UV/Fenton-Fe0降解水中阿特拉津动力学及影响因素

Study on the Dynamics and Influence Factors of UV/Fenton Based on the Fe^0 Degradation of Atrazine in Aqueous Solution

研究采用Fe^0非均相UV/Fenton技术去除水中阿特拉津(ATZ)。结果表明,UV/Fenton-Fe^0技术能够实现水中ATZ的快速去除,当p H为3.0,H_2O_2、Fe^0的质量浓度分别为17、25 mg/L时反应速率最快,5 min后ATZ去除率可达97.5%,反应符合准1级降解动力学。初始ATZ含量升高,反应速率降低,ATZ的绝对去除量增加。UV/Fenton-Fe^0体系拓宽了p H适用范围,在初始p H为3.0~7.0时,反应7 min后ATZ去除率均达到95%以上。水中少量天然有机物(TOC的质量浓度5~10 mg/L)对ATZ降解有明显促进,ATZ降解速率较纯水基质中提高7倍以上。水中Cl-和SO42-的存在对UV/Fenton-Fe^0过程也有明显促进,而NO3-则表现为抑制;自由基抑制实验证实了降解过程符合·OH氧化机理。

The heterogeneous UV/Fenton technology based on Fe~ was investigated in this study to remove atrazine （ATZ） in aqueous solution. The results indicated that the UV/Fenton-Fe0 process could remove ATZ rapidly in aqueous solution. At the optimum conditions ofpH was 3.0, HzO2 was 17mg/L, Fe0 was 25mg/L, the reaction rate was fastest, the removal rate of ATZ could reach 97.5% after 5 rain reaction and the degradation of ATZ was conformed to the pseudo-first-order kinetics. With the increase of the initial ATZ content, ATZ removal rate gradually reduced and the mass of ATZ removing was increasing. Results also demonstrated that UV/Fenton-Fe~ process widened the pH application range. With solution pH varied from 3 to 7, the degradation rate of ATZ could achieve 95% after 7 min reaction. Low concentration of natural organic matters （mass concentration of TOC 5-10 mg/L） obviously promoted the degradation of ATZ in aqueous solution and the removal rates of ATZ in above matrix were 7 times more than that in the ultrapure water. Meanwhile, Cl and SO42- existing in the.solution also had beneficial effects on the degradation of ATZ in the UV/Fenton-Fe0 process. In addition, NO3 displayed a significant inhibitory effect on ATZ degradation. Free radical inhibition tests confirmed the ATZ degradation confonned to the hydroxyl radical oxidation mechanism.