增强纳滤膜结构稳定性和仿生涂层纳滤膜制备研究
发布时间：2018-09-09 20:34
【摘要】：纳滤是介于超滤与反渗透间的一种新型分离技术,由于具有低能耗、低操作压力、对二价离子高截留等特点已被应用于料液浓缩、饮用水净化、污水处理等领域。但复合纳滤膜的低界面稳定性、较差的分离性能、制膜过程中有机溶剂的使用等缺点限制了复合纳滤膜的发展。本论文以解决膜分离过程中的结构稳定性和提高膜的分离性能为主要目标,通过改进成膜材料(共混改性基膜材料)、优化成膜工艺(构建界面共价键)、创新制膜方法(基于配位作用制备新型复合膜),实现强稳定性、高性能纳滤膜的制备。通过共混改性基膜材料,将含有羟基官能团的聚乙烯醇缩甲醛(PVF)与聚醚砜(PES)共混,亲水基团羟基通过表面偏析在基膜表面富集,参与界面聚合反应,在基膜与活性层间构建共价键连接,实现了结构稳定性PA/PES-PVF复合纳滤膜的制备。所制备的PA/PES-PVF复合纳滤膜纯水通量为34.9 L/m~2h(0.2 MPa),对Na_2SO_4截留率为92.7%,对橙黄钠及刚果红的截留率高达98%以上。同时将制备的稳定性PA/PES-PVF复合纳滤膜应用于原花青素乙醇溶液的分离浓缩中,体现了较好的分离性能和结构稳定性,纳滤替代传统蒸发浓缩工艺在活性组分的浓缩提取中具有广泛的应用前景。受自然界中生物粘合现象,特别是金属离子增强的海洋贻贝类粘合系统启发,利用Fe~Ⅲ与单宁酸(TA)间的配位作用在PES超滤膜表面形成稳定的配位网状结构,制备了新型TA-Fe~Ⅲ/PES复合纳滤膜。其纯水通量为45.6 L/m~2h,对Na_2SO_4的截留率为44.1%,对染料橙黄钠与刚果红的截留率分别为94.8%与98.5%。相比于传统的界面聚合法,基于配位作用制备复合纳滤膜具有以下优点:反应在水溶液中进行,绿色环保;单相反应,操作简便,反应过程易控。以TA与Fe~Ⅲ间配位作用为推动力,进一步采用层层自组装技术制备了(TAFe~Ⅲ)_n/PES自组装纳滤膜。考察了单体浓度及组装层数对复合膜性能的影响,所制备的纳滤膜通量为10.4 L/m~2h,对Na_2SO_4的截留率为81.8%,对橙黄钠及刚果红的截留率均为99%以上。
[Abstract]:Nanofiltration is a new separation technology between ultrafiltration and reverse osmosis (RO). Because of its low energy consumption, low operating pressure and high retention of bivalent ions, nanofiltration has been applied in the fields of concentration of feed liquid, purification of drinking water, sewage treatment and so on. However, the development of composite nanofiltration membrane is limited by its low interface stability, poor separation performance and the use of organic solvents in the process of membrane preparation. In this thesis, the main purpose of this thesis is to solve the structural stability and improve the separation performance of the membrane in the process of membrane separation. By improving the film-forming material (blending modified base membrane material), optimizing the film-forming process (constructing the interface covalent bond) and innovating the method of preparing the new composite membrane based on the coordination action, the strong stability and high performance preparation of the nanofiltration membrane were realized. Poly (vinyl alcohol) formaldehyde (PVF) and polyethersulfone (PES) were blended with polyvinyl alcohol formaldehyde (PVF) and polyether sulfone (PES) by blending the modified base membrane material. The hydrophilic group hydroxyl groups were enriched on the substrate surface by surface segregation and participated in the interfacial polymerization reaction. The structure stability PA/PES-PVF composite nanofiltration membrane was prepared by covalent bonding between the substrate and the active layer. The pure water flux of PA/PES-PVF composite nanofiltration membrane was 34.9 L/m~2h (0.2 MPa),) and the rejection rate of Na_2SO_4 was 92.7%. The rejection rate of orange sodium and Congo red was over 98%. At the same time, the prepared PA/PES-PVF composite nanofiltration membrane was applied to the separation and concentration of procyanidin ethanol solution, which showed good separation performance and structural stability. Nanofiltration has a wide application prospect in the concentration and extraction of active components instead of traditional evaporative concentration process. Inspired by the biological bonding phenomena in nature, especially the metal-ion enhanced marine mussel bonding system, a stable coordination network structure was formed on the surface of PES ultrafiltration membrane by the coordination between Fe~ 鈪，
本文编号：2233497
[Abstract]:Nanofiltration is a new separation technology between ultrafiltration and reverse osmosis (RO). Because of its low energy consumption, low operating pressure and high retention of bivalent ions, nanofiltration has been applied in the fields of concentration of feed liquid, purification of drinking water, sewage treatment and so on. However, the development of composite nanofiltration membrane is limited by its low interface stability, poor separation performance and the use of organic solvents in the process of membrane preparation. In this thesis, the main purpose of this thesis is to solve the structural stability and improve the separation performance of the membrane in the process of membrane separation. By improving the film-forming material (blending modified base membrane material), optimizing the film-forming process (constructing the interface covalent bond) and innovating the method of preparing the new composite membrane based on the coordination action, the strong stability and high performance preparation of the nanofiltration membrane were realized. Poly (vinyl alcohol) formaldehyde (PVF) and polyethersulfone (PES) were blended with polyvinyl alcohol formaldehyde (PVF) and polyether sulfone (PES) by blending the modified base membrane material. The hydrophilic group hydroxyl groups were enriched on the substrate surface by surface segregation and participated in the interfacial polymerization reaction. The structure stability PA/PES-PVF composite nanofiltration membrane was prepared by covalent bonding between the substrate and the active layer. The pure water flux of PA/PES-PVF composite nanofiltration membrane was 34.9 L/m~2h (0.2 MPa),) and the rejection rate of Na_2SO_4 was 92.7%. The rejection rate of orange sodium and Congo red was over 98%. At the same time, the prepared PA/PES-PVF composite nanofiltration membrane was applied to the separation and concentration of procyanidin ethanol solution, which showed good separation performance and structural stability. Nanofiltration has a wide application prospect in the concentration and extraction of active components instead of traditional evaporative concentration process. Inspired by the biological bonding phenomena in nature, especially the metal-ion enhanced marine mussel bonding system, a stable coordination network structure was formed on the surface of PES ultrafiltration membrane by the coordination between Fe~ 鈪，
本文编号：2233497
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