Multi-functional well-dispersed pomegranate-like nanospheres organized by ultrafine ZnFe2O4 nanocrystals for high-efficiency visible-light-Fenton catalytic activities

The Photo-Fenton-like reaction has gained widespread attention, as an effective method in wastewater treatment. Herein, uniformly highly dispersible pomegranate-like ZnFe2O4 nanospheres (ZFO-PNSs) was prepared through a novel, facile, straightforward and general approach. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images are employed to verify that ZFO-PNSs mainly presents pomegranate-like nanospheres morphology with diameter of 210 ± 20 nm in size. Interestingly, the results of photodegradation test indicated that ZFO-PNSs was an excellent photo-Fenton catalyst which could degraded the oxytetracycline, norfloxacin, tetracycline, rhodamine B, methyl orange and Cr(Ⅵ) in solution under visible light irradiation. The unusual structure, which consists of ultra-small ZFO, is responsible for the excellent photocatalytic activity. Furthermore, the reaction parameters influenced the degradation performance was investigated, such as the calcination temperature, the catalyst dosage, the pH of solution and H2O2 volume used. The probable photocatalytic degradation pathways of OTC were analyzed by LC-MS. Finally, the possible photocatalytic reaction mechanism of ZFO-PNSs were tentatively proposed, which may help with the further understanding of the photo-Fenton mechanism. This work affords a novel and simple method to construct pomegranate-like transition metal oxides nanostructures, which provides impetus for further development in environmental and energy applications.