Kinetics of ozone reactions with 1-naphthalene, 1,5-naphthalene and 3-nitrobenzene sulphonic acids in aqueous solutions

This paper describes the ozone oxidation kinetics of I-naphthalene (1NS), 1 ,5-naphthalene (1,5NDS), and 3-nitrobanzene (3NBS) sulphonic acid. The pres ence of hydroxyl radicals and their effect on the overall rate of reaction was studied. Second order kinetic constants of direct reactions were estima ted at around 252 M-1 s(-1), 41 M-1 s(-1) and 22 M-1 s(-1), for 1NS, 1,5NDS , and 3NBS sulphonic acids, respectively. At pH 3, the indirect reaction ac counted for 2%, 15% and 4% of total primary oxidation of 1NS, 1,5NBS, and 3 NBS sulphonic acids, respectively. At pH 9, indirect reaction contribution increased to 73%, 84% and 48%, respectively, C4 compounds (maleic and fumar ic acids), C2 (oxalic), CI (formic) and sulphate were identified as oxidati on by-products in all cases. TOC slowly decreased throughout ozonation, rea ching around 40-60% and 60-70% reduction over 90 minutes at pH 7 and 3, res pectively.