CHEMICAL KINETICS OF THE PHOTOCATALYTIC DEGRADATION OF TRANS-CINNAMIC, DIHYDROCINNAMIC, TRANS-CAFFEIC, AND DIHYDROCAFFEIC ACIDS

Abstract

Quantitative studies of the catalysed degradation of aqueous solutions of cinnamic 1, dihydrocinnamic 2, trans-caffeic 3 and dihydrocaffeic 4 acids in the presence of TiO₂ and UV radiation at pH 3 and 10 are reported. The phenolic and aliphatic unsaturated groups in caffeic acid 3 caused it to be adsorbed more strongly than the phenolic saturated acid 4, and these two acids were much more strongly adsorbed than cinnamic and hydrocinnamic acids. The kinetics of the degradation of each acid has been studied at pH 3 and 10. TIC analysis showed complete mineralisation of the acids after 9 h.

Keywords:

• trans-cinnamic
• Dihydrocinnamic
• trans-caffeic
• Dihydrocaffeic acids
• Photocatalysed degradation
• Titanium dioxide
• Kinetics
• TOC
• TIC

Acknowledgments