Fabrication of PDMS Composite Membrane With Reduced Graphene Oxide@Silica Core-Shell for Ethanol Separation by Pervaporation

This study reports the development of ethanol-selective composite membranes for pervaporation (PV) based on polydimethylsiloxane (PDMS) embedded with reduced graphene oxide@silica core-shell (GSCS) particles. To enhance interfacial compatibility and particle dispersion within the matrix, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FDTS) was immobilized onto the GSCS to entangle with PDMS chains. A pre-polymerization strategy was adopted to increase the viscosity of the casting suspension, facilitating higher filler loading and improved ethanol separation performance. Optimal separation performance was achieved with a casting solution viscosity of 4 Pa s, yielding a maximum selectivity of 3.94. The scanning electron microscope (SEM) confirmed the formation of smooth defect-free PDMS/FDTS-GSCS composite membranes. The PV testing of these membranes demonstrated a high separation factor of 11.03 and a permeation flux of 242 g m −2 h −1 for separating a 10 wt% ethanol/water mixture at 40°C. Critically, the composite membranes exhibited excellent operational stability over a continuous 168-h test period. These findings indicate that incorporating FDTS-modified GSCS into PDMS significantly enhances ethanol selectivity, highlighting the potential of these membranes for bioethanol recovery applications.