Comparison of initial photocatalytic degradation pathway of aromatic and linear amino acids
Résumé
Amino acids are at the origin of the formation of odourous compounds after chlorination treatment. Our objectives were to test the efficiency of a photocatalytic process to remove these types of compounds. Five amino acids (AA) - phenylalanine, tyrosine, tryptophan, glycine and alanine - have been chosen as model molecules. The photocatalytic degradation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalysts, in order to assess the adsorption, the disappearance rate and the mechanism of degradation. Results showed that only a small amount of amino acid is adsorbed corresponding to less than 1% of OH covered for aromatic amino acids and about 10% for linear amino acids. A comparison of disappearance rate, total organic carbon (TOC) removal and intermediate for these five amino acids are presented and discussed, taking into account their nature.