脉冲放电等离子体/活性炭协同降解染料废水及过氧化氢的生成

Formation of Hydrogen Peroxide and Degradation of Dye Wastewater by Pulsed Discharge Plasma Combined with Activated Carbon

为了提高脉冲放电等离子体（pulsed discharge plasma,PDP）对染料废水的降解率,以酸性橙II（acid orange,AO7）作为目标污染物,建立了多针-板电极形式的PDP与活性炭（activated carbon,AC）相协同的循环脱色体系,即PDP/AC协同体系。研究考察了PDP/AC协同体系中AC的添加、AC粒径、电极间距、溶液p H值、载气种类、载气体积流量等关键参数对AO7降解率的影响,同时考察了相同操作参数条件下以去离子水为介质且放电60 min时间后PDP/AC协同体系中的过氧化氢（hydrogen peroxide,H2O2）生成浓度,以说明各参数变化对系统活性物种浓度的影响。研究结果表明：PDP/AC协同体系降解AO7废水的效果优于PDP单独体系;粒径为1-2 mm的AC添加更有利于AO7降解,降解率可以提高20.4%,但此时AC损耗较大;同时,PDP/AC协同体系的H2O2生成浓度高于PDP单独体系的H2O2生成浓度,且粒径为1-2 mm的AC添加体系中可以产生更多的H2O2;15 mm电极间距比8 mm电极间距更不利于系统中AO7的降解和H2O2的生成;酸性溶液条件下AO7降解率较高且相应的H2O2生成浓度较高;载氧气体积流量为2 L/min时,AO7降解效果最佳,降解率可达到81.5%,该条件下水溶液中的H2O2生成浓度可达0.531 6 mmol/L。

In order to improve the degradation efficiency of dye wastewater by pulsed discharge plasma（PDP）, we established a circulatory synergistic decoloration system of PDP with a multi-needle-to-plate geometry electrode combined with activated carbon（AC）. Selecting Acid Orange 7（AO7） as the typical pollutant, we investigated the influences of many critical parameters in PDP/AC system, including particle size of AC, electrode distance, solution p H value, varieties and bubbling rate of gas, on the degradation efficiency of AO7. Furthermore, we reviewed the formation of hydrogen peroxide（H2O2） in deionized water after 60 min discharge under the same reaction condition to illustrate the effects of different parameters on active species formation in the synergistic system. The obtained results showed that degradation of AO7 in the PDP/AC system was superior to that in the sole PDP system; the AC with 1~2 mm particle size addition was more favorable for the AO7 degradation than that of the AC with 2~3 mm size addition, but the carbon loss was higher in the case; H2O2 formation in the PDP/AC system was higher than that in the sole PDP system, and the formation of H2O2 in the synergistic system with 1~2 mm AC addition was also higher than that in the system with 2~3 mm AC addition; compared to 15 mm electrode distance, the degradation of AO7 was higher under the condition of 8 mm electrode distance and the generated H2O2 concentration was higher; the acidic solution was benefit for AO7 degradation and H2O2 formation in the synergistic system; under the condition of 2 L/min oxygen bubbling rate, the degradation of AO7 achieved in the synergistic system was 81.5% and formed H2O2 concentration was 0.531 6 mmol/L.