摘要：

采用柱状降膜介质阻挡放电（Dielectric barrier discharge，DBD）反应器处理初始质量浓度为100 mg/L的亚甲基蓝（MB）模拟废水，通过研究放电电压、液体流速对降膜DBD降解MB的效果，确定最佳反应条件为放电电压70 V，泵转速100 r/min。在最佳反应条件下，对比了添加酸、碱对MB降解率的影响，结果表明：H₂SO₄的加入能提升DBD放电初期对MB的降解速率，NaOH的加入显著提升了放电后期对MB的降解速率。根据实验结果改进降解过程中酸碱投入方式为放电前期投入H₂SO₄放电后期投入NaOH，1 h内MB降解率高达92%。考察了H₂O₂、O₃与叔丁醇的添加对DBD降解MB的效果及能量利用率，结果表明H₂O₂与O₃对MB降解有促进作用，叔丁醇的加入对MB的降解有明显的抑制作用，H₂O₂与O₃的加入可以明显提升DBD反应装置的能量利用率，H₂O₂投加量为400 μL反应30 min时能量利用率最高，为587.698 mg/（kW·h），O₃投加量为600 mL/min反应30 min时能量利用率最高，为307.600 mg/（kW·h）。拉曼光谱表明H₂O₂、O₃与DBD耦合可以产生更多的·OH，由MS分析推测DBD耦合添加剂降解MB有3种途径。

关键词: 低温等离子体, 介质阻挡放电, 亚甲基蓝, 降解, 氧化剂

Abstract:

The simulated wastewater of methylene blue (MB) with initial mass concentration of 100 mg/L was treated using a cylindrical falling-film dielectric barrier discharge (DBD) reactor. By examining how discharge voltage and the rate of liquid flow influence MB degradation by the falling-film DBD, the optimal conditions for the reaction were identified as a discharge voltage of 70 V and a pump rotation speed of 100 r/min. Under the optimal conditions, the effects of acid and alkali on MB’s breakdown rate were analyzed, revealing that H₂SO₄ accelerated MB’s degradation during the initial phase of DBD discharge, while NaOH markedly increased MB's degradation in the final stage. The resultant improvement of the degradation process with acid and alkali inputs in the form of H₂SO₄ at the pre-discharge stage and NaOH at the late stage of discharge resulted in a methylene blue degradation rate of up to 92% within 1 h. The effect and energy utilization of the addition of H₂O₂, O₃ and tert-butanol on the degradation of MB by DBD were investigated. The results indicated that H₂O₂ and O₃ had a promotional effect on MB’s degradation, while tert-butanol clearly hindered MB’s degradation. Additionally, H₂O₂ and O₃ significantly improved the DBD reaction device’s energy consumption. The highest energy utilization rate was 587.698 mg/(kW·h) for 30 min with 400 μL of H₂O₂, or 307.600 mg/(kW·h) for 30 min with 600 mL/min of O₃. Raman spectroscopy distinctly revealed that combining H₂O₂ and O₃ with DBD resulted in increased ·OH production, leading to the deduction of three routes for MB degradation by additives linked to DBD from the mass spectrometry analysis.

Key words: low temperature plasma, dielectric barrier discharge, methylene blue, degradation, oxidizer

中图分类号: 

• X703