Photocatalytic performance assessment of Fe-N co-doped TiO2/beta-cyclodextrin hybrid systems prepared by supercritical antisolvent micronization for organic dyes removal

This work aims to demonstrate that micronized beta-cyclodextrin (beta-CD) improves the photocatalytic activity of Fe-N-TiO2. Fe-N-TiO2/beta-CD hybrid systems were employed in the photocatalytic removal of Acid Orange7 (AO7) and Methylene Blue (MB). The supercritical antisolvent process (SAS) was used to micronize beta-CD at different pressures. The chemical-physical properties of the hybrid photocatalysts were detected through various characterization methods. Wide angle X-ray diffraction patterns evidenced the anatase as the typical TiO2 crystalline phase. FT-IR spectra showed interactions between beta-CD and Fe-N-TiO2. The activity of photocatalysts in the degradation of AO7 and MB dyes was analyzed under UV and visible light irradiation. Fe-N-TiO2/beta-CD120 photocatalyst led to the total UV light-driven discoloration of the AO7 aqueous solution. Instead, the Fe-N-TiO2/beta-CD120 system allowed for achieving an MB discoloration kinetic constant under visible light higher than the AO7 discoloration kinetic constant. Reuse cycle tests proved that the Fe-N-TiO2/beta-CD120 sample is a stable photocatalytic material.