Department of Physical Chemistry, Kuban State University, 149 Stavropolskaya st., 350040 Krasnodar, Russia.
Institut UTINAM (UMR CNRS 6213), Université de Bourgogne-Franche-Comté, 16 Route de Gray, 25030 Besançon CEDEX, France.
Int J Mol Sci. 2020 Feb 1;21(3):973. doi: 10.3390/ijms21030973.
Electrodialysis (ED) has been demonstrated as an effective membrane method for desalination, concentration, and separation. Electroconvection (EC) is a phenomenon which can essentially increase the mass transfer rate and reduce the undesirable water splitting effect. Efforts by a number of researchers are ongoing to create conditions for developing EC, in particular, through the formation of electrical heterogeneity on the membrane surface. We attempt, for the first time, to optimize the parameters of surface electrical heterogeneity for ion-exchange membranes used in a laboratory ED cell. Thirteen different patterns on the surface of two Neosepta anion-exchange membranes, AMX and AMX-Sb, were tested. Low-conductive fluoropolymer spots were formed on the membrane surface using the electrospinning technique. Spots in the form of squares, rectangles, and circles with different sizes and distances between them were applied. We found that the spots' shape did not have a visible effect. The best effect, i.e., the maximum mass transfer rate and the minimum water splitting rate, was found when the spots' size was close to that of the diffusion layer thickness, (about 250 μm in the experimental conditions), and the distance between the spots was slightly larger than , such that the fraction of the screened surface was about 20%.
电渗析（ED）已被证明是一种有效的膜分离方法，可用于脱盐、浓缩和分离。电对流（EC）是一种可以显著提高传质速率并减少不良水分解效应的现象。许多研究人员正在努力创造条件来发展 EC，特别是通过在膜表面形成电异质性。我们首次尝试优化用于实验室 ED 池的离子交换膜表面的电异质性参数。在两种 Neosepta 阴离子交换膜 AMX 和 AMX-Sb 的表面测试了十三种不同的图案。使用静电纺丝技术在膜表面形成低导电性氟聚合物斑点。应用了具有不同大小和间距的正方形、矩形和圆形斑点。我们发现斑点的形状没有明显的影响。当斑点的大小接近扩散层厚度（实验条件下约为 250μm），并且斑点之间的距离略大于 时，发现了最佳效果，即最大传质速率和最小水分解速率，此时屏蔽表面的分数约为 20%。
