Unraveling the role of sponge matrix in the design of a 3D nature-inspired TiO2-based photocatalyst for ketoprofen removal from wastewater

Abstract

Despite growing interest in bioinspired photocatalytic systems, the influence of natural sponge-derived scaffolds on TiO₂-based photocatalyst performance has not been comprehensively investigated. This study investigates the influence of four biomimetic scaffolds—marine sponge, Luffa cylindrica, silk, and konjac—on the physicochemical and photocatalytic properties of TiO₂-based composites designed for the removal of ketoprofen from wastewater. A one-step immobilization procedure was employed to deposit TiO₂ nanoparticles onto pretreated natural matrices, yielding structurally stable and porous three-dimensional photocatalysts. Comprehensive material characterization confirmed the formation of TiO₂ with uniform surface distribution and preserved scaffold morphology. The materials were evaluated under UV-A LED irradiation in both model and real conditions. Photocatalytic degradation followed pseudo-first-order kinetics, with the marine sponge-based composite (MS_TiO₂) exhibiting the highest performance (up to 90 % removal efficiency), attributed to its high porosity, improved light penetration, and effective charge separation. Interestingly, surface Ti content did not correlate directly with activity, underscoring the significance of oxide dispersion and accessibility over total loading. The degradation pathway of ketoprofen was elucidated using ESI-MS, while ecotoxicity of intermediates was assessed via ECOSAR modeling, indicating progressive detoxification. Reusability tests confirmed long-term stability of the MS_TiO₂ system. The findings demonstrate that scaffold selection critically affects photocatalyst architecture and performance, offering a rational route toward scalable, sustainable materials for pharmaceutical removal in wastewater treatment.