生物炭在可渗透性反应墙上的应用

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摘 要

论文作者签名：＿＿＿＿＿导师签名：＿＿＿＿日期：＿＿＿＿

生物炭在可渗透反应墙中的应用

21813129 钱福健

指导老师 王菲

摘要

目前，我国有大量的人口饮用地下水，然而我国许多城市的地下水污染程度呈不断恶化的趋势，特别是地下水重金属污染问题。重金属会随着食物链进入人体并在累积，从而。生物炭作为一种新型的材料，生物炭由于而具有较高的重金属吸附能力，在重金属污染吸附方面得到广泛的应用。研究生物炭理化性质、吸附性能以及吸附机理，有助于未来更好地将生物炭应用到地下水重金属污染修复技术当中。

本文采用四种不同的生物炭，包括木质生物炭、椰壳生物炭、水稻秸秆生物炭、果壳生物炭（最高热解温度分别为600、550、500、500℃，简称WD600、CS550、RS500、FS500），进行了一系列实验，包括生物炭pH和CEC的测定、pH系列吸附实验、等温吸附实验以及吸附动力学实验，研究这四种生物炭的理化性能及对Zn² 的吸附性能，并进行比较，并得出以下结论：

（1）生物炭pH值的大小排序为FS500＞WD600＞CS550＞RS500，生物炭FS500具有更高的CEC值。高CEC值和pH值能导致良好的重金属吸附性能，因此FS500具有更高的重金属吸附性能，这与后文中的实验数据相符合。

（2）pH系列吸附实验中，溶液初始pH从2-7范围内的增加，四种生物炭对Zn² 的去除率整体呈增长趋势，并且初始溶液pH=7的去除率为最高值。在相同pH条件下，四种生物炭对Zn2 去除率的大小顺序为FS500＞WD600＞CS550＞RS500。

（3）等温吸附实验中，随着溶液初始Zn² 浓度从10-200mg/L范围内增加,四种生物炭对Zn² 的吸附量不断增加，但浓度达到300mg/L时，生物炭对Zn² 的吸附量有所下降。同时，WD600、RS500和FS500均能较好地拟合Langmuir吸附模型，而CS500能较好地拟合Freundlich吸附模型。

（4）吸附动力学实验中，FS500和RS500对Zn² 的吸附在5min内达到平衡。然而WD600、CS550的70%的吸附量分别在30min和5min完成。四种生物炭的平衡时刻吸附量大小排序为FS500＞WD600＞CS550＞RS500。在吸附动力学模型的拟合中，WD600和CS550对Zn2 的吸附遵循伪二阶吸附动力学模型，吸附机理接近化学吸附。

关键词：地下水污染、可渗透反应墙、生物炭、批量吸附实验、等温吸附模型、吸附动力学模型

Abstract

At present, China has a large number of people drinking groundwater, but groundwater pollution of many China’s cities is deteriorating, especially the heavy water pollution of groundwater. Heavy metals will enter the body with the food chain and continue to accumulate in the human body, resulting in a series of health problems. As a new type of groundwater pollution remediation material, biochar has a high adsorption capacity of heavy metals due to its high pH, high CEC, high surface area, active functional groups and aromatic structure, and has been widely used in heavy metal pollution adsorption. It is helpful to study the physicochemical properties, adsorption performance and adsorption mechanism of biochar to help the application of biochar to groundwater heavy metal pollution remediation technology in the future.

In this paper, four different biochar, including wood biochar, coconut shell biochar, rice straw biochar, shell biochar (maximum pyrolysis temperature of 600,550,500,500℃, referred to as WD600, CS550, RS500，FS500). A series of experiments were carried out, including the determination of biochar pH and CEC, pH series adsorption experiment, isothermal adsorption experiment and adsorption kinetics experiment. The properties of these four kinds of biochar and the adsorption performance of . The experimental results are compared and the following conclusions are drawn:

(1) The pH of the biochar is sorted by FS500gt; WD600gt; CS550gt; RS500,and biochar FS500 has a . High CEC values and pH values can lead to good heavy metal adsorption properties, so the FS500 has a higher adsorption capacity of heavy metals, which is consistent with the experimental data later.

(2) In theexperiment, the increased from , and the removal percentage of Zn² in four kinds of biochar showed an increasing trend, and the removal percentage of pH=7 was the highest. At the same pH, the removal percentage of Zn² in four kinds of biochar was followed by FS500gt; WD600gt; CS550gt; RS500.

(3) In the isothermal adsorption experiment, the absorbed amount of Zn² increased with the increase of Zn² from 10 to 200mg/L. However, when the concentration reached 300mg/L, the absorbed amount of Zn² decline. At the same time, the WD600, RS500 and FS500 can well fit the Langmuir adsorption model, while the CS500 can fit the Freundlich adsorption model.

(4) In adsorption kinetic experiments, the adsorption of Zn² by FS500 and RS500 reached equilibrium within 5 mins. However, 70% of the absorbed amount in WD600 and CS550 were completed in 30 mins and 5mins. The equilibrium absorbed amount of four kinds of biochar is the order of FS500gt; WD600gt; CS550gt; RS500. , the adsorption of Zn² on WD600 and CS550 follows the pseudo second order adsorption kinetics model, and the adsorption mechanism is close to chemical adsorption.

Keywords: Groundwater pollution, permeable reaction barrier, biochar, batch adsorption experiment, isothermal adsorption model, adsorption kinetics model

目 录

摘要 I

Abstract II

目 录 III

第一章 绪论 1

1.1地下水污染现状 1

1.2地下水重金属污染修复技术 2

1.2.1异位修复技术 2

1.2.2原位修复技术——PRB技术 2

1.2.3生物炭 4

1.3 本课题的研究内容以及研究意义 7

1.3.1 研究内容 7

1.3.2 研究技术路线 8

1.3.3 课题研究意义 9

第二章 实验材料和方法 10

2.1 实验材料 10

2.2实验仪器及设备 10

2.3 实验试剂 11

2.4 实验设计和方法 12

2.4.1 标准溶液的配置 12

2.4.2 生物炭pH的测定 13

2.4.3 生物炭CEC的测定 13

2.4.4 批量吸附试验 14

2.5 数据处理以及计算方法 17

2.5.1 pH系列的批量吸附试验 17

2.5.2 等温吸附实验 17

2.5.3 动力吸附实验 18

2.5.4 数据处理及图表绘制 18

2.6 本章小结 18

第三章 生物炭对重金属Zn² 吸附性能的研究 19

3.1 生物炭理化性质的结果分析 19

3.2 初始溶液pH对生物炭吸附重金属Zn² 的影响 20

3.3初始溶液Zn² 浓度对生物炭吸附重金属Zn² 的影响 23

3.4 四种不同生物炭的吸附动力学研究 25

3.5 本章小结 29

第四章 结论与展望 30

4.1 研究结论 30

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