Improved photocatalytic degradation of dye using coal fly ash-based zinc ferrite (CFA/ZnFe2O4) composite

In this research work, the ZnFe2O4 and its composites with coal fly ash (CFA) were synthesized. Three photocatalysts ZnFe2O4, CFA-ZnFe2O4 (1:2), and CFA-ZnFe2O4 (1:1) were prepared, and their comparative dye degradation efficiencies have been evaluated. The catalysts were well characterized using FTIR spectroscopy, X-ray diffraction analysis, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, vibrating sample magnetometer, and X-ray photoelectron spectroscopy. The bandgap energies were calculated using Tauc plot method. The process optimization of various parameters like pH, catalysts dose, oxidant dose, reaction time in degradation studies under UV irradiations (254 nm) was done. The optimized conditions of parameters were pH = 3 and 6 for ZnFe2O4 and CFA-ZnFe2O4 (1:2, 1:1) composite, catalysts dose = 8 mg and 10 mg/100 mL for ZnFe2O4 and CFA-ZnFe2O4 (1:2, 1:1) composite, oxidant dose = 14 mM and 10 mM for ZnFe2O4 and CFA-ZnFe2O4 (1:2, 1:1) composite and reaction time = 60 min. The ZnFe2O4, CFA-ZnFe2O4(1:2), and CFA-ZnFe2O4(1:1) showed 76, 92, and 97% degradation of MB under optimized conditions, respectively. The photocatalytic degradation results showed that the loading of ZnFe2O4 nanoparticles on CFA improves the degradation of MB. The proposed research not only provided a simple approach for the synthesis of CFA-based nanocomposites but also reported the reclamation of waste residual material (CFA) to support solid waste management. The catalysts showed negligible Fe leaching with a small reduction in degradation efficiency after five reusability runs.

Automated summary

In this research, ZnFe2O4 and its composites with coal fly ash (CFA) were synthesized to evaluate their dye degradation efficiencies. The results showed that loading ZnFe2O4 nanoparticles on CFA can improve the degradation of dyes, suggesting a potential for waste utilization and solid waste management support.