Acrylate-based Polymerizable Sol–Gel Synthesis of Magnetically Recoverable TiO2 Supported Fe3O4 for Cr(VI) Photoreduction in Aerobic Atmosphere

TiO 2 synthesized by polymerizable sol–gel approach is used to demonstrate the photoreduction of Cr(VI) in aqueous medium. Fe 3 O 4 is chosen as the magnetically recoverable support, onto which, 10, 20, 30 and 50% of TiO 2 have been dispersed following the polymerizable sol–gel approach. The synthesized materials are characterized using XRD, SEM, XPS, Raman spectroscopy, diffuse reflectance spectroscopy and BET surface area measurement. Different hole-scavengers (oxalic acid, ammonium oxalate and ethanol) and an electron scavenger (potassium periodate) have been studied to compare the efficiency of Cr(VI) photoreduction in nitrogen as well as air atmosphere. With 5 mM oxalic acid as the hole-scavenger, the TiO 2 /Fe 3 O 4 materials have demonstrated superior activity to the nonsupported bulk TiO 2 toward Cr(VI) photoreduction in aerobic atmosphere. Particularly, 30% TiO 2 /Fe 3 O 4 has shown the highest Cr(VI) photoreduction rate among the lot. The 30% TiO 2 /Fe 3 O 4 catalyst has also demonstrated good recoverability as well as recyclability.