【作者】 刘鲜红；

【导师】 孙元；

【作者基本信息】 天津工业大学 ， 材料物理与化学， 2008， 硕士

【摘要】 本论文主要的研究内容是制备用于分离甲醇/水溶液优先透水渗透汽化复合膜,本研究是在制备了PVA缩甲醛膜（PVA）、AA和AN的共聚膜（PAA-Co-AN）、纳米SiO₂改性的AA和AN共聚膜（PAA-Co-AN（SiO₂））、PVA/PAA-Co-AN/PVA三层结构复合膜（PVA/PAA-Co-AN/PVA）基础上,又制备出水优先透过的三层夹心复合渗透汽化膜PVA/PAA-Co-AN（SiO₂）/PVA用所制得的各种膜对不同浓度的甲醇/水溶液在不同温度下进行渗透汽化实验,对所得结果进行比较,结果发现PVA/PAA-Co-PAN（SiO₂）/PVA三层结构复合膜的分离性能较好。进而研究了三层夹心结构PVA/PAA-Co-PAN（SiO₂）/PVA复合膜,不同纳米SiO₂粉末含量以及不同操作温度、料液浓度等操作条件对甲醇含量70%—98%的水溶液分离效果的影响。结果表明,添加纳米SiO₂粉末后膜的分离性有明显提高,并且纳米SiO₂含量为0.1%的复合膜的分离性能最好,60℃对甲醇含量98%的溶液,分离因子可达1458,渗透通量可达415g/（m²h）,与不添加SiO₂纳米粉末的膜相比,分离因子可提高10倍以上,但是渗透通量稍有下降（10%左右）。用扫描电镜（SEM）、红外分析（FT-IR）、热重分析（TG）、机械性能测试、热机械分析（DMA）等方法研究了膜的结构和性能,扫描电镜照片给出添加纳米SiO₂后膜的形貌结构变得更致密;热重分析表明膜具有良好的热稳定性:动态热机械分析得到膜的玻璃化转变温度Tg随纳米SiO₂的含量增加而升高,并当纳米SiO₂的含量相对于AA和AN质量的0.1%时达到最大值。更多还原

【Abstract】 In this paper the composite pervaporation membranes were prepared,and the performance has been studied in the separation of methanol/water mixtures.In the study,Acrylic acid（AA）and acrylonitrile（AN）were synthesized by solution polymerization with nanometer SiO₂.The copolymer solution was made into main body of the membrane,then composite with the polyvinyl alcohol（PVA）acetal membrane,to make the three-tier sandwich composite pervaporation membrane.The pervaporation experiments were carried out with the membranes of PVA acetal membrane,PAA-Co-AN membrane,PAA-Co-AN（nanometer SiO₂）membrane, PVA/PAA-Co-AN/PVA composite membrane and PVA/PAA-Co-AN（nanometer SiO₂） /PVA composite membrane.The result showed that PVA/PAA-Co-AN（nanometer SiO₂）/PVA has the best separate performance.Different membranes were prepared by change the content of nanometer SiO₂. Pervaporation experiments were carried out using these membranes to separate the mixtures of methanol/water over the complete concentration range 70%-98%.The influencing factors of operating temperature and feed concentration have been researched.The separation performance and the change of feed′s concentration enriched have been studied in the continuous operation of the dehydration experiments.Results showed that the selectivity of the membrane with nanometer SiO₂ had notable improvement.The membrane contained 0.1%nanometer SiO₂ has the best separate performance,for the 98%mixture at 60℃,the separate factor is up to 1458,which is improved more then 10 times compared with the membrane without nanometer SiO₂,the permeate flux is up to 415g/（m²h）,which has a little decreased.It was concluded that the pervaperation performance of the membrane can improve greatly by adding nanometer SiO₂.The structure and the performance of the membranes were characterized by Scanning Electron Microscope（SEM）,Fourier Transform Infrared Spectroscopy （FT-IR）,Thermogravimetry（TG）,mechanical performance testing and DynamicThemomechanical analysis apparatus.There is a great improvement in the heat stability and size stability of the membranes which were modified by nanometer SiO₂.更多还原