Changes in the Composition of Humic Acids under Exposure to Dielectric-Barrier Discharge Plasma

Key Points

• This research investigates how dielectric-barrier discharge plasma affects the composition of humic acids from brown coal.
• Isolated humic acids from oxidized brown coal at pH 2 and pH 7.
• Applied dielectric-barrier discharge plasma at power levels ranging from 11 to 22 W.
• Analyzed changes in C/N atomic ratio and group concentrations in humic acids.
• C/N atomic ratio increases with higher discharge power at pH 2.
• Number of NO2- groups in humic acids increases with discharge power.
• Concentration of ArCOOH groups decreases with increasing discharge power.
• Antioxidant activity of humic acids increases in a neutral medium with higher discharge power.