TiO2 13X MCM-41分子筛基光催化材料去除水中邻苯二甲酸酯的研究

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摘 要
邻苯二甲酸酯(phthalate esters)，缩写为 PAEs，是环境内分泌干扰物中的一类
化合物，邻苯二甲酸二乙酯(DEP)属于 PAEs 中的一种化合物，对环境和人类产生
了一定的危害。本文以 13X 分子筛为原料，水热合成一种新型微介孔光催化降解
材料 TiO2/13X/MCM-41，研究了复合材料的最佳制备工艺参数，包括硅铝比、溶
液pH、钛硅比、晶化时间、焙烧温度等，以对 DEP 的去除率为主要判别标准。通
过各种表征手段获取合成的 TiO2/13X/MCM-41 微介孔复合材料的形貌、结构、孔
径和比表面积等信息。同时将最佳条件制备出来的复合材料用于 DEP 的光催化降
解实验，研究材料用量、DEP 初始浓度、光照时间、pH 值等对 DEP 降解效率的
影响，初步建立 DEP 光降解的动力学方程，并通过气相色谱/质谱法(GC-MS)分析
DEP 光降解产物，推测 DEP 可能的降解途径。
本文的主要结论：
1、采用水热合成法制备 TiO2/13X/MCM-41 微介孔复合材料，并通过正交试
验法确定制备复合材料的最佳工艺参数如下：硅铝比 15，pH 为8、钛硅比 0.2、
晶化时间 48h、焙烧温度 300℃，最佳条件下制备的材料对 DEP 去除率可达 97%；
2、通过 XRD 、SEM 、FI-IR 和BET 及孔径分析等技术证明合成的
TiO2/13X/MCM-41 微介孔复合材料，表面疏松多孔，吸附性能极强，具有较大的
孔径，孔壁较厚，其介孔相的水热稳定性和酸性均有所提高；
3、研究TiO2/13X/MCM-41与TiO2、13X/MCM-41相比，复合材料对DEP的吸
附和光催化作用，发现所制备的材料吸附能力与光催化能力均大于其他两种材料；
4、紫外光能诱发水中DEP的光降解，TiO2/13X/MCM-41的存在使得光降解速
率加快，并且通过对DEP模拟废水的光催化降解实验表明，当催化剂投加量为
0.1g/L，初始DEP浓度为10mg/L，光照时间120min，pH值为8时，去除率可达97%；
5、在模拟DEP废水浓度2-10mg/L范围内，DEP的光降解效率与浓度成正比，
反应过程符合一级动力学方程；
6、GC-MS联用分析DEP光降解产物，推测TiO2/13X/MCM-41对DEP催化光降
解的主要反应途径是：•OH攻击DEP的脂肪链，从而生成一些中间产物，比如苯甲
酸、邻苯二甲酸、邻苯二甲酸酐等。随着时间的推移，中间产物继续分解转化成
小分子的酸和醇，最后，完全矿化生成CO2和H2O。
关键词：邻苯二甲酸二乙酯 TiO2/13X/MCM-41 光降解 动力学 降解
机理
ABSTRACT
The phthalate esters (PAEs) are environmental endocrine disruptors which pose a
huge threat on the survival of humans and natural environment. Diethyl phthalate (DEP)
is a compound of PAEs. This article reported a composite material TiO2/13X/MCM-41
which was synthesized by hydrothermal method with the raw of 13X molecular sieves.
The catalytic activity of the composite material was tested by the photodegradation of
DEP. The optimum conditions such as Si/Al, pH value, Ti/Si, crystal duration,
calcination temperature have been researched. The material TiO2/13X/MCM-41 was
characterized by different techniques. Also the photo-degradation of DEP was carried
out in the presence of the TiO2/13X/MCM-41. The many factors, such as catalyst
amount, degradation time, pH value and initial concentrations of DEP, affected on the
degradation were evaluated. Furthermore, the intermediate products of DEP during the
photocatalysis process have been identified by gas chromatography-mass spectrometry
(GC–MS). The degradation pathway was proposed.
Conclusion presented in this thesis can be summarized as follows:
1. The optimum conditions for Si/Al=10, Ti/Si=0.2, crystal duration=48h and
calcination temperature=300℃has a removal efficiency above 97%.
2. The research of microscopic structure illustrated the composite material
possessed mesoporous and microporous bimodel pore systems. And the loose surface,
large aperture and thick pore wall increased its hydrothermal stability and practicability
extraordinarily.
3. The enhancement of TiO2/13X/MCM-41 to photodegradation of DEP mainly
resulted from the enhancement of DEP adsorption on TiO2surface．
4. The optimum conditions of photodegradation at 97% as the following: the
catalyst dosage was 0.1g/L; reaction time was 120min; pH was 8.
5. The photocatalytic degradation process was found to obey first-order reaction.
6. The possible degradation pathway for DEP was proposed as follows: •OH free
radicals attacked the aliphatic chain of DEP, to produce some intermediate products.
During mineralization processes ，some minor degradation products, such as alcohols
and acids may be formed . CO2 and H2O were the final products of mineralization.
Key Words ：Diethyl phthalate, TiO2/13X/MCM-41, Photocatalytic
degradation, Kinetics, Degradation mechanism
目 录
中文摘要
ABSTRACT
第一章 引言············································································· 1
§1.1 邻苯二甲酸酯··································································1
§1.1.1 PAEs 的物化特性························································1
§1.1.2 PAEs 的应用······························································3
