Hydrophobic alkyl chain grafted porous graphene oxide-PEBA mixed matrix membrane for efficient butanol/water pervaporation

Abstract

High-performance pervaporation membranes play a crucial role in the separation of biobutanol. Graphene oxide (GO) shows remarkable potential in membrane separation applications due to its tunable interlayer channel, good hydrophilicity and excellent surface modifiability. However, the narrow d-spacing between GO layers and the weak interlayer interaction forces impose limitations on its application in alcohol permselective pervaporation. Herein, porous graphene oxide (PGO) was prepared via etching of the surface functional groups. Subsequently, 4-dodecylaniline was covalently grafted with PGO nanosheets to fabricate C12H-PGO/PEBA mixed matrix membranes (MMMs) featuring in-plane and interlayer dual transport channels. The introduction of long alkyl chains not only enlarges the d-spacing of PGO and augments its hydrophobicity but also bolsters the mechanical integrity of the framework. At 40 °C, the 1 wt% C12H-PGO/PEBA membrane exhibited a 25.4 % increase in separation factor and a 106.9 % improvement in permeation flux compared to the pristine PEBA membrane. In addition, the adsorption and diffusion behaviors of GO/PEBA, PGO/PEBA, and C12H-PGO/PEBA were investigated using Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) simulations. The results reveal that C12H-PGO incorporation enhances affinity toward butanol molecules while suppresses water diffusion, accounting for the improved separation performance. This microstructural modification strategy of GO paves the way for the development of novel butanol pervaporation membrane.