ISSN: 2574-2701
Authors:
Osmotic distillation (OD) was evaluated as a gentle, non-thermal route for partial removal of ethanol from beer using an in-house hydrophobic flat sheet polyvinylidene fluoride (PVDF) membrane to produce a healthy beverage. A 16 wt.% PVDF membrane prepared by non-solvent induced phase inversion was mounted in a transparent acrylic cell that separated circulating feed and NaCl draw solutions at ambient temperature and zero transmembrane pressure. Membrane characterization by SEM, FTIR, and water contact angle confirmed an asymmetric porous structure, chemically intact PVDF, and stable hydrophobicity (θ ≈ 92°), suitable for vapor phase mass transfer without wetting. Ethanol-water model solutions (5 and 8 % v/v) and three commercial beers (Budweiser, Kingfisher Strong, and Kingfisher Lite) were treated with 2-3 M NaCl draws, and ethanol concentrations in both circuits were monitored by refractive index measurements calibrated with matrix-matched standards. For model solutions, the feed ethanol content decreased from 5.0 to ~2.5% and from 8.0 to 3.6%, corresponding to removal efficiencies of ~50% and ~55%, respectively, consistent with the higher vapor pressure driving force at elevated initial concentrations. For beers, single pass OD with 3 M NaCl achieved ethanol reductions of ~52 % (Budweiser), ~53 % (Kingfisher Strong), and ~58 % (Kingfisher Lite) over 24 h, with no evidence of salt passage or liquid breakthrough. These results demonstrate that a simple flat-sheet OD configuration can reproducibly deliver reduced alcohol beers under mild operating conditions and provide a practical platform for further membrane and process intensification toward continuous industrial dealcoholization.
Keywords: Osmotic Distillation; Beer Dealcoholization; Hydrophobic PVDF Membrane; Non-Thermal Membrane Process; Reduced-Alcohol Beer; Low-Alcohol Beverage; Ethanol Mass Transfer
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