论文总字数：25867字

摘 要

本课题以天然多糖壳聚糖和正硅酸四乙酯为主要原料，采用溶胶-凝胶法和CO₂超临界干燥技术制备纯壳聚糖气凝胶与壳聚糖-SiO₂复合气凝胶。首先，采用溶胶-凝胶法制得壳聚糖湿凝胶，再用CO₂超临界干燥，得到壳聚糖气凝胶，随后在相同正硅酸四乙酯含量的条件下制得壳聚糖-SiO₂复合气凝胶，探讨不同壳聚糖含量对复合气凝胶表观及微观性质的影响。红外谱图与SEM扫描结果表明，成功制得了两种目标气凝胶。随着壳聚糖含量由3 g/L到10 g/L，复合气凝胶的本体密度呈现先下降后升高的趋势。当壳聚糖含量为5 g/L时，本体密度达到最小值(0.0768 g/cm³)。此外，对气凝胶吸附水中重金属离子(Cu(II))的性能进行了一定程度的研究。结果显示，复合气凝胶对Cu(II)的吸附率随气凝胶中壳聚糖含量的上升而上升，当壳聚糖含量为10 g/L时对Cu(II)的吸附量达到约5 mg/g。

壳聚糖气凝胶具有众多优异性能，如良好的生物相容性，光谱的抗菌性且生物可降解。其较高的比表面积赋予其较强的吸附能力。本研究以溶胶-凝胶法,经CO₂超临界干燥制得壳聚糖气凝胶，并对其工艺进行改进，复合SiO₂后得到壳聚糖-SiO₂复合气凝胶，并探究壳聚糖-SiO₂气凝胶对水中重金属离子（Cu(II)）的吸附效果。

关键词：壳聚糖 复合气凝胶 CO₂超临界干燥 重金属离子 吸附

ABSTRACT

In this project, chitosan aerogels and chitosan-silica composite aerogels with chitosan and TEOS as precursors were prepared by sol-gel method and CO₂ supercritical drying technology. First, the chitosan aerogel was prepared by the sol-gel method and CO₂ supercritical drying technology. The chemical structure of the aerogel was analyzed by infrared spectroscopy (FT-IR). X ray diffraction (XRD) analyze phase of the aerogels. The surface morphology of the gel was studied by scanning electron microscope (SEM), and the effect of crosslinking concentration on the properties of chitosan aerogel was investigated. Based on it, the chitosan-silica composite aerogels were prepared with the same content of TEOS, and the effects of different chitosan content on the bulk density and porosity of the composite aerogels were investigated. The results showed that the two aerogels were prepared successfully. The microstructure of the chitosan aerogels showed a large number of micropore holes, and the composite aerogels had a more homogeneous nano porous structure. With the increase of chitosan content, the bulk density and porosity showed a tendency to decrease and increase respectively. When the content of chitosan reached 5 g/L, the bulk density was close to the minimum (0.0768 g/cm³) and the porosity reached the highest (93%). In addition, the adsorption of the aerogels on heavy metal ions was investigated. The results showed that the adsorption rate of copper ions increased with the increase of chitosan content. When the content of chitosan was 10 g/L, the adsorption capacity of copper ions was about 5 mg/g.

Chitosan aerogels have good biocompatibility, antibacterial activity and biodegradability. Because of its high specific surface area, it has strong adsorption capacity. In this study, the chitosan aerogel was prepared by sol-gel method and CO₂ supercritical drying. After that, the chitosan-silica composite aerogel was prepared by combined with silica,the adsorption ability of chitosan -SiO₂ aerogels on heavy metal ions (Cu(II)) in water was also studied.

KeyWords: Chitosan aerogel; CO₂ supercritical drying; Heavy metal ions adsorption

目 录

摘 要 I

ABSTRACT II

第一章 绪论 1

1.1 引言 1

1.2 气凝胶概述 1

1.2.1 气凝胶的定义 1

1.2.2 气凝胶的分类 2

1.2.3 气凝胶的制备工艺 3

1.2.4 气凝胶的干燥工艺 3

1.3 气凝胶的应用 4

1.3.1 储氢材料 4

1.3.2 隔热材料 5

1.3.3 生物医药类材料 5

1.3.4 催化剂类材料 6

1.3.5 吸油过滤类材料 6

1.4 研究目的和内容 6

第二章 壳聚糖气凝胶与壳聚糖-SiO₂复合气凝胶的制备 8

2.1 引言 8

2.2 实验原料与仪器 9

2.2.1 实验原料 9

2.2.2 实验仪器 9

2.3 实验方法 10

第三章 壳聚糖气凝胶与壳聚糖-SiO₂复合气凝胶的性能研究 12

3.1 表征方法 12

3.1.1 扫描电子显微镜(SEM)分析 12

3.1.2 X射线衍射(XRD)分析 12

3.1.3 红外光谱(FT-IR)分析 12

3.1.4 BET分析 12

3.1.5 TG分析 12

3.1.6 密度 12

3.1.7 Cu(II)吸附测试 13

3.2 表征仪器 14

3.3 表征结果与分析讨论 14

3.3.1 表面形貌 14

3.3.2 物相分析 15

3.3.3 化学结构 15

3.3.4 BET分析 16

3.3.5 TG分析 17

3.3.6 密度分析 18

3.3.7 Cu(II)吸附性能研究 19

第四章 结论与展望 21

4.1 结论 21

4.2 展望 21

参考文献 22

致谢 27

第一章 绪论

1.1 引言

随着水污染日益严重，极大的威胁着人类的生存和安全，严重阻碍着人类社会的可持续发展。水中污染物主要包括:无机酸、碱和盐类污染物、富营养化污染物、氰化物污染物以及重金属污染物等。而在其中，重金属离子污染是水污染中较为严重的一种污染。重金属离子是不可降解的，通过食物链积累在生物组织中，引起一些疾病，危害人类健康^[1]。其中，Cu(II)对生物组织结构，尤其是蛋白质活性有显著的破坏作用，引发人体组织坏死，对人类生命健康具有较大危害。因此，开发高效可回收的重金属离子吸附剂成为了水污染控制研究领域的一个重大课题。

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