Assessment of the capability of Fe and Al modified BEA zeolites to promote advanced oxidation processes in aqueous phase

Abstract

Iron-containing zeolites were prepared using two-step postsynthesis and wet impregnation methods and characterized using conventional techniques. The materials were tested for production of hydroxyl radicals using N,N-dimethyl-p-nitrosoaniline (pNDA) as radical scavenger and discoloration of Congo Red (CR) using advanced oxidation processes (AOPs). The characterization showed that the materials were morphologically homogeneous and had different iron amounts incorporated into the framework and extra-framework of the BEA structure. The pNDA bleaching curves suggested that FexHAlBEA is more effective for producing hydroxyl radicals because of the presence of higher amounts of octahedral Fe(III) in the extra-framework positions. A similar trend was found for CR discoloration. The use of hydrogen peroxide increased both hydroxyl radical generation and CR discoloration, which suggests that the Fe in the zeolites decomposed the oxidant and increased the production of free radicals. Fe-containing zeolites were found as interesting catalysts for AOPs to remove organic contaminants in water.