超临界水氧化处理偶氮染料废水的实验研究

Experimental study on supercritical water oxidation of azo dye wastewater

在间歇式反应器中进行偶氮染料C.I.活性橙7的超临界水氧化实验,探索染料分子中的偶氮基团在氧化反应中的转化规律。选取反应温度、氧化系数、初始COD质量浓度、反应时间和pH值为过程参数,总氮去除率和氨氮质量浓度为响应量,通过中心组合设计方法进行实验设计,设计了一个五因素、五水平包含22个实验点的实验矩阵。采用响应面分析法对实验结果进行模拟及分析,建立了总氮去除率与5个过程参数关系的二次多项式数学模型,分析了各个参数单独的及相互作用对总氮去除率的影响。实验结果表明:在实验条件范围内,C.I.活性橙7的超临界水氧化反应过程中,总氮有明显的去除,可达到20.10%—64.16%,但产生的氨氮质量浓度却极少,并且5个过程参数对总氮去除率的一次影响都为正向的积极作用。

For exploring the transformation mechanism of azo group during the oxidation reaction,the supercritical water oxidation of the azo dye C.I.Reactive Orange 7 was investigated in a batch reactor.Temperature,oxidant coefficient,initial COD mass concentration,reaction time and solution pH value were selected as process parameters and the total nitrogen removal rate and ammonia-nitrogen mass concentration as the responses.Central Composite Design（CCD）method was employed for the experimental design,of which an experimental matrix of five-factorial,five-level CCD consisting of 22 experimental runs was obtained.The experimental results were simulated and analyzed by response surface methodology.A quadratic polynomial equation was established for describing the relationship between the total nitrogen removal rate and five process parameters.The analysis of individual and interactive effects of the five variables on responses was conducted in accordance with the simulated equation.The experimental results demonstrate that during the supercritical water oxidation for C.I.Reactive Orange 7,total nitrogen degrades obviously,which can reach 20.10%-64.16%,but NH3-N mass concentration is rarely produced.Moreover,the five variables all made a positive one-order contribution on total nitrogen removal rate.