摘要
渗透汽化膜分离液体混合物不但能耗低,且具有明显的经济优势,因而被广泛应用于食品、医药、农业和化工等多个领域,但其分离性能、热稳定性、耐酸碱性和环保性等方面还有待提高。壳聚糖因具有强亲水性和易改性而使其分离性能优异,此外,壳聚糖稳定性好,来源广泛且具有生物可降解性,是一种极具发展潜力的渗透汽化膜材料。然而,由于单一的壳聚糖膜易吸水溶胀而分离选择性较差,限制了其在渗透汽化领域的应用。因此,对壳聚糖进行改性,使其具有良好的力学性能和选择性至关重要。常用的改性方法有交联、接枝、共混和复合等。交联可提高壳聚糖膜的力学性能,但是会消耗大量的亲水基团,并显著降低渗透通量;共混使壳聚糖膜具有更佳的渗透选择性和渗透通量,但更易吸水溶胀;复合膜中掺入少量的无机粒子可在提高材料分离性的基础上改善其力学性能和热性能,然而,复合膜受聚合物和无机离子之间的界面差异以及无机粒子团聚性影响较大。为了使壳聚糖膜具有更加优异的综合性能,研究者往往会同时采用多种改性方法。本文介绍了渗透汽化技术的研究背景和分离机理,分析了壳聚糖膜的成膜机理、制备和应用。重点从有机物/水和有机物/有机物两个方面综述了壳聚糖膜材料在渗透汽化分离中的研究进展,对其未来的发展趋势进行了展望,以期为快速制备稳定性高、分离性能优异的新型壳聚糖膜提供参考。
Pervaporation membranes were extensively applied in many fields such as food,medicine,agriculture,and chemical industry as an energy efficient alternative and economy technology of separating liquid mixtures. However,most membranes suffer from the drawback of separation performance,thermal stability,acid and alkaline resistance and environmental protection in aqueous solution. Chitosan is one of the most promising pervaporation membrane materials,that exhibits excellent separation performance due to its strong hydrophilicity and easy modification,good stability,wide sources and biodegradability.However,pure chitosan membranes usually show low separation selectivity due to high swelling which limits the performance of these membranes in PV separations. To enhance the membrane performance,chitosan needs modification to get good mechanical property and achieve better selectivity towards water. Grafting,crosslinked,blending with other polymers and filling with inorganic chemicals are easy methods to adjust the structure and properties of chitosan membranes. A convenient and effective approach to improve their mechanical strength is to form a crosslinked network in the membranes. Nevertheless,this approach usually consumes vast amounts of hydrophilic groups and significantly depresses the permeation flux. Compared with pristine chitosan membranes,blended membranes have higher permselectivity and permeation flux,while they suffer more swelling for pervaporation dehydration of organics. The incorporation of a small amount of inorganic particles in the composite membranes not only improves the separation characteristics,but also influences the mechanical and thermal properties significantly. However,the interface differentiation,between the chitosan and inorganic particles,and the presence of a strong agglomeration tendency of these inorganic particles make it highly critical to fabricate a suitable composite membranes. To make the chitosan membranes have more excellent comprehensive properties,researchers often adopt multiple modification methods at the same time.This paper introduces the background and separation mechanism of pervaporation and analyzes the film formation mechanism,preparation and application of chitosan membranes. The research and development of chitosan pervaporation membranes was summarized from the perspective of organic/water and organic/organic. Finally,the future development trend was prospected in order to provide a reference for the rapid preparation of new chitosan membranes with high stability and excellent separation performance.
作者
刘晓琦
张廷安
刘燕
赵昕昕
LIU Xiaoqi;ZHANG Ting’an;LIU Yan;ZHAO Xinxin(Key Laboratory for Ecological Metallurgy of Multimetal Mineral(Ministry of Education),Northeast University,Shenyang 110819,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第1期224-231,共8页
Materials Reports
基金
国家自然科学基金(51774078,51874078,U1702253,U1508217)。
关键词
壳聚糖
渗透汽化
膜分离
chitosan
pervaporation
membrane separation
