Microporous Benzimidazole-linked Polymer And Its Derivatives For Organic Solvent Nanofiltration
Published 2019 · Materials Science
Abstract Organic solvent nanofiltration (OSN) has emerged as a robust separation technology for solvent recovery and microporous polymer membranes are considered as promising OSN membranes. A molecular simulation study is reported here to investigate a new type of microporous membranes for OSN, including a benzimidazole-linked polymer (BILP-4) and its derivatives (PILP-1 and PILP-3). PILP-1 and PILP-3 are computationally designed, they consist of tetrahedral cores in BILP-4 and contorted linkers in polymer of intrinsic microporosity (PIM-1). From molecular dynamics simulations, three membranes are found to possess considerable stability in organic solvents (methanol, ethanol and acetonitrile). The mean pore sizes of the swollen membranes have a linear relationship with swelling degrees. Intriguingly, methanol, ethanol and acetonitrile exhibit distinctly different permeation behavior through the three membranes. Specifically, the permeation of methanol is solely governed by the pore size, whereas both the pore size and the membrane-solvent interaction play a role in the permeation of ethanol; for acetonitrile, the permeation is mainly determined by the membrane-solvent interaction. A dye molecule (methylene blue) is tested for OSN and complete rejection is observed by all the three membranes. This simulation study reveals the complex permeation behavior of different solvents, identifies the key factors governing permeation, and suggest the three microporous membranes as interesting candidates for OSN.