Evaluation of atrazine degradation applied to different energy systems

Abstract

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 process MW-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.

Caracterização de reator fotoquímico para aplicações em processos oxidativos avançados

“…Quanto maior a frequência e a intensidade dos fótons emitidos, maior será a eficiência em degradar o respectivo contaminante. Assim, nos últimos anos a aplicação das lâmpadas Hg-MDEL tem sido amplamente investigada para a degradação de contaminantes emergentes como herbicidas (Horikoshi, Kajitani, Sato, & Serpone, 2007;Moreira, Pinheiro, Araújo, & Freschi, 2016) e fármacos (Moreira et al, 2019a). Sua elevada eficiência para degradar esses (a) (b) contaminantes tem sido reportada, mesmo quando esta é aplicada na ausência de reagentes (como peróxidos) ou nanomateriais (semicondutores) que atuam como catalisadores (Moreira et al, 2019).…”

Utilização De Ferramentas De Inteligência Competitiva Para Delinear Estratégias De Posicionamento De Mercado De Equipamentos Eletromédicos De Monitoramento

“…Com a análise em espectro UV-Vis nota-se uma mudança no formato e na intensidade das curvas obtidas, indicando o desaparecimento total do herbicida e o surgimento de um novo pico em 240 nm, na região delimitada no gráfico. De acordo com Moreira et al (2016), o composto que aparece no comprimento de onda de 240 nm é a Atrazina-2-hidroxi, um dos subprodutos mais comuns da atrazina e, possivelmente, menos tóxico devido a hidroxilação do anel triazinico junto ao carbono halogenado. Ao que tudo indica e conforme a literatura, o aumento do pico Atrazina-2-hidroxi, também conhecida como Hidroxiatrazina foi procedido da queda do pico da atrazina (SILVA et al, 2017).…”

UV and temperature effects on chloroacetanilide and triazine herbicides degradation and cytotoxicity

“…When temperature and UV effects are applied in tandem to degrade pesticides and herbicides, the exposure can result in different byproducts, which can alter toxicity in relation to parent compounds. Moreira's study showed that atrazine after radiation could generate 3 main hydroxyl byproducts: atrazine-2-hydroxy, atrazine-desethyl-2-hidroxy, and atrazine-desisopropyl-2-hydroxy [ 31 ].…”