Clarizia Gabriele, Tasselli Franco, Bernardo Paola
Institute on Membrane Technology (ITM-CNR), c/o University of Calabria, via P. Bucci 17/C, 87036 Rende (CS), Italy.
Polymers (Basel). 2020 Feb 13;12(2):441. doi: 10.3390/polym12020441.
The systematic evaluation of the gas transport properties related to differences in the history of the samples is a useful tool to appropriately design a membrane-based gas separation system. The permeation rate of six pure gases was measured over time in asymmetric hollow-fiber (HF) samples, that were prepared according to the non-solvent-induced phase separation in different operation conditions, in order to identify their response to physical aging. Four types of HFs having a different structure were analyzed, comparing samples spun in a triple-orifice spinneret to HFs prepared using a conventional spinneret. A generalized gas permeance decline, coupled to a maintained permselectivity for the different gas pairs, was observed for all HFs. Instead, H/N permselectivity values were enhanced upon aging. Cross-linked hollow-fiber samples showed a marked size-sieving behavior that favored the separation of small species, e.g., hydrogen, from other larger species and a good stability over time. Some HFs, post-treated using different alcohols, presented a permeance decay independently on the alcohol type and a greater selectivity over time.
对与样品历史差异相关的气体传输特性进行系统评估，是合理设计基于膜的气体分离系统的有用工具。在不对称中空纤维（HF）样品中，随着时间的推移测量了六种纯气体的渗透速率，这些样品是根据不同操作条件下的非溶剂诱导相分离制备的，以确定它们对物理老化的响应。分析了四种具有不同结构的HF，将在三孔喷丝头中纺丝的样品与使用传统喷丝头制备的HF进行了比较。观察到所有HF的气体渗透系数普遍下降，同时不同气体对的渗透选择性保持不变。相反，H/N渗透选择性值在老化后有所提高。交联中空纤维样品表现出明显的尺寸筛分行为，有利于从小分子物种（如氢气）与其他大分子物种中分离出来，并且随着时间的推移具有良好的稳定性。一些用不同醇类后处理的HF，其渗透系数衰减与醇类类型无关，并且随着时间的推移选择性更高。
