Plasma-chemical and photo-catalytic degradation of methyl orange

Abstract

Non-thermal atmospheric humid air plasma is used to investigate chemical reactions mechanisms of pr edominantly produced neutral hydroxyl radicals by gliding arc discharges with Methyl Orange (MO). UV/Visible spectroscopy and electrochemical measurements were performed. Treated solutions show that highly reactive HO • radicals interaction favours the creation of intermediate species followed by their degradation leading to one aromatic ring end product. Photocatalytic (UV/TiO 2 and UV/H 2 O 2 ) treatments lead to the complete decolourisation of MO w ithin few minutes. The results obtained may confirm that the final product of ai r plasma MO interaction contains NO 2 and NH 2 groups, the consequence of • NO presence in plasma.