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摘要以壳聚糖(CTS)的接枝共聚物2-羟丙基三甲基氯化铵壳聚糖(HTCC)为表面活性层,聚醚砜超滤膜(PES)为支撑层，环氧氯丙烷(ECH)为交联剂，采用涂敷交联法制备出荷正电的HTCC/PES复合纳滤膜。利用所制备的荷正电纳滤膜对有机物分子及个人护理品(PPCPs)进行分离实验，探讨了相对分子质量、大小尺寸、极性、荷电性对纳滤膜截留性能的影响。
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结果表明，HTCC/PES复合纳滤膜对有机物的截留效率受尺寸效应、电荷效应、分子极性等因素的影响。在纳滤膜的截留分子量范围内，截留率随分子量增大而增大，其相关性系数为0.6711；基于筛分效应和尺寸效应，分子的尺寸参数和截留率存在一定的相关性，说明分子的尺寸大小对截留效率产生影响。与具有相似分子质量或粒径的非极性分子相比，极性分子具有更低的截留率。另外，由于膜表面存在一定的电荷作用，带正电的有机物不易接近荷正电的膜表面，无法吸附穿透膜，从而使截留率普遍较高。而对于带负电的有机物，荷正电的膜使其更易吸附并穿透膜，从而大大降低了截留效率。在室温和中性条件下，纳滤膜对四中PPCPs物质截留率均在70%以上，说明纳滤膜对于PPCPs的去除以静电排斥作用为主。25827
关键词 纳滤膜；尺寸效应；电荷效应；分子极性；PPCPs
毕业论文设计说明书外文摘要
Title Effect of steric effects on nanofiltration of micropollutants
in water PPCPs
Abstract
2-Hydroxypropyltrimethyl ammonium chloride chitosan (HTCC) with different substitution degrees were synthesized by reaction of chitosan (CTS) and glycidyl trimethyl ammonium chloride (GTMAC) in isopropanol. Then a positively charged composite nanofiltration membrane was prepared by using HTCC as the selective layer, PES UF membrane as support layer and epichlorohydrin (ECH) as cross-linking reagent. Use of the positively charged nanofiltration membrane separation of organic compounds and personal care products (PPCPs) experiment and explore the molecular molecular mass, size, polarity and electric charge of nanofiltration membrane interception performance.
Results showed that Effect of HTCC/PES composite nanofiltration membrane for organic matter retention efficiency by size effect, charge effect, molecular polarity and other factors. In the nanofiltration membrane mwcos range, the rejection increases with the increase of molecular weight, the correlation coefficient is 0.6711; based on the screening effect and size effect, the size parameters and rejection has certain correlation, and further explain the molecular size of interception efficiency has obvious influence. Compared with non-polar molecules have similar molecular weight or particle size, the polar molecules have a lower rejection. In the charge, since there is a certain charge effect in the surface of the film, positively charged organic inaccessibility the surface of positively charged film, unable to penetrate the membrane, so that the rejection were generally higher. The negatively charged organic, positively charged membrane to make it easier to adsorb and penetrate the membrane, thereby greatly reducing the rejection. Under the room temperature and neutral conditions, the rejection of PPCPs with the nanofiltration membrane was above 70%, indicating that nanofiltration membranes for the removal of PPCPs is based on electrostatic repulsion.
Keywords Nanofiltration membrane Size effect Charge effect Molecular polarity PPCPs
目 次
1 引言•1
1.1 膜分离技术概述1
1.1.1 膜分离技术特点•1
1.1.2 膜分离技术分类•2
1.1.3 分离膜的分类2
1.2 纳滤膜分离技术的概述3
1.2.1 纳滤膜分离技术的特点3
1.2.2 纳滤膜材料•3
1.3 影响纳滤膜分离性能的因素•4