Master of Science (MS)
Semester of Degree Completion
Douglas G. Klarup
The degradation of dissolved dimethoxyatrazine (2-chloro-4,6-dimethoxy-1,3,5-triazine), terbutylazine (2-chloro-4-ethylamino-6-terbutylamino-1,3 ,5-triazine) and deisopropylatrazine (2-amino-4-chloro-6-ethylamino-1,3,5-triazine) via metallic iron was studied as a function of solution pH. Generally, degradation was more rapid the lower the solution pH and higher the compound pKa. For dimethoxyatrazine kSA (kSA= k' (min-1)* V (L) / M (g) I SA(m2/g)) was found to be 1.33 (± 0.07) E-4 min-1 m-2 L at pH 2, 6.1 (± 0.6) E-5 min-1 m-2 L at pH 3 and 4.4 (± 0.6) E-5 min-1 m-2 L at pH 4. For deisopropylatrazine kSA was found to be 7.2 (± 0.2) E-4 min-1 m-2 L at pH 2 and 1.0 (± 0.4) E-4 min-1 m-2 L at pH 3. For terbutylazine kSA was found to be 2.41 (± 0.06) E-3 min-1 m-2 L at pH 2, 6.9 (± 0.9) E-4 min-1 m-2 L at pH 3 and 2.4 (± 0.4) E-4 min-1 m-2 L at pH 4. Dechlorinated dimethoxyatrazine and terbutylazine products were detected in the reaction solutions.
The electrochemical reduction of these compounds on mercury electrodes was examined. Cyclic voltammetry and differential pulse polarography experiments with these triazines yielded a general pattern of two pH dependent irreversible reduction waves.
These results suggest the triazine degradation reaction via metallic iron begins with a 2-electron dechlorination reduction step and that the actual species undergoing reduction is the protonated triazine.
Dombek, Tracy, "Degradation of Trazine Compounds via Metallic Iron Under Acidic Conditions" (2000). Masters Theses. 1613.