Efficient degradation of rhodamine B by magnetically separable ZnS-ZnFe₂O₄ composite with the synergistic effect from...

Novel ZnS-ZnFe₂O₄ composites were successfully synthesized via a simple and green hydrothermal route. X-ray diffraction (XRD) patterns of the synthesized composite proved the presence of both ZnS and ZnFe₂O₄. The other characteristics of the composites were further characterized in detail using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and vibrating sample magnetometry (VSM). The performance of ZnS-ZnFe₂O₄ in the presence of persulfate (PS, K₂S₂O₈) as a co-catalyst was tested for degrading rhodamine B (RhB) under UV light illumination. ZnS-ZnFe₂O₄ composites could remove about 97.67% of RhB in 90 min, which was much higher removal than either ZnS or ZnFe₂O₄ alone. Moreover, the recovery of catalyst and its recycling performance were found to be good after testing three times. A feasible mechanism analysis of RhB degradation was validated by simple classical quenching experiments. The enhanced performance was attributed to the high-efficiency separation rate of photo induced electron-hole pairs and highly active free radicals of O₂^-, OH and SO₄^-.