Analysis of hydroxyl radical formation in a gas‐liquid electrical discharge plasma reactor utilizing liquid and gaseous radical scavengers

Abstract

Production rates of hydroxyl radical ( • OH) formation in a gas‐liquid plasma discharge reactor with pure water and argon were quantified using gas (carbon monoxide: CO) and liquid (ethanol) radical scavengers. The major oxidation products were acetaldehyde from ethanol and carbon dioxide (CO 2 ) from CO. Total • OH production rates were estimated from the • OH required to form these products and hydrogen peroxide (H 2 O 2) . Ethanol completely depleted H 2 O 2 suggesting that it is formed in or near the plasma‐liquid interface. • OH production rates were higher with CO, and CO had a smaller effect on H 2 O 2 suggesting additional • OH is available for other reactions at the plasma‐gas interface. The best case total • OH production was approximately 25% of the thermodynamic limit for water dissociation based upon measured CO 2 from CO.