Solvent resistant hollow fiber membranes comprising P84 polyimide and amine-functionalized carbon nanotubes with potential applications in pharmaceutical, food, and petrochemical industries

Robust P84 and NH2-MWCNT/P84 hollow fiber membranes have been designed by adjusting spinning parameters and then crosslinking them by 1,6-hexanediamine to achieve desirable separation performance for organic solvent nanofiltration (OSN). A weak bore fluid, an adequately high dope flow rate and a small air gap length were required to produce the desired hollow fiber membranes. Compared the neat P84 hollow fiber, the addition of NH2-MWCNTs into P84 resulted in an amidation reaction between the imide groups of P84 and the amine groups of NH2-MWCNTs, leading to greater mechanical properties and thermal stability as well as higher dope viscosity. Moreover, NH2-MWCNT/P84 hollow fibers exhibited great permeances of 4.31, 2.26, 1.45, and 1.17 LMH/bar for acetone, methanol, ethyl acetate, and ethanol, respectively, while having smaller pore sizes with notable rejections. The crosslinked P84 and NH2-MWCNT/P84 membranes showed extraordinary rejections of 97.2, and 99.8% to methylene blue (320 g/mol), respectively. Also, the newly developed hollow fibers demonstrated great potential for separating tetracycline/IPA, L-alpha-lecithin/hexane, and BINAP-Ru(II)/methanol solutions, representing their applicability in the pharmaceutical, food, and petrochemical industries.