Institute of Macromolecular Compounds of the Russian Academy of Sciences, Bolshoi pr. VO 31, St. Petersburg 199004, Russian Federation.
Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of the Russian Academy of Sciences, Pr. 100-letiya Vladivostoka 159, Vladivostok 690022, Russian Federation.
Carbohydr Polym. 2018 Feb 1;181:86-92. doi: 10.1016/j.carbpol.2017.10.050. Epub 2017 Oct 14.
A polyelectrolyte complex (PEC) was prepared from chitosan (CS) and λ-carrageenan (λ-CAR) using a layer-by-layer deposition of polyion solutions on a plated nonporous support. This material was then used as a multilayer membrane for the pervaporation separation of aqueous ethanol solutions. The fabricated complex film (25-30μm thick) was a multilayer system (λ-CAR-PEC-CS) containing a polycation CS (MW 3.1×10, DDА 0.93), a polyanion λ-CAR (MW 3.5×10, extracted from the alga Chondrus armatus), and a PEC layer formed between the two polyion layers. X-ray diffraction indicated a significant structuring of the film in the region of the composite PEC-CS bilayer. The structural and morphological characteristics of the CS surface in the multilayer membrane, as revealed by atomic force microscopy, were close to the characteristics of the dense CS film. However, this structure changed following pervaporation (i.e., the distinct spherical structures on the surface disappeared). Similarly, the initially loose surface of λ-CAR in the composite changed to an ordered domain after pervaporation. The transport properties of the pervaporation membranes were tested by examining the separation of ethanol-water mixtures of different compositions. The flux increased with an increase in the weight percentage of water in the feed mixture, but the separation capacity of the membrane was unchanged. In a range of feed concentrations of 50-94wt%, the membrane mainly releases water with a corresponding concentration in the permeate of 99.9-99.8wt% and substantial fluxes of 0.003-1.130kgmh at 40°C. The obtained results indicate significant prospects for the use of non-gelling type CARs for the formation of highly effective pervaporation membranes.
一种聚电解质复合物（PEC）是通过在 plated 非多孔支撑体上逐层沉积聚离子溶液由壳聚糖（CS）和 λ-卡拉胶（λ-CAR）制备而成的。然后，该材料被用作用于渗透蒸发分离含水乙醇溶液的多层膜。所制备的复合膜（25-30μm 厚）是一个多层系统（λ-CAR-PEC-CS），其中包含聚阳离子 CS（MW 3.1×10，DDА 0.93），聚阴离子 λ-CAR（MW 3.5×10，从角叉菜属植物中提取）和两个聚离子层之间形成的 PEC 层。X 射线衍射表明，复合 PEC-CS 双层膜的区域存在明显的结构化。原子力显微镜揭示了多层膜中 CS 表面的结构和形态特征接近致密 CS 膜的特征。然而，这种结构在渗透蒸发后发生了变化（即表面上明显的球形结构消失了）。同样，复合膜中 λ-CAR 的初始疏松表面在渗透蒸发后变成了有序区域。通过检查不同组成的乙醇-水混合物的分离来测试渗透蒸发膜的传输性能。通量随着进料混合物中水的重量百分比的增加而增加，但膜的分离能力保持不变。在进料浓度为 50-94wt%的范围内，膜主要释放水，对应的渗透物浓度为 99.9-99.8wt%，通量为 0.003-1.130kgmh，在 40°C 下。获得的结果表明，非胶凝型 CAR 用于形成高效渗透蒸发膜具有很大的应用前景。
