Synthesis and characterization of a new photocatalyst based on TiO2 nanoparticles supported on magnetic zeolite from iron and steel industrial waste

In the current work, a new nanometric TiO2-based magnetic catalyst has been developed from an innovative material obtained from the treatment of iron and steel industrial wastes, i.e. Fly Ash. This magnetic material, “MaM”, contains iron in the chemical-mineralogical composition and it represent an excellent example of circular economy: the industrial waste is converted into a high technological valued product. Through a one-step hydrothermal activation, the precursor is transformed in a zeolite with good magnetic properties. These properties could be exploited in the environmental field, such as the degradation of emerging pollutants in aqueous media by coupling it with a photocatalyst. In particular, in this work, TiO2 nanoparticles are synthesized through a sol-gel synthesis and then mixed with MaM by means of ultrasounds, in different pH conditions: acidic (0.1 M HNO3), neutral and alkaline (0.1 M NaOH). The MaM-TiO2 composites are subjected afterward to a mild thermal treatment. The synthesized devices are characterized by means of X-Ray diffraction measurements (XRD) and scanning electron microscopy (SEM-EDS), while their photocatalytic activity is evaluated through the abatement of methylene blue (MB) solutions, according to the ISO norm 10678:2010. Based on experimental evidence, alkaline conditions lead to a homogeneous covering of the supporting material and therefore they are preferred to achieve a good photocatalytic activity; eventually the same conditions appeared to be crucial for the possibility to recover and subsequently reuse the composite material.