§1.1.3 PAEs 的危害······························································3
§1.1.4 PAEs 的检测方法························································5
§1.2 环境中的 PAEs 污染现状··················································· 6
§1.2.1 大气········································································ 6
§1.2.2 水体········································································ 7
§1.2.3 土壤与沉积物···························································· 8
§1.3 PAEs 的降解与去除·························································9
§1.3.1 环境中 PAEs 的自然降解··············································9
§1.3.2 PAEs 污染物治理的现有技术······································· 10
§1.3.3 其他降解技术···························································13
§1.3.4 小结和展望······························································13
§1.4 论文选题意义、研究内容及创新········································14
§1.4.1 课题来源及选题的意义···············································14
§1.4.2 研究内容·································································14
§1.4.3 创新点····································································15
第二章 微孔-介孔复合分子筛的研究现状······································ 16
§2. 1 微孔 13X 分子筛····························································16
§2.1.1 13X 分子筛简介························································16
§2.1.2 13X 分子筛的应用与发展前景······································17
§2. 2 介孔 MCM-41 分子筛的简介············································ 17
§2.2.1 MCM-41 介孔分子筛的表征········································ 17
§2.2.2 MCM-41 介孔分子筛的形成机理·································· 19
§2.3 微介孔复合分子筛的合成·················································19
§2.3.1 原位合成法······························································20
§2.3.2 后合成法·································································21
§2.3.3 静电匹配法······························································21
§2.3.4 包埋法····································································21
§2.3.5 纳米组装法······························································22
§2.4 微介孔复合分子筛的表征·················································22
§2.4.1 X 射线衍射(XRD)····················································· 22
§2.4.2 扫描电镜(SEM)和透射电镜(TEM) 表征························· 23
§2.4.3 孔结构特征表征························································24
§2.4.4 傅里叶变换红外光谱表征(FT-IR)·································· 24
§2.5 微介孔复合分子筛的应用前景···········································25
§2.5.1 微介孔复合分子筛在工业催化方面的应用价值················ 25
§2.5.2 微介孔复合分子筛在环保方面的应用潜力······················ 26
第三章 TiO2/13X/MCM-41 复合材料的制备··································· 27
§3.1 实验部分······································································ 27
§3.1.1 材料及试剂······························································27
§3.1.2 仪器及设备······························································27
§3.1.3 实验方法·································································28
§3.2 结果与讨论··································································· 31
§3.2.1 正交试表分析方法·····················································31
§3.2.2 实验正交表分析························································32
§3.2.3 Si / Al 的影响··························································· 34
§3.2.4 溶液 pH 值的影响······················································35
§3.2.5 Ti / Si 的影响····························································35
§3.2.6 晶化时间的影响························································36
§3.2.7 焙烧温度·································································37
§3.3 复合材料的表征····························································· 38
§3.3.1 X 射线衍射(XRD)分析··············································· 38
§3.3.2 扫描电镜(SEM)分析·················································· 39
§3.3.3 傅里叶变换红外光谱(FT-IR)分析·································· 40
§3.3.4 BET 及孔径分析······················································· 40
