Abstract: In order to enhance the effect of pulse discharge on degradation of organic matter, a pulse discharge system of single needle-plate electrode aimed at phenol was established. The paper investigated the effect of various factors on phenol degradation and analyzed the degradation of intermediate products and their concentrations in the degradation process. Such factors, as pulse voltage, electrode spacing, needle-liquid spacing, pulse frequency, and air volume, had a great influence on the degradation rate of phenol. Phenol degradation rate increased with the increase of pulse voltage and tended to stablize while pulse voltage reached a specific value. With the increase of electrode spacing, needle-liquid spacing, pulse frequency, air volume, degradation rate of phenol increased, but, would decrease while each factor was greater than a specific value. Under the best condition of 10mm electrode spacing, 7.5mm needle-liquid spacing, 26kV pulse voltage, 70Hz pulse frequency and 1.5L/min aeration, phenol degradation rate was 64.63% when 100mL concentration of 100mg/L of phenol wastewater was discharged for 60min. In addition, phenol degradation rate reached 85.02% when wastewater was discharged for 140min. The concentration of byproducts such as resorcinol, hydroquinone, benzoquinone and catechol increased firstly, then decreased gradually and eventually disappeared with the increase of discharge time. Besides, concentration of resorcinol was the lowest and appeared in two stages, that of benzoquinone was the largest, and catechol disappeared first. The completeness of phenol degradation could be improved by studying the change of byproducts.

Key words: waste water, pulse discharge, single needle-plate, degradation, byproducts, environment

摘要： 为了提高脉冲放电对有机物的降解效果,以苯酚为处理对象建立了单针-板电极形式的脉冲放电体系,考察了各因素对苯酚降解的影响并分析了降解过程中间产物及其浓度变化。结果表明,脉冲电压、电极间距、针-液间距、脉冲频率、曝气量等影响因素对苯酚降解率有很大影响;随着脉冲电压的增大,苯酚降解率增大,电压达到一定值后,苯酚降解率增大不再明显,趋于稳定;随着电极间距、针-液间距、脉冲频率、曝气量的增大,苯酚降解率增大,但当这些因素达到一定值后继续增大,苯酚降解率反而降低。100mL浓度为100mg/L的苯酚废水在电极间距10mm、针-液间距7.5mm、脉冲电压26kV、脉冲频率70Hz、曝气量1.5L/min的最佳条件下,放电60min时苯酚降解率为64.63%,放电140min时达到了85.02%。中间产物间苯二酚、对苯二酚、对苯醌、邻苯二酚在放电过程中浓度随着放电时间的延长先增大后减小,最后浓度都趋于零。其中,间苯二酚浓度最低并且分段出现,对苯醌浓度最大,邻苯二酚最先消失,考察产物变化规律以提高苯酚降解的彻底性。

关键词: 废水, 脉冲放电, 单针-板电极, 降解, 中间产物, 环境