Synergistic SA/Pebax composite membranes on ceramic supports for efficient ethanol–water separation

Abstract

Efficient ethanol–water separation is vital for sustainable biofuel production, yet conventional techniques remain energy-intensive. This work presents synergistic sodium alginate (SA)/Pebax composite membranes supported on ceramic tubes for high-performance pervaporation. By tuning SA/Pebax ratios (5 : 1 to 3 : 2) and applying glutaraldehyde crosslinking, the membranes exhibit enhanced thermal stability, mechanical strength, and hydrophilicity. FTIR and SEM confirm successful blending and uniform morphology, while AFM reveals controlled surface roughness. Increasing the Pebax composition in the polymer blend improved thermal stability while reducing the swelling degree. Tensile strength tests showed that the 4 : 1 ratio provided a balanced performance, with a tensile strength of 12.04 MPa and elongation of 30.65%. At 50 °C and 90 wt% ethanol feed, the SA/Pebax (4 : 1) membrane achieves a flux of 133 g m⁻² h⁻¹ and a separation factor of 281, raising the separation factor from 5 for pure SA to 281 (56 times). These findings demonstrate that SA/Pebax composite membranes provide opportunities for energy-efficient solutions for water/ethanol separation, aligning with sustainable chemical processing goals.