Magnetically separable attapulgite−TiO2−FexOy composites with superior activity towards photodegradation of methyl orange under visible light radiation

A magnetically recoverable composite photocatalyst was obtained by introducing TiO2–FexOy hybrid oxide onto the surface of attapulgite via an in-situ deposit technique (marked as ATT–TiO2–FexOy-r, r represents molar ratio of r = nTi/(nTi + nFe)). The obtained composites were carefully characterized and results showed TiO2–FexOy particles with an average size of 10 nm were successfully loaded onto attapulgite fibers’ surface. The FexOy (mixture of Fe2O3 and Fe3O4) acted not only as magnetic source but also took part in the formation of TiO2–Fe2O3 heterojunction structure, which resulted in the obvious absorption in visible light region for the obtained ATT–TiO2–FexOy. The obtained ATT–TiO2–FexOy-r exhibited quite good catalytic activity towards photodegradation of methyl orange under visible light irradiation. The highest degradation ratio and COD removal of methyl orange reached to 94.13% and 90.91% for ATT–TiO2–FexOy-0.5. Moreover, ATT–TiO2–FexOy could be readily recovered and the degradation ratio maintains 83.89% after 5 cycles. Possible mechanism for this enhancement was proposed.