Roles of oxysulfur radicals in the oxidation of acid orange 7 in the Fe(III)–sulfite system

Here, a detailed theoretical analysis was made on the inhibitory activities of the inhibitors (ethanol, tert -butyl alcohol, 1-hexanol, aniline, diphenylamine, and pyrogallol (PA)) to examine the roles of oxysulfur radicals in the oxidation of the azo dye acid orange 7 (AO7) in the Fe(III)–sulfite system.

Experimental results confirm the expected concentration of inhibitors for the complete inhibition of specific radicals and establish that the combination of 1-hexanol and PA was suitable for analyzing the role of and . and contributed 57.1% and 42.9%, respectively, to the oxidation in the presence of oxygen at pH 3, which means that makes comparable contribution as in the oxidation of specific organic pollutants like AO7 in this system. reacts with AO7 only in the absence of oxygen.