Synthesis and characterization of iron photocatalysts supported on microporous zeolites

ABSTRACT ZSM11 and BETA zeolitic materials were synthesized by the hydrothermal method and were further impregnated with a 6 wt% of iron and characterized by different physicochemical techniques in order to be employed in the photocatalytic degradation of methyl orange (MO). Matrices structures and crystallinity were verified by X Ray Diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR), even for modified zeolites. XRD patterns showed the characteristic signals at 2θ=7, 9, 23 and 24° for ZSM11 matrix, and 2θ= 7-8° and 21- 22°, for BETA. According to BET results, specific surface area were 392 m2/g for ZSM11 and 585 m2/g for BETA. In both cases, an area reduction with metal incorporation were obtained. Iron con-tent was confirmed by Atomic Absorption (AA) spectroscopy, finding similar values than the theoretical ones. Additionaly, iron signals (0,5 y 6,5 KeV) were detected by SEM EDX. Band gap energies of the materials were calculated employing Diffuse Reflectance Spectroscopy- UVvis (DRS-UVvis), obtaining similar values than α-Fe2O3. A reduction of the band gap energy in comparison with the correspondent material was also found by this technique. The materials were further evaluated as catalysts for MO photodegradation obtaining a 96 % and 56% of degradation for Fe-ZSM11 and Fe-BETA, respectively.