Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an 710127, China.
Environ Sci Pollut Res Int. 2023 May;30(23):64352-64362. doi: 10.1007/s11356-023-26866-w. Epub 2023 Apr 17.
As a typical carbamate pesticide, methomyl was once widely used in agriculture for its excellent broad-spectrum insecticidal effect. However, due to its high toxicity, long half-life, and difficult degradation properties, it poses a serious challenge to water environment pollution. In this study, an electrode-free discharge microwave-induced plasma technology was used to rapidly and efficiently degrade methomyl in aqueous solution. In this experiment, the statistical design of experiments (DOE) was adopted to optimize the plasma degradation parameters. Under the optimized parameters (P = 140 W, D = 0 mm, R = 0.5 L/min), 78.4% removal of 50 mg/L of methomyl was achieved after 8 min. The optical emission spectrometry and free radical detection experiments showed that the active substances generated by the collision reaction between plasma and water molecules occurring at the gas-liquid interface were the key factors to exert the degradation effect. The degradation rate of methomyl decreased by 73.2% after the addition of tert-butanol (OH burster), while it decreased by only about 12.0% after the addition of peroxidase. These implied that ∙OH was largely responsible for methomyl degradation. In addition, based on the detected intermediates, possible degradation mechanisms and pathways were analyzed.
作为一种典型的氨基甲酸酯类农药，灭多威因其优异的广谱杀虫效果而在农业中被广泛应用。然而，由于其高毒性、半衰期长且难以降解的特性，对水环境造成了严重的污染挑战。在本研究中，采用无电极放电微波诱导等离子体技术快速有效地降解水中的灭多威。在本实验中，采用统计实验设计（DOE）来优化等离子体降解参数。在优化的参数（P = 140 W，D = 0 mm，R = 0.5 L/min）下，经过 8 分钟后，50 mg/L 的灭多威的去除率达到了 78.4%。发射光谱和自由基检测实验表明，在气液界面处发生的等离子体与水分子碰撞反应生成的活性物质是发挥降解效果的关键因素。加入叔丁醇（OH 猝灭剂）后，灭多威的降解率下降了 73.2%，而加入过氧化物酶后，降解率仅下降了约 12.0%。这表明 ∙OH 是灭多威降解的主要原因。此外，根据检测到的中间产物，分析了可能的降解机制和途径。
