Lamellar MFI Zeolite with TiO2 Pillars: Structural, Textural, and Photocatalytic Properties in Rhodamine B Dye Degradation

In this study, lamellar MFI (Mobile Five-membered ring Intergrowth) zeolites pillared with TiO2 were synthesized using tetraethyl orthotitanate (TEOTi) as titanium precursor and evaluated as photocatalysts for Rhodamine B (RhB) degradation under UV irradiation. The materials were characterized by X-ray diffraction (XRD), UV–Vis spectroscopy, N2 adsorption–desorption, photoluminescence spectroscopy (PL), and transmission electron microscopy (TEM). XRD confirmed the preservation of the lamellar MFI structure and the formation of anatase TiO2 pillars within the interlayer space. The composites exhibited hierarchical micro/mesoporosity, high surface areas (>320 m2 g−1), and mesopore sizes of approximately 4.1–4.2 nm. Photocatalytic experiments revealed that the incorporation of TiO2 into the lamellar MFI framework significantly enhanced the degradation kinetics of RhB compared with bare TiO2. The apparent pseudo-first-order rate constants followed the order MFIPTi-6 > MFIPTi-3 > MFIPTi-12 > TiO2 > MFIPTi-24, with MFIPTi-6 exhibiting the highest activity (kapp = 0.049 min−1), approximately 1.6 times higher than that of pure TiO2. Scavenger experiments identified hydroxyl radicals as the predominant reactive species involved in the degradation process. TOC (Total Organic Carbon) measurements showed approximately 80% organic carbon removal, while recyclability tests demonstrated stable photocatalytic performance over six consecutive cycles. These results highlight the potential of lamellar TiO2/MFI composites as efficient and reusable photocatalysts for water treatment applications.