Zhou Minghua, Lei Lecheng
Institute of Environmental Engineering, Zhejiang University, Hangzhou 310027, China.
Chemosphere. 2006 May;63(6):1032-40. doi: 10.1016/j.chemosphere.2005.08.057. Epub 2005 Nov 15.
p-nitrophenol (PNP) was investigated as a model pollutant under the improved UV/Fe3+ process by combination with electrocatalysis. In the individual UV/Fe3+ process, PNP degradation rate was dependent on Fe(III) concentration and decreased during degradation due to the depletion of ferric ion and thus it was very difficult to reach the quick mineralization of organics. These drawbacks could be significantly overcome in the modified UV/Fe3+ process, and synergetic effects for PNP and COD removal were observed at two investigated Fe(III) concentrations. The enhancements on the degree of conversion for PNP and COD in presence of 0.5 mM Fe(III) were 184% and 242%, respectively, and PNP of initial concentration of 1.0 mM could be completely removed within 1 h. Thus such a process would be very attractive to the rapid mineralization of the biorefractory compounds for wastewater treatment. The possible reasons for the synergetic effects were the electrochemical regeneration of ferric ion and the role of the oxygen that formed on the anode. Based on degradation intermediates identification and synergetic effect probe, a general reaction pathway for PNP degradation in the improved process was proposed.
通过与电催化相结合，研究了对硝基苯酚（PNP）在改进的UV/Fe³⁺工艺下作为模型污染物的情况。在单独的UV/Fe³⁺工艺中，PNP的降解速率取决于Fe(III)浓度，并且由于铁离子的消耗，降解过程中降解速率会降低，因此很难实现有机物的快速矿化。在改进的UV/Fe³⁺工艺中可以显著克服这些缺点，并且在两个研究的Fe(III)浓度下都观察到了对PNP和COD去除的协同效应。在存在0.5 mM Fe(III)的情况下，PNP和COD的转化程度提高分别为184%和242%，初始浓度为1.0 mM的PNP可以在1小时内完全去除。因此，这样的工艺对于难生物降解化合物在废水处理中的快速矿化将非常有吸引力。协同效应的可能原因是铁离子的电化学再生以及阳极上形成的氧的作用。基于降解中间体的鉴定和协同效应探究，提出了改进工艺中PNP降解的一般反应途径。
