Electroplating sludge derived zinc-ferrite catalyst for the efficient photo-Fenton degradation of dye

摘要

A zinc-dominant ferrite catalyst for efficient degradation of organic dye was prepared by the calcination of electroplating sludge (ES). Characterizations indicated that zinc ferrite (ZnFe_2O_4) coexisted with Fe_2O_3 structure was the predominant phase in the calcined electroplating sludge (CES). CES displayed a high decolorization ratio (88.3%) of methylene blue (MB) in the presence of H_2O_2 combined with UV irradiation. The high efficiency could be ascribed to the photocatalytic process induced by ZnFe_2O_4 and the photo-Fenton dye degradation by ferrous content, and a small amount of Al and Mg in the sludge might also contribute to the catalysis. Moreover, the degradation capability of dye by CES was supported by the synthetic ZnFe_2O_4 with different Zn to Fe molar ratio (n(Zn): n(Fe)), as 84.81%-86.83% of dye was removed with n(Zn): n(Fe) ranged from 1:0.5 to 1:3. All synthetic ferrite samples in the simulation achieved adjacent equilibrium decolorization ratio, the flexible proportioning of divalent metal ions (M~(2+)) to trivalent metal ions (M~(3+)) applied in the synthesis indicated that the catalyst has a high availability. Therefore, an efficacious catalyst for the degradation of dye can potentially be derived from heavy metal-containing ES, it's a novel approach for the reutilization of ES.