臭氧作为一种强氧化剂和杀菌剂, 在污染物降解, 食品加工, 杀菌消毒, 医疗卫生等方面有着非常广泛的应用。 大气压介质阻挡放电是一种极为高效的产生臭氧的方法, 利用平行平板介质阻挡放电装置, 采用交流高压激励, 产生了大气压空气非平衡态等离子体。 通过测量其电压和发光信号, 发现在电压的正、 负半周期均存在着许多随机的放电脉冲, 并且其脉宽均在几十到几百纳秒之间, 这表明其机制是流光放电。 放电的光学发射谱包含氮分子的第二正带系( C³ Π-B³ Π)和第一正带系( B³ П-A³ П), 氮分子离子的第一负带系( B² Σ-X² Σ), 以及氧原子谱线(715.7和799.5 nm)。 由于流光放电在紫外区域(200~300 nm)没有明显的发射谱线, 但臭氧在此区域存在吸收峰, 因此可以利用此区域的紫外吸收光谱测量放电产生的臭氧浓度。 吸收光谱法可以有效的监测其臭氧浓度的变化情况, 其优势在于操作简单, 对实验环境要求低, 可在放电条件下使用, 并且可以连续监测臭氧浓度变化。 基于此, 通过Beer-Lambert定律计算了臭氧浓度随实验参数的变化, 结果发现随外加电压幅值和驱动频率的增加, 臭氧浓度升高。 这些结果对于大气压介质阻挡放电的工业应用具有重要价值。

As a strong oxidant and bactericide, oxygen has great potentials in various applications, such as pollutant degradation, food processing, sterilization, and medical services. Atmospheric pressure dielectric barrier discharge (DBD) is an extremely efficient method of generating ozone. DBD is generated in atmospheric pressure air between two parallel-plate electrodes excited by alternating current voltage. Waveforms of applied voltage and light emission are measured by optical and electrical methods. It can be found that the light emission presents lots of narrow pulses, which distribute stochastically in every half cycle of applied voltage. These narrow pulses only sustain about several tens ns to several hundred ns, which indicates that barrier discharge in atmospheric pressure air belongs to a streamer regime. Based on 200 and 900 nm scanned optical spectrum emitted from the discharge, the emissions mainly include those from the second positive system of the nitrogen molecule ( C³ Π-B³ Π), the first negative system of the nitrogen molecular ion ( B² Σ-X² Σ), the first positive system of the nitrogen molecule ( B³ П-A³ П), and oxygen atomic (OⅠ: 715.7 nm, 799.5 nm). Moreover, no emission line is observed between 200 nm and 300 nm (ultraviolet (UV) region). Due to a strong absorption peak in this UV region, absorption spectrum in UV region between 230 and 300 nm can be used to obtain the ozone density. In doing so, UV lamp irradiates the plasma area from one side of the discharge region, and transmitted light is received by the spectrometer on the other side. Absorption spectra are measured when DBD is on and off. Absorption spectroscopy can effectively monitor the change of ozone concentration. Its advantages are simple operation, low requirements on the experimental environment, being able to be used under discharge conditions, and continuous monitoring of ozone concentration changes. Ozone concentration is calculated as a function of peak voltage and driving frequency based on Beer-Lambert’s law. It is found that ozone concentration increases with increasing peak voltage or driving frequency. These results are of great significance to industrial application of dielectric barrier discharge at atmospheric pressure.