Degradation of Atrazine by UV/PMS in Phosphate Buffer

The degradation of atrazine (ATZ) by ultraviolet/peroxymonosulfate (UV/PMS) under different conditions was investigated in phosphate buffer, and the degradation mechanism and kinetics were discussed. The results showed that the degradation rate of 2.5 mu mol/L ATZ in UV/PMS system was 97.63% in 20 min when the reaction temperature was 20 degrees C, the concentration of PMS was 20 mu mol/L and the UV intensity was 50 mW/cm(2) in pH7 phosphate buffer. The mechanism analysis showed that PB with partial alkalinity promoted the degradation of ATZ by UV/PMS more than that with acidic PB. The effect of PB with alkaline conditions on the degradation of ATZ by UV/PMS was more complicated and mainly related to the state of phosphate ions. The UV/PMS system contained both HO center dot and SO4-center dot, and the ratio of HO center dot, SO4-center dot and UV-degraded ATZ was nearly 1: 1 in pH7 PB. Inorganic anions experiments showed that Cl-and HCO3- inhibited the degradation of ATZ under UV/PMS, and the inhibitory effect of Cl-was more obvious. NO3- promoted the degradation of ATZ by UV/PMS. Kinetic analysis showed that UV/PMS degradation of ATZ reaction kinetics was more in line with the quasi first-order reaction kinetics, the inhibition effect of the same concentration of ETA and Cl-on UV/PMS degradation of ATZ are the same, and UV/PMS degradation of ATZ decreased by 38.54% and 36.29% respectively. The addition of NO3- increased the rate of degradation of ATZ by UV/PMS by 31.21%. By LC-MS analysis, 5 kinds of production m/z and 6 kinds of products were obtained.