[Degradation of the Nitrogenous Heterocyclic Compound Quinoline by O₃/UV]

The influences of various factors including initial concentration of quionline solution, static duration after reaction, initial pH, HCO₃^-on the degradation of quinoline by O₃/UV were analyzed in this study. In addition, the degradation mechanism and pathways were also analyzed. The results showed that reaction rate constants and removal rate of quinoline decreased with the increase of the initial concentration of quinoline. The best degradation efficiency of quinoline was achieved under the alkaline conditions (pH 7-9). Removal rate of quinoline was obviously influenced by HCO₃^-, and was reduced by 42.01% within 6 min when the concentration of HCO₃^- was 100 mg·L^-1. There was neglected effect of static duration after reaction on the removal rate and mineralization rate of quinolone. The intermediate products of quinoline were mainly 8-hydroxyquinoline, 5-hydroxyquinoline, 2(1H)-quinoline ketone, 2-pyridinecarboxaldehyde and so on. The main degradation pathways of quinoline in the O₃/UV system were addition reaction, substitution reaction and electrophilic substitution mediated by O₃ and·OH.