超重力强化非均相催化臭氧矿化苯酚废水的响应面分析与优化

为了探究超重力强化非均相催化臭氧矿化苯酚废水最优工艺条件和各影响因素之间存在的交互关系,采用响应面法(RSM)进行实验优化。根据Box-Behnken Design(BBD)中心组合设计原理,设计四因素三水平实验,考察超重力因子(β)、初始pH值,液体流量(QL),臭氧浓度(CO3)对矿化苯酚废水的影响,构建该工艺的数学模型及确定优化后的工艺参数。结果表明,β与初始pH值存在极显著的交互关系,β与QL存在显著的交互关系。最优的工艺参数条件:β为60,初始pH值为5.47,CO3为60 mg·L^-1,QL为90 L·h^-1,预测值为91.54%,比实测值高0.97%(<2%),由此可知,二次数学模型对超重力强化非均相催化臭氧矿化苯酚废水的工艺条件的优化及苯酚的矿化率的预测具有良好的可靠性。此外,超重力技术与非均相催化臭氧氧化技术相耦合有助于液相中的臭氧快速分解产生更多的羟基自由基(·OH)与有机物反应,因此,超重力强化非均相催化臭氧矿化苯酚废水遵循·OH机理,30 min可对苯酚废水实现较为彻底的矿化。

Response Surface Analysis and Optimization of High Gravity-Enhanced Heterogeneous Catalytic Ozonation for Mineralization of Phenol Wastewater

In order to explore the interaction between the optimal technologic conditions and influencing factors of high gravity-enhanced heterogeneous catalytic ozonation for phenol mineralization,response surface methodology(RSM)was used to optimize the experiment.According to the principle of Box-Behnken Design(BBD)center combination design,four-factor and three-level experiments were designed.The effect of high gravity factor(β),initial pH,liquid flow rate(QL),ozone concentration(CO3)on the mineralized phenol wastewater was investigated.The mathematical model of the technology was established and the optimized technologic parameters were determined.Results show that there is an extremely significant interaction betweenβand initial pH,and a significant interaction betweenβand QL.The optimal technologic parameters are as follows:βis 60,initial pH 5.47,CO362.5 mg·L^-1,and QL 89.95 L·h^-1.The predicted value is 91.54%,0.97%(<2%)higher than the measured value.It can be concluded that the obtained secondary mathematical model for the phenol mineralization via high gravity-enhanced heterogeneous catalytic ozonation has a good reliability for the optimization of technologic conditions and prediction of mineralization rate of phenol wastewater.In addition,the coupling between high gravity technology and heterogeneous catalytic ozonation technology is beneficial to the formation of OH radical,which reacts with organics,from the rapid decomposition of ozone in liquid phase.Thus,the phenol mineralization via high gravity-enhanced heterogeneous catalytic ozonation follows OH mechanism,and the phenol wastewater could be completely mineralized within 30 min.