论文总字数：30519字

摘 要

2 活化过硫酸钠氧化甲苯的过程受到Fe² 浓度的影响，当Fe² 与过硫酸钠浓度为1：1时，对甲苯的氧化速率最高。通过动力学实验及反应数据拟合，发现过硫酸钠对甲苯的氧化反应符合二级反应动力学规律。在存在柠檬酸络合剂的条件下，过硫酸钠的活化效果基本不受pH的影响。实验选取了乙醇和叔丁醇作为自由基清除剂以考察反应过程中不同自由基的贡献率，结果表明硫酸根自由基贡献率约为60%，高于羟基自由基。表面活性剂的影响实验表明，当其浓度高于临界胶束浓度时，会降低甲苯氧化速率，且浓度越高影响越大；低浓度表面活性剂对降解速率基本无影响。采用污染土壤开展的增溶、氧化实验表明，表面活性剂能够促进土壤中甲苯的解吸，表面活性剂对土壤中甲苯的氧化修复效果的影响总体表现为促进作用，且浓度越高，效果越明显。

关键词：过硫酸钠；苯系物；表面活性剂；土壤

Study on the effects of surfactants on the oxidative remediation of BTEX contaminated soil

03212727 Xiaodong Zhang

Supervised by Ran Yu, Tao Long

Abstract： BTEX is a class of volatile organic compounds. It's harmful to the environment and has toxic effects on the human body. Since BTEX is contained in many kinds of industrial solvents and fuels, it’s widely existed in chemical contaminated sites in our country. Solubilization-oxidation technology is a new technology used in remediation of organic contaminated soil. The method utilizes solubilization of surfactant on organic contaminant to promote the desorption of contaminants from solid phase to liquid phase, and then increase the reaction rate of oxidants and contaminants. But the reaction system and the process is so complex that the removal efficiency of soil contaminants is influenced by many factors, such as soil characteristics, physical and chemical properties of contaminants, solubilization condition, pH, composition of oxidation system. In this paper, toluene is chosen as the target contaminant, and the oxidative degradation of toluene by sodium persulfate under the condition of Tween80 solubilization is studied. Firstly, the kinetics and influencing factors of the oxidation of toluene by sodium persulfate are studied. On the basis of the last part of experiments, the influences of the surfactant on the process of aqueous phase oxidation of toluene are studied, and then the removal efficiency of toluene in soil by Fe² /Na₂S₂O₈ under the condition of Tween80 solubilization is studied. The research results show that the oxidation of toluene by Fe² activated persulfate is influenced by the concentration of Fe² , and when the molar concentration ratio of Fe² and sodium persulfate is 1:1, toluene oxidation rate is the highest. According to the reaction kinetics experiments and data fitting, it is found that the reaction between toluene and sodium persulfate is in accordance with the laws of the second-order reaction kinetics. In the presence of citric acid as the complexing agent, the activation effect of ferrous on sodium persulfate is hardly influenced by pH. Ethanol and tert butyl alcohol are used as free radical scavenging agents in order to study the contribution of different free radicals in the reaction process. The results showed that the contribution rate of sulfate radical is 60%, higher than that of hydroxyl radical. The experiments of surfactant shows that when the surfactant concentration is higher than the critical micelle concentration (CMC), it will reduce the rate of toluene oxidation, and higher concentration results in greater impact while low concentration has no effect. The results of solubilization and oxidation experiments showed that the surfactant can promote the desorption of toluene in the soil, and can promote the oxidative remediation of toluene in soil, and higher concentration results in greater impact.

Key words: sodium persulfate；BTEX；surfactant；soil

目 录

1 绪论 1

1.1 苯系物污染 1

1.1.1 挥发性有机物污染的来源与特性 1

1.1.2 苯系物污染的毒性与危害 2

1.2 挥发性有机污染修复技术介绍 2

1.2.1 生物修复技术 2

1.2.2 物理修复技术 3

1.2.3 化学修复技术 3

1.3 过硫酸钠高级氧化技术 3

1.3.1 高级氧化技术简介 3

1.3.2 过硫酸盐高级氧化技术的研究进展及应用 3

1.4 表面活性剂增溶技术 5

1.4.1 表面活性剂的结构与分类 5

1.4.2 表面活性剂的性质和功能 5

1.4.3 表面活性剂的增溶作用与应用 6

1.5. 增溶氧化修复技术 6

1.5.1 有机污染土壤修复中过硫酸钠氧化技术的局限 6

1.5.2 增溶氧化技术的原理与优势 7

1.6 研究目的与技术路线 7

2 实验设计与方法 9

2.1 实验材料 9

2.2 实验设备 10

2.3 实验方法 10

2.4 分析方法 10

2.5 质量控制 11

3 过硫酸钠氧化甲苯的反应特性及其影响因素探究 12

3.1 前言 12

3.2 结果与讨论 12

3.2.1 Fe² 浓度对甲苯氧化效率的影响 12

3.2.2 过硫酸钠浓度对甲苯降解效率的影响 13

3.2.3 pH对甲苯降解效率的影响 15

3.2.4 主要自由基的鉴别 16

3.3 本章小结 17

4 表面活性剂对水相及土壤中甲苯降解效果的影响研究 18

4.1 前言 18

4.2 结果与讨论 18

4.2.1 表面活性剂对溶液中甲苯降解速率的影响 18

4.2.2 表面活性剂对土壤中甲苯的增溶作用 19

4.2.3 表面活性剂对土壤中甲苯氧化降解的影响 19

3.3 本章小结 20

5 结论与展望 21

5.1 结论 21

5.2 展望 21

致谢 22

参考文献 23

表面活性剂对苯系物污染土壤氧化修复效果的影响研究

1、 绪论

土壤是人类生存和发展过程中必要的自然资源，也是地球生物圈物质循环的储库，对环境具有很强的敏感性^[1]。土壤是地球上绝大多数人为的和自然的污染物的最终去向与归宿，环境中大部分的污染物最终滞留在土壤中^[2]。

一些重污染企业在长期的历史生产中，由于处理处置不当、泄漏、缺乏环境监管等原因，将大量有毒有害物质遗留在场地土壤内，对当地生态环境造成了严重污染，危害周边居民身体健康，严重影响土地的再次开发利用^[3]。

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