Preparation and evaluation of magnetic iron oxide-MgCeAl lamellar composite-TiO2 in the photocatalytic degradation of methylene blue dye

Abstract

A new photocatalyst prepared from ternary lamellar double hydroxides (Mg, Ce, Al) by coprecipitation method and impregnated with TiO2 and magnetic properties was successfully synthesized. Different molar ratios between the trivalent cations were used, varying the proportion of Ce3+ in the Ce3+/(Ce3++Al3+) ratio. The synergistic effect between Ce3+ and TiO2 led to a significant increase in the photocatalytic and kinetic activity of MgCeAl-TiO2 for the photodegradation of the dye Methylene Blue (MB) at a concentration of 20 mg L−1, using UV–visible radiation (filter cut-off for λ > 300 nm). The materials studied were characterized by the techniques of IR Spectroscopy (FT-IR), Raman Spectroscopy, X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Scanning Electron Microscope (SEM), determination of Zeta Potential and Differential Pulse Voltammetry (DPV). The synthesized photocatalyst that showed the highest efficiency was the one with a composition of Ce3+ = 5 % and Al3+ = 95 %, besides having 5 % of its weight composed of magnetic iron oxide (5Fe/MgCe5Al-TiO2), presenting high photocatalytic activity, completely degrading (∼100 %) the dye in the time of 90 minutes.