超声Fenton法处理毒死蜱中间体废水的工艺优化

Process Optimization of Chlorpyrifos Intermittent Wastewater Treatment by Ultrasonic-Combined Fenton Reaction

针对毒死蜱中间体生产的化工废水有机物浓度高、生物抑制性强的特点,以实际生产废水为研究对象,基于响应曲面法,进行了超声/Fenton法降解有机物效能研究与运行参数的优化.结果表明:1通过单因素试验确定响应曲面设计的自变量中心点为H2O2投加量0.5 mol/L、Fe2+投加量0.93 g/L、反应时间90 min.2采用Box-Behnken试验设计,建立了以H2O2及Fe2+投加量、反应时间为自变量的回归模型,经方差分析,模型显著(P<0.000 1);对有机物去除率影响最大的因素为Fe2+投加量,其与反应时间的交互作用显著.3最优工况为H2O2投加量0.7 mol/L、Fe2+投加量1.36 g/L、反应时间96 min,该条件下模型预测CODCr去除率为96.63%,试验值与模型预测值的相对误差为1.36%,出水水质指标远低于GB 8978—1996《污水综合排放标准》三级标准,ρ(BOD5)/ρ(CODCr)从0.09升至0.22,CODCr单位去除负荷的H2O2及Fe2+用量相对较低,分别为0.14 mmol/mg和0.28 mg/mg.研究显示,采用超声/Fenton法处理高浓度难降解有机废水可有效提高CODCr去除率及其可生化性.

Among chemical industrial wastewaters with high concentrations of organic compounds,wastewater from intermittent chlorpyrifos production with high organic concentration is particularly harmful to the environment and resistant to biodegradation. The ultrasoniccombined Fenton reaction is being assessed as a promising process for the treatment of refractory wastewater. A response surface method（ RSM） was utilized to optimize the ultrasonic-combined Fenton process for industrial wastewater treatment. The results showed that： 1）The center points of the response surface design were investigated in detail based on the effects of H2O2 dosage,Fe2 ＋dosage and reaction time on organic removal efficiency. H2O2 dosage,Fe2 ＋dosage and the reaction time were 0. 5 mol/L,0. 93 g/L and 90 min,respectively.2） A regressive model for CODCrremoval efficiency in terms of H2O2 dosage,Fe2 ＋dosage and reaction time was developed based on a Box-Behnken Design（ BBD）. The analysis of variance indicated that the model was significant（ P〈0. 0001）. Fe2 ＋dosage had a greater effect on CODCrremoval efficiency than the other two factors. Moreover,the interaction between Fe2 ＋dosage and reaction time was significant. 3） The relative error between the experimental results and the prediction of the model was 1. 36% under the predicted optimum conditions（ H2O2 dosage of 0. 7 mol/L,Fe2 ＋dosage of 1. 36 g/L,reaction time of 96 min）. Effluent quality indexes were far below the grade 3 concentration limits established by the Integrated Wastewater Discharge Standard,and the ratio of B/C increased from 0. 09 to 0. 22. Moreover,the H2O2 and Fe2 ＋contents in each CODCrremoval load were 0. 14 mmol/mg and0. 28 mg/mg,respectively. The H2O2 and Fe2 ＋dosage in thewastewater treatment subjected to the combined process were relatively low. The ultrasonic-combined Fenton process was successfully applied for the pretreatment of the refractory organic wastewater with a favorable CODCrremoval efficiency,and could improve the biodegradability of wastewater.