Dudek Gabriela, Borys Przemysław, Strzelewicz Anna, Krasowska Monika
Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice, Poland.
Polymers (Basel). 2020 Feb 11;12(2):411. doi: 10.3390/polym12020411.
The structure and transport properties of alginate/chitosan microparticle membranes used in ethanol dehydration processes were investigated. The membranes were characterized based on images obtained from high-resolution microscopy. The following parameters were determined: the observed total amount of void space, the average size of the void domains, their length and diameter, the fractal dimension, and the generalized stochastic fractal parameters. The total amount of void space was determined to be between 54% and 64%. The average size of the void domains is smaller for alginate membranes containing neat (CS) and phosphorylated (CS-P) chitosan particles when compared to those membranes filled with glycidol-modified (CS-G) and glutaraldehyde crosslinked (CS-GA) chitosan particles. Furthermore, the transport of ethanol and water particles through the studied membranes was modelled using a random walk framework. It was observed that the results from the theoretical and experimental studies are directly correlated. The smallest values of water to ethanol diffusion coefficient ratios (i.e., 14) were obtained for Alg (sodium alginate) membranes loaded with the CS and CS-P particles, respectively. Significantly larger values (27 and 19) were noted for membranes filled with CS-G and CS-GA particles, respectively. The simulation results show that the size of channels which develop in the alginate matrix is less suited for ethanol molecules compared to water molecules because of their larger size. Such a situation facilitates the separation of water from ethanol. The comparison of the structural analysis of the membranes and random walk simulations allows one to understand the factors that influence the transport phenomena, in the studied membranes, and comment on the effect of the length, diameter, number of channels, and variations in the pore diameters on these transport parameters.
研究了用于乙醇脱水过程的海藻酸钠/壳聚糖微粒膜的结构和传输特性。基于从高分辨率显微镜获得的图像对膜进行了表征。确定了以下参数：观察到的空隙空间总量、空隙域的平均尺寸、其长度和直径、分形维数以及广义随机分形参数。确定空隙空间总量在54%至64%之间。与填充有缩水甘油改性（CS-G）和戊二醛交联（CS-GA）壳聚糖颗粒的膜相比，含有纯（CS）和磷酸化（CS-P）壳聚糖颗粒的海藻酸钠膜的空隙域平均尺寸较小。此外，使用随机游走框架对乙醇和水颗粒通过所研究膜的传输进行了建模。观察到理论研究和实验研究的结果直接相关。分别装载CS和CS-P颗粒的海藻酸钠（Alg）膜获得了最小的水与乙醇扩散系数比（即14）。对于分别填充CS-G和CS-GA颗粒的膜，注意到的值明显更大（27和19）。模拟结果表明，由于乙醇分子尺寸较大，海藻酸钠基质中形成的通道尺寸与水分子相比不太适合乙醇分子。这种情况有利于从乙醇中分离出水。对膜的结构分析和随机游走模拟的比较使人们能够理解影响所研究膜中传输现象的因素，并评论通道的长度、直径、数量以及孔径变化对这些传输参数的影响。