§3.4 小结············································································ 43
第四章 TiO2/13X/MCM-41 对水中 DEP 的去除······························· 44
§4.1 实验部分··································································· 44
§4.1.1 材料及试剂······························································44
§4.1.2 仪器·······································································44
§4.1.3 实验方法·································································44
§4.2 结果与讨论··································································· 45
§4.2.1 三种材料在暗室和光照条件下对 DEP 去除率的影响········· 45
§4.2.2 催化剂用量对 DEP 去除率的影响································· 46
§4.2.3 光照时间对 DEP 去除率的影响···································· 47
§4.2.4 初始 pH 值对 DEP 去除率的影响·································· 47
§4.2.5 DEP 初始浓度对 DEP 去除率的影响······························48
§4.3 DEP 光降解产物的 GC-MS 联用分析·································· 49
§4.4 小结············································································ 52
第五章 结论与建议·································································· 54
§5.1 结论············································································ 54
§5.1.1 TiO2/13X/MCM-41 复合材料的制备·······························54
§5.1.2 TiO2/13X/MCM-41 复合材料对水中 DEP 的去除·············· 54
§5.2 建议············································································ 54
参考文献··················································································55
硕士研究生期间科研成果···························································· 66
致谢·····················································································67
第一章 引 言
1
第一章 引 言
环境内分泌干扰物(Endocrine disrupting compounds, EDCs)是指能改变机体内
分泌功能并对机体、后代或(亚)群引起有害效应的环境物质[1]。随着人类社会的进
步，科学技术带来的工业化程度提高，EDCs 通过水、大气和土壤等介质，进入人
体体内，导致人类内分泌系统、神经系统、免疫系统等出现异常现象，影响人类
的发育、生殖功能，甚至引起某些肿瘤的发生，被喻为“威胁人类生存的定时炸弹”。
因此，EDCs 被称为是继工业革命带来的煤烟污染及汽车工业发展带来的光化学烟
雾污染之后的“第三代环境污染物”[2]。环境化学污染物属于 EDCs 中比较常见的
一类，它包括烷基酚类，多氯联苯类(PCBs)，邻苯二甲酸酯类(PAEs)，双酚 A及
金属(Pb、Hg、Cd)等[3~4]。
其中 PAEs 是一类广泛应用的化学品，主要用于塑料的增塑剂和软化剂，随着
工业生产和使用的进一步扩大，已经成为环境领域研究的一个热点问题。
§1.1 邻苯二甲酸酯
§1.1.1 PAEs 的物化特性
PAEs 是一类重要的合成有机物(见表 1-1)，共约 30 多种，一般是通过酞酸酐
与各种醇类之间的酯化反应获得(如图 1-1 所示)。
图1-1 PAEs 的合成反应
其中，R1和R2代表不同的或相同的烷基或芳基。例如，酞酸二正丁酯的
R1=R2=-CH2-CH2-CH2-CH3；酞酸苄基丁基酯的 R1=-CH2-C8H5，
R2=-CH2-CH2-CH2-CH3。
PAEs 的挥发性很低，一般为无色透明的粘稠液体，不溶于水，可溶于有
机溶剂，同时对固体颗粒、生物体能表现出很强的吸附性和亲和性。表 1-2
列出了几种常见的 PAEs 的一些物理化学性质。
O
O
O+HOR1
HOR2
O
OR1
O
OR2
(1)
TiO2/13X/MCM-41 分子筛基光催化材料去除水中邻苯二甲酸酯的研究
2
表1-1 具有环境激素作用的 PAEs 化合物
中文名称
英文名称
用途
邻苯二甲酸二甲酯(Ⅰ、
Ⅱ)
Dimethyl phthalate(DMP)
塑料增塑剂；驱蚊剂
邻苯二甲酸二乙酯(Ⅰ、
Ⅱ)
Diethyl phthalate(DEP)
塑料和合成橡胶等的增
塑剂；清漆的溶剂
邻苯二甲酸二丙酯(Ⅰ)
Di-n-propyl
phthalate(DPP)
塑料增塑剂
邻苯二甲酸二丁酯(Ⅰ)
Di-n-butyl phthalate(DBP)
塑料、合成橡胶、人造革
等常用的增塑剂；香料的
溶剂；卫生害虫驱避剂
邻苯二甲酸二戊酯
Di-n-pentyl
phthalate(DDP)
塑料增塑剂
邻苯二甲酸二己酯
Dihexyl phthalate(DHP)
塑料增塑剂
邻苯二甲酸二辛酯(Ⅰ、
Ⅱ)
Di-n-octyl phthalate(DOP)
塑料增塑剂
邻苯二甲酸丁苄酯
Butyl benzyl
phthalate(BBP)
塑料增塑剂；涂料；人造
革材料
邻苯二甲酸二(2-乙基己
基)酯(Ⅰ)
Di(2-ethylhexyl)
phthalate(DEHP)
聚氯乙烯和氯乙烯共聚
物的优良增塑剂；硝酸纤
维的软化剂
邻苯二甲酸二环己烷酯
Dicycl ohexyl
phthalate(DCHP)
丙烯酸稀释剂；热粘合剂
的可塑剂
注：Ⅰ.美国环保局的优先污染物 Ⅱ.中国国家环境监测中心的优先污染物
表1-2 部分 PAEs 的物理化学性质
物质
名称
分子
量
熔
点
℃
沸
点
℃
相对
密度
性状
毒性
DMP
194.19
5.5
284
1.189
无色、无
臭、耐晒
的油状液
体
低毒
DBP
278.36
-35
340
1.045-
1.050
无色透明
油状液体
剧毒
DOP
390.62
-50
231
0.982
无色油状
液体
低毒
DEP
222.2
-67
296
1.117
无色透明
油状液体
低毒
摘要：

摘要邻苯二甲酸酯(phthalateesters)，缩写为PAEs，是环境内分泌干扰物中的一类化合物，邻苯二甲酸二乙酯(DEP)属于PAEs中的一种化合物，对环境和人类产生了一定的危害。本文以13X分子筛为原料，水热合成一种新型微介孔光催化降解材料TiO2/13X/MCM-41，研究了复合材料的最佳制备工艺参数，包括硅铝比、溶液pH、钛硅比、晶化时间、焙烧温度等，以对DEP的去除率为主要判别标准。通过各种表征手段获取合成的TiO2/13X/MCM-41微介孔复合材料的形貌、结构、孔径和比表面积等信息。同时将最佳条件制备出来的复合材料用于DEP的光催化降解实验，研究材料用量、DEP初始浓度、光照...

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TiO2 13X MCM-41分子筛基光催化材料去除水中邻苯二甲酸酯的研究.pdf

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作者：侯斌 分类：高等教育资料 价格：15积分 属性：70 页 大小：2.35MB 格式：PDF 时间：2024-11-19

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