Removal of Bromocresol Green from aqueous solution by electro-Fenton and electro-Fenton-like processes with different catalysts: laboratory and kinetic model investigation

Abstract

This study presents the removal of triarylmethane dye Bromocresol Green from aqueous solution by the electro-Fenton process. As catalysts five different cations were used: Fe2+, Ce3+, Ni2+, Mn2+, and Co2+. They play crucial roles in the whole process because they react with H2O2 producing hydroxyl radicals that are capable of breaking down dye molecules. Based on this, a comparison of catalytic activity of these cations in the electro-Fenton process is made for Bromocresol Green degradation. A simple and universal kinetic model is also applied to study the catalytic activity of investigated catalysts. Due to its multidimensionality it is fitted to experimental data using a genetic algorithm. The procedure of fitting using a genetic algorithm is thoroughly described and demonstrated. The activity of utilized catalysts is compared based on both experimental and model data revealing that for Bromocresol Green removal all alternative catalysts (Ni2+, Co2+, Ce3+, Mn2+) are better than the typical one (Fe2+, 51.83% degradation). The best catalyst is Co2+ with 78.35% degradation efficiency. Moreover, the adopted kinetic model proved its universality and outlined different interactions between catalysts and dye molecules. HIGHLIGHTS Bromocresol Green was degraded in an electro-Fenton process with different catalysts.; Five different catalysts were compared in terms of their catalytic activity.; A simplified kinetic model was used to simulate experimental data.; A genetic algorithm fits the kinetic model to experimental data very well.; Both experimental and model data show that the best catalyst is Co2+.;

Keywords

• bromocresol green
• decolorization
• electro-fenton process
• genetic algorithm
• kinetic model