摘要
正渗透(FO)技术作为一种新的、极具潜力的膜分离技术,以低能耗、低污染的优势得到了人们的广泛关注。但缺乏性能优异的正渗透膜是阻碍其发展的一个重要因素。到目前为止,研究人员在正渗透膜材料方面进行了大量的研究工作,并在膜结构的优化、寻找新型膜材料方面都取得了长足的进步。常见的正渗透膜材料如醋酸纤维素、芳香聚酰胺及聚苯并咪唑等虽然在正渗透过程中得到了广泛的应用,但这几种膜材料也存在较突出的缺点,比如:醋酸纤维素膜容易水解、耐酸碱性差,聚酰胺类复合膜的结垢倾向较高、耐氯性较差,聚苯并咪唑膜的韧性较差、价格较高。因此,开发新型的正渗透膜材料,提高膜性能对推动正渗透技术的发展具有重要的意义。膜结构的优化对提高FO膜的性能至关重要,而优化分离层和支撑层结构是优化膜结构的主要途径。纳米粒子由于具有优异的抗污染性和亲水性,在正渗透过程中得到了应用。研究者们通过将氧化石墨烯等纳米粒子添加到FO膜的分离层中来提高膜表面的亲水性,从而使FO膜性能得到改善。除此之外,层层自组装技术、双皮层结构等也被用来对膜的分离层进行优化,使膜的性能得到提高。由于发生在支撑层中的内浓差极化(ICP)现象是影响正渗透性能的主要因素,因此优化膜的支撑层结构是提高膜性能的重要途径。研究者通过提高支撑层亲水性、降低支撑层厚度以及改善孔结构等对膜的支撑层进行优化。选择亲水性好的支撑层材料、对支撑层进行表面改性等方法都可使支撑层的亲水性得到提高。厚度小、孔隙率高且曲折度小的孔结构及机械强度高、抗污染性能好等优点是高性能FO膜必不可少的条件。本文综述了近几年来正渗透膜制备方面的研究进展,通过列举几种常见的正渗透膜以及一些新型正渗透膜的制备方法,
As a novel membrane separation technique with high potential, forward osmosis technique has attracted extensive attention in recent years. However, the lack of high performance forward osmosis membranes has been a key factor impeding the advancement of forward osmosis technique. To date, a great many researches have been devoted to membrane structure optimization and the search for new membrane materials. Several common forward osmosis membranes, such as cellulose acetate (CA) membranes, aromatic polyamide (PA) membranes and polybenzimidazole (PBI) membranes have been widely applied in forward osmosis process. However, the disadvantages of these membrane materials are also prominent. For example, cellulose acetate membrane is easy to be hydrolyzed, poor in acid and alkali resistance;polyamide composite membrane has higher fouling tendency and poor chlorine resistance and PBI membrane has poor toughness with high price. Therefore, the deve- lopment of new types of forward osmosis membrane materials is of great significance for the improvement of membrane properties. As we all known, FO technique is developing rapidly, so FO membrane performance needs to be improved as well. The optimization of membrane structure is crucial to improve the performance of FO membrane, and the optimization of separation layer and support layer structure is the key. In recent years, nanoparticles with the advantages of anti-fouling and hydrophilicity have been widely used in forward osmosis process. The membrane surface hydrophilicity is improved by adding nanoparticles such as zeolite, TiO 2 nanoparticles and graphene oxide into the separation layer of the membrane to improve the FO membrane performance. In addition, layer-by-layer (LBL) assembly and double-layer structures are also used to optimize the separation layer of the membrane. The internal concentration polarization (ICP) occurring in support layer is the main factor affecting the FO performance. Therefore, optimizing the support layer of the membrane is important to improve
作者
孙娜
王铎
汪锰
SUN Na;WANG Duo;WANG Meng(College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第17期2966-2975,2996,共11页
Materials Reports
基金
国家自然科学基金(21576249)~~
关键词
正渗透
膜结构
优化
膜污染
forward osmosis
membrane structure
optimization
membrane fouling
