Gamma radiolytic degradation of 3,4-dichloroaniline in aqueous solution

Abstract Degradation of aqueous 3,4-dichloroaniline (3,4-DCA) using gamma-ray irradiation was attempted in this study. The role of e aq - during the degradation process was analyzed in detail. The results demonstrated that effective degradation of aqueous 3,4-DCA using gamma-ray irradiation was realized; when the initial concentration of 3,4-DCA was 0.050 mmol L −1 , and the irradiation dose was 0.4 kGy, the degradation efficiency of 3,4-DCA reached 96.2%. The degradation process of 3,4-DCA could be depicted by the pseudo first order reaction kinetics. Dechlorination was observed during the degradation process, and the concentration of detected Cl − in the treated 3,4-DCA solution increased with increasing irradiation dose. The sequence of the contribution of free radicals to the 3,4-DCA degradation was OH >  e aq -  >  H. The quantum efficiency ratio of OH, e aq - and H for the degradation of 3,4-DCA was 1:1:4. The degradation efficiency of 3,4-DCA was accelerated by the addition of H 2 O 2 , and the appropriate addition amount was 0.05% (v/v). However, HCO 3 − , NO 3 − and NO 2 − (as additives) reduced the degradation efficiency of 3,4-DCA. A gas chromatograph–mass spectrometer was employed to identify the degradation intermediates, indicating that p -chloroaniline was the primary degradation intermediate with the addition of 2-propanol.