LAFFEQ, Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, 37715-400, Poços de Caldas, MG, Brazil.
Environ Sci Pollut Res Int. 2017 Mar;24(7):6398. doi: 10.1007/s11356-017-8622-4.
Atrazine is an herbicide widely used in crops and has drawn attention due to potential pollution present in soil, sediment, water, and food. Since conventional methods are not potentially efficient to persistent degradation of organic compounds, new technology has been developed to remove them, especially practices utilizing advanced oxidation processes (AOPs). This work aims to evaluate the use of different energies (ultraviolet (UV), microwaves (MW), and radiations (MW-UV)) to the herbicide atrazine through the process of photo-oxidation. These systems found degradation rates of around 12% (UV), 28% (MW), and 83% (MW-UV), respectively, with time intervals of 120 s. After the photolytic processes, the samples were analyzed at a wavelength scanning the range of 190 to 300 nm, where the spectral analysis of the signal was used to evaluate the degradation of atrazine and the appearance of some other peaks (degradation products). The spectrum evaluation resulting from photolytic processes gave rise to a new signal which was confirmed by chromatography. This spectrum indicated the possible pathway of atrazine degradation by the process of photolytic MW-UV, generating atrazine-2-hydroxy, atrazine-desethyl-2-hidroxy, and atrazine-desisopropyl-2-hydroxy. The process indicated that in all situations, chloride was present in the analytic structure and was substituted by a hydroxyl group, which lowered the toxicity of the compound through the photolytic processMW-UV. Chromatographic analysis ascertained these preliminary assessments using spectrophotometry. It was also significantly observed that the process can be optimized by adjusting the pH of the solution, which was evident by an improvement of 10% in the rate of degradation when subjected to a pH solution equal to 8.37.
莠去津是一种广泛应用于农作物的除草剂，由于其在土壤、沉积物、水和食物中存在潜在污染而受到关注。由于常规方法对持久性有机化合物的降解效果不理想，因此开发了新技术来去除它们，特别是利用高级氧化工艺（AOPs）的实践。本工作旨在评估不同能量（紫外线（UV）、微波（MW）和辐射（MW-UV））在光氧化过程中对莠去津的应用。这些系统分别在 120 秒的时间间隔内，达到了约 12%（UV）、28%（MW）和 83%（MW-UV）的降解速率。在光解过程之后，用波长扫描范围为 190 至 300nm 的方法对样品进行分析，其中信号的光谱分析用于评估莠去津的降解和一些其他峰（降解产物）的出现。光解过程的光谱评价产生了一个新的信号，该信号通过色谱法得到了证实。该光谱表明，莠去津在光解 MW-UV 过程中可能的降解途径是生成莠去津-2-羟基、莠去津-去乙基-2-羟基和莠去津-去异丙基-2-羟基。该过程表明，在所有情况下，氯都存在于分析结构中，并被羟基取代，通过光解 MW-UV 过程降低了化合物的毒性。使用分光光度法对色谱分析进行了这些初步评估。还明显观察到，通过调整溶液的 pH 值可以优化该过程，当溶液的 pH 值等于 8.37 时，降解速率提高了 10%，这一点显而易见。
