利用热活化过硫酸盐技术去除阿特拉津

利用热活化过硫酸盐(S2O2-8)技术去除水中的阿特拉津(ATZ).结果表明,增加溶液中S2O2-8浓度或提高溶液反应温度,可加速ATZ的降解.ATZ的降解是一个二级反应,其速率和溶液中ATZ和S2O2-8的浓度都成正比.初始pH为3.0~10.0时,S2O2-8对ATZ都有很好的降解效果,在酸性和中性时,降解效率高于碱性条件.利用自由基探针发现,在酸性和中性条件下,起降解作用的主要是SO·-4,而碱性条件下OH·占主导.ATZ的降解受到Cl-、CO2-3和腐殖质(HA)的影响.其中,Cl-对反应的影响比较复杂,低浓度时Cl-会生成具有高氧化还原电位的Cl·促进ATZ的降解,而高浓度时Cl·会继续反应生成氧化能力相对较弱的Cl2·-,从而抑制反应的进行.HA和CO2-3都对反应有明显的抑制作用.

Removal of atrazine in heat activated persulfate oxidation process

The removal of atrazine (ATZ) by heat activated persulfate was systematically studied in this work. We focused on the influences of persulfate concentration, temperature, pH, humic acid (HA), Cl^- and CO₃^2- on the performance of the treatment process. It was demonstrated that the degradation of ATZ was a second-order reaction. The reaction rate was proportional to the concentrations of both ATZ and persulfate. The reaction rate increased with elevated temperature. The removal of ATZ was optimal at a wide range of pH (3.0~10.0), although slightly less efficient at basic condition. Radical scavenger test indicated that OH·was the predominant radical species at basic condition while SO₄^·- played a critical role at neutral and acidic conditions. The removal of ATZ was slightly inhibited in the presence of HA. The adverse effect of CO₃^2- was more prominent. Cl^- showed a complicated effect on the removal of targeted pollutant. When Cl^- was less than 10 mmol·L^-1, the degradation was promoted. However, removal efficiency of ATZ was reduced at higher concentrations due to its competence with oxidants.