Organic solvent separation using carbon nanotube-interlayered thin film composite membrane

Abstract

The intercalation of carbon nanotubes (CNTs) interlayer has been considered an effective way to improve the membrane performance in water treatment process. However, the effectiveness of CNTs interlayer on membrane performance enhancement for organic solvent separation has not been examined yet. Herein, a polyketone (PK)-based CNTs-interlayered thin-film composite (TFC) polyamide (PA) membrane was fabricated and applied in organic solvent reverse osmosis (OSRO) process for the first time. The role of CNTs interlayer on both PA formation regulation and permeance enhancement was investigated. Results demonstrate that the membrane permeance was enhanced three times higher with rejection remained at 99.2% when using 5 wt% methyl tert-butyl ether (MTBE) in methanol. By comparing the separation performances of three different kinds of solvent combinations (methanol/toluene, methanol/MTBE, and acetonitrile/toluene), the interactions between selective layer and different solvent mixtures were first considered as one of the factors affecting the rejection, and were analyzed based on Hansen solubility parameters (HSP) theory. This work provides insights into the high-performance OSRO membrane design and the solvent separation mechanism.