三维电催化氧化处理对硝基苯酚废水

p-Nitrophenol Wastewater Treatment by Three-Dimensional Electrochemical Oxidation Process

为有效降解对硝基苯酚(PNP)废水中有机污染物,自制粒子电极,运用三维电催化氧化反应器,探讨了外加电压、初始pH、粒子电极投加量及曝气量对PNP和化学需氧量(CODCr)去除效果的影响,并初步研究了氧化过程中的活性物质及其降解过程。结果表明:电压5V,pH=5,粒子电极投加质量浓度200g/L,曝气量0.5L/min,反应75min时,PNP去除率为99.0%,CODCr去除率为90.6%。降解过程近似符合一级动力学方程,主要活性物质为游离氯和·OH,中间产物较少,矿化率较高。

In order to degrade the organic pollutant in p-nitrophenol wastewater,the effects of operating parameters such as the impressed voltage,pH of inflow,volume of particle electrode,aeration rate and reaction time were examined on PNP and CODCr removal rate.The active materials during degradation and degradation pathway were also studied by three-dimensional electrocatalytic oxidation reactor,in which self-made particle electrode was used.The experiment results indicated that the degradation efficiency of PNP increased with the impressed voltage but the gap was closed when the impressed voltage was up to a certain degree.In addition,the degradation efficiency of PNP rose first and then fell with the decreasing of the inflow pH,the addition of the particle electrode＇s volume and the gradually rise of the aeration. When the impressed voltage was 5 V,initial pH was 5,the mass concentration of particle electrode was 200 g/L and the aeration rate was 0.5 L/min,the PNP and CODCr removal rate reached 99.0% and 90.6% after 75 min.Besides,by comparing the degradation efficiency of PNP of the two-dimensional electrochemical oxidation to the three-dimensional electrocatalytic oxidation process,and by comparing commercial columnar activated carbon to self-made particle electrode system,the treatment of the p-nitrophenol wastewater by the three-dimensional electrochemical oxidation and the self-made partical electrode system were much better.Through curve fitting,the degradation of PNP and CODCrin p-nitrophenol wastewater was a pseudo-first-order kinetics which could be represented as ln（ρPNP,0/ρPNP）=0.090 2 t＋0.239 7 and ln（ρCODCr,0/ρCODCr）=0.065 0 t＋0.262 3 respectively.By analyzing the active substances such as free chlorine,·OH and H2 O2 and the degradation pathway by UV-vis spectra and FT-IR spectra during the process of the PNP degradation,the main active materials were free chlorine and·OH.There are few intermediate products and the mineralization rate during electrocatalytic oxidation is high.