Silva Marcela Prado, Batista Ana Paula dos Santos, Borrely Sueli Ivone, Silva Vanessa Honda Ogihara, Teixeira Antonio Carlos Silva Costa
Chemical Engineering Department, University of São Paulo, Avenida Prof. Luciano Gualberto, tr. 3, 380, São Paulo, Brazil,
Environ Sci Pollut Res Int. 2014 Nov;21(21):12135-42. doi: 10.1007/s11356-014-2881-0. Epub 2014 Apr 26.
Photochemical advanced oxidation processes have been considered for the treatment of water and wastewater containing the herbicide atrazine (ATZ), a possible human carcinogen and endocrine disruptor. In this study, we investigated the effects of the photon emission rate and initial concentration on ATZ photolysis at 254 nm, an issue not usually detailed in literature. Moreover, the role of reactive oxygen species (ROS) is discussed. Photon emission rates in the range 0.87 × 10(18)-3.6 × 10(18) photons L(-1) s(-1) and [ATZ]0 = 5 and 20 mg L(-1) were used. The results showed more than 65 % of ATZ removal after 30 min. ATZ photolysis followed apparent first-order kinetics with k values and percent removals decreasing with increasing herbicide initial concentration. A fivefold linear increase in specific degradation rate constants with photon emission rate was observed. Also, regardless the presence of persistent degradation products, toxicity was efficiently removed after 60-min exposure to UV radiation. Experiments confirmed a noticeable contribution of singlet oxygen and radical species to atrazine degradation during photolysis. These results may help understand the behavior of atrazine in different UV-driven photochemical degradation treatment processes.
光化学高级氧化工艺已被用于处理含有除草剂阿特拉津（ATZ）的水和废水，阿特拉津是一种可能的人类致癌物和内分泌干扰物。在本研究中，我们研究了光子发射速率和初始浓度对254 nm下阿特拉津光解的影响，这一问题在文献中通常没有详细阐述。此外，还讨论了活性氧物种（ROS）的作用。使用的光子发射速率范围为0.87×10¹⁸ - 3.6×10¹⁸ 光子L⁻¹ s⁻¹ ，[ATZ]₀ = 5和20 mg L⁻¹ 。结果表明，30分钟后阿特拉津的去除率超过65%。阿特拉津光解遵循表观一级动力学，k值和去除百分比随除草剂初始浓度的增加而降低。观察到比降解速率常数随光子发射速率呈五倍线性增加。此外，无论是否存在持久性降解产物，在暴露于紫外线辐射60分钟后毒性都能有效去除。实验证实了单线态氧和自由基物种在光解过程中对阿特拉津降解有显著贡献。这些结果可能有助于理解阿特拉津在不同紫外线驱动的光化学降解处理过程中的行为。
