Photocatalytic Degradation of Organic Pollutants using TiO₂-Based Nanomaterials

Abstract

Photocatalytic degradation leveraging TiO₂-based nanomaterials offers a promising pathway for removing organic pollutants from water via solar and UV light activation. This study explores the synthesis, optimization, and application of TiO₂ nanostructures—including nanoparticles, nanotubes, and doped variants—for the degradation of a range of organic contaminants (dyes, pharmaceuticals, endocrine disruptors). We employed sol–gel and hydrothermal synthesis to prepare anatase-rich TiO₂ with different morphologies, further modified through metal doping (Fe, Ag) and non-metal doping (N, C) to enhance visible light responsiveness. Comprehensive characterization was performed using XRD, SEM/TEM, BET surface area analysis, UV–Vis spectroscopy, and photoluminescence. Photocatalytic performance was evaluated using batch reactor setups under controlled illumination, monitoring degradation of model pollutants (methylene blue, rhodamine B, phenol derivatives) through HPLC, UV–Vis absorbance, and TOC measurements. Optimized nanomaterials achieved >90% degradation within 60 minutes and 70–80% TOC removal in 120 minutes under UV-A, with visible-light variants achieving comparable performance under solar-simulated light. Kinetic studies align with pseudo-first-order decay, and radical trapping experiments identify •OH and O₂•– as primary reactive species. Catalyst recyclability was confirmed with minimal loss in efficiency over five cycles. Comparative analysis shows that Fe/N-doped TiO₂ nanotubes outperform commercial P25 (~1.5× faster degradation rates) while maintaining >90% post-use activity. The results underscore the significant potential of TiO₂-based nanostructures for efficient photocatalytic removal of organic pollution in water, with enhancements through intelligent morphology control and bandgap modification.