DBD 等离子体降解水中邻苯二甲酸二乙酯研究

邻苯二甲酸酯在水环境中具有难降解和较高毒性的特点,普通污水厂的处理难以达到理想的效果。介质阻挡放电(dielectric barrier discharge, DBD)因其高效且简易被广泛应用于水体污染物的降解处理,文章通过DBD等离子体来揭示邻苯二甲酸二乙酯(DEP)的降解机制,分析DBD等离子系统中功率、DEP初始质量浓度和载气种类对DEP降解效果的影响,深入研究5种活性物质在降解过程中的作用,通过超高效液相色谱-质谱分析DEP的降解路径和毒性。结果表明:增强功率或调低初始质量浓度均可以提升等离子体对DEP的降解率,氧气氛围下,DEP降解率最高达到97.6%;反应中溶液温度升高和pH值降低导致水中 $ H_{2}O_{2} $、 $ O_{3} $质量浓度下降;淬灭实验表明: $ \cdotOH $、 $ \cdotO_{2}^{-} $和 $ ^{1}O_{2} $对DEP的降解有重要作用;DEP降解过程包括脱去甲基、脂基、支链以及矿化为 $ CO_{2} $和 $ H_{2}O $;对6种中间产物进行毒性分析,其中5种产物毒性降低。

Phthalates are challenging to degrade and highly toxic in the water environment, making it difficult for ordinary sewage treatment plants to achieve ideal results. Dielectric barrier discharge (DBD) is widely used in the degradation treatment of water pollutants due to its high efficiency and simplicity. This paper uses DBD plasma to reveal the degradation mechanism of diethyl phthalate (DEP). The effects of power, DEP initial concentration, and carrier gas type on the DEP degradation effect in the DBD plasma system were evaluated. The role of five active substances in the degradation process was explored, and the degradation pathways and toxicity of DEP were analyzed through ultra performance liquid chromatography-mass spectrometry (UPLC-MS) technology. Experimental results show that increasing the power or lowering the initial concentration can increase the degradation rate of DEP by plasma. Under an oxygen atmosphere, the DEP degradation rate reaches up to 97.6%. During the reaction, the temperature of the solution increases, and the pH value decreases, resulting in a decrease in the concentration of $ H_{2}O_{2} $ and $ O_{3} $ in the water. The quenching experiment shows that $ \cdot OH $, $ \cdot O_{2}^{-} $and $ {}^{1}O_{2} $ play a vital role in the degradation of DEP. The DEP degradation process includes removing methyl groups, lipid groups and branched chains, and mineralization into $ CO_{2} $ and $ H_{2}O $. The toxicity analysis of six intermediate products reveals that five of them exhibit reduced toxicity.