Ethanol purification with ozonation, activated carbon adsorption, and gas stripping

• A combination of three approaches effectively removes 8 out of 10 impurities.
• Ozonation removed >56% and >36% of styrene and 2-pentylfuran, respectively.
• No significant generation of byproducts was observed with ozonation.
• Activated carbon removed esters.
• Gas stripping was effective with acetaldehyde, ethyl vinyl ether and acetal removal.

Fermentation of sugar to produce ethanol also produces volatile byproducts. This study was aimed at purifying corn-based ethanol for industrial and pharmaceutical use. The research was on treatment for 10 impurities removal after distillation. The ethanol headspace was sampled with solid-phase microextraction and analyzed with gas chromatography–mass spectrometry. A 40 mg/L ozone treatment resulted in >56% and >36% removal of styrene and 2-pentylfuran, respectively, without significant generation of byproducts. A 60 g/L activated carbon (AC) treatment with 270 min adsorption time resulted in 84%, >72%, and >78% removal of ethyl hexanoate, ethyl octanoate, and ethyl decanoate respectively. CO2-based stripping, at 675 LStripping gas/LSample, removed 65%, >82%, and >83% acetaldehyde, ethyl vinyl ether, and 1,1-diethoxyethane respectively. A combination of three approaches effectively removes these 8 impurities.

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