电活化硫酸盐处理四环素类废水的研究

Study on the Treatment of Tetracycline Wastewater by Electro-Activated Sulfate

本文构建以掺硼金刚石(Boron-doped diamond,BDD)为阳极、不锈钢为阴极、硫酸盐为电解质的电化学体系,考察了电流密度、pH值、硫酸盐浓度以及初始四环素浓度等四个因素对电化学氧化降解废水中四环素的影响,运用响应曲面法对运行参数进行优化;通过电子自旋共振检测技术分析电化学反应中产生的自由基,探究了间歇通电模式下电化学体系持续氧化机理。结果表明,四个因素对TOC去除率的影响大小次序为:电流密度>初始四环素浓度>初始pH值>硫酸盐浓度,其中初始pH值和硫酸盐浓度与电流密度和初始四环素浓度的交互作用对TOC去除率的影响较为显著;最佳运行参数为pH值为5,电流密度为100 mA·cm^(-2),硫酸盐浓度为0.25 mol·L^(-1),初始四环素浓度为1000 mg·L^(-1);间歇通电模式下,BDD电极表面产生的SO_(4)^(·-)等高活性物质间相互转化提供了体系的可持续氧化能力。该研究结果为电化学氧化技术的实际应用提供了节省能耗的有效途径。

In this paper,a electrochemical system in which boron diamond(BDD)as anode,stainless steel as cathode and sulfate as electrolyte were constructed to degrade tetracycline.The effects of initial pH,current intensity,the concentration of sulfate and initial concentration of tetracycline on the removal of tetracycline were studied and the response surface method(REM)was used to optimize the operation parameters.The free radicals produced in electrochemical reaction were analyzed by electron spin resonance(ESR),and the mechanism of continuous oxidation of electrochemical system under intermittent power-on mode was discussed.The results show that the order of influence of four factors on TOC removal rate is current density>initial tetracycline concentration>initial pH value>sulfate concentration.The interaction of initial pH value and sulfate concentration with current density and initial tetracycline concentration has a significant effect on TOC removal rate.The optimal operating parameters are pH value 5,current density 100 mA·cm^(-2),sulfate concentration 0.25 mol·L^(-1) and initial tetracycline concentration 1000 mg·L^(-1).In intermittent energized mode,the conversion of SO_(4)^(·-) and other highly active substances generated on the surface of BDD electrode provides the sustainable oxidation capacity of the system.The results provide an effective way to save energy for the practical application of electrochemical oxidation technology.