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.