Photocatalytic Degradation of the Azo Dye “Congo-Red” by ZnFe₂O₄/ ZnO Nanocomposite

Abstract

This paper reports the preparation of ZnFe2O4/ZnO metal oxide nanocomposite by solution combustion synthesis. Zinc nitrate and ferric nitrate were utilized as oxidizers in this work, while glycine served as fuel. The powder X-ray diffraction pattern indicated that the nanocomposite consisted of ZnFe2O4 and ZnO having spinel and wurtzite phases respectively. The efficiency of the nanocomposite in the photocatalytic degradation of Congo Red (CR) dye from its aqueous solution was studied. The effects of CR starting concentration, photocatalyst dose, and irradiation duration were investigated. More than 90 % degradation of 10 ppm CR solution was achieved for a photocatalyst dosage of 1.0g/litre of the dye solution in 40 minutes. The excellent photocatalytic activity of the nanocomposite was considered as the result of the synergistic mechanism between its constituent phases, significantly reducing electron-hole recombination. It was noticed that the photocatalyst after the first regeneration was about 85 % efficient compared to the original one. The water contamination with human activity can be reduced by the usage of ZnFe2O4/ZnO metal oxide nanoparticles.