Shen Yongjun, Lei Lecheng, Zhang Xingwang, Zhou Minghua, Zhang Yi
Institute of Environmental Pollution Control Technologies, Zhejiang University, Hangzhou 310028, PR China.
J Hazard Mater. 2008 Feb 11;150(3):713-22. doi: 10.1016/j.jhazmat.2007.05.024. Epub 2007 May 13.
The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC-MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone>oxygen>argon>nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC-MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed.
研究了在几种放电气氛（氧气、氩气、氮气和臭氧）以及化学催化剂（亚铁离子和过氧化氢）存在下，脉冲放电降解苯酚的过程。分别采用高效液相色谱（HPLC）和气相色谱 - 质谱联用仪（GC - MS）监测苯酚及其中间产物浓度随时间的变化。结果发现，各种气体鼓泡对苯酚降解速率的影响顺序如下：含臭氧的氧气＞氧气＞氩气＞氮气。高气体鼓泡流速有利于苯酚的去除。研究发现，在有催化剂和无催化剂存在时，降解过程有所不同。添加亚铁离子时苯酚去除率提高。这种显著的提高可能归因于芬顿反应。此外，向反应器中加入化学添加剂过氧化氢会导致苯酚降解速率急剧增加。其机理是由于等离子体通道中的直接或间接光解和热解破坏。此外，在三种降解条件下通过GC - MS监测中间产物。在无气体鼓泡或不添加任何催化剂的降解条件下生成更多的三卤甲烷（THBs），在添加亚铁离子的条件下生成更多的二卤甲烷（DHBs），在含臭氧的氧气鼓泡条件下生成更多的羧酸。因此，基于不同条件提出了三种不同的降解途径。
