Efficacy of the Fenton reaction for degrading Allura red azo dye: Applications for use in hair salon greywater treatment systems

Azo dyes are one of the most common dyes used in the world. Traditional methods of removing azo dyes are ineffective, and some azo dyes have been found to be harmful to humans and the environment. This study looked at degrading the azo dye Allura red AC using the Fenton reaction. Of the conditions tested, the most effective for dye degradation involved ferrous sulfate in the range of 0.54 mM to 0.11 mM, and hydrogen peroxide in the 0.404 mM to 0.0404 mM range. The pH levels 2, 5, and 7 were analyzed with and without the buffers phosphate and citrate. For all cases, pH 2 was ineffective at degrading dye. The conditions where the solution was adjusted to pH 5 with and without phosphate degraded dye well, but pH 7 without buffers was the most effective. These findings are unexpected because the literature around the Fenton reaction states it is ineffective at pH levels near neutral.