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Methyl Orange Degradation Using Ag-Doped TiO2, H2O2, and Hydrodynamic Cavitation

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide This study investigates the photocatalytic degradation of Methyl Orange (MO) using doped photocatalysts, specifically Ag-TiO 2 synthesized via a novel solid-state method, with varying silver concentrations (0%, 0.5%, 1%, 1.5%, and 2.5% w/w relative to TiO 2 ) under different UV light intensities (60 and 200 W). The photocatalysts were characterized using XRD, SEM-EDS, and BET. The optimal performance was observed with a 0.5% Ag-TiO 2 concentration, achieving a degradation efficiency of 59% under 200 W UV light over 180 min of treatment. The effect of photocatalyst loading was then optimized, followed by an investigation of the synergistic effects of photocatalysis (PC) coupled with hydrogen peroxide (H 2 O 2 ). The highest degradation efficiency of 94% was achieved at 0.01% v/v H 2 O 2 with a synergistic coefficient of 24, within 60 min. Further enhancement was observed when combining PC, H 2 O 2, and hydrodynamic cavitation (HC), achieving complete degradation of MO in just 3 min (1.5 passes) with a high synergistic coefficient of 42. The degradation process was represented as pseudo-first-order kinetics for PC alone and combined with H 2 O 2, and a per-pass degradation model for HC. The impact of various scavengers on the photocatalytic process was examined, highlighting the crucial roles of hydroxyl radicals (•OH) and photogenerated holes (h + ) in the degradation mechanism. The influence of anions and the water matrix on the reactive oxygen species (ROS) generation and efficiency, as well as the environmental fate of Ag-TiO 2 catalysts, is also discussed. This research underscores the importance of optimizing doped photocatalyst composition and operational conditions to maximize pollutant degradation efficiency, demonstrating significant advancements in advanced oxidation processes through synergy.

Source: ACS Omega

DOI: 10.1021/acsomega.5c00034