-二氯酚的性能及机理研究
摘 要
由于 2,4-二氯酚毒性大、难以生物降解，具有遗传毒性且在环境中可以长期残
留，美国环境保护局以将其列为优先控制污染物。但是常规的生物处理对 2,4-二氯
酚的作用不大，因此人们将目光投向了光催化降解技术。本研究利用介孔分子筛
SBA-15 的良好负载性和孔道均匀性，以四异丙醇钛、硫代硫酸钠、氯化镧分别作
为钛、硫、镧源，水热合成了 La-S-TiO2/SBA-15 材料。对材料进行 XRD、BET、
SEM、TEM、XPS 和UV-Vis 分析，光催化实验考察了材料对 2,4-二氯酚（2,4-DCP）
的去除效果，并通过催化实验优化合成条件如镧钛比、硫钛比、pH 和煅烧温度等，
确定了最佳制备工艺参数。对催化实验的影响因素如污染物浓度、光照时间和催化
剂用量进行了研究。通过紫外可见光谱分析、高效液相色谱分析和气质联用分析了
2,4-二氯酚光催化降解的中间产物，并对其降解途径进行了简单分析。
本文的主要内容有：
1. 在强酸性条件下，以三嵌段共聚物 P123 为模板剂，正硅酸乙酯为硅源，
水热合成了 SBA-15 介孔分子筛，各反应物的物质的量比为：n(P123):n(HCl):
n(H2O):n(TEOS)=0.0138:4.8:139:1。而后分别用 LaCl3 和 Na2S2O3作为镧源和硫源，
在酸性条件中水热合成了不同 La、S掺杂量的 La-S-TiO2/SBA-15 介孔材料。
2. 表征结果显示 TiO2的负载并没有破坏 SBA-15 的介孔结构，UV-Vis 分析发
现掺杂 La、S后，样品对光的吸收范围拓展到可见光区，XPS 分析证实了硫以阳
离子 S6+进入 TiO2晶格，而 La3+形成 La-O-Ti 存在于晶格间隙中。与未掺杂的纯
TiO2相比，La-S-TiO2微晶的粒径较小，晶格畸变应力较大，所以光催化活性增加。
3. La-S-TiO2/SBA-15 催化剂对 2,4-二氯酚具有良好的光催化去除效果，在催化
剂投加量为 0.3g/L，光照时间为 2h 的条件下，对 10mg/L 的2,4-二氯酚的降解率达
到了 50.09%，分别是未掺杂样品 TiO2/SBA-15 和P25的2.9 和7.9 倍。
4. 对2,4-二氯酚的光催化降解产物进行分析发现，苯环上的 C-Cl 键被光催
化剂产生的·OH 自由基氧化断裂，生成的 Cl-游离于溶液中，生成的有机小分子中
间产物则进一步被羟基自由基降解，动力学分析发现 La-S-TiO2/SBA-15 催化剂对
水中 2,4-二氯酚的降解属于一级反应。
关键词：La-S-TiO2/SBA-15 2,4-二氯酚 介孔 光催化 可见光
ABSTRACT
2,4-dichlorophenol,high toxicity, bioaccumulation and carcinogenic potential,is
widely found in the environment and are significant for cleanup on the USEPA top priority
toxic pollutants.Because 2,4-DCP is difficult to be biodegraded,as a viable
method,photodegradation technology has earned much attention. In accord to the easiness
for loading other materials of SBA-15 and the uniformity of its channels, using titanium
isopropoxide, sodium thiosulfate and lanthanum chloride as the Ti, S and La source
respectively, La-S-TiO2/SBA-15 were synthesized by the ex-situ method under
hydrothermal treatment and then characterized by XRD, BET, SEM,TEM, XPS and UV-
Vis techniques. The photodegradation experiments of photocatalytic oxidation of 2,4-
dichlorophenol(2,4-DCP) solutions under visible irradiation were carried out to evaluate
the catalytic activity of the composite material and optimize the experimental conditions
such as molar ratio of La/Ti and S/Ti, pH value and calcination temperature.The
influencing factors of the 2,4-DCP photodegradation were also evaluated，for example，
initial concentration of 2,4-DCP,photocatalytic reaction time and quality of catalysis,etc.
Furthermore, the intermediates of 2,4-DCP during the photodegradation process were
identified using UV-Vis spectrum, HPLC and GC-MS, and the 2,4-DCP degradation
pathway was proposed.
Conclusions presented in this thesis are summarized as follows:
1．Hydrothermal synthesis method was applied to prepare SBA-15 by using TEOS
as silicate material and triblock copolymer P123 as the template in the acidic condition
and the molar ratio of reactants was n(P123):n(HCl):n(H2O):n(TEOS)= 0.0138:4.8:139:1.
Then La-S-TiO2/SBA-15 mesoporous material with different La/Ti and S/Ti ratios was
synthesized in a hydrothermal method under acid medium using LaCl3 and Na2S2O3 as
La and S source,respectively.
2. Results showed that the SBA-15 maintained complete mesoporous structure after
loaded TiO2 relatively. The results of UV-Vis show that co-doping La and S into TiO2
induce the red-shift of its absorption edge to the visible-light region. The results of XPS
show that S atoms as S6+ state have been incorporated into the lattice of TiO2, and La3+
ions formed La-O-Ti that ispositioned an interstitial lattice site. Compared with that pure
TiO2，the size of La-S-TiO2 decrease, the lattice stress increases, and thus the
photocatalytic activity is improved.
3. The La-S-TiO2/SBA-15 catalyst, especially, displays the highest degradation
ability with degradation rate up to 50.09% in concentration of 2,4-dichlorophenol 10mg/L
under conditions of catalyst dosage 0.3g/L and illumination time of 2h,which is almost
2.9 times and 7.9 times the photocatalytic activity of TiO2/SBA-15 and Degussa
P25,respectively.
4. Photocatalytic degradation of 2,4-DCP products were found through analysis that
C-Cl bond on benzene ring was oxidized and then fractured by hydroxyl radical from
photocatalyst，Cl substitute became free Cl-existing in the solution，2,4-dichlorophenol
was degraded by·OH and generated intermediate product of small molecule organic，and
small molecule organics were further degraded under photocatalysis. Through kinetic
analysis of reaction La-S-TiO2/SBA-15 catalysis on degradation rate of 2,4-
dichlorophenol followed first-order reaction.
Key Word：La-S-TiO2/SBA-15, 2,4-DCP, Mesoporous, Photocatalysis,
Visible light
目 录
中文摘要
ABSTRACT
第一章 绪 论 ............................................................................................................. 1
1.1 课题背景及研究意义 ........................................................................................ 1
1.1.1 氯酚简介 .................................................................................................. 1
1.1.2 氯酚的危害 .............................................................................................. 1
1.1.3 氯酚的传统处理技术 .............................................................................. 2
1.1.4 氯酚的高级氧化技术 .............................................................................. 3
1.2 TiO2光催化的研究进展 ................................................................................... 5
1.2.1 TiO2光催化概述 ........................................................................................ 5
1.2.2 TiO2光催化机理 ........................................................................................ 8
1.2.3 TiO2光催化剂的改性 .............................................................................. 10
1.2.4 TiO2光催化剂的负载 .............................................................................. 14
1.2.5 负载型 TiO2光催化剂的制备 ................................................................. 16
1.3 SBA-15 分子筛的研究进展 ........................................................................... 18
1.3.1 介孔分子筛概述 .................................................................................... 18
1.3.2 介孔分子筛的发展 ................................................................................ 19
1.3.3 SBA-15 的制备 ...................................................................................... 20
1.3.4 SBA-15 的形成机理 .............................................................................. 22
1.3.5 SBA-15 的改性研究 .............................................................................. 23
1.4 TiO2/SBA-15 分子筛的研究进展 .................................................................. 26
1.5 论文的研究内容及创新性 ............................................................................. 27
1.5.1 研究内容 ................................................................................................ 28
1.5.2 实施方案 ................................................................................................ 28
第二章 复合材料的制备、表征与催化 ................................................................ 29
2.1 材料的制备 ................................................................................................... 29
2.1.1 仪器与设备 ............................................................................................ 29
2.1.2 试剂与药品 ............................................................................................ 30
2.1.3 材料的制备 ............................................................................................ 30
2.2 材料的表征方法 ........................................................................................... 31
2.2.1 X 射线衍射分析 .................................................................................... 31
2.2.2 N2吸附-脱附分析 .................................................................................. 31
2.2.3 XPS 分析 ................................................................................................ 31
2.2.4 紫外可见漫反射分析 ............................................................................ 31
2.2.5 扫描电子显微镜测试 ............................................................................ 32
2.2.6 透射电子显微镜测试 ............................................................................ 32
2.3 二氯酚的催化研究 ....................................................................................... 32
2.3.1 光催化实验 ............................................................................................ 32
2.3.2 紫外可见分光光度法分析 .................................................................... 32
2.3.3 高效液相色谱分析 ................................................................................ 33
2.3.4 离子吸收色谱分析 ................................................................................ 34
2.3.5 气质联用分析 ........................................................................................ 34
第三章 结果与讨论 ................................................................................................ 35
3.1 复合材料的表征结果 ................................................................................... 35
3.1.1 XRD 分析 ............................................................................................... 35
3.1.2 N2吸-脱附分析 ...................................................................................... 37
3.1.3 UV-Vis 分析 ........................................................................................... 39
3.1.4 XPS 分析 ................................................................................................ 40
3.1.5 SEM 分析 ............................................................................................... 41
3.1.6 TEM 分析 ............................................................................................... 42
3.2 工艺条件对复合材料的影响 ....................................................................... 43
3.2.1 S/Ti 对复合材料的影响 ........................................................................ 43
3.2.2 La/Ti 对复合材料的影响 ...................................................................... 44
3.2.3 pH 对复合材料的影响 .......................................................................... 45
3.2.4 煅烧温度对复合材料的影响 ................................................................ 46
3.3 实验条件对催化结果的影响 ....................................................................... 47
3.3.1 不同复合材料的吸附性能及光催化性能 ............................................ 47
3.3.2 光照时间对降解效率的影响 ................................................................ 48
3.3.3 复合材料用量对降解效率的影响 ........................................................ 49
3.3.4 初始浓度对降解效率的影响 ................................................................ 49
3.4 2,4-二氯酚的降解机理研究 ......................................................................... 50
3.4.1 紫外可见分析 ........................................................................................ 50
3.4.2 离子色谱分析 ........................................................................................ 51
3.4.3 高效液相色谱分析 ................................................................................ 52
3.4.4 气质联用分析 ........................................................................................ 54
3.4.5 动力学研究 ............................................................................................ 56
第四章 结论与建议 ................................................................................................ 59
4.1 结论 ............................................................................................................... 59
4.1.1 材料的制备 ............................................................................................ 59
4.1.2 材料的表征 ............................................................................................ 59
4.1.3 材料的催化性能 .................................................................................... 59
4.1.4 2,4-二氯酚的降解机理 .......................................................................... 59
4.2 建议 ............................................................................................................... 60
参考文献 .................................................................................................................... 61
在读期间公开发表的论文和承担科研项目及取得成果 ........................................ 77
致 谢 .......................................................................................................................... 78
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作者：牛悦
分类：高等教育资料
价格：15积分
属性：82 页
大小：4.65MB
格式：PDF
时间：2025-01-09
