Experimental Design to Optimize the Oxidation of Orange II Dye Solution Using a Clay-based Fenton-like Catalyst

Abstract

In this work, an experimental design methodology was applied to optimize the degradation of an Orange II (OII) solution, a non-biodegradable azo dye, while minimizing also the leaching of iron from the catalyst support in a heterogeneous Fenton-like process. The independent variables considered were the temperature, H2O2 concentration, and catalyst (iron-impregnated pillared saponite clay) load. The multivariate experimental design allowed the development of empiric quadratic models for dye degradation, TOC removal, and iron leaching after 1, 2, 3, and 4 h of reaction, which were adequate to predict responses in all of the range of experimental conditions used. Data obtained revealed that the heterogeneous Fenton-like process is promising for the degradation of the studied azo dye. Actually, after 4 h oxidation color removals near 100% and TOC reductions of at least 65% were experimentally achieved when the temperature was 40 °C or higher. Iron leaching was also quite small after 4 h of oxidation (in the ...