Developing a novel Ti-doped γAl2O3 xerogel with high photocatalytic chemical and microbial removal performance: Characterization and mechanistic insights

In this work, a Ti-doped alumina (Ti-gamma Al2O3) xerogel (TAX) was synthesized from Al powder as a cost-effective precursor. Full physical, chemical, structural, and electrochemical characterization of the prepared materials were performed. It was shown that as-made Ti-gamma Al2O3 is a mesoporous nanomaterial with high specific surface area, uniform morphology, the existence of polyhedral coordinated Al3+ ions, many acidity active sites, high light absorption efficiency, and effective bandgap energy. These features made it an efficient photocatalyst for water photocatalytic treatment. In the photocatalytic process with the TAX as the catalyst irradiated by the ultraviolet A photons, around 97% of 10 mg/L Remdesivir (RDV) was degraded within 30 min (pH = 7, TAX = 100 mg/L), and elucidation of the degradation pathway was achieved; low adsorption and minimal O-2(center dot-) contribution was found in the otherwise HO center dot-dominated photocatalytic process, as suggested by the scavenger tests. The Electron Paramagnetic Resonance spectroscopy validated the proposed species (but not O-1(2)), while the RDV degradation pathway towards mineralization was proposed by Liquid Chromatography-Mass Spectrometry analysis. Besides, concerning its applicability, the effect of operational parameters (pH, [TAX], [RDV], water matrix) was scrutinized and validated a notable performance over several consecutive reused cycles. Finally, almost 6.5 log E. coli inactivation was attained (in mild conditions), all indicating the high photocatalytic potential of this material.