Abstract: In order to degrade organic dyes in wastewater, the photocatalytic degradation of organic dyes by composite catalyst ZnFe₂O₄/FeVO₄ was studied to promote the healthy growth of aquatic organisms and the balance of the entire ecosystem. ZnFe₂O₄ was prepared by PVP assisted hydrothermal method, FeVO₄ was prepared by hydrothermal method and the composite catalyst ZnFe₂O₄/FeVO₄ was synthesized according to the different mass ratios of ZnFe₂O₄ and FeVO₄. The activities of ZnFe₂O₄, FeVO₄ and composite catalyst ZnFe₂O₄/FeVO₄ were tested under the same conditions with the methyl orange as the degradation dye. The experimental results indicate that composite catalyst ZnFe₂O₄/FeVO₄ is a high efficiency catalyst. Through SEM analysis, it is seen that the ZnFe₂O₄ and FeVO₄ are combined together. With the condition of adding H₂O₂, after 20 min of reaction, the dye degradation rates of ZnFe₂O₄ and FeVO₄ are only 15% and 25% respectively, and the dye degradation rate of ZnFe₂O₄/FeVO₄ reaches 75%. The effects of catalyst dosage, H₂O₂ concentration and pH value on the catalytic activity ZnFe₂O₄/FeVO₄ were investigated. The results show that ZnFe₂O₄/FeVO₄ samples have the best photocatalytic efficiency when pH value of the solution is 5.0, H₂O₂ concentration is 0.044 mol/L and the catalyst dosage is 1.0 g/L.

Key words: ferrite, ferric vanadate, catalyst, methyl orange, degradation, photocatalytic property