超声波/零价铁降解对氯苯胺性能及机理研究

Research on properties and mechanism of p-chloroaniline degraded by ultrasound/Fe^0

在超声波/零价铁体系中考察了溶液初始pH值、浓度对对氯苯胺降解的影响。在pH值为3~11范围内最佳条件为pH=9;初始浓度为0.1、0.2和0.4 mmol/L时的降解率(180 min)分别为83.2%、63.5%和36.1%。对氯苯胺在单纯铁粉、单纯超声波和超声波/零价铁3种体系中降解符合拟一级反应动力学规律,速率常数分别为6.83×10-4、3.95×10-3和1.01×10-2min-1,增强因子为218%,表明铁粉与超声波对对氯苯胺降解有明显的协同效应。在体系中加入自由基捕捉剂正丁醇能抑制对氯苯胺的降解,证实对氯苯胺降解主要是依靠羟基自由基的氧化作用。

The objective of this work is to explore the influence of solution pH and solute concentration on the p-chloroaniline degradation by ultrasound/Fe^0. The degradation efficiencies of p-chloroaniline in the pH range 3 - 11 and the concentration range 0. 1 - 0, 4 mmol/L were investigated in the ultrasound/Fe^0 system, The results showed that the optimal pH was 9 for degradation of p-chloroaniline. The degradation efficiencies of p-chloroaniline reached 83.2% , 63.5% and 36. 1% at the initial concentration of 0. 1, 0.2 and 0.4mmol/L （HRT=180 min） , respectively. Degradation of p-chloroaniline in the systems of iron powder, ultrasound and ultrasound/Fe^0 was also compared, which showed that the degradation complied the pseudo-first-order reaction. The rate constants were 6.83 × 10^-4, 3.95 × 10^-3 and 1.01 × 10^-2min^-1 for the three systems, respectively, and the enhancement factor of p-chloroaniline degradation was around 218 % , which indicated that ultrasound and F^0 had synergistic effect on the degradation of p-chloroaniline. Degradation efficiency of p-chloroaniline could be restrained with the addition of hydroxyl radical capture （n-butanol） , which indicated that in the ultrasound/Fe^0 system p-chloroaniline was degraded primarily by the hydroxyl oxidation process.