论文总字数：19862字

摘 要

茶是我国传统保健饮品，深受世界人民的喜爱，其特有的芳香物不仅决定了了茶叶的风味品质，同时还具有重要的生理活性和医学功能。近年来，随着人们生活方式和科学技术进步的变化，瓶装和罐装茶受到消费者的欢迎,它们以茶叶为原料，与此同时也成为世界各地茶饮料的原料，这引发了市场对速溶茶粉需求量的快速增长。目前，速溶茶粉的生产工艺中广泛采用了浓缩、干燥等热加工工序，极易导致茶叶芳香物的流失和破坏，严重影响速溶茶及其下游产品的风味品质。如果我们想要让茶饮料香精回收和改善技术在将来具有重要的讨论价值和实用意义，所以我们现在就要加深对茶叶香气回收的理论研究。

渗透汽化分离技术有很多独特的优点。

本文自制了无机/有机杂化膜Silicalite-1/PDMS，考察了其对乙醇—水体系的渗透汽化分离性能，具体内容和主要结论如下：

（1）以PVDF为支撑体，涂布沸石分子筛（Silicalite-1）含量不同的PDMS膜液，制备Silicalite-1/PDMS杂化膜。结果显示，Silicalite-1添加量为5 wt%时，粒子分散较为均匀，表面平整完好，支撑层与膜层结合紧密；膜面与水滴的接触角为124^o，表明膜层水不润湿，为疏水性表面；FT-IR分析显示，复合膜层中存在-CH₃、Si-CH₃、Si-O-Si、Si-C等官能团的特征吸收峰，表明PDMS膜液和Silicalite-1粒子已成功沉积在支撑层上；

（2）分别测试了不同沸石分子筛添加量的Silicalite-1/PDMS杂化膜在乙醇/水体系中的渗透汽化性能。结果显示，添加沸石分子筛可明显改善PDMS膜的分离性能。当Silicalite-1添加量为5 wt%时，杂化膜对乙醇的分离性能最好，分离因子和通量分别为9.30和676.2 gm^-2h^-1

关键词：渗透汽化；混合基质膜；沸石分子筛；分离

ABSTRACT

The pervaporation separation technology has the advantages of moderate condition, without thermal damage for heat-sensitive aromatic substance, low energy consumption, no additional processing in adding solvent or other adsorbent and small loss of aromatic compounds. So it is a promising alternative in aromatic substance recovery.

In this study, based on the analysis of the composition and contents changes of the volatile aromatic substance in before and after the rapid concentrated black tea, we created the Silicalite-1/PDMS mixed matrix membrane which priority in permeating alcohol and investigated the separating property of the alcohol/water system. It demonstrated that it is feasibility to use the pervaporation membrane separation technology to separate the aromatic substance from the black tea.

The contents and conclusions are as follows:

1. When the loading degree of zeolite silicalite-1 is 5wt%, the Silicalite-1/PDMS mixed matrix membrane has the flat surface, balance layer structure and combined with the support layer closely. It indicates that membrane layer will not be wetted, so it is the hydrophobic surface. The FT-IR data displayed that there are some characteristic absorption peak of  functional groups like -CH3、Si-CH3、Si-O-Si、Si-C in the mixed matrix membrane layer. It shows that the zeolite silicalite-1 was kept stably in the polymer solution and the mixed matrix membrane layer was successfully deposited on the support layer.
2. The pervaporation performance of the self-made Silicalite-1/PDMS mixed matrix membrane with different loading degree of zeolite silicalite-1 was tested in the alcohol/water system with the equipments constructed by self. The result shows that the separation performance of the self-made membrane is good and the separation factor and the flux of the alcohol are 9.30 and 676.2gm^-2h^-1 respectively at 30℃.

KEYWORDS:Pervaporation; Mixed substrate membrane; Zeolite sieve ;Separation

目录

摘要 I

ABSTRACT II

目录 i

第一章 文献综述 1

1.1渗透汽化概述 1

1.1.1速溶茶简介 1

1.1.2渗透汽化简介 1

1.1.3渗透汽化原理 1

1.1.4渗透汽化过程的影响因素 2

1.1.5渗透汽化技术的应用 3

1.2渗透汽化膜简介 3

1.2.1渗透汽化优先透醇有机膜材料 4

1.2.2渗透汽化优先透醇膜无机材料 5

1.3渗透汽化杂化膜概述 5

1.3.1 渗透汽化杂化膜 5

1.3.2 渗透汽化杂化膜的研究现状 5

1.4本文的研究目的、意义及主要内容 6

第二章 实验材料与方法 8

2.1实验材料 8

2.1.1主要试剂 8

2.1.2主要实验仪器 8

2.2实验方法 8

2.2.1 Silicalite-1/PDMS杂化膜的制备 9

2.2.2 silicalite-1/PDMS膜的表征 9

2.2.3渗透汽化实验装置 9

2.2.4 渗透汽化性能计算方法 10

第三章 实验结果与讨论 11

3.1 PDMS/PVDF膜的结构表征 11

3.1.1 SEM 11

3.1.2 接触角（Contact angle） 12

3.1.3 FT-IR分析 12

3.2.1 乙醇标准曲线的建立 13

3.2.2 乙醇/水体系的性能测试 13

第四章 结论与展望 15

4.1结论 15

4.2展望 15

参考文献 16

致 谢 20

第一章 文献综述

1.1渗透汽化概述

1.1.1速溶茶简介

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