Facile approach developed for low-pressure separation of ethanol-water using cellulose membrane grafted with acrylic polyelectrolyte

Conventional ethanol separation from low-concentration aqueous solutions is energy-intensive and can affect flavor, highlighting the need for efficient, economical alternatives. This study presents a selective, porous polyelectrolyte membrane fabricated by grafting polyacrylate salt (PAS) onto regenerated cellulose membranes using surface-initiated atom transfer radical polymerization (SI-ATRP). The pH-responsive PAS layer enables tunable selectivity, achieving ethanol rejection rates up to 80 % for 15 vol% ethanol solutions at pressures ≤ 0.2 MPa which shows improved comprehensive separation performance and development potential compared to commercial separation membranes. In addition, molecular dynamics simulations (MDS) reveal the interactions of polyelectrolyte chain behavior and ethanol–water molecules, as well as free volume changes drive separation. This green, scalable fabrication strategy offers a potential and promising pathway for ethanol/water separation, which is desirable for applications in areas such as efficient bioethanol dehydration and processing of low-content alcoholic beverages.