Abstract
The kinetic oxidation of antipyrine by activated persulfate oxidation was investigated. The reaction kinetic rates under different temperature (T, 40–70°C), initial persulfate concentration ([PS]0), and initial antipyrine concentration ([AP]0) were examined in batch experiments. The results show that higher temperature, higher persulfate concentration, and lower initial antipyrine favored antipyrine degradation. A deep investigation into the reaction order obtained a more accurate kinetics rate equation (−d[AP]/dt = 0.34 [PS]0 [AP]) with the limits of the experimental conditions applied here. The removal of antipyrine in 120 min was 54.3% at pH 4.5, and antipyrine degradation at different pH followed the order: pH 4.5 > pH 11.0 > pH 7.0 > pH 9.5. The persulfate disappearance fits pseudo-first-order kinetics well, the calculated disappearance rate of persulfate (kobs-PS) was 2.33 ± 0.23 × 10−4 min−1 at 60°C. Although 71.4% of initial antipyrine was degraded at 60°C, only 12.5% of initial antipyrine was mineralized. At last, norantipyrine and 5-pyrazolidinone-3-methyl-1-phenyl were identified to be the degradation products of antipyrine in heat activated persulfate system for the first time, and the degradation pathway of antipyrine was also tentatively proposed.
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China (No. 51178321), the National Major Project of Science & Technology Ministry of China (No. 2012ZX07403-001), and the research and development Project of Ministry of Housing and Urban-Rural Development (No. 2009-K7-4).