芬顿试剂对土壤有机质的氧化效果及对其吸附特性的影响

论文总字数：39714字

摘 要

本研究通过芬顿对土壤有机质的氧化降解行为的研究，探索氧化过程对SOM吸附性质的影响，揭示氧化后SOM性质的变化对目标物4-硝基氯苯和六氟苯的吸附行为的影响，为化学氧化修复有机污染场地的施工提供方案设计、工艺过程控制方面的参考与建议。

获得的主要研究成果如下：

1、在研究p-NCB 和HFB在土壤有机质上的吸附实验中，对硝基氯苯和六氟苯这两种极性存在差异的有机物在土壤上的吸附机制不同，土壤对六氟苯的吸附主要依赖于其在SOM中的分配作用，而p-NCB 带有较强极性的NO₃^-基团，可以通过氢键等特殊作用力与土壤中的极性成分发生相互作用。

2、在研究p-NCB 和HFB 在氧化后土壤上的吸附实验中，发现氧化后的土壤中有机质含量明显降低，导致土壤对p-NCB这种带有极性基团的污染物的吸附发生了本质的改变，然而有机质含量的减少并未对土壤吸附HFB这一非极性有机物造成太大影响。

3、在研究p-NCB 和HFB 在“氧化后土壤 DOM”体系上的吸附实验中，氧化后土壤 DOM前后对p-NCB的吸附差异并不大，且只有在低浓度时DOM的增溶理论才适用，而氧化后土壤 DOM前后对HFB的吸附则较好地证明了DOM的增溶性。

4、在土壤的芬顿氧化反应中，过氧化氢破坏了土壤中的极性官能团，使原土中的大分子有机质转化成小分子的DOM（即可溶性有机质），从而溶解在溶液中随着固液分离流失。

5、DOM与不同有机污染物的相互作用机制有所不同。对于非极性有机污染物，认为其主要通过疏水键与DOM中的疏水组分进行相互作用；而类似p-NCB这样含有极性官能团的有机化合物，疏水性只是影响它们与DOM作用强度的因素之一，二者的作用可能还与π电子和氢键有关。

关键词：化学氧化；土壤有机质；氧化机制； 4-硝基氯苯；六氟苯

Effects of Fenton Reagent on Soil Organic Matter Oxidation and Its Adsorption Characteristics

03213715 ZhangTong

Supervised by ZengSu

Abstract：Chemical oxidation technology is mainly through the injection of oxidation reagents to the contaminated sites and make the pollutants degradation into low or no toxicity products. This technology is relatively mature today, and is used widely in our country and abroad. Soil organic matter (SOM) is the most important link of Organic pollutants in Soil. The SOM sources and chemical properties have significant difference, therefore, the degradability and rate are different. The existing technologies most focus on the realization of concentration level of the target pollutants, rarely consider the influence of oxidation process on the SOM character and the its sorption ability which control the the main environmental behaviors of organic pollutants in soil. Therefore, clear the influence of chemical oxidation on SOM properties and redistribution of the pollutants and its intermediate products in the process of remediation system, and repaired after the assessment of the soil has the vital significance.

This study pay attention to the oxidation mechanisms and degradation behavior of SOM by fenton, explores the influence of oxidation process on SOM properties, reveals the property change of SOM on the redistribution of the target pollutants（p-Nitrochlorobenzene, p-NCB; Hexafluorobenzene, HFB）and its intermediate products in the oxidation system. This research can also serve as the reference for project design, process control of the remediation and reconstruction of organic contaminated sites.

The main conclusions were as follows:

1、In the study of the adsorption of p-NCB and HFB on soil organic matter, the adsorption mechanism of organic matter with different polarities of nitrochlorobenzene and hexafluorobenzene was different, and the adsorption of hexafluorobenzene was mainly Depending on its distribution in the SOM, and p-NCB with a strong polarity of the NO3-group, through the hydrogen bond and other special forces and soil polar components of the interaction.

2、In the study of p-NCB and HFB adsorption on soil after oxidation, it was found that the content of organic matter in the soil after oxidation was significantly decreased, leading to the adsorption of p-NCB with polar groups However, the decrease in organic matter content did not have much effect on the adsorption of HFB, a nonpolar organic substance.

3、In the adsorption experiments of p-NCB and HFB on the "soil after oxidation" system, the adsorption of p-NCB before and after oxidation of soil DOM was not significant, and only the solubilization theory of DOM at low concentration And the adsorption of HFB before and after oxidation of soil DOM is a better proof of the solubilization of DOM.

4、In the soil Fenton oxidation reaction, hydrogen peroxide destroyed the polar functional groups in the soil, so that the macromolecular organic matter in the original soil into a small molecule DOM (ie, soluble organic matter), which dissolved in the solution with the solid Separation loss.

5、The mechanism of interaction between DOM and different organic pollutants is different. For non-polar organic contaminants, it is believed that it interacts primarily with hydrophobic components in the DOM by hydrophobic bonds; and organic compounds containing polar functional groups like p-NCB, hydrophobic are only factors that affect their intensity of action with DOM One of the two may also be related to the π-electron and hydrogen bonds.

Key words: chemical oxidation; soil organic matter; oxidation mechanism;

p-Nitrochlorobenzene; Hexafluorobenzene

目 录

1绪论………………………………………………………………………………………...…………1

1.1前言……………………………………………………………………..……………………..……1

1.2选题背景………………………………..……………………………………….…………….……1

1.2.1 SOM的氧化机理研究现状……………………………………………………………...………1

1.2.2 SOM 的组分对有机污染物的吸附贡献………………………………………………….……2

1.2.3 “氧化剂—土壤—有机污染物”体系的特点……………………………………………………2

1.3 研究切入点........……………………………………………………………………….……….… 3

1.3.1 4-硝基氯苯…………………………………………………………………………….…....……3

1.3.2六氟苯……………………………………………………………………………………….........3

1.4 土壤有机质与有机污染物之间吸附机理的研究进展…………………………...…..…………. 4

1.4.1实验室研究………………………….….………………………………………………..………4

1.4.2场地修复试验研究………...…………………………………………………………….…….…4

1.5 项目的研究内容及研究技术路线……………………………………………..…..….…….…… 4

1.5.1研究内容………………………….….……………………………………………….….…….…4

1.5.2研究技术路线………...…………………………………………………………….……….……5

1.6 项目特点及创新之处……………………………………………………..……..…….……….… 6

2 p-NCB 和HFB在土壤有机质上的吸附实验………………………...…..……....………………7

2.1 实验材料与设备……………………………………………...…………..……….…….…………7

2.1.1材料与试剂…..……..…………….….…………………………………………………...………7

2.1.2仪器设备………...........……………………………………………………………….….………8

2.2 吸附实验……………………............…………………………………..……………….…………8

2.2.1吸附质储备液配制…..……..…….….…………………………….………………….….………8

2.2.2批量吸附实验…...........…………………………………………….……………….……………9

2.2.3目标物浓度的色谱分析方法……….……………………………..…………….……….………9

2.2.4吸附质浓度的计算方法……………...……………………………….………….………………9

2.3 实验结果与分析………….................………………………...………..…...……………………10

2.2.1吸附等温线.……………………………………….…………………...…….…………….……10

2.2.2实验数据处理…...........…………………………………………………………………………11

2.2.3数据分析……………………………..………………………………….………………………14

3 p-NCB 和HFB 在氧化后土壤上的吸附实验……...………………..........…..……...…………17

3.1土壤的芬顿氧化反应…….……………………………….…….........................…………...……17

3.2实验结果与讨论…………............….....……………………...………..……….………...………17

3.2.1实验数据处理..................…..…….….……………………………………….……...….………17

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