Metoprolol removal and mineralization by TiO₂ and iron pillared clay nanocomposite: Impact of operating parameters, water matrices, and solar light

This study investigates the photocatalytic degradation of metoprolol tartrate (MET) using TiO₂ nanostructures supported on Fe pillared activated bentonite (FeAB) under UV, visible, and solar irradiation. The TiO₂/FeAB nanocomposite was synthesized via sol-gel and hydrothermal methods, and was characterized using techniques such as XRD, EDS, FTIR, SEM, BET and UV-Vis spectroscopy. The TiO₂ nanoparticles were uniformly distributed on the clay surface, with a red shift observed in UV-visible spectroscopy. Thus, a reduction in the band gap values of TiO₂ and TiO₂/FeAB from 3.1 to 2.85 eV respectively. The photocatalytic performance depended on parameters such as catalyst dosage, initial MET concentration, pH, and light sources. MET degradation was complete within pH 6.2-9.7, with superior efficiency under solar and visible light compared to UV light. The composite showed no significant interference from chloride, sulfate, or carbonate ions and demonstrated effective degradation across various water matrices (tap water, spring water, seawater, and river water). Under solar light, MET degradation rates followed the order: ultra-pure water and seawater ≫ source water and tap water ≫ river water. Total Organic Carbon (TOC) measurement showed 73 %, 100 %, and 76 % mineralization after 10 h under UV, visible, and solar light, respectively. The TiO₂/FeAB composite exhibited excellent stability and reusability, highlighting its potential as a clean technology for pharmaceutical removal from diverse water sources.