稀有金属电极增强电化学臭氧耦合体系降解双氯酚酸研究

摘要

通过比较钛镀钌铱、钛镀铱钽、钛镀钌铱锡、钛镀铂四种不同的钛镀稀有金属电极增强电化学臭氧耦合体系协同去除水中双氯酚酸的效率，选择降解效能较优的钛镀铱钽金属电极，并研究在该电极下双氯芬酸初始浓度、臭氧浓度、电流强度、自由基捕获剂＼电解质种类、温度、初始pH值等因素对该耦合体系降解效率的影响。实验结果表明：电化学臭氧耦合氧化体系对水中双氯芬酸的去除有一定的协同作用，相同条件下处理16 min，钛镀铱钽电极在耦合体系中对双氯芬酸的去除率最高，接近100％，比单独臭氧和单独电化学氧化去除率的加和值增大了16.90％。该体系影响因素实验表明：初始pH值和电流强度分别为5和0.10 A时，双氯芬酸降解率最高。臭氧浓度与双氯芬酸降解率呈正相关。随着体系温度的升高，该耦合体系对双氯芬酸的降解率先升高后降低，硫酸钠和硝酸钠作为电解质对双氯芬酸的降解较有利，而使用氯化钠作为电解质时，双氯芬酸的降解率较低。加入自由基捕获剂叔丁醇对反应速率有明显的抑制现象，说明反应体系中产生了强氧化性的羟基自由基。%The oxidation efficiency of the electrolysis-ozonation system with four kinds of titanium plating rare metal(titanium ruthe-nium plating iridium,titanium plating iridium tantalum,titanium ruthenium plating iridium tin and titanium plating platinum)under the circumstance that all of them were as electrode respectively was compared,then the titanium plating iridium tantalum was chose as the electrode which was better at degradation efficiency than the other three to analyze the influencing factors of the coupling sys-tem under the optimal electrode condition,including the initial concentration of diclofenac,ozone concentration,the intensity of elec- tric current,the radical scavenger,types of electrode,temperature andthe initial pH value. The experimental results indicated that the electrolysis-ozonation had a synergistic effect on the remove of diclofenac,and after a 16-minute experiment under the same con-dition,titanium plating iridium tantalum electrode had the highest removal efficiency among the four electrodes closing to 100%, which was 16.90%higher than the combination value of single ozone and single electrochemistry. In addition,the degradation rate of diclofenac reached to the highest level when initial pH value was 5 and current intensity was 0.10 A respectively;the degradation rate of diclofenac had a positive correlation with ozone concentration. With the temperature increasing,the decomposition rate in-creased firstly,and then declined. When sodium sulfate or sodium nitrate was used as the electrolyte,the two decomposition rates were higher than before;whereas,if the sodium chloride was used as the electrolyte,the degradation of diclofenac rate is lower. Mo-reover,if adding radical scavenger tert-butyl alcohol,the diclofenac degradation would get restrained,which indicated that strong oxi-dizing hydroxyl radicals were generated in the system.