabrics. (C) 2009 Elsevier B.V. All rights reserved.