摘要：

石油行业污染场地地下水污染浓度高，单一方法处理无法同时满足COD和氮化物的处理要求。在光Fenton耦合电氧化处理过程中，通过考察离子对自由基产生的影响、分析有机污染物的转化过程和宏观指标变化来支撑处理工艺的选择和过程参数的控制。结果表明：氯离子和硫酸根离子分别存在的情况下，电氧化过程能够产生氯自由基、羟基自由基，铵根离子的加入会抑制这两种自由基但可捕获到硫酸根自由基，根据污染场地地下水中离子种类和浓度，在电氧化过程中起氧化作用的活性物质优先级和强度依次为氯胺、氯自由基等活性氯、硫酸根自由基；酚类是污染场地地下水中主要的有机污染物，光Fenton将其降解为酮类、含氮副产物和氯代烃，再经电氧化实现了前两类物质的彻底降解，但也发生进一步氯仿反应，使处理后残留的有机物中氯代烃占绝对优势。根据以上研究结果可知，对于含氮化物的有机污水处理，适合在偏碱性条件下进行电氧化，氯离子和硫酸根离子能够促进氧化，但硫酸根离子质量浓度建议在5 000 mg/L以下，使电氧化产生的羟基自由基能够更充分地氧化有机污染物，光Fenton耦合电氧化处理能够实现有机污染物和氮化物的高效去除，但需注意副产物氯化脂肪族等持久性污染物的后续处理，以及电氧化过程中离子浓度变化可能导致的供电调节。

关键词: 石油污染场地, 地下水, 自由基, 电氧化, 光Fenton

Abstract:

The pollution of contaminated sites groundwater in the petroleum industry exhibits high concentration,and single treatment can not meet the requirements of COD and nitride treatment simultaneously. Through the analysis of the influence of ions on free radicals, the transformation process of organic pollutants and the change of macro indicators in the process of photo-Fenton coupling electro oxidation treatment, the selection of treatment process and the control of process parameters were supported. The results showed that in the presence of chloride ion and sulfate ion, the electro oxidation process could produce chlorine radicals and hydroxyl radicals, and the addition of ammonium ion would inhibit these two free radicals, but sulfate radicals could be captured. According to the type and concentration of ions in the groundwater of the contaminated site, the order of active substances that played an oxidation role in the electro oxidation was chloramine, chlorine radicals and other active chlorine, sulfate radicals. Phenols were the main organic pollutants in the groundwater of the contaminated site, which were degraded into ketones,nitrogen-containing byproducts and chlorinated hydrocarbons by photo-Fenton. The first two types of substances were completely degraded by electro oxidation, while further chloroform reaction occured, resulting in chlorinated hydrocarbons dominating the residual organic matter after treatment. According to the above research, for the treatment of organic wastewater containing nitrides, it was suitable to conduct electrooxidation under alkaline conditions. Chloride ions and sulfate ions could promote oxidation, but the mass concentration of sulfate ions was recommended to be less than 5 000 mg/L, so that the hydroxyl radicals generated by electrooxidation could more fully act on the oxidation of organic pollutants. The photo-Fenton coupling electrooxidation treatment could achieve the efficient removal of organic pollutants and nitrides,but attention should be paid to the subsequent treatment of persistent pollutants such as chlorinated aliphatic compounds and the power supply regulation caused by the change of ion concentration in the electrooxidation process.

Key words: oil contaminated sites, groundwater, free radicals, electro oxidation, photo-Fenton

中图分类号: 

• X703.1