【作者】 李凌云；

【导师】 叶齐政；

【作者基本信息】 华中科技大学 ， 环境工程， 2005， 硕士

【摘要】 本文对尖-板电极水中脉冲放电产生的活性粒子进行了研究。通过光谱法在线检测了·OH、·O、·H自由基,通过化学方法检测了放电结束后的H₂O₂。研究了水中通入的气体成分、气体流量、溶液电导率、电极间距和电压大小对活性粒子产率的影响。实验结果和分析表明: 1)水中脉冲放电有流注放电和火花击穿两种形式,随着气体流量和电压的增强,放电逐渐加强,流注放电会向火花击穿转变。·H谱线强度的变化由于较少受其它成分的影响,（相对·OH和·O）,可以作为一个转变的标志,特别是通入氧气的放电中。2)长间隙时（5cm）,可以形成较为稳定的流注放电; 短间隙时（3cm）,容易发生火花击穿。通入氧气易于形成火花击穿; 通入氮气可以形成较为稳定的流注放电,流注长度也较氧气要略长一些。3)在流注放电中（5cm）,通入氮气比通入氧气产生的H₂O₂浓度要略高。在火花击穿中（3cm）,通入氮气比通入氧气产生的H₂O₂浓度明显要低。4)随着溶液起始电导率的增加,H₂O₂的生成速率增加; 继续增加起始电导率,H2O2的生成速率开始下降; 峰值出现在40μS/cm处。5)在流注放电中（5cm）,溶液电导率随放电时间的增加明显增大,特别通入氮气放电中增加的幅度特别大。在火花击穿中（3cm）,溶液电导率变化不大,在通入氧气放电中还略有减少。6)随着放电时间的增加,溶液温度升高。上述实验结果对放电等离子体水处理技术中提高活性粒子的产率和降低能耗有指导意义。更多还原

【Abstract】 Using needle-to-plane electrodes plasma discharge in water,active species generated has been studied in this paper. Hydroxyl radicals, hydrogen atom,oxygen atom are measured on-line by spectrum method. Hydrogen peroxide is measured after discharge by chemical method. We investigate what influence the gas constituent and the gas-flow rate which be inlet water, the conductive of water , the distance between the two electrodes and the voltage contribute to the formation rate of active species. The experimental results and analyse indicate that as follow: 1) In plasma discharge in water there are two type: streamer corona and spark breakdown. With the increment of the gas-flow rate and the voltage, discharge will strengthen, streamer discharge will transit to spark breakdown. The light intensity can be considered as the transition marker, specially in oxygen-water mixture discharge, because the light intensity of H atom is little ifluenced by other species. 2) When the distance of the two electrodes is longer (5cm), it can form more stable streamer discharge. When the distance is shorter (3cm), it is easy to occur spark breakdown. When oxygen is inlet, it is easy to form spark breakdown. While nitrogen is inlet, it can form more stable streamer discharge, the streamer is little longer than that when oxygen is inlet. 3) In streamer discharge (the distance of two electrodes is 5cm), hydrogen peroxide formed in nitrogen-water mixture discharge is more than that in oxygen-water mixture discharge. In spark breakdown(the distance of two electrodes is 3cm),hydrogen peroxide formed in nitrogen-water mixture discharge is obviously little than that in oxygen-water mixture discharge. 4) With the increment of the initiate conductive of water, the concentration of hydrogen peroxide raise. When the initiate conductive of water increasing continuously, it begins to descend. When the conductive is about 40μS/cm, it reaches maximum. 5) In streamer discharge (the distance of two electrodes is 5cm), the conductive of water increases obviously with the increment of discharge time, what’s more, the increasing range is very large in nitrogen-water mixture discharge. In spark breakdown (the distance of two electrodes is 3cm), the conductive of water varies little, there is minish current in oxygen-water mixture discharge. 6) With the increment of discharge time, the water tempreture raises. The experimental result above-mentioned can instruct to improve the formation rate of active species and reduce power.更多还原