Enhanced degradation of Rhodamine B via α-Fe2O3 microspheres induced persulfate to generate reactive oxidizing species.

The porous α-Fe2O3 microspheres (MS-Fe2O3) were obtained through in-situ ion exchange-calcination method and then utilized to activate persulfate (PS) for Rhodamine B (Rh B) degradation. The influences of some important operational parameters were investigated for the MS-Fe2O3/PS system. Additionally, the physicochemical properties of the as-fabricated MS-Fe2O3 were revealed with the assistance of some analytical instruments (i.e., X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS), Brunauer-Emmett-Teller (BET) and vibrating sample magnetometer (VSM)). The results showed that the physicochemical properties of MS-Fe2O3 played an important role in the activation of PS, which promoted MS-Fe2O3 to effectively induce PS to generate reactive oxidizing species, thus Rh B could be nearly 100% degraded within 30 min under near-neutral pH solution. Noticeably, the as-prepared MS-Fe2O3 revealed magnetism and could be separated conveniently through external magnetic, which was beneficial to reuse the catalyst. Finally, the reactive oxidizing species (SO4- and OH) participating in the oxidation process were illustrated by electron paramagnetic resonance (EPR) and radical quenching studies, and then a rational mechanism was proposed to better understand the catalytic oxidation degradation of organic pollutants.