Ethanol purification from methanol via pervaporation using polybеnzoхazinonеimidе membrane

• Pervaporation membranes were developed for bioethanol purification.
• The methanol impurities were effectively removed from bioethanol by permeation though membrane in pervaporation.
• The effects of operation temperature on separation were studied in detail.
• The polybenzoxazinoneimide membrane shows extremely high separation factors and selectivity.

Polybenzoxazinoneimide membrane was prepared in three steps: a dichlorodianhydride (obtained by the reaction of trimellitic anhydride with 4,4′-oxydianiline) was treated with methylene-bis(anthranilic acid). The resulting polyamic acid was dissolved in N-methylpyrrolidone, the solution was cast as a thin film, the solvent was evaporated and the membrane was heated under controlled conditions to convert polyamic acid into polybenzoxazinoneimide. Density, free volume parameters, sorption parameters for methanol and ethanol of the membrane were determined. The membrane was used for the pervaporation of methanol/ethanol mixtures containing 5–20 wt.% methanol which are mixtures modeling bioalcohol. The membrane was preferentially permeated by methanol with high separation factors.

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