臭氧氧化处理页岩气钻井废水的机理与动力学

Kinetics and Mechanism of Ozonation Treatment of Shale Gas Drilling Wastewater

采用臭氧氧化法处理页岩气钻井废水经混凝沉淀后的出水(COD=759.63 mg/L),重点研究了废水中有机污染物的去除机理与反应动力学。实验结果表明:在废水pH为11.2、臭氧通入量为8 mg/min、反应时间为50 min的最佳工艺条件下,废水的COD去除率为42.51%;羟基自由基抑制剂CO_3^(2-)、HCO_3^-和叔丁醇的引入抑制了废水COD的臭氧氧化去除,尤其是叔丁醇的加入使COD去除率显著下降,说明废水中有机物的臭氧氧化去除过程遵循羟基自由基机理;臭氧氧化法对钻井废水中有机物的氧化去除过程符合表观二级反应动力学规律。

The shale gas drilling wastewater after coagulation （COD 759.63 mg/L）was treated by ozonation. The mechanism and reaction kinetics of organic pollutants removal were investigated. The experimental results show that： Under the optimum conditions of wastewater pH 11.2, ozone flow 8 mg/min and reaction time 50 min, the COD removal rate is 42.51%; The COD removal by ozonation can be inhibited by hydroxyl radical inhibitor such as CO3^2- , HCO^- and tert-butyl alcohol, and decreases significantly by tert-butyl alcohol, which indicates that the removal of organic pollutants in wastewater by ozonation follows the mechanism of hydroxyl radical reaction; The ozonation process accords with the apparent second-order reaction kinetic.