Visible light induced photocatalytic degradation of rhodamine B by magnetic bentonite.

The photocatalytic activity of magnetic bentonite, Fe3O4 nanoparticles decorated Al-pillared bentonite (Fe3O4/Al-B), for the degradation of rhodamine B (RhB) in the presence of H2O2 under visible light (VL) was evaluated. The effects of different reaction parameters such as catalyst dose, dye concentration and externally added H2O2 were also investigated. The magnetic bentonite showed good photocatalytic activity, magnetic separability and stability for repeated use. More than 95% of 40 mg/L RhB was converted within 3 h under VL with a catalyst dose of 0.5 g/L. Suitable mechanisms have been proposed to account for the photocatalytic activities in the presence and absence of H2O2. The efficiency of H2O2 in VL process was much higher than that of the dark process. Results obtained in the current study may be useful to develop a suitable photocatalyst for photocatalytic remediation of different water contaminants including organic dyes.