Fabrication of novel magnetic ZnO hollow spheres/pumice nanocomposites for photodegradation of Rhodamine B under visible light irradiation

The present study deals with the synthesis of ZnO hollow spheres-pumice nanocomposite via a hydrothermal method by employing pumice as the magnetic support. The physicochemical properties of prepared nanocomposites were characterized by XRD, XRF, FT-IR, FE-SEM, TEM, DRS, VSM, PL, BET, and ICP-OES. The photocatalytic activity of samples was evaluated by photocatalytic degradation of Rhodamine B (RhB) as a model pollutant. The influence of operating parameters such as solution pH, initial concentration of pollutant, ZnO loading, photocatalyst dosage, light source, and pumice effect was investigated. The sample with 15 wt% ZnO gave the highest photocatalytic activity at initial concentration of 5 mg/L, pH = 9, and 10 g/L of nanocomposite under visible light irradiation. According to obtained results, the major active species in the photodegradation process were the holes. Also, the obtained results from the COD technique indicated that about 86% of RhB was mineralized at the optimized conditions